array:24 [
  "pii" => "S0300289619302364"
  "issn" => "03002896"
  "doi" => "10.1016/j.arbres.2019.04.011"
  "estado" => "S300"
  "fechaPublicacion" => "2020-01-01"
  "aid" => "2162"
  "copyright" => "SEPAR"
  "copyrightAnyo" => "2019"
  "documento" => "article"
  "crossmark" => 1
  "subdocumento" => "fla"
  "cita" => "Arch Bronconeumol. 2020;56:28-34"
  "abierto" => array:3 [
    "ES" => true
    "ES2" => true
    "LATM" => true
  ]
  "gratuito" => true
  "lecturas" => array:2 [
    "total" => 164
    "formatos" => array:2 [
      "HTML" => 111
      "PDF" => 53
    ]
  ]
  "Traduccion" => array:1 [
    "en" => array:19 [
      "pii" => "S1579212919304288"
      "issn" => "15792129"
      "doi" => "10.1016/j.arbr.2019.04.019"
      "estado" => "S300"
      "fechaPublicacion" => "2020-01-01"
      "aid" => "2162"
      "copyright" => "SEPAR"
      "documento" => "article"
      "crossmark" => 1
      "subdocumento" => "fla"
      "cita" => "Arch Bronconeumol. 2020;56:28-34"
      "abierto" => array:3 [
        "ES" => false
        "ES2" => false
        "LATM" => false
      ]
      "gratuito" => false
      "lecturas" => array:2 [
        "total" => 1
        "HTML" => 1
      ]
      "en" => array:14 [
        "idiomaDefecto" => true
        "cabecera" => "<span class="elsevierStyleTextfn">Original Article</span>"
        "titulo" => "Effects on Humidification and Ventilatory Parameters of Three Single-limb Heated-wired Circuits for Non-invasive Ventilation&#58; A Bench Study"
        "tienePdf" => "en"
        "tieneTextoCompleto" => "en"
        "tieneResumen" => array:3 [
          0 => "en"
          1 => "en"
          2 => "es"
        ]
        "paginas" => array:1 [
          0 => array:2 [
            "paginaInicial" => "28"
            "paginaFinal" => "34"
          ]
        ]
        "titulosAlternativos" => array:1 [
          "es" => array:1 [
            "titulo" => "Efectos sobre la humidificaci&#243;n y los par&#225;metros de ventilaci&#243;n de 3 circuitos de ramal &#250;nico con cable calefactado para la ventilaci&#243;n mec&#225;nica no invasiva&#58; estudio experimental"
          ]
        ]
        "contieneResumen" => array:2 [
          "en" => true
          "es" => true
        ]
        "contieneTextoCompleto" => array:1 [
          "en" => true
        ]
        "contienePdf" => array:1 [
          "en" => true
        ]
        "resumenGrafico" => array:2 [
          "original" => 1
          "multimedia" => array:5 [
            "identificador" => "fig0035"
            "tipo" => "MULTIMEDIAFIGURA"
            "mostrarFloat" => false
            "mostrarDisplay" => true
            "figura" => array:1 [
              0 => array:4 [
                "imagen" => "fx1.jpeg"
                "Alto" => 484
                "Ancho" => 1333
                "Tamanyo" => 83651
              ]
            ]
          ]
        ]
        "autores" => array:1 [
          0 => array:2 [
            "autoresLista" => "Jose M&#46; Alonso-I&#241;igo, Mar&#237;a J&#46; Fas, Alejandro Albert, Abel Dolz, Jos&#232;c&#41; M&#46; Carratal&#225;, Salvador D&#237;az-Lobato"
            "autores" => array:6 [
              0 => array:2 [
                "nombre" => "Jose M&#46;"
                "apellidos" => "Alonso-I&#241;igo"
              ]
              1 => array:2 [
                "nombre" => "Mar&#237;a J&#46;"
                "apellidos" => "Fas"
              ]
              2 => array:2 [
                "nombre" => "Alejandro"
                "apellidos" => "Albert"
              ]
              3 => array:2 [
                "nombre" => "Abel"
                "apellidos" => "Dolz"
              ]
              4 => array:2 [
                "nombre" => "Jos&#232;c&#41; M&#46;"
                "apellidos" => "Carratal&#225;"
              ]
              5 => array:2 [
                "nombre" => "Salvador"
                "apellidos" => "D&#237;az-Lobato"
              ]
            ]
          ]
        ]
        "resumen" => array:1 [
          0 => array:3 [
            "titulo" => "Graphical abstract"
            "clase" => "graphical"
            "resumen" => "<span id="abst0005" class="elsevierStyleSection elsevierViewall"><p id="spar0005" class="elsevierStyleSimplePara elsevierViewall"><elsevierMultimedia ident="fig0035"></elsevierMultimedia></p></span>"
          ]
        ]
      ]
      "idiomaDefecto" => "en"
      "Traduccion" => array:1 [
        "en" => array:9 [
          "pii" => "S0300289619302364"
          "doi" => "10.1016/j.arbres.2019.04.011"
          "estado" => "S300"
          "subdocumento" => ""
          "abierto" => array:3 [
            "ES" => true
            "ES2" => true
            "LATM" => true
          ]
          "gratuito" => true
          "lecturas" => array:1 [
            "total" => 0
          ]
          "idiomaDefecto" => "en"
          "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0300289619302364?idApp=UINPBA00003Z"
        ]
      ]
      "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S1579212919304288?idApp=UINPBA00003Z"
      "url" => "/15792129/0000005600000001/v3_202001222229/S1579212919304288/v3_202001222229/en/main.assets"
    ]
  ]
  "itemSiguiente" => array:19 [
    "pii" => "S030028961930273X"
    "issn" => "03002896"
    "doi" => "10.1016/j.arbres.2019.05.017"
    "estado" => "S300"
    "fechaPublicacion" => "2020-01-01"
    "aid" => "2195"
    "copyright" => "SEPAR"
    "documento" => "article"
    "crossmark" => 1
    "subdocumento" => "fla"
    "cita" => "Arch Bronconeumol. 2020;56:35-41"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:2 [
      "total" => 273
      "formatos" => array:2 [
        "HTML" => 165
        "PDF" => 108
      ]
    ]
    "en" => array:13 [
      "idiomaDefecto" => true
      "cabecera" => "<span class="elsevierStyleTextfn">Special article</span>"
      "titulo" => "Upcoming Scenarios for the Comprehensive Management of Obstructive Sleep Apnea&#58; An Overview of the Spanish Sleep Network"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "tieneResumen" => array:2 [
        0 => "en"
        1 => "es"
      ]
      "paginas" => array:1 [
        0 => array:2 [
          "paginaInicial" => "35"
          "paginaFinal" => "41"
        ]
      ]
      "titulosAlternativos" => array:1 [
        "es" => array:1 [
          "titulo" => "Escenarios futuros en el manejo integral de la apnea obstructiva del sue&#241;o&#58; perspectiva del Spanish Sleep Network"
        ]
      ]
      "contieneResumen" => array:2 [
        "en" => true
        "es" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 0
        "multimedia" => array:7 [
          "identificador" => "fig0005"
          "etiqueta" => "Fig&#46; 1"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => true
          "mostrarDisplay" => false
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "gr1.jpeg"
              "Alto" => 1691
              "Ancho" => 2925
              "Tamanyo" => 380688
            ]
          ]
          "descripcion" => array:1 [
            "en" => "<p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">Spanish Sleep Network &#40;SSN&#41; 1st World Caf&#233; main conclusion&#46;</p>"
          ]
        ]
      ]
      "autores" => array:2 [
        0 => array:2 [
          "autoresLista" => "Olga Mediano, Irene Cano-Pumarega, Manuel S&#225;nchez-de-la-Torre, Mar&#237;a Luz Alonso-&#193;lvarez, Mar&#237;a Fernanda Troncoso, Francisco Garc&#237;a-R&#237;o, Carlos Egea"
          "autores" => array:8 [
            0 => array:2 [
              "nombre" => "Olga"
              "apellidos" => "Mediano"
            ]
            1 => array:2 [
              "nombre" => "Irene"
              "apellidos" => "Cano-Pumarega"
            ]
            2 => array:2 [
              "nombre" => "Manuel"
              "apellidos" => "S&#225;nchez-de-la-Torre"
            ]
            3 => array:2 [
              "nombre" => "Mar&#237;a Luz"
              "apellidos" => "Alonso-&#193;lvarez"
            ]
            4 => array:2 [
              "nombre" => "Mar&#237;a Fernanda"
              "apellidos" => "Troncoso"
            ]
            5 => array:2 [
              "nombre" => "Francisco"
              "apellidos" => "Garc&#237;a-R&#237;o"
            ]
            6 => array:2 [
              "nombre" => "Carlos"
              "apellidos" => "Egea"
            ]
            7 => array:1 [
              "colaborador" => "the Spanish Sleep Network"
            ]
          ]
        ]
        1 => array:2 [
          "autoresLista" => ""
          "autores" => array:1 [
            0 => array:1 [
              "colaborador" => "on behalf of the Spanish Sleep Network"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "Traduccion" => array:1 [
      "en" => array:9 [
        "pii" => "S157921291930429X"
        "doi" => "10.1016/j.arbr.2019.05.020"
        "estado" => "S300"
        "subdocumento" => ""
        "abierto" => array:3 [
          "ES" => false
          "ES2" => false
          "LATM" => false
        ]
        "gratuito" => false
        "lecturas" => array:1 [
          "total" => 0
        ]
        "idiomaDefecto" => "en"
        "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S157921291930429X?idApp=UINPBA00003Z"
      ]
    ]
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S030028961930273X?idApp=UINPBA00003Z"
    "url" => "/03002896/0000005600000001/v5_202003060711/S030028961930273X/v5_202003060711/en/main.assets"
  ]
  "itemAnterior" => array:19 [
    "pii" => "S0300289619302340"
    "issn" => "03002896"
    "doi" => "10.1016/j.arbres.2019.04.010"
    "estado" => "S300"
    "fechaPublicacion" => "2020-01-01"
    "aid" => "2160"
    "copyright" => "SEPAR"
    "documento" => "article"
    "crossmark" => 1
    "subdocumento" => "fla"
    "cita" => "Arch Bronconeumol. 2020;56:23-7"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:2 [
      "total" => 1409
      "formatos" => array:2 [
        "HTML" => 1364
        "PDF" => 45
      ]
    ]
    "es" => array:14 [
      "idiomaDefecto" => true
      "cabecera" => "<span class="elsevierStyleTextfn">Original</span>"
      "titulo" => "Modificaci&#243;n del riesgo de mortalidad y morbilidad tras resecci&#243;n pulmonar en los &#250;ltimos 20 a&#241;os"
      "tienePdf" => "es"
      "tieneTextoCompleto" => "es"
      "tieneResumen" => array:3 [
        0 => "es"
        1 => "es"
        2 => "en"
      ]
      "paginas" => array:1 [
        0 => array:2 [
          "paginaInicial" => "23"
          "paginaFinal" => "27"
        ]
      ]
      "titulosAlternativos" => array:1 [
        "en" => array:1 [
          "titulo" => "Changes in the Risk of Mortality and Morbidity After Lung Resection in the Last 20 Years"
        ]
      ]
      "contieneResumen" => array:2 [
        "es" => true
        "en" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "es" => true
      ]
      "contienePdf" => array:1 [
        "es" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 1
        "multimedia" => array:5 [
          "identificador" => "fig0020"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => false
          "mostrarDisplay" => true
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "fx1.jpeg"
              "Alto" => 528
              "Ancho" => 1333
              "Tamanyo" => 68893
            ]
          ]
        ]
      ]
      "autores" => array:1 [
        0 => array:2 [
          "autoresLista" => "Mar&#237;a Teresa G&#243;mez Hern&#225;ndez, Nuria Novoa Valent&#237;n, Israel Rodr&#237;guez Alvarado, Marta Fuentes Gago, Gonzalo Varela Sim&#243;, Marcelo F&#46; Jim&#233;nez L&#243;pez"
          "autores" => array:6 [
            0 => array:2 [
              "nombre" => "Mar&#237;a Teresa"
              "apellidos" => "G&#243;mez Hern&#225;ndez"
            ]
            1 => array:2 [
              "nombre" => "Nuria Novoa"
              "apellidos" => "Valent&#237;n"
            ]
            2 => array:2 [
              "nombre" => "Israel"
              "apellidos" => "Rodr&#237;guez Alvarado"
            ]
            3 => array:2 [
              "nombre" => "Marta"
              "apellidos" => "Fuentes Gago"
            ]
            4 => array:2 [
              "nombre" => "Gonzalo"
              "apellidos" => "Varela Sim&#243;"
            ]
            5 => array:2 [
              "nombre" => "Marcelo F&#46;"
              "apellidos" => "Jim&#233;nez L&#243;pez"
            ]
          ]
        ]
      ]
      "resumen" => array:1 [
        0 => array:3 [
          "titulo" => "Graphical abstract"
          "clase" => "graphical"
          "resumen" => "<span id="abst0005" class="elsevierStyleSection elsevierViewall"><p id="spar0005" class="elsevierStyleSimplePara elsevierViewall"><elsevierMultimedia ident="fig0020"></elsevierMultimedia></p></span>"
        ]
      ]
    ]
    "idiomaDefecto" => "es"
    "Traduccion" => array:1 [
      "en" => array:9 [
        "pii" => "S1579212919303519"
        "doi" => "10.1016/j.arbr.2019.11.002"
        "estado" => "S300"
        "subdocumento" => ""
        "abierto" => array:3 [
          "ES" => false
          "ES2" => false
          "LATM" => false
        ]
        "gratuito" => false
        "lecturas" => array:1 [
          "total" => 0
        ]
        "idiomaDefecto" => "en"
        "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S1579212919303519?idApp=UINPBA00003Z"
      ]
    ]
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0300289619302340?idApp=UINPBA00003Z"
    "url" => "/03002896/0000005600000001/v5_202003060711/S0300289619302340/v5_202003060711/es/main.assets"
  ]
  "en" => array:19 [
    "idiomaDefecto" => true
    "cabecera" => "<span class="elsevierStyleTextfn">Original Article</span>"
    "titulo" => "Effects on Humidification and Ventilatory Parameters of Three Single-limb Heated-wired Circuits for Non-invasive Ventilation&#58; A Bench Study"
    "tieneTextoCompleto" => true
    "paginas" => array:1 [
      0 => array:2 [
        "paginaInicial" => "28"
        "paginaFinal" => "34"
      ]
    ]
    "autores" => array:1 [
      0 => array:4 [
        "autoresLista" => "Jose M&#46; Alonso-I&#241;igo, Mar&#237;a J&#46; Fas, Alejandro Albert, Abel Dolz, Jos&#233; M&#46; Carratal&#225;, Salvador D&#237;az-Lobato"
        "autores" => array:6 [
          0 => array:4 [
            "nombre" => "Jose M&#46;"
            "apellidos" => "Alonso-I&#241;igo"
            "email" => array:1 [
              0 => "jmalonso@me.com"
            ]
            "referencia" => array:2 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">a</span>"
                "identificador" => "aff0005"
              ]
              1 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">&#42;</span>"
                "identificador" => "cor0005"
              ]
            ]
          ]
          1 => array:3 [
            "nombre" => "Mar&#237;a J&#46;"
            "apellidos" => "Fas"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">b</span>"
                "identificador" => "aff0010"
              ]
            ]
          ]
          2 => array:3 [
            "nombre" => "Alejandro"
            "apellidos" => "Albert"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">c</span>"
                "identificador" => "aff0015"
              ]
            ]
          ]
          3 => array:3 [
            "nombre" => "Abel"
            "apellidos" => "Dolz"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">d</span>"
                "identificador" => "aff0020"
              ]
            ]
          ]
          4 => array:3 [
            "nombre" => "Jos&#233; M&#46;"
            "apellidos" => "Carratal&#225;"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">e</span>"
                "identificador" => "aff0025"
              ]
            ]
          ]
          5 => array:3 [
            "nombre" => "Salvador"
            "apellidos" => "D&#237;az-Lobato"
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">f</span>"
                "identificador" => "aff0030"
              ]
            ]
          ]
        ]
        "afiliaciones" => array:6 [
          0 => array:3 [
            "entidad" => "Department of Anesthesiology&#44; Critical Care and Pain Medicine&#44; Hospital Universitari i Polit&#232;cnic La Fe&#44; Valencia&#44; Spain"
            "etiqueta" => "a"
            "identificador" => "aff0005"
          ]
          1 => array:3 [
            "entidad" => "Department of Hospital Managing&#44; Hospital de Manises&#44; Manises&#44; Valencia&#44; Spain"
            "etiqueta" => "b"
            "identificador" => "aff0010"
          ]
          2 => array:3 [
            "entidad" => "Emergency Department&#44; Hospital General Universitario de Alicante&#44; Alicante&#44; Spain"
            "etiqueta" => "c"
            "identificador" => "aff0015"
          ]
          3 => array:3 [
            "entidad" => "Emergency Department&#44; Hospital de Sagunto&#44; Sagunto&#44; Valencia&#44; Spain"
            "etiqueta" => "d"
            "identificador" => "aff0020"
          ]
          4 => array:3 [
            "entidad" => "Short-stay Medical Unit&#44; Emergency Department&#44; Hospital General Universitario de Alicante&#44; Alicante&#44; Spain"
            "etiqueta" => "e"
            "identificador" => "aff0025"
          ]
          5 => array:3 [
            "entidad" => "Department of Pneumology&#44; Hospital Universitario Ram&#243;n y Cajal&#44; Madrid&#44; Spain"
            "etiqueta" => "f"
            "identificador" => "aff0030"
          ]
        ]
        "correspondencia" => array:1 [
          0 => array:3 [
            "identificador" => "cor0005"
            "etiqueta" => "&#8270;"
            "correspondencia" => "Corresponding author&#46;"
          ]
        ]
      ]
    ]
    "titulosAlternativos" => array:1 [
      "es" => array:1 [
        "titulo" => "Efectos sobre la humidificaci&#243;n y los par&#225;metros de ventilaci&#243;n de 3 circuitos de ramal &#250;nico con cable calefactado para la ventilaci&#243;n mec&#225;nica no invasiva&#58; estudio experimental"
      ]
    ]
    "resumenGrafico" => array:2 [
      "original" => 1
      "multimedia" => array:5 [
        "identificador" => "fig0035"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => false
        "mostrarDisplay" => true
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "fx1.jpeg"
            "Alto" => 484
            "Ancho" => 1333
            "Tamanyo" => 83651
          ]
        ]
      ]
    ]
    "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0070">Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall">Non-invasive ventilation &#40;NIV&#41; is currently the treatment of choice in various forms of acute respiratory failure&#46;<a class="elsevierStyleCrossRefs" href="#bib0105"><span class="elsevierStyleSup">1&#44;2</span></a> This therapy involves the use of pressurized cold and dry medical gases with the possibility of signs of dryness in the respiratory tract&#46; The effects of the absence of humidification of inspired gases can on the one hand cause the rejection of this technique due to discomfort and&#44; on the other hand&#44; the possibility of atelectasis appearing as a result of respiratory secretion dryness&#46;<a class="elsevierStyleCrossRef" href="#bib0115"><span class="elsevierStyleSup">3</span></a> The American Association for Respiratory Care &#40;AARC&#41; recommends active humidification for NIV&#44; as it may improve adherence and comfort&#46;<a class="elsevierStyleCrossRef" href="#bib0120"><span class="elsevierStyleSup">4</span></a> Despite the benefits of conditioned gas administration&#44; there is currently no clear recommendation regarding the type of heated humidifier &#40;HH&#41;&#44; or the humidification values to be applied during NIV treatment in acute respiratory failure&#46;<a class="elsevierStyleCrossRef" href="#bib0125"><span class="elsevierStyleSup">5</span></a> There are many conditions that can affect humidification performance during NIV&#46; The use of different NIV heated circuits and humidification chambers may influence the temperature and humidity of the gases supplied to the patient&#46;<a class="elsevierStyleCrossRef" href="#bib0130"><span class="elsevierStyleSup">6</span></a> The ventilatory system can also affect the performance of the HH in relation to the flow generator used&#46;<a class="elsevierStyleCrossRef" href="#bib0135"><span class="elsevierStyleSup">7</span></a> Most of the dedicated NIV ventilators are turbine-driven with a better performance in terms of patient&#8211;ventilator synchrony and leak compensation compared to intensive care &#40;ICU&#41; ventilators&#46;<a class="elsevierStyleCrossRefs" href="#bib0140"><span class="elsevierStyleSup">8&#44;9</span></a> Some studies have shown that these turbine-ventilators deliver higher ventilator output temperatures leading to low humidification values compared to ICU ventilators&#46;<a class="elsevierStyleCrossRefs" href="#bib0135"><span class="elsevierStyleSup">7&#44;10</span></a></p><p id="par0010" class="elsevierStylePara elsevierViewall">There are no current studies about the interaction of HH on ventilatory variables during NIV with turbine ventilators&#46; The use of different single limb circuits may influence the inspiratory flow rate&#44; due to turbulent flow generation inside the circuit&#46; This can affect the amount of gas delivered to the patient and produce asynchronies&#46; The aim of this study is to evaluate the effects of three single-limb heated wired circuits &#40;SHWC&#41; for NIV&#44; on ventilatory parameters and humidification performance in a simulation lung model&#46;</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0075">Methods</span><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0080">Installing the system</span><p id="par0015" class="elsevierStylePara elsevierViewall">For the experiment&#44; three SHWC&#44; with its specific humidification chamber&#44; were used&#58; RT-319 &#40;FP&#41; &#40;Fisher &#38; Paykel&#44; Auckland&#44; New Zealand&#41;&#44; Respironics 1045770 &#40;RP&#41; &#40;DEAS&#44; Castel Bolognese&#44; Italy&#41; and Intersurgical B&#47;SYS 5809001 &#40;IT&#41; &#40;Intersurgical&#44; Wokingham&#44; UK&#41;&#46; FP circuit is designed specifically for use with Fisher &#38; Paykel Healthcare humidification systems&#46; It has a 25-mm inner diameter with a spiral heater wire inside to reduce condensate in varying environments&#44; and to provide a low resistance to flow&#46; RP and IT are circuits with an internal diameter of 22<span class="elsevierStyleHsp" style=""></span>mm&#46; The difference between them is that the IT has a linear heating wire inside&#44; while the RP integrates the heater wires into the circuit wall&#46; All of them are compatible with the MR-850 Heated Humidifier &#40;HH&#41; &#40;Fisher &#38; Paykel&#44; Auckland&#44; New Zealand&#41; &#40;<a class="elsevierStyleCrossRef" href="#fig0005">Fig&#46; 1</a>&#41;&#46; The MR-850 uses a heated pass-over system to add water vapor to the gas flow and has and automatic flow compensation algorithm&#44; able to maintain constant humidity&#44; recording only minor variations related to changes in the gas flow employed&#46;<a class="elsevierStyleCrossRef" href="#bib0150"><span class="elsevierStyleSup">10</span></a> All the circuits had an exhalation port piece &#40;<a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>&#41;&#46;</p><elsevierMultimedia ident="fig0005"></elsevierMultimedia><elsevierMultimedia ident="fig0010"></elsevierMultimedia><p id="par0020" class="elsevierStylePara elsevierViewall">For simulation&#44; we used a Bipap Vision ventilator &#40;Philips Respironics&#44; Murrysville&#44; PA&#44; USA&#41; connected to a test lung simulator &#40;Adult&#47;Pediatric Demo Lung&#44; Ingmar Medical&#44; Pittsburgh&#44; USA&#41;&#46; The lung simulator consists in two-bellows system with an adjustable resistance and compliance&#44; and a standard 15<span class="elsevierStyleHsp" style=""></span>mm ISO connector&#46; We tested a low compliance model with the following simulation settings&#58; compliance&#44; 20<span class="elsevierStyleHsp" style=""></span>mL&#47;cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#59; and respiratory resistance&#44; 15<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#47;L&#47;s&#46; A capacitive hygrometer &#40;HygroPalm&#44; Rotronic AG&#44; Bassersdorf&#44; Switzerland&#41; with a high-performance linear probe &#40;HC2-C05&#44; Rotronic AG&#44; Bassersdorf&#44; Switzerland&#41; was used to measure temperature and relative humidity&#46; This system has a very low dead time and is accurate &#40;humidity range&#58; 0 to 100&#37;&#44; temperature range&#58; &#8722;40 to 85<span class="elsevierStyleHsp" style=""></span>&#176;C&#41;&#44; recording an error of 0<span class="elsevierStyleHsp" style=""></span>&#176;C and no variations over time&#46;<a class="elsevierStyleCrossRef" href="#bib0155"><span class="elsevierStyleSup">11</span></a> At the end of each measurement&#44; the tip of the capacitive hygrometer was dried to avoid any possible measurement error&#46; The probe was placed in the distal part of the tube before connecting it to the test lung&#46; During the experiment&#44; we examined relative ambient humidity and temperature using an additional hygrometer &#40;HygroPalm&#44; Rotronic AG&#44; Bassersdorf&#44; Switzerland&#41; connected to a cylindrical probe &#40;HC2-S&#44; Rotronic AG&#44; Bassersdorf&#44; Switzerland&#44; humidity range&#58; 0 to 100&#37;&#44; temperature range&#58; &#8722;50 to 100<span class="elsevierStyleHsp" style=""></span>&#176;C&#41;&#46; Hygrometric data were stored on a computer using specific software &#40;Rotronic HW4 version 2&#46;3&#46;0&#46;21699&#44; Bassersdorf&#44; Switzerland&#41; to be later analyzed and calculated&#46; Ventilatory measurements were continuously recorded with a respiratory mechanics monitor &#40;FluxMed GrT&#44; MBMed&#44; Buenos Aires&#44; Argentina&#41; and analyzed with a specific software&#46; &#40;FluxView Software&#44; MBMed&#44; Buenos Aires&#44; Argentina&#41; &#40;<a class="elsevierStyleCrossRef" href="#fig0010">Fig&#46; 2</a>&#41;&#46;</p></span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0085">Measurements</span><p id="par0025" class="elsevierStylePara elsevierViewall">The study was conducted under conditions of stable environmental temperature and humidity &#40;20<span class="elsevierStyleHsp" style=""></span>&#176;C and 50&#37; relative humidity&#41;&#44; which were measured throughout the experiment as a means of control&#46; Measurements of relative environmental humidity and temperature were taken every 5<span class="elsevierStyleHsp" style=""></span>min throughout the various phases of the study&#46; The ventilator was set in pressure-controlled ventilation mode &#40;PCV&#41; with a respiratory rate &#40;RR&#41; of 12<span class="elsevierStyleHsp" style=""></span>breaths&#47;min&#44; rise time &#40;RS&#41; 0&#46;1<span class="elsevierStyleHsp" style=""></span>s&#44; and an expiratory positive airway pressure &#40;EPAP&#41; of 5<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#46; For each circuit&#44; an exhalation port test was performed to ensure the accuracy of estimated tidal volume and minute ventilation readings&#44; according to manufacturer&#39;s recommendation&#46; Each SHWC performance was evaluated in four ventilatory conditions&#58; inspiratory positive airway pressure &#40;IPAP&#41; of 15<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O with FiO<span class="elsevierStyleInf">2</span> 0&#46;3 and 1&#44; respectively&#59; and&#44; IPAP of 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O with FiO<span class="elsevierStyleInf">2</span> 0&#46;3 and 1&#44; respectively &#40;<a class="elsevierStyleCrossRef" href="#fig0015">Fig&#46; 3</a>&#41;&#46; Before modifying ventilator settings&#44; the system was stabilized to achieve the target temperature values of the HH&#46; Under these conditions&#44; we tested the MR using the active compensation algorithm &#40;software 722&#41; and NIV mode&#46; In each of the phases mentioned above&#44; hygrometric and ventilatory measurements including&#58; relative humidity &#40;RH&#41;&#44; temperature &#40;<span class="elsevierStyleItalic">T</span>&#41;&#44; peak inspiratory pressure &#40;PIP&#41;&#44; positive end expiratory pressure &#40;PEEP&#41;&#44; peak inspiratory flow &#40;PIF&#41;&#44; and tidal volume &#40;Vt&#41; were measured&#46;</p><elsevierMultimedia ident="fig0015"></elsevierMultimedia><p id="par0030" class="elsevierStylePara elsevierViewall">We obtained 120 measurements &#40;one measurement each 30<span class="elsevierStyleHsp" style=""></span>s for 60<span class="elsevierStyleHsp" style=""></span>min continuously&#41; in each experimental situation&#46; A total of 1440 measurements were taken&#46; In order to calculate absolute humidity&#44; the following formulae were used<a class="elsevierStyleCrossRef" href="#bib0155"><span class="elsevierStyleSup">11</span></a>&#58;<elsevierMultimedia ident="eq0005"></elsevierMultimedia><elsevierMultimedia ident="eq0010"></elsevierMultimedia>where <span class="elsevierStyleItalic">T</span> is the probe temperature in degrees Celsius&#44; RH is relative humidity&#44; AH is absolute humidity and SAH is saturated absolute humidity&#44; both of which are expressed in mg<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#47;L&#46;</p></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0090">Statistics</span><p id="par0035" class="elsevierStylePara elsevierViewall">Statistical analysis was performed using IBM SPSS 21 software&#46; Descriptive statistics were obtained for all values with the mean and standard deviation&#46; In order to analyze the differences between groups analysis of variance &#40;ANOVA&#41; was used&#44; while the Bonferroni test was employed for multiple comparisons&#46; A Kolmogorov&#8211;Smirnov analysis was used to test normality&#46; A <span class="elsevierStyleItalic">P</span>-value of &#60;&#46;05 was considered statistically significant&#46;</p></span></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0095">Results</span><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0100">Hygrometric variables</span><p id="par0040" class="elsevierStylePara elsevierViewall">We obtained a total of 144 environmental measurements&#46; Absolute and relative humidity and temperature remained stable throughout the experiment &#40;24&#46;1<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;5<span class="elsevierStyleHsp" style=""></span>&#176;C ambient temperature&#44; 51&#46;3<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>3&#46;2&#37; ambient RH&#44; 11&#46;3<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;8<span class="elsevierStyleHsp" style=""></span>mg<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#47;L ambient AH&#41;&#46;</p><p id="par0045" class="elsevierStylePara elsevierViewall">Absolute humidity for the four study groups with different FiO<span class="elsevierStyleInf">2</span> and IPAP levels is shown in <a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>&#46; AH was significantly lower in FP compared to RP and IT&#44; regardless of the FiO<span class="elsevierStyleInf">2</span> and IPAP level selected &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41; &#40;<a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>&#41;&#46; In RP and IT groups AH values were significantly higher with a FiO<span class="elsevierStyleInf">2</span> of 1 at IPAP level 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O compared to those at 15<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46; <a class="elsevierStyleCrossRef" href="#fig0020">Fig&#46; 4</a> shows the evolution of AH with IPAP changes at different FiO<span class="elsevierStyleInf">2</span> levels to evaluate the ability of each SHWC to maintain a constant range of values&#46; AH values obtained with FP were similar regardless of the IPAP level employed&#46; In the case of IT and RP&#44; AH values were significantly different for a selected IPAP level of 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O compared to 15<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46;</p><elsevierMultimedia ident="tbl0005"></elsevierMultimedia><elsevierMultimedia ident="fig0020"></elsevierMultimedia><p id="par0050" class="elsevierStylePara elsevierViewall">Relative humidity was significantly lower in FP compared to RP and IT &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#44; except for RP with FiO<span class="elsevierStyleInf">2</span> of 0&#46;3 at IPAP level of 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41; &#40;<a class="elsevierStyleCrossRef" href="#fig0025">Fig&#46; 5</a>&#41;&#46; In the IT group&#44; RH values increased significantly as the IPAP increased regardless of the FiO<span class="elsevierStyleInf">2</span> applied &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46; The opposite was observed with the FP&#44; with a significant decreased in RH as the IPAP increased with a FiO<span class="elsevierStyleInf">2</span> of 0&#46;3 &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46; The RH values in RP were significantly higher at IPAP level of 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O compared to 15<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#44; when a FiO<span class="elsevierStyleInf">2</span> of 1 was set &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46;</p><elsevierMultimedia ident="fig0025"></elsevierMultimedia><p id="par0055" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#fig0030">Fig&#46; 6</a> displays the behaviour of temperature&#46; In all of the study groups&#44; the temperature raised significantly when the IPAP level increased from 15 to 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#44; regardless of FiO<span class="elsevierStyleInf">2</span> selected &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#44; except for RP group at FiO<span class="elsevierStyleInf">2</span> of 0&#46;3 with IPAP of 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#44; where temperature decreased significantly &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46;</p><elsevierMultimedia ident="fig0030"></elsevierMultimedia></span><span id="sec0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0105">Ventilatory variables</span><p id="par0060" class="elsevierStylePara elsevierViewall">Ventilatory measurements are shown in <a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>&#46; All measurements in the IT group were significantly lower compared to RP and FP &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46; At IPAP level of 15<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#44; a significant increase in PIF and Vt was observed in the FP group compared to RP &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46; Measurements obtained at IPAP level of 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O were similar between FP and RP&#44; except for Vt and PEEP with higher values in the FP and RP&#44; respectively &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46;</p><elsevierMultimedia ident="tbl0010"></elsevierMultimedia></span></span><span id="sec0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0110">Discussion</span><span id="sec0050" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0115">Heater humidifier performance</span><p id="par0065" class="elsevierStylePara elsevierViewall">During NIV&#44; the absence of medical gas humidification may cause dryness in the respiratory tract&#46; The ideal humidification value to preserve the function of the mucociliary system is 44<span class="elsevierStyleHsp" style=""></span>mg<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#47;L&#44; measured after the carina&#46;<a class="elsevierStyleCrossRef" href="#bib0160"><span class="elsevierStyleSup">12</span></a> Although&#44; upper airways are not bypassed during NIV&#44; high-flow from turbine-driven ventilators can make physiological gas humidification less effective&#46; These data suggest that the use of humidification systems to condition gas during NIV may be beneficial to prevent respiratory complications&#46;</p><p id="par0070" class="elsevierStylePara elsevierViewall">The performance of the HH can be influenced by several factors&#44; but the main ones are room temperature and gas temperature before passing through the heating chamber&#46;<a class="elsevierStyleCrossRef" href="#bib0150"><span class="elsevierStyleSup">10</span></a> Differences in ambient conditions&#44; HH&#44; respiratory circuit&#44; ventilator&#44; and wall gas temperature can influence on the humidity and temperature of the gases delivered to the patient&#46;<a class="elsevierStyleCrossRefs" href="#bib0135"><span class="elsevierStyleSup">7&#44;10&#44;13&#44;14</span></a> In our study we tested in similar ambient conditions the influence of three different SHWC on MR-850 HH automatic humidity compensation algorithm performance&#44; using a turbine-driven NIV ventilator&#46; Although&#44; the FP circuit had the lowest AH values of the three circuits evaluated&#44; it was able to maintain constant AH values&#44; recording only minor variations related to changes in the IPAP level employed&#44; with no influence from the FiO<span class="elsevierStyleInf">2</span> used&#46; In the case of IT and RP&#44; humidification values varied in relation to the IPAP level used&#44; being higher as the IPAP increased&#44; regardless of the FiO<span class="elsevierStyleInf">2</span> selected &#40;<a class="elsevierStyleCrossRef" href="#fig0020">Fig&#46; 4</a>&#41;&#46; One explanation to these results are the differences in the type of chamber and the different heated wired systems between the three circuits&#46; The MR-850 HH in non-invasive mode is programmed to generate theoretical values of absolute humidity of 32<span class="elsevierStyleHsp" style=""></span>mg<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#47;L regardless of changes in flow&#44; FiO<span class="elsevierStyleInf">2</span> level and&#44; ventilator outlet temperature&#46; This is possible due to the automatic humidity compensation mode that was developed by the manufacturer to optimized HH performance&#46; When the automatic mode is selected the humidifier calculates the power required to adequately humidify the gas flow through the chamber&#44; providing constant humidification values&#46; The humidifier monitors the temperature and gas flow at the chamber outlet with the chamber probe&#44; and the limb temperature with the distal probe&#46; The system controls the amount of power delivered to the heater plate&#44; in order to maintain the chamber&#39;s set values of humidity and temperature&#46; In addition&#44; the circuit is heated to achieve a positive temperature gradient of 3<span class="elsevierStyleHsp" style=""></span>&#176;C at the end of the limb&#46; This temperature gradient causes the RH to drop from 100&#37; to 80&#37;&#44; maintaining the same amount of AH and avoiding condensation between the end limb and the mask&#46; For an optimal system performance&#44; it is necessary that the HH recognizes the type of circuit and the humidification chamber used&#44; in order to adjust the amount of energy necessary to produce humidity in the range of values of the compensation algorithm&#46; In the case of FP&#44; the system performed more stable&#44; because the HH was able to automatically recognize the circuit&#46; The expected RH values with the FP circuit were around 80&#37;&#44; as a result of increasing the temperature of the limb in order to avoid circuit condensation &#40;<a class="elsevierStyleCrossRef" href="#fig0025">Fig&#46; 5</a>&#41;&#46; In the case of IT and RP&#44; RH values were higher showing that the MR-850 automatic compensation mode did not perform as well as with the FP circuit&#46; Although AH with FP were slightly lower than the theoretical values&#44; those were relatively constant regardless of IPAP and FiO<span class="elsevierStyleInf">2</span> levels&#46; It is interesting to note that in the case of RP there was a sudden decrease with IPAP level of 25 at FiO<span class="elsevierStyleInf">2</span> of 0&#46;3&#44; with a mean AH values of 22&#46;68<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>5&#46;82<span class="elsevierStyleHsp" style=""></span>mg<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#47;L&#46; This can be due to a malfunction of the proximal temperature sensors or a faulty connection between the sensor and the tube&#44; leading to a decrease in the amount of power delivered to the heater plate&#44; with the result of lower humidification values&#46;</p></span><span id="sec0055" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0120">Ventilator variables</span><p id="par0075" class="elsevierStylePara elsevierViewall">The type of respiratory circuit can influence in the amount of gas delivered to the patient&#46; The flow of gas through a tube depends on one hand on the pressure exerted&#44; and on the other hand on the resistance of the tube&#46; In the present study we evaluated three circuits with different resistance to flow&#46; In the case of IT we observed a significant decrease on PIF&#44; Vt and PIP compared to the other two circuits evaluated&#44; in all the experimental conditions&#46; These results can be explained by the presence of a linear wire inside the IT tube that can increase the turbulent flow inside the tube&#46; The precise relationship between pressure gradient and flow rate depends on the nature of the flow which can be laminar&#44; turbulent or a mixture of the two&#46;<a class="elsevierStyleCrossRef" href="#bib0175"><span class="elsevierStyleSup">15</span></a> Situations of high flow rates with irregular tubes result in a breakdown of the orderly laminar flow&#44; with an irregular movement superimposed on the general progression along the tube&#44; creating turbulent flow&#46; In mechanical ventilation&#44; with constant gas viscosity&#44; the major determinant of turbulent flow is the inner diameter of the tube so&#44; factors that affect this diameter can influence in the performance of the ventilator&#46; The linear wire of the IT circuit can generate frictional forces between the gas and the tube wire leading to turbulent flow and making the inner diameter irregular&#46; In the case of FP&#44; the higher inner diameter and the spiral heater wire make the circuit less resistant to flow generating more flow with the same driving pressure compared to IT&#46; The same occurs with the RP that integrates the wire in the tube wall&#44; allowing a smooth surface for the gas to flow&#44; and decreasing the generation of turbulent flow&#46;</p><p id="par0080" class="elsevierStylePara elsevierViewall">In a recent bench study&#44; Ferrone et al&#46; evaluated two ventilator circuits during helmet NIV&#58; a double limb circuit &#40;with one inspiratory and one expiratory line&#41; and a standard circuit &#40;a Y-piece connected only to one side of the helmet&#44; closing the other side&#41;&#46;<a class="elsevierStyleCrossRef" href="#bib0180"><span class="elsevierStyleSup">16</span></a> They concluded that&#44; using a standard circuit&#44; both the inspiratory and the expiratory flows were forced to pass through the Y-piece of the circuit&#44; probably generating turbulence that may increase resistances inside the passage&#44; thus inducing alterations in patient&#8211;ventilator interaction&#46; These results highlight the effects of ventilator circuits on respiratory mechanics&#46;</p><p id="par0085" class="elsevierStylePara elsevierViewall">The differences in flow rate between the three circuits observed in our study can influence in clinical practice specially in the presence of patient&#8211;ventilator asynchrony&#46; Vignaux et al&#46; demonstrated that asynchronies are common during NIV&#46;<a class="elsevierStyleCrossRef" href="#bib0185"><span class="elsevierStyleSup">17</span></a> They reported an incidence of auto-triggering of 13&#37;&#44; and delayed cycling of 23&#37; in multicenter study of patients with acute respiratory failure treated with NIV&#46; Patient&#8211;ventilator asynchrony can significantly increase the work of breathing&#44;<a class="elsevierStyleCrossRefs" href="#bib0190"><span class="elsevierStyleSup">18&#44;19</span></a> and a high incidence of patient&#8211;ventilator asynchrony is associated with a longer duration of mechanical ventilation&#46;<a class="elsevierStyleCrossRef" href="#bib0200"><span class="elsevierStyleSup">20</span></a> In order to minimized this problem&#44; manufactures have developed dedicated NIV ventilators&#44; particularly oriented towards leakage management and comfort&#46; Some bench studies have observed that dedicated turbine-driven NIV ventilators allow a better patient&#8211;ventilator synchrony than ICU and transport ventilators&#46;<a class="elsevierStyleCrossRefs" href="#bib0140"><span class="elsevierStyleSup">8&#44;9</span></a> The results our study suggest that the type of humidification circuit&#44; beyond the ventilatory settings and leak compensation algorithms&#44; can influence the flow and volume delivered to the patient&#46; In our study&#44; FP and RP circuits have better flow performance compared to IT&#46; The linear wire jointly with an inner diameter of 22<span class="elsevierStyleHsp" style=""></span>mm in the IT circuit may generate turbulence flow specially in situations of increase flow demand or leak compensation&#44; making the ventilation less effective&#46; Due to the use of a passive lung simulator it is not possible to infer directly from the results of the study the possibility of generating flow asynchronies&#46; However&#44; the differences observed in the peak inspiratory flow between the different circuits&#44; with a fixed rise time&#44; give an idea that the behaviour of the inspiratory flow is different as a consequence of variations in the internal diameter of the circuits&#46; The fact that one of the circuits has a greater resistance to flow could influence the synchronization&#44; even if the patient did not present a high inspiratory effort&#46;</p></span></span><span id="sec0060" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0125">Limitations</span><p id="par0090" class="elsevierStylePara elsevierViewall">Bearing in mind that this is a pilot study that was performed under ideal conditions&#44; the hygrometric and respiratory values obtained may be different to those obtained in real conditions&#46; Moreover&#44; we evaluated respiratory mechanics in a continuous mandatory ventilation model&#44; and the results can differ from those obtained either in a spontaneous ventilation model or with patients&#46; It is interesting to note that we evaluated normal ventilatory conditions with a RR of 12&#44; that is not usual in patients with respiratory failure treated with NIV&#44; and this can limit our results when extrapolating them in real conditions&#46; However&#44; we think that in clinical conditions the differences between the three circuits&#44; in terms of ventilatory parameters&#44; would be the same&#44; although it would be necessary to confirm this point with clinical studies&#46; Other limitation is related to the ventilator use in our study&#46; This ventilator does not identify the resistances and compliance of the circuit&#46; Newer ventilators can calibrate the resistances and compliance of the circuit and therefore modify the pressurization according to these&#46; This fact could limit the differences in the values identified for each circuit if we had evaluated such type of ventilators&#46;</p><p id="par0095" class="elsevierStylePara elsevierViewall">In our study&#44; we did not evaluate the effect of the nasopharyngeal conditioning system on temperature and humidity&#44; which in real terms during NIV partially contributes to conditioning inspired gas&#46; It is important to mention that ventilatory parameters measurements in our study were obtained under ideal conditions without leaks and may therefore differ to those obtained in clinical practice&#46; It would be necessary to conduct clinical studies to ascertain the impact of heated circuits in patient&#39;s respiratory mechanics and asynchronies generation&#46;</p></span><span id="sec0065" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0130">Conclusions</span><p id="par0100" class="elsevierStylePara elsevierViewall">This study is the first to undertake an in vitro evaluation of humidification and respiratory mechanics performance of three different SHWC&#46; From the analysis of the results it can be seen that the type of circuit used&#44; influences both humidification values and ventilatory variables&#46; The FP circuit was the most reliable in terms of two factors combined&#58; stable humidification values independently from changes in ventilator settings and&#44; low resistance to flow tested with the BiPAP Vision compared to the other two circuits&#46; This study suggests that heated circuits can affect humidification and ventilator performance&#46;</p></span><span id="sec0070" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0135">Funding</span><p id="par0110" class="elsevierStylePara elsevierViewall">This study was conducted at <span class="elsevierStyleGrantSponsor" id="gs1">Centro de Simulaci&#243;n Cl&#237;nica Avanzada &#40;CESIMAV&#41;&#44; Meliana &#40;Spain&#41;</span> and was supported by institutional funds&#46;</p></span><span id="sec0075" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0140">Conflict of interests</span><p id="par0115" class="elsevierStylePara elsevierViewall">The authors declare no conflict of interests&#46;</p></span></span>"
    "textoCompletoSecciones" => array:1 [
      "secciones" => array:14 [
        0 => array:3 [
          "identificador" => "xres1315757"
          "titulo" => "Graphical abstract"
          "secciones" => array:1 [
            0 => array:1 [
              "identificador" => "abst0005"
            ]
          ]
        ]
        1 => array:3 [
          "identificador" => "xres1315758"
          "titulo" => "Abstract"
          "secciones" => array:4 [
            0 => array:2 [
              "identificador" => "abst0010"
              "titulo" => "Background"
            ]
            1 => array:2 [
              "identificador" => "abst0015"
              "titulo" => "Methods"
            ]
            2 => array:2 [
              "identificador" => "abst0020"
              "titulo" => "Results"
            ]
            3 => array:2 [
              "identificador" => "abst0025"
              "titulo" => "Conclusions"
            ]
          ]
        ]
        2 => array:2 [
          "identificador" => "xpalclavsec1214353"
          "titulo" => "Keywords"
        ]
        3 => array:3 [
          "identificador" => "xres1315756"
          "titulo" => "Resumen"
          "secciones" => array:4 [
            0 => array:2 [
              "identificador" => "abst0030"
              "titulo" => "Introducci&#243;n"
            ]
            1 => array:2 [
              "identificador" => "abst0035"
              "titulo" => "M&#233;todos"
            ]
            2 => array:2 [
              "identificador" => "abst0040"
              "titulo" => "Resultados"
            ]
            3 => array:2 [
              "identificador" => "abst0045"
              "titulo" => "Conclusiones"
            ]
          ]
        ]
        4 => array:2 [
          "identificador" => "xpalclavsec1214352"
          "titulo" => "Palabras clave"
        ]
        5 => array:2 [
          "identificador" => "sec0005"
          "titulo" => "Introduction"
        ]
        6 => array:3 [
          "identificador" => "sec0010"
          "titulo" => "Methods"
          "secciones" => array:3 [
            0 => array:2 [
              "identificador" => "sec0015"
              "titulo" => "Installing the system"
            ]
            1 => array:2 [
              "identificador" => "sec0020"
              "titulo" => "Measurements"
            ]
            2 => array:2 [
              "identificador" => "sec0025"
              "titulo" => "Statistics"
            ]
          ]
        ]
        7 => array:3 [
          "identificador" => "sec0030"
          "titulo" => "Results"
          "secciones" => array:2 [
            0 => array:2 [
              "identificador" => "sec0035"
              "titulo" => "Hygrometric variables"
            ]
            1 => array:2 [
              "identificador" => "sec0040"
              "titulo" => "Ventilatory variables"
            ]
          ]
        ]
        8 => array:3 [
          "identificador" => "sec0045"
          "titulo" => "Discussion"
          "secciones" => array:2 [
            0 => array:2 [
              "identificador" => "sec0050"
              "titulo" => "Heater humidifier performance"
            ]
            1 => array:2 [
              "identificador" => "sec0055"
              "titulo" => "Ventilator variables"
            ]
          ]
        ]
        9 => array:2 [
          "identificador" => "sec0060"
          "titulo" => "Limitations"
        ]
        10 => array:2 [
          "identificador" => "sec0065"
          "titulo" => "Conclusions"
        ]
        11 => array:2 [
          "identificador" => "sec0070"
          "titulo" => "Funding"
        ]
        12 => array:2 [
          "identificador" => "sec0075"
          "titulo" => "Conflict of interests"
        ]
        13 => array:1 [
          "titulo" => "References"
        ]
      ]
    ]
    "pdfFichero" => "main.pdf"
    "tienePdf" => true
    "fechaRecibido" => "2018-11-26"
    "fechaAceptado" => "2019-04-16"
    "PalabrasClave" => array:2 [
      "en" => array:1 [
        0 => array:4 [
          "clase" => "keyword"
          "titulo" => "Keywords"
          "identificador" => "xpalclavsec1214353"
          "palabras" => array:5 [
            0 => "Heated humidifiers"
            1 => "Respiratory mechanics"
            2 => "Humidification"
            3 => "Non-invasive ventilation"
            4 => "Mechanical ventilation"
          ]
        ]
      ]
      "es" => array:1 [
        0 => array:4 [
          "clase" => "keyword"
          "titulo" => "Palabras clave"
          "identificador" => "xpalclavsec1214352"
          "palabras" => array:5 [
            0 => "Humidificadores calefactados"
            1 => "Mec&#225;nica respiratoria"
            2 => "Humidificaci&#243;n"
            3 => "Ventilaci&#243;n no invasiva"
            4 => "Ventilaci&#243;n mec&#225;nica"
          ]
        ]
      ]
    ]
    "tieneResumen" => true
    "resumen" => array:2 [
      "en" => array:3 [
        "titulo" => "Abstract"
        "resumen" => "<span id="abst0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0015">Background</span><p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">The objective of this study was to evaluate the effects of three single-limb heated wired circuits &#40;SLHWC&#41; for NIV&#44; on ventilatory parameters and humidification performance in a simulation lung model&#46;</p></span> <span id="abst0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0020">Methods</span><p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">Three SLHWC compatible with the MR-850 Heated Humidifier &#40;HH&#41; &#40;Fisher &#38; Paykel&#44; Auckland&#44; New Zealand&#41; were tested&#58; RT-319 &#40;FP&#41; &#40;Fisher &#38; Paykel&#44; Auckland&#44; New Zealand&#41;&#44; Respironics 1045770 &#40;RP&#41; &#40;DEAS&#44; Castel Bolognese&#44; Italy&#41; and Intersurgical B&#47;SYS 5809001 &#40;IT&#41; &#40;Intersurgical&#44; Wokingham&#44; UK&#41;&#46; A Bipap Vision ventilator &#40;Philips Respironics&#44; Murrysville&#44; PA&#44; USA&#41; in pressure control ventilation &#40;PCV&#41; connected to a test lung was used for simulation&#46; Each SHWC performance was evaluated in four ventilatory conditions&#58; IPAP of 15<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O with FiO<span class="elsevierStyleInf">2</span> 0&#46;3 and 1&#44; respectively&#59; and&#44; IPAP of 25<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O with FiO<span class="elsevierStyleInf">2</span> 0&#46;3 and 1&#44; respectively&#46; EPAP was set at 5<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#46; Hygrometric and ventilatory measurements including&#58; relative humidity &#40;RH&#41;&#44; temperature &#40;<span class="elsevierStyleItalic">T</span>&#41;&#44; Pplat&#44; PIP&#44; PEEP&#44; peak inspiratory flow &#40;PIF&#41;&#44; and tidal volume &#40;Vt&#41; were measured&#46;</p></span> <span id="abst0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0025">Results</span><p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">In each FiO<span class="elsevierStyleInf">2</span> group absolute humidity &#40;AH&#41; was similar with FP regardless of the IPAP level employed compared to IT and RP &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46; Except for RP at FiO<span class="elsevierStyleInf">2</span> 0&#46;3&#44; AH increased significantly in IT and RP groups as IPAP increased &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46; PIP&#44; Pplat&#44; PEEP&#44; PIF&#44; and Vt values were significantly higher with FP and RP in each FiO<span class="elsevierStyleInf">2</span> group compared to IT &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41;&#46;</p></span> <span id="abst0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0030">Conclusions</span><p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">Humidification performance varied significantly among the three circuits&#44; being FP the only one able to maintain stable AH values during the study with no influence on ventilatory parameters&#46;</p></span>"
        "secciones" => array:4 [
          0 => array:2 [
            "identificador" => "abst0010"
            "titulo" => "Background"
          ]
          1 => array:2 [
            "identificador" => "abst0015"
            "titulo" => "Methods"
          ]
          2 => array:2 [
            "identificador" => "abst0020"
            "titulo" => "Results"
          ]
          3 => array:2 [
            "identificador" => "abst0025"
            "titulo" => "Conclusions"
          ]
        ]
      ]
      "es" => array:3 [
        "titulo" => "Resumen"
        "resumen" => "<span id="abst0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0040">Introducci&#243;n</span><p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">El objetivo de este estudio fue evaluar los efectos de 3 circuitos de ramal &#250;nico &#40;SLHWC&#41; para la ventilaci&#243;n mec&#225;nica no invasiva &#40;VNI&#41; en los par&#225;metros de ventilaci&#243;n y la humidificaci&#243;n en un modelo de simulaci&#243;n pulmonar&#46;</p></span> <span id="abst0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0045">M&#233;todos</span><p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">Se evaluaron 3 SLHWC compatibles con el humidificador calefactado MR-850 &#40;HH&#41; &#40;Fisher &#38; Paykel&#44; Auckland&#44; Nueva Zelanda&#41;&#58; RT-319 &#40;FP&#41; &#40;Fisher &#38; Paykel&#44; Auckland&#44; Nueva Zelanda&#41;&#44; Respironics 1045770 &#40;RP&#41; &#40;DEAS&#44; Castel Bolognese&#44; Italia&#41; y Intersurgical B&#47;SYS 5809001 &#40;IT&#41; &#40;Intersurgical&#44; Wokingham&#44; Reino Unido&#41;&#46; Para la simulaci&#243;n se emple&#243; un ventilador Bipap Vision &#40;Philips Respironics&#44; Murrysville&#44; PA&#44; EE&#46; UU&#46;&#41; con ventilaci&#243;n controlada por presi&#243;n &#40;PCV&#41; conectado a un simulador pulmonar&#46; El rendimiento de cada SHWC se evalu&#243; en 4 condiciones ventilatorias&#58; IPAP de 15<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O con FiO<span class="elsevierStyleInf">2</span> igual a 0&#44;3 o igual a 1&#59; IPAP de 25<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O con FiO<span class="elsevierStyleInf">2</span> igual a 0&#44;3 o igual a 1&#46; La EPAP se estableci&#243; en 5<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O&#46; Las medidas ventilatorias e higrom&#233;tricas incluyeron&#58; humedad relativa &#40;HR&#41; humedad absoluta &#40;AH&#41;&#44; temperature &#40;T&#41;&#44; Pplat&#44; PIP&#44; PEEP&#44; pico de flujo inspiratorio &#40;PIF&#41; y volumen tidal &#40;Vt&#41;&#46;</p></span> <span id="abst0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0050">Resultados</span><p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">Para cada grupo de FiO<span class="elsevierStyleInf">2</span> FP detect&#243; valores similares de humedad absoluta &#40;HA&#41; en comparaci&#243;n con IT y RP &#40;p<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>0&#44;001&#41;&#44; independientemente del nivel IPAP utilizado&#46; Se registr&#243; un incremento significativo de la HA en todos los grupos medidos con IT y RP conforme aumentaron los valores de IPAP &#40;p<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>0&#44;001&#41;&#44; excepto en el grupo de FiO<span class="elsevierStyleInf">2</span>&#44; igual a 0&#44;3 medido con RP&#46; Los valores de PIP&#44; Pplat&#44; PEEP&#44; PIF y Vt resultaron significativamente m&#225;s elevados con FP y RP en cada grupo FiO<span class="elsevierStyleInf">2</span> en comparaci&#243;n con IT &#40;p<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>0&#44;001&#41;&#46;</p></span> <span id="abst0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0055">Conclusiones</span><p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">La evaluaci&#243;n de la humidificaci&#243;n vari&#243; significativamente entre los 3 circuitos&#44; siendo FP el &#250;nico capaz de mantener estables los valores de HA durante el estudio sin influencia alguna de los par&#225;metros ventilatorios&#46;</p></span>"
        "secciones" => array:4 [
          0 => array:2 [
            "identificador" => "abst0030"
            "titulo" => "Introducci&#243;n"
          ]
          1 => array:2 [
            "identificador" => "abst0035"
            "titulo" => "M&#233;todos"
          ]
          2 => array:2 [
            "identificador" => "abst0040"
            "titulo" => "Resultados"
          ]
          3 => array:2 [
            "identificador" => "abst0045"
            "titulo" => "Conclusiones"
          ]
        ]
      ]
    ]
    "multimedia" => array:11 [
      0 => array:7 [
        "identificador" => "fig0005"
        "etiqueta" => "Fig&#46; 1"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr1.jpeg"
            "Alto" => 1697
            "Ancho" => 1508
            "Tamanyo" => 230836
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">Heated wired-circuits&#46;</p>"
        ]
      ]
      1 => array:7 [
        "identificador" => "fig0010"
        "etiqueta" => "Fig&#46; 2"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr2.jpeg"
            "Alto" => 1224
            "Ancho" => 2341
            "Tamanyo" => 169694
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">Diagram of experimental setting&#46;</p>"
        ]
      ]
      2 => array:7 [
        "identificador" => "fig0015"
        "etiqueta" => "Fig&#46; 3"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr3.jpeg"
            "Alto" => 1013
            "Ancho" => 2341
            "Tamanyo" => 144606
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">Study protocol&#46; One hundred and twenty measurements were taken in each experimental scenario&#46;</p>"
        ]
      ]
      3 => array:7 [
        "identificador" => "fig0020"
        "etiqueta" => "Fig&#46; 4"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr4.jpeg"
            "Alto" => 1179
            "Ancho" => 1508
            "Tamanyo" => 81724
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0065" class="elsevierStyleSimplePara elsevierViewall">Evolution of absolute humidity &#40;AH&#41; following a change in IPAP levels at different FiO<span class="elsevierStyleInf">2</span>&#46; Data expressed as means and CI 95&#37;&#46; &#42;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#44; IT at IPAP 25 compared to 15&#59; <span class="elsevierStyleSup">&#43;</span><span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#44; RP at IPAP 25 compared to 15&#46; <span class="elsevierStyleItalic">Key</span>&#58; FP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Fisher &#38; Paykel RT-319&#59; RP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Respironics 1045770&#59; IT<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Intersurgical B&#47;SYS 5809001&#46;</p>"
        ]
      ]
      4 => array:7 [
        "identificador" => "fig0025"
        "etiqueta" => "Fig&#46; 5"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr5.jpeg"
            "Alto" => 1229
            "Ancho" => 1508
            "Tamanyo" => 52670
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0070" class="elsevierStyleSimplePara elsevierViewall">Evolution of relative humidity &#40;RH&#41; following a change in IPAP levels at different FiO<span class="elsevierStyleInf">2</span>&#46; Data expressed as means and CI 95&#37;&#46; <span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001 for each FiO<span class="elsevierStyleInf">2</span> study group between different IPAP levels&#44; except those marked with &#42; in the same study group&#46; <span class="elsevierStyleItalic">Key</span>&#58; FP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Fisher &#38; Paykel RT-319&#59; RP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Respironics 1045770&#59; IT<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Intersurgical B&#47;SYS 5809001&#46;</p>"
        ]
      ]
      5 => array:7 [
        "identificador" => "fig0030"
        "etiqueta" => "Fig&#46; 6"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr6.jpeg"
            "Alto" => 1179
            "Ancho" => 1508
            "Tamanyo" => 72824
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0075" class="elsevierStyleSimplePara elsevierViewall">Evolution of temperature &#40;<span class="elsevierStyleItalic">T</span>&#41; following a change in IPAP levels at different FiO<span class="elsevierStyleInf">2</span>&#46; Data expressed as means and CI 95&#37;&#46; <span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001 for each FiO<span class="elsevierStyleInf">2</span> study group between different IPAP levels&#46; <span class="elsevierStyleItalic">Key</span>&#58; FP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Fisher &#38; Paykel RT-319&#59; RP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Respironics 1045770&#59; IT<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Intersurgical B&#47;SYS 5809001&#46;</p>"
        ]
      ]
      6 => array:8 [
        "identificador" => "tbl0005"
        "etiqueta" => "Table 1"
        "tipo" => "MULTIMEDIATABLA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "detalles" => array:1 [
          0 => array:3 [
            "identificador" => "at1"
            "detalle" => "Table "
            "rol" => "short"
          ]
        ]
        "tabla" => array:2 [
          "leyenda" => "<p id="spar0090" class="elsevierStyleSimplePara elsevierViewall">All data in each FiO<span class="elsevierStyleInf">2</span> group was significantly different &#40;<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001&#41; except for those marked with &#42;&#44; <span class="elsevierStyleSup">&#43;</span>&#44; <span class="elsevierStyleSup">&#35;</span>&#46; <span class="elsevierStyleItalic">Key</span>&#58; IPAP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Inspiratory Positive Airway Pressure&#59; FP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Fisher &#38; Paykel RT-319&#59; RP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Respironics 1045770&#59; IT<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Intersurgical B&#47;SYS 5809001&#46;</p>"
          "tablatextoimagen" => array:1 [
            0 => array:2 [
              "tabla" => array:1 [
                0 => """
                  <table border="0" frame="\n
                  \t\t\t\t\tvoid\n
                  \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td-with-role" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col">Heated wired circuits&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " colspan="2" align="center" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">FiO<span class="elsevierStyleInf">2</span> 0&#46;3</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " colspan="2" align="center" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">FiO<span class="elsevierStyleInf">2</span> 1</th></tr><tr title="table-row"><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">IPAP 15&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">IPAP 25&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">IPAP 15&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">IPAP 25&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td-with-role" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">FP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">29&#46;52<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>2&#46;23<span class="elsevierStyleSup">&#43;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">28&#46;97<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>1&#46;40<span class="elsevierStyleSup">&#43;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">29&#46;14<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;37<span class="elsevierStyleSup">&#43;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">29&#46;20<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>1&#46;19<span class="elsevierStyleSup">&#43;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">RP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">30&#46;84<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>1&#46;76&#42;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">22&#46;68<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>5&#46;82&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">30&#46;44<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>2&#46;45&#42;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">32&#46;00<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>2&#46;55&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">IT&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">31&#46;48<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>3&#46;49&#42;<span class="elsevierStyleSup">&#44;&#35;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">32&#46;86<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>1&#46;07<span class="elsevierStyleSup">&#35;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">30&#46;68<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>1&#46;68&#42;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">33&#46;10<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>3&#46;32&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr></tbody></table>
                  """
              ]
              "imagenFichero" => array:1 [
                0 => "xTab2255486.png"
              ]
            ]
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0080" class="elsevierStyleSimplePara elsevierViewall">Absolute humidity &#40;in mg<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#47;L&#41; of the medical gas with different heated wired-circuits at different FiO<span class="elsevierStyleInf">2</span> and IPAP levels&#46; Data expressed as mean and standard deviation&#46;</p>"
        ]
      ]
      7 => array:8 [
        "identificador" => "tbl0010"
        "etiqueta" => "Table 2"
        "tipo" => "MULTIMEDIATABLA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "detalles" => array:1 [
          0 => array:3 [
            "identificador" => "at2"
            "detalle" => "Table "
            "rol" => "short"
          ]
        ]
        "tabla" => array:3 [
          "leyenda" => "<p id="spar0095" class="elsevierStyleSimplePara elsevierViewall"><span class="elsevierStyleItalic">Key</span>&#58; IPAP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Inspiratory Positive Airway Pressure&#59; FP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Fisher &#38; Paykel RT-319&#59; RP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Respironics 1045770&#59; IT<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>Intersurgical B&#47;SYS 5809001&#59; PIP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>peak inspiratory pressure&#59; PEEP<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>positive end expiratory pressure&#59; PIF<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>peak inspiratory flow&#59; Vt<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>tidal volume&#46;</p>"
          "tablatextoimagen" => array:1 [
            0 => array:2 [
              "tabla" => array:1 [
                0 => """
                  <table border="0" frame="\n
                  \t\t\t\t\tvoid\n
                  \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td-with-role" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col">IPAP &#40;cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " colspan="3" align="center" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">15</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " colspan="3" align="center" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">25</th></tr><tr title="table-row"><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Heated circuit&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">IT&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">RP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">FP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">IT&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">RP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th><th class="td" title="\n
                  \t\t\t\t\ttable-head\n
                  \t\t\t\t  " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t" scope="col" style="border-bottom: 2px solid black">FP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td-with-role" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">PIP &#40;cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">14&#46;20<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;21<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">15&#46;82<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;26&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">15&#46;76<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;57&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">25&#46;68<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;62<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">26&#46;40<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;18&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">26&#46;36<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;20&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">PEEP &#40;cm<span class="elsevierStyleHsp" style=""></span>H<span class="elsevierStyleInf">2</span>O&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">4&#46;12<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;18<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">4&#46;86<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;40&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">4&#46;82<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;19&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">4&#46;99<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;28<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">5&#46;35<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;23<a class="elsevierStyleCrossRef" href="#tblfn0010"><span class="elsevierStyleSup">b</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">5&#46;14<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>0&#46;26<a class="elsevierStyleCrossRef" href="#tblfn0015"><span class="elsevierStyleSup">c</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">PIF &#40;mL&#47;min&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">29&#46;81<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>1&#46;57<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">38&#46;37<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>2&#46;66<a class="elsevierStyleCrossRef" href="#tblfn0010"><span class="elsevierStyleSup">b</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">40&#46;62<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>3&#46;10<a class="elsevierStyleCrossRef" href="#tblfn0015"><span class="elsevierStyleSup">c</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">65&#46;79<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>4&#46;76<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">76&#46;63<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>8&#46;18&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">76&#46;45<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>3&#46;01&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">Vt &#40;mL&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">183<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>12<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">205<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>17<a class="elsevierStyleCrossRef" href="#tblfn0010"><span class="elsevierStyleSup">b</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">250<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>36<a class="elsevierStyleCrossRef" href="#tblfn0015"><span class="elsevierStyleSup">c</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">485<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>24<a class="elsevierStyleCrossRef" href="#tblfn0005"><span class="elsevierStyleSup">a</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">531<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span><span class="elsevierStyleHsp" style=""></span>65<a class="elsevierStyleCrossRef" href="#tblfn0010"><span class="elsevierStyleSup">b</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="\n
                  \t\t\t\t\ttable-entry\n
                  \t\t\t\t  " align="char" valign="\n
                  \t\t\t\t\ttop\n
                  \t\t\t\t">570<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>53<a class="elsevierStyleCrossRef" href="#tblfn0015"><span class="elsevierStyleSup">c</span></a>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr></tbody></table>
                  """
              ]
              "imagenFichero" => array:1 [
                0 => "xTab2255487.png"
              ]
            ]
          ]
          "notaPie" => array:3 [
            0 => array:3 [
              "identificador" => "tblfn0005"
              "etiqueta" => "a"
              "nota" => "<p class="elsevierStyleNotepara" id="npar0005"><span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001 IT compared to RP and FP&#44; in each IPAP group&#46;</p>"
            ]
            1 => array:3 [
              "identificador" => "tblfn0010"
              "etiqueta" => "b"
              "nota" => "<p class="elsevierStyleNotepara" id="npar0010"><span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001 RP compared to IT and FP&#44; in each IPAP group&#46;</p>"
            ]
            2 => array:3 [
              "identificador" => "tblfn0015"
              "etiqueta" => "c"
              "nota" => "<p class="elsevierStyleNotepara" id="npar0015"><span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>&#46;001 FP compared to IT and RP&#44; in each IPAP group&#46;</p>"
            ]
          ]
        ]
        "descripcion" => array:1 [
          "en" => "<p id="spar0085" class="elsevierStyleSimplePara elsevierViewall">Ventilator variables values with different heated wired-circuits at different IPAP levels&#46; Data expressed as mean and standard deviation&#46;</p>"
        ]
      ]
      8 => array:5 [
        "identificador" => "fig0035"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => false
        "mostrarDisplay" => true
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "fx1.jpeg"
            "Alto" => 484
            "Ancho" => 1333
            "Tamanyo" => 83651
          ]
        ]
      ]
      9 => array:5 [
        "identificador" => "eq0005"
        "tipo" => "MULTIMEDIAFORMULA"
        "mostrarFloat" => false
        "mostrarDisplay" => true
        "Formula" => array:5 [
          "Matematica" => "SAH&#61;16&#46;451563&#8722;0&#46;731T&#43;0&#46;03987T2&#8201;&#8202;&#8202;&#40;mg&#8201;H2O&#47;L&#41;"
          "Fichero" => "STRIPIN_si1.jpeg"
          "Tamanyo" => 3389
          "Alto" => 17
          "Ancho" => 376
        ]
      ]
      10 => array:5 [
        "identificador" => "eq0010"
        "tipo" => "MULTIMEDIAFORMULA"
        "mostrarFloat" => false
        "mostrarDisplay" => true
        "Formula" => array:5 [
          "Matematica" => "AH&#61;SAH&#8727;HR100&#8201;&#8202;&#8202;&#40;mg&#8201;H2O&#47;L&#41;"
          "Fichero" => "STRIPIN_si2.jpeg"
          "Tamanyo" => 2316
          "Alto" => 32
          "Ancho" => 203
        ]
      ]
    ]
    "bibliografia" => array:2 [
      "titulo" => "References"
      "seccion" => array:1 [
        0 => array:2 [
          "identificador" => "bibs0015"
          "bibliografiaReferencia" => array:20 [
            0 => array:3 [
              "identificador" => "bib0105"
              "etiqueta" => "1"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "International Consensus Conferences in Intensive Care Medicine&#58; non-invasive positive pressure ventilation in acute respiratory failure&#46; Organised jointly by the American Thoracic Society&#44; the European Respiratory Society&#44; the European Society of Intensive Care Medicine&#44; and the Societe de Reanimation de Langue Francaise&#44; and approved by the ATS Board of Directors&#44; December 2000"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "T&#46;W&#46; Evans"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1007/s001340000721"
                      "Revista" => array:6 [
                        "tituloSerie" => "Intensive Care Med"
                        "fecha" => "2001"
                        "volumen" => "27"
                        "paginaInicial" => "166"
                        "paginaFinal" => "178"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/11280630"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            1 => array:3 [
              "identificador" => "bib0110"
              "etiqueta" => "2"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Noninvasive ventilation in acute cardiogenic pulmonary edema&#58; systematic review and meta-analysis"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "J&#46; Masip"
                            1 => "M&#46; Roque"
                            2 => "B&#46; Sanchez"
                            3 => "R&#46; Fernandez"
                            4 => "M&#46; Subirana"
                            5 => "J&#46;A&#46; Exposito"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1001/jama.294.24.3124"
                      "Revista" => array:6 [
                        "tituloSerie" => "JAMA"
                        "fecha" => "2005"
                        "volumen" => "294"
                        "paginaInicial" => "3124"
                        "paginaFinal" => "3130"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16380593"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            2 => array:3 [
              "identificador" => "bib0115"
              "etiqueta" => "3"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Heat and moisture exchangers and breathing filters"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "R&#46;M&#46; Hedley"
                            1 => "J&#46; Allt-Graham"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1093/bja/73.2.227"
                      "Revista" => array:6 [
                        "tituloSerie" => "Br J Anaesth"
                        "fecha" => "1994"
                        "volumen" => "73"
                        "paginaInicial" => "227"
                        "paginaFinal" => "236"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/7917741"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            3 => array:3 [
              "identificador" => "bib0120"
              "etiqueta" => "4"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Humidification during invasive and noninvasive mechanical ventilation&#58; 2012"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "R&#46;D&#46; Restrepo"
                            1 => "B&#46;K&#46; Walsh"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.4187/respcare.01766"
                      "Revista" => array:6 [
                        "tituloSerie" => "Respir Care"
                        "fecha" => "2012"
                        "volumen" => "57"
                        "paginaInicial" => "782"
                        "paginaFinal" => "788"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22546299"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            4 => array:3 [
              "identificador" => "bib0125"
              "etiqueta" => "5"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Is humidification always necessary during noninvasive ventilation in the hospital&#63;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "R&#46;D&#46; Branson"
                            1 => "M&#46;A&#46; Gentile"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Respir Care"
                        "fecha" => "2010"
                        "volumen" => "55"
                        "paginaInicial" => "209"
                        "paginaFinal" => "216"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/20105346"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            5 => array:3 [
              "identificador" => "bib0130"
              "etiqueta" => "6"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Active humidification with Boussignac CPAP&#58; in vitro study of a new method"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "J&#46;M&#46; Alonso-I&#241;igo"
                            1 => "A&#46; Almela"
                            2 => "A&#46; Albert"
                            3 => "J&#46;M&#46; Carratala"
                            4 => "M&#46;J&#46; Fas"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.4187/respcare.01959"
                      "Revista" => array:6 [
                        "tituloSerie" => "Respir Care"
                        "fecha" => "2013"
                        "volumen" => "58"
                        "paginaInicial" => "647"
                        "paginaFinal" => "654"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22906896"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            6 => array:3 [
              "identificador" => "bib0135"
              "etiqueta" => "7"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Water content of delivered gases during non-invasive ventilation in healthy subjects"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "F&#46; Lellouche"
                            1 => "S&#46;M&#46; Maggiore"
                            2 => "A&#46; Lyazidi"
                            3 => "N&#46; Deye"
                            4 => "S&#46; Taille"
                            5 => "L&#46; Brochard"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1007/s00134-009-1455-y"
                      "Revista" => array:6 [
                        "tituloSerie" => "Intensive Care Med"
                        "fecha" => "2009"
                        "volumen" => "35"
                        "paginaInicial" => "987"
                        "paginaFinal" => "995"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19294366"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            7 => array:3 [
              "identificador" => "bib0140"
              "etiqueta" => "8"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Patient&#8211;ventilator asynchrony during noninvasive ventilation&#46; A bench and clinical study"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "G&#46; Carteaux"
                            1 => "A&#46; Lyazidi"
                            2 => "A&#46; Cordoba-Izquierdo"
                            3 => "L&#46; Vignaux"
                            4 => "P&#46; Jolliet"
                            5 => "A&#46;W&#46; Thille"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1378/chest.11-2279"
                      "Revista" => array:6 [
                        "tituloSerie" => "Chest"
                        "fecha" => "2012"
                        "volumen" => "142"
                        "paginaInicial" => "367"
                        "paginaFinal" => "376"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/22406958"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            8 => array:3 [
              "identificador" => "bib0145"
              "etiqueta" => "9"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "A comparison of leak compensation in acute care ventilators during noninvasive and invasive ventilation&#58; a lung model study"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "J&#46; Oto"
                            1 => "C&#46;T&#46; Chenelle"
                            2 => "A&#46;D&#46; Marchese"
                            3 => "R&#46;M&#46; Kacmarek"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.4187/respcare.02466"
                      "Revista" => array:6 [
                        "tituloSerie" => "Respir Care"
                        "fecha" => "2013"
                        "volumen" => "58"
                        "paginaInicial" => "2027"
                        "paginaFinal" => "2037"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23696688"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            9 => array:3 [
              "identificador" => "bib0150"
              "etiqueta" => "10"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Influence of ambient air and ventilator output temperature on performances of heated-wire humidifiers"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Lellouche"
                            1 => "S&#46; Taille"
                            2 => "S&#46;M&#46; Maggiore"
                            3 => "S&#46; Qader"
                            4 => "E&#46; L&#8217;Her"
                            5 => "N&#46; Deye"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1164/rccm.200309-1245OC"
                      "Revista" => array:6 [
                        "tituloSerie" => "Am J Respir Crit Care Med"
                        "fecha" => "2004"
                        "volumen" => "170"
                        "paginaInicial" => "1073"
                        "paginaFinal" => "1079"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/15271695"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            10 => array:3 [
              "identificador" => "bib0155"
              "etiqueta" => "11"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Bedside evaluation of efficient airway humidification during mechanical ventilation of the critically ill"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "J&#46;D&#46; Ricard"
                            1 => "P&#46; Markowicz"
                            2 => "K&#46; Djedaini"
                            3 => "L&#46; Mier"
                            4 => "F&#46; Coste"
                            5 => "D&#46; Dreyfuss"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1378/chest.115.6.1646"
                      "Revista" => array:6 [
                        "tituloSerie" => "Chest"
                        "fecha" => "1999"
                        "volumen" => "115"
                        "paginaInicial" => "1646"
                        "paginaFinal" => "1652"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/10378563"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            11 => array:3 [
              "identificador" => "bib0160"
              "etiqueta" => "12"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Relationship between the humidity and the temperature of inspired gas and the function or airway mucosa"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "R&#46; Williams"
                            1 => "N&#46; Rankin"
                            2 => "T&#46; Smith"
                            3 => "D&#46; Galler"
                            4 => "P&#46; Seakins"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1097/00003246-199611000-00025"
                      "Revista" => array:6 [
                        "tituloSerie" => "Crit Care Med"
                        "fecha" => "1996"
                        "volumen" => "24"
                        "paginaInicial" => "1920"
                        "paginaFinal" => "1929"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/8917046"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            12 => array:3 [
              "identificador" => "bib0165"
              "etiqueta" => "13"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "The effect of inlet gas temperatures on heated humidifier performance"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "B&#46;G&#46; Carter"
                            1 => "N&#46; Whittington"
                            2 => "M&#46; Hochmann"
                            3 => "A&#46; Osborne"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1089/08942680252908539"
                      "Revista" => array:6 [
                        "tituloSerie" => "J Aerosol Med"
                        "fecha" => "2002"
                        "volumen" => "15"
                        "paginaInicial" => "7"
                        "paginaFinal" => "13"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/12006141"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            13 => array:3 [
              "identificador" => "bib0170"
              "etiqueta" => "14"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Temperature of gas delivered from ventilators"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "Y&#46; Chikata"
                            1 => "M&#46; Izawa"
                            2 => "H&#46; Imanaka"
                            3 => "M&#46; Okuda"
                            4 => "M&#46; Nishimura"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1186/2052-0492-1-16"
                      "Revista" => array:5 [
                        "tituloSerie" => "J Intensive Care"
                        "fecha" => "2013"
                        "volumen" => "1"
                        "paginaInicial" => "16"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/25960876"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            14 => array:3 [
              "identificador" => "bib0175"
              "etiqueta" => "15"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Respiratory system resistance"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "A&#46;B&#46; Lumb"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "LibroEditado" => array:6 [
                        "editores" => "A&#46;B&#46;Lumb"
                        "titulo" => "Nunn&#39;s applied respiratory physiology"
                        "paginaInicial" => "43"
                        "paginaFinal" => "59"
                        "edicion" => "7th ed&#46;"
                        "serieFecha" => "2010"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            15 => array:3 [
              "identificador" => "bib0180"
              "etiqueta" => "16"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "A bench study of 2 ventilator circuits during helmet noninvasive ventilation"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "G&#46; Ferrone"
                            1 => "F&#46; Cipriani"
                            2 => "G&#46; Spinazzola"
                            3 => "O&#46; Festa"
                            4 => "A&#46; Arcangeli"
                            5 => "R&#46; Proietti"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.4187/respcare.02060"
                      "Revista" => array:6 [
                        "tituloSerie" => "Respir Care"
                        "fecha" => "2013"
                        "volumen" => "58"
                        "paginaInicial" => "1474"
                        "paginaFinal" => "1481"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/23431311"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            16 => array:3 [
              "identificador" => "bib0185"
              "etiqueta" => "17"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Patient&#8211;ventilator asynchrony during non-invasive ventilation for acute respiratory failure&#58; a multicenter study"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "L&#46; Vignaux"
                            1 => "F&#46; Vargas"
                            2 => "J&#46; Roeseler"
                            3 => "D&#46; Tassaux"
                            4 => "A&#46;W&#46; Thille"
                            5 => "M&#46;P&#46; Kossowsky"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1007/s00134-009-1416-5"
                      "Revista" => array:6 [
                        "tituloSerie" => "Intensive Care Med"
                        "fecha" => "2009"
                        "volumen" => "35"
                        "paginaInicial" => "840"
                        "paginaFinal" => "846"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/19183949"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            17 => array:3 [
              "identificador" => "bib0190"
              "etiqueta" => "18"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Patient&#8211;ventilator interaction and inspiratory effort during pressure support ventilation in patients with different pathologies"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "S&#46; Nava"
                            1 => "C&#46; Bruschi"
                            2 => "C&#46; Fracchia"
                            3 => "A&#46; Braschi"
                            4 => "F&#46; Rubini"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1183/09031936.97.10010177"
                      "Revista" => array:6 [
                        "tituloSerie" => "Eur Respir J"
                        "fecha" => "1997"
                        "volumen" => "10"
                        "paginaInicial" => "177"
                        "paginaFinal" => "183"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/9032512"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            18 => array:3 [
              "identificador" => "bib0195"
              "etiqueta" => "19"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "The effect of breath termination criterion on breathing patterns and the work of breathing during pressure support ventilation"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => true
                          "autores" => array:6 [
                            0 => "H&#46; Tokioka"
                            1 => "T&#46; Tanaka"
                            2 => "T&#46; Ishizu"
                            3 => "T&#46; Fukushima"
                            4 => "T&#46; Iwaki"
                            5 => "Y&#46; Nakamura"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1097/00000539-200101000-00031"
                      "Revista" => array:6 [
                        "tituloSerie" => "Anesth Analg"
                        "fecha" => "2001"
                        "volumen" => "92"
                        "paginaInicial" => "161"
                        "paginaFinal" => "165"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/11133620"
                            "web" => "Medline"
                          ]
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
            19 => array:3 [
              "identificador" => "bib0200"
              "etiqueta" => "20"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Patient&#8211;ventilator asynchrony during assisted mechanical ventilation"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:5 [
                            0 => "A&#46;W&#46; Thille"
                            1 => "P&#46; Rodriguez"
                            2 => "B&#46; Cabello"
                            3 => "F&#46; Lellouche"
                            4 => "L&#46; Brochard"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:2 [
                      "doi" => "10.1007/s00134-006-0301-8"
                      "Revista" => array:7 [
                        "tituloSerie" => "Intensive Care Med"
                        "fecha" => "2006"
                        "volumen" => "32"
                        "paginaInicial" => "1515"
                        "paginaFinal" => "1522"
                        "link" => array:1 [
                          0 => array:2 [
                            "url" => "https://www.ncbi.nlm.nih.gov/pubmed/16896854"
                            "web" => "Medline"
                          ]
                        ]
                        "itemHostRev" => array:3 [
                          "pii" => "S074937971630438X"
                          "estado" => "S300"
                          "issn" => "07493797"
                        ]
                      ]
                    ]
                  ]
                ]
              ]
            ]
          ]
        ]
      ]
    ]
  ]
  "idiomaDefecto" => "en"
  "url" => "/03002896/0000005600000001/v5_202003060711/S0300289619302364/v5_202003060711/en/main.assets"
  "Apartado" => array:4 [
    "identificador" => "45423"
    "tipo" => "SECCION"
    "es" => array:2 [
      "titulo" => "Original Articles / Originales"
      "idiomaDefecto" => true
    ]
    "idiomaDefecto" => "es"
  ]
  "PDF" => "https://static.elsevier.es/multimedia/03002896/0000005600000001/v5_202003060711/S0300289619302364/v5_202003060711/en/main.pdf?idApp=UINPBA00003Z&text.app=https://archbronconeumol.org/"
  "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0300289619302364?idApp=UINPBA00003Z"
]
Share
Journal Information
Vol. 56. Issue 1.
Pages 28-34 (January 2020)
Share
Share
Download PDF
More article options
Visits
3513
Vol. 56. Issue 1.
Pages 28-34 (January 2020)
Original Article
Full text access
Effects on Humidification and Ventilatory Parameters of Three Single-limb Heated-wired Circuits for Non-invasive Ventilation: A Bench Study
Efectos sobre la humidificación y los parámetros de ventilación de 3 circuitos de ramal único con cable calefactado para la ventilación mecánica no invasiva: estudio experimental
Visits
3513
Jose M. Alonso-Iñigoa,
Corresponding author
jmalonso@me.com

Corresponding author.
, María J. Fasb, Alejandro Albertc, Abel Dolzd, José M. Carrataláe, Salvador Díaz-Lobatof
a Department of Anesthesiology, Critical Care and Pain Medicine, Hospital Universitari i Politècnic La Fe, Valencia, Spain
b Department of Hospital Managing, Hospital de Manises, Manises, Valencia, Spain
c Emergency Department, Hospital General Universitario de Alicante, Alicante, Spain
d Emergency Department, Hospital de Sagunto, Sagunto, Valencia, Spain
e Short-stay Medical Unit, Emergency Department, Hospital General Universitario de Alicante, Alicante, Spain
f Department of Pneumology, Hospital Universitario Ramón y Cajal, Madrid, Spain
This item has received
Article information
Abstract
Full Text
Bibliography
Download PDF
Statistics
Figures (7)
Show moreShow less
Tables (2)
Table 1. Absolute humidity (in mgH2O/L) of the medical gas with different heated wired-circuits at different FiO2 and IPAP levels. Data expressed as mean and standard deviation.
Table 2. Ventilator variables values with different heated wired-circuits at different IPAP levels. Data expressed as mean and standard deviation.
Show moreShow less
Abstract
Background

The objective of this study was to evaluate the effects of three single-limb heated wired circuits (SLHWC) for NIV, on ventilatory parameters and humidification performance in a simulation lung model.

Methods

Three SLHWC compatible with the MR-850 Heated Humidifier (HH) (Fisher & Paykel, Auckland, New Zealand) were tested: RT-319 (FP) (Fisher & Paykel, Auckland, New Zealand), Respironics 1045770 (RP) (DEAS, Castel Bolognese, Italy) and Intersurgical B/SYS 5809001 (IT) (Intersurgical, Wokingham, UK). A Bipap Vision ventilator (Philips Respironics, Murrysville, PA, USA) in pressure control ventilation (PCV) connected to a test lung was used for simulation. Each SHWC performance was evaluated in four ventilatory conditions: IPAP of 15cmH2O with FiO2 0.3 and 1, respectively; and, IPAP of 25cmH2O with FiO2 0.3 and 1, respectively. EPAP was set at 5cmH2O. Hygrometric and ventilatory measurements including: relative humidity (RH), temperature (T), Pplat, PIP, PEEP, peak inspiratory flow (PIF), and tidal volume (Vt) were measured.

Results

In each FiO2 group absolute humidity (AH) was similar with FP regardless of the IPAP level employed compared to IT and RP (P<.001). Except for RP at FiO2 0.3, AH increased significantly in IT and RP groups as IPAP increased (P<.001). PIP, Pplat, PEEP, PIF, and Vt values were significantly higher with FP and RP in each FiO2 group compared to IT (P<.001).

Conclusions

Humidification performance varied significantly among the three circuits, being FP the only one able to maintain stable AH values during the study with no influence on ventilatory parameters.

Keywords:
Heated humidifiers
Respiratory mechanics
Humidification
Non-invasive ventilation
Mechanical ventilation
Resumen
Introducción

El objetivo de este estudio fue evaluar los efectos de 3 circuitos de ramal único (SLHWC) para la ventilación mecánica no invasiva (VNI) en los parámetros de ventilación y la humidificación en un modelo de simulación pulmonar.

Métodos

Se evaluaron 3 SLHWC compatibles con el humidificador calefactado MR-850 (HH) (Fisher & Paykel, Auckland, Nueva Zelanda): RT-319 (FP) (Fisher & Paykel, Auckland, Nueva Zelanda), Respironics 1045770 (RP) (DEAS, Castel Bolognese, Italia) y Intersurgical B/SYS 5809001 (IT) (Intersurgical, Wokingham, Reino Unido). Para la simulación se empleó un ventilador Bipap Vision (Philips Respironics, Murrysville, PA, EE. UU.) con ventilación controlada por presión (PCV) conectado a un simulador pulmonar. El rendimiento de cada SHWC se evaluó en 4 condiciones ventilatorias: IPAP de 15cmH2O con FiO2 igual a 0,3 o igual a 1; IPAP de 25cmH2O con FiO2 igual a 0,3 o igual a 1. La EPAP se estableció en 5cmH2O. Las medidas ventilatorias e higrométricas incluyeron: humedad relativa (HR) humedad absoluta (AH), temperature (T), Pplat, PIP, PEEP, pico de flujo inspiratorio (PIF) y volumen tidal (Vt).

Resultados

Para cada grupo de FiO2 FP detectó valores similares de humedad absoluta (HA) en comparación con IT y RP (p<0,001), independientemente del nivel IPAP utilizado. Se registró un incremento significativo de la HA en todos los grupos medidos con IT y RP conforme aumentaron los valores de IPAP (p<0,001), excepto en el grupo de FiO2, igual a 0,3 medido con RP. Los valores de PIP, Pplat, PEEP, PIF y Vt resultaron significativamente más elevados con FP y RP en cada grupo FiO2 en comparación con IT (p<0,001).

Conclusiones

La evaluación de la humidificación varió significativamente entre los 3 circuitos, siendo FP el único capaz de mantener estables los valores de HA durante el estudio sin influencia alguna de los parámetros ventilatorios.

Palabras clave:
Humidificadores calefactados
Mecánica respiratoria
Humidificación
Ventilación no invasiva
Ventilación mecánica
Full Text
Introduction

Non-invasive ventilation (NIV) is currently the treatment of choice in various forms of acute respiratory failure.1,2 This therapy involves the use of pressurized cold and dry medical gases with the possibility of signs of dryness in the respiratory tract. The effects of the absence of humidification of inspired gases can on the one hand cause the rejection of this technique due to discomfort and, on the other hand, the possibility of atelectasis appearing as a result of respiratory secretion dryness.3 The American Association for Respiratory Care (AARC) recommends active humidification for NIV, as it may improve adherence and comfort.4 Despite the benefits of conditioned gas administration, there is currently no clear recommendation regarding the type of heated humidifier (HH), or the humidification values to be applied during NIV treatment in acute respiratory failure.5 There are many conditions that can affect humidification performance during NIV. The use of different NIV heated circuits and humidification chambers may influence the temperature and humidity of the gases supplied to the patient.6 The ventilatory system can also affect the performance of the HH in relation to the flow generator used.7 Most of the dedicated NIV ventilators are turbine-driven with a better performance in terms of patient–ventilator synchrony and leak compensation compared to intensive care (ICU) ventilators.8,9 Some studies have shown that these turbine-ventilators deliver higher ventilator output temperatures leading to low humidification values compared to ICU ventilators.7,10

There are no current studies about the interaction of HH on ventilatory variables during NIV with turbine ventilators. The use of different single limb circuits may influence the inspiratory flow rate, due to turbulent flow generation inside the circuit. This can affect the amount of gas delivered to the patient and produce asynchronies. The aim of this study is to evaluate the effects of three single-limb heated wired circuits (SHWC) for NIV, on ventilatory parameters and humidification performance in a simulation lung model.

MethodsInstalling the system

For the experiment, three SHWC, with its specific humidification chamber, were used: RT-319 (FP) (Fisher & Paykel, Auckland, New Zealand), Respironics 1045770 (RP) (DEAS, Castel Bolognese, Italy) and Intersurgical B/SYS 5809001 (IT) (Intersurgical, Wokingham, UK). FP circuit is designed specifically for use with Fisher & Paykel Healthcare humidification systems. It has a 25-mm inner diameter with a spiral heater wire inside to reduce condensate in varying environments, and to provide a low resistance to flow. RP and IT are circuits with an internal diameter of 22mm. The difference between them is that the IT has a linear heating wire inside, while the RP integrates the heater wires into the circuit wall. All of them are compatible with the MR-850 Heated Humidifier (HH) (Fisher & Paykel, Auckland, New Zealand) (Fig. 1). The MR-850 uses a heated pass-over system to add water vapor to the gas flow and has and automatic flow compensation algorithm, able to maintain constant humidity, recording only minor variations related to changes in the gas flow employed.10 All the circuits had an exhalation port piece (Fig. 2).

Fig. 1.

Heated wired-circuits.

(0.22MB).
Fig. 2.

Diagram of experimental setting.

(0.16MB).

For simulation, we used a Bipap Vision ventilator (Philips Respironics, Murrysville, PA, USA) connected to a test lung simulator (Adult/Pediatric Demo Lung, Ingmar Medical, Pittsburgh, USA). The lung simulator consists in two-bellows system with an adjustable resistance and compliance, and a standard 15mm ISO connector. We tested a low compliance model with the following simulation settings: compliance, 20mL/cmH2O; and respiratory resistance, 15cmH2O/L/s. A capacitive hygrometer (HygroPalm, Rotronic AG, Bassersdorf, Switzerland) with a high-performance linear probe (HC2-C05, Rotronic AG, Bassersdorf, Switzerland) was used to measure temperature and relative humidity. This system has a very low dead time and is accurate (humidity range: 0 to 100%, temperature range: −40 to 85°C), recording an error of 0°C and no variations over time.11 At the end of each measurement, the tip of the capacitive hygrometer was dried to avoid any possible measurement error. The probe was placed in the distal part of the tube before connecting it to the test lung. During the experiment, we examined relative ambient humidity and temperature using an additional hygrometer (HygroPalm, Rotronic AG, Bassersdorf, Switzerland) connected to a cylindrical probe (HC2-S, Rotronic AG, Bassersdorf, Switzerland, humidity range: 0 to 100%, temperature range: −50 to 100°C). Hygrometric data were stored on a computer using specific software (Rotronic HW4 version 2.3.0.21699, Bassersdorf, Switzerland) to be later analyzed and calculated. Ventilatory measurements were continuously recorded with a respiratory mechanics monitor (FluxMed GrT, MBMed, Buenos Aires, Argentina) and analyzed with a specific software. (FluxView Software, MBMed, Buenos Aires, Argentina) (Fig. 2).

Measurements

The study was conducted under conditions of stable environmental temperature and humidity (20°C and 50% relative humidity), which were measured throughout the experiment as a means of control. Measurements of relative environmental humidity and temperature were taken every 5min throughout the various phases of the study. The ventilator was set in pressure-controlled ventilation mode (PCV) with a respiratory rate (RR) of 12breaths/min, rise time (RS) 0.1s, and an expiratory positive airway pressure (EPAP) of 5cmH2O. For each circuit, an exhalation port test was performed to ensure the accuracy of estimated tidal volume and minute ventilation readings, according to manufacturer's recommendation. Each SHWC performance was evaluated in four ventilatory conditions: inspiratory positive airway pressure (IPAP) of 15cmH2O with FiO2 0.3 and 1, respectively; and, IPAP of 25cmH2O with FiO2 0.3 and 1, respectively (Fig. 3). Before modifying ventilator settings, the system was stabilized to achieve the target temperature values of the HH. Under these conditions, we tested the MR using the active compensation algorithm (software 722) and NIV mode. In each of the phases mentioned above, hygrometric and ventilatory measurements including: relative humidity (RH), temperature (T), peak inspiratory pressure (PIP), positive end expiratory pressure (PEEP), peak inspiratory flow (PIF), and tidal volume (Vt) were measured.

Fig. 3.

Study protocol. One hundred and twenty measurements were taken in each experimental scenario.

(0.14MB).

We obtained 120 measurements (one measurement each 30s for 60min continuously) in each experimental situation. A total of 1440 measurements were taken. In order to calculate absolute humidity, the following formulae were used11:

where T is the probe temperature in degrees Celsius, RH is relative humidity, AH is absolute humidity and SAH is saturated absolute humidity, both of which are expressed in mgH2O/L.

Statistics

Statistical analysis was performed using IBM SPSS 21 software. Descriptive statistics were obtained for all values with the mean and standard deviation. In order to analyze the differences between groups analysis of variance (ANOVA) was used, while the Bonferroni test was employed for multiple comparisons. A Kolmogorov–Smirnov analysis was used to test normality. A P-value of <.05 was considered statistically significant.

ResultsHygrometric variables

We obtained a total of 144 environmental measurements. Absolute and relative humidity and temperature remained stable throughout the experiment (24.1±0.5°C ambient temperature, 51.3±3.2% ambient RH, 11.3±0.8mgH2O/L ambient AH).

Absolute humidity for the four study groups with different FiO2 and IPAP levels is shown in Table 1. AH was significantly lower in FP compared to RP and IT, regardless of the FiO2 and IPAP level selected (P<.001) (Table 1). In RP and IT groups AH values were significantly higher with a FiO2 of 1 at IPAP level 25cmH2O compared to those at 15cmH2O (P<.001). Fig. 4 shows the evolution of AH with IPAP changes at different FiO2 levels to evaluate the ability of each SHWC to maintain a constant range of values. AH values obtained with FP were similar regardless of the IPAP level employed. In the case of IT and RP, AH values were significantly different for a selected IPAP level of 25cmH2O compared to 15cmH2O (P<.001).

Table 1.

Absolute humidity (in mgH2O/L) of the medical gas with different heated wired-circuits at different FiO2 and IPAP levels. Data expressed as mean and standard deviation.

Heated wired circuits  FiO2 0.3FiO2 1
  IPAP 15  IPAP 25  IPAP 15  IPAP 25 
FP  29.52±2.23+  28.97±1.40+  29.14±0.37+  29.20±1.19+ 
RP  30.84±1.76*  22.68±5.82  30.44±2.45*  32.00±2.55 
IT  31.48±3.49*,#  32.86±1.07#  30.68±1.68*  33.10±3.32 

All data in each FiO2 group was significantly different (P<.001) except for those marked with *, +, #. Key: IPAP=Inspiratory Positive Airway Pressure; FP=Fisher & Paykel RT-319; RP=Respironics 1045770; IT=Intersurgical B/SYS 5809001.

Fig. 4.

Evolution of absolute humidity (AH) following a change in IPAP levels at different FiO2. Data expressed as means and CI 95%. *P<.001, IT at IPAP 25 compared to 15; +P<.001, RP at IPAP 25 compared to 15. Key: FP=Fisher & Paykel RT-319; RP=Respironics 1045770; IT=Intersurgical B/SYS 5809001.

(0.08MB).

Relative humidity was significantly lower in FP compared to RP and IT (P<.001), except for RP with FiO2 of 0.3 at IPAP level of 25cmH2O (P<.001) (Fig. 5). In the IT group, RH values increased significantly as the IPAP increased regardless of the FiO2 applied (P<.001). The opposite was observed with the FP, with a significant decreased in RH as the IPAP increased with a FiO2 of 0.3 (P<.001). The RH values in RP were significantly higher at IPAP level of 25cmH2O compared to 15cmH2O, when a FiO2 of 1 was set (P<.001).

Fig. 5.

Evolution of relative humidity (RH) following a change in IPAP levels at different FiO2. Data expressed as means and CI 95%. P<.001 for each FiO2 study group between different IPAP levels, except those marked with * in the same study group. Key: FP=Fisher & Paykel RT-319; RP=Respironics 1045770; IT=Intersurgical B/SYS 5809001.

(0.05MB).

Fig. 6 displays the behaviour of temperature. In all of the study groups, the temperature raised significantly when the IPAP level increased from 15 to 25cmH2O, regardless of FiO2 selected (P<.001), except for RP group at FiO2 of 0.3 with IPAP of 25cmH2O, where temperature decreased significantly (P<.001).

Fig. 6.

Evolution of temperature (T) following a change in IPAP levels at different FiO2. Data expressed as means and CI 95%. P<.001 for each FiO2 study group between different IPAP levels. Key: FP=Fisher & Paykel RT-319; RP=Respironics 1045770; IT=Intersurgical B/SYS 5809001.

(0.07MB).
Ventilatory variables

Ventilatory measurements are shown in Table 2. All measurements in the IT group were significantly lower compared to RP and FP (P<.001). At IPAP level of 15cmH2O, a significant increase in PIF and Vt was observed in the FP group compared to RP (P<.001). Measurements obtained at IPAP level of 25cmH2O were similar between FP and RP, except for Vt and PEEP with higher values in the FP and RP, respectively (P<.001).

Table 2.

Ventilator variables values with different heated wired-circuits at different IPAP levels. Data expressed as mean and standard deviation.

IPAP (cmH2O)  1525
Heated circuit  IT  RP  FP  IT  RP  FP 
PIP (cmH2O)  14.20±0.21a  15.82±0.26  15.76±0.57  25.68±0.62a  26.40±0.18  26.36±0.20 
PEEP (cmH2O)  4.12±0.18a  4.86±0.40  4.82±0.19  4.99±0.28a  5.35±0.23b  5.14±0.26c 
PIF (mL/min)  29.81±1.57a  38.37±2.66b  40.62±3.10c  65.79±4.76a  76.63±8.18  76.45±3.01 
Vt (mL)  183±12a  205±17b  250±36c  485±24a  531±65b  570±53c 

Key: IPAP=Inspiratory Positive Airway Pressure; FP=Fisher & Paykel RT-319; RP=Respironics 1045770; IT=Intersurgical B/SYS 5809001; PIP=peak inspiratory pressure; PEEP=positive end expiratory pressure; PIF=peak inspiratory flow; Vt=tidal volume.

a

P<.001 IT compared to RP and FP, in each IPAP group.

b

P<.001 RP compared to IT and FP, in each IPAP group.

c

P<.001 FP compared to IT and RP, in each IPAP group.

DiscussionHeater humidifier performance

During NIV, the absence of medical gas humidification may cause dryness in the respiratory tract. The ideal humidification value to preserve the function of the mucociliary system is 44mgH2O/L, measured after the carina.12 Although, upper airways are not bypassed during NIV, high-flow from turbine-driven ventilators can make physiological gas humidification less effective. These data suggest that the use of humidification systems to condition gas during NIV may be beneficial to prevent respiratory complications.

The performance of the HH can be influenced by several factors, but the main ones are room temperature and gas temperature before passing through the heating chamber.10 Differences in ambient conditions, HH, respiratory circuit, ventilator, and wall gas temperature can influence on the humidity and temperature of the gases delivered to the patient.7,10,13,14 In our study we tested in similar ambient conditions the influence of three different SHWC on MR-850 HH automatic humidity compensation algorithm performance, using a turbine-driven NIV ventilator. Although, the FP circuit had the lowest AH values of the three circuits evaluated, it was able to maintain constant AH values, recording only minor variations related to changes in the IPAP level employed, with no influence from the FiO2 used. In the case of IT and RP, humidification values varied in relation to the IPAP level used, being higher as the IPAP increased, regardless of the FiO2 selected (Fig. 4). One explanation to these results are the differences in the type of chamber and the different heated wired systems between the three circuits. The MR-850 HH in non-invasive mode is programmed to generate theoretical values of absolute humidity of 32mgH2O/L regardless of changes in flow, FiO2 level and, ventilator outlet temperature. This is possible due to the automatic humidity compensation mode that was developed by the manufacturer to optimized HH performance. When the automatic mode is selected the humidifier calculates the power required to adequately humidify the gas flow through the chamber, providing constant humidification values. The humidifier monitors the temperature and gas flow at the chamber outlet with the chamber probe, and the limb temperature with the distal probe. The system controls the amount of power delivered to the heater plate, in order to maintain the chamber's set values of humidity and temperature. In addition, the circuit is heated to achieve a positive temperature gradient of 3°C at the end of the limb. This temperature gradient causes the RH to drop from 100% to 80%, maintaining the same amount of AH and avoiding condensation between the end limb and the mask. For an optimal system performance, it is necessary that the HH recognizes the type of circuit and the humidification chamber used, in order to adjust the amount of energy necessary to produce humidity in the range of values of the compensation algorithm. In the case of FP, the system performed more stable, because the HH was able to automatically recognize the circuit. The expected RH values with the FP circuit were around 80%, as a result of increasing the temperature of the limb in order to avoid circuit condensation (Fig. 5). In the case of IT and RP, RH values were higher showing that the MR-850 automatic compensation mode did not perform as well as with the FP circuit. Although AH with FP were slightly lower than the theoretical values, those were relatively constant regardless of IPAP and FiO2 levels. It is interesting to note that in the case of RP there was a sudden decrease with IPAP level of 25 at FiO2 of 0.3, with a mean AH values of 22.68±5.82mgH2O/L. This can be due to a malfunction of the proximal temperature sensors or a faulty connection between the sensor and the tube, leading to a decrease in the amount of power delivered to the heater plate, with the result of lower humidification values.

Ventilator variables

The type of respiratory circuit can influence in the amount of gas delivered to the patient. The flow of gas through a tube depends on one hand on the pressure exerted, and on the other hand on the resistance of the tube. In the present study we evaluated three circuits with different resistance to flow. In the case of IT we observed a significant decrease on PIF, Vt and PIP compared to the other two circuits evaluated, in all the experimental conditions. These results can be explained by the presence of a linear wire inside the IT tube that can increase the turbulent flow inside the tube. The precise relationship between pressure gradient and flow rate depends on the nature of the flow which can be laminar, turbulent or a mixture of the two.15 Situations of high flow rates with irregular tubes result in a breakdown of the orderly laminar flow, with an irregular movement superimposed on the general progression along the tube, creating turbulent flow. In mechanical ventilation, with constant gas viscosity, the major determinant of turbulent flow is the inner diameter of the tube so, factors that affect this diameter can influence in the performance of the ventilator. The linear wire of the IT circuit can generate frictional forces between the gas and the tube wire leading to turbulent flow and making the inner diameter irregular. In the case of FP, the higher inner diameter and the spiral heater wire make the circuit less resistant to flow generating more flow with the same driving pressure compared to IT. The same occurs with the RP that integrates the wire in the tube wall, allowing a smooth surface for the gas to flow, and decreasing the generation of turbulent flow.

In a recent bench study, Ferrone et al. evaluated two ventilator circuits during helmet NIV: a double limb circuit (with one inspiratory and one expiratory line) and a standard circuit (a Y-piece connected only to one side of the helmet, closing the other side).16 They concluded that, using a standard circuit, both the inspiratory and the expiratory flows were forced to pass through the Y-piece of the circuit, probably generating turbulence that may increase resistances inside the passage, thus inducing alterations in patient–ventilator interaction. These results highlight the effects of ventilator circuits on respiratory mechanics.

The differences in flow rate between the three circuits observed in our study can influence in clinical practice specially in the presence of patient–ventilator asynchrony. Vignaux et al. demonstrated that asynchronies are common during NIV.17 They reported an incidence of auto-triggering of 13%, and delayed cycling of 23% in multicenter study of patients with acute respiratory failure treated with NIV. Patient–ventilator asynchrony can significantly increase the work of breathing,18,19 and a high incidence of patient–ventilator asynchrony is associated with a longer duration of mechanical ventilation.20 In order to minimized this problem, manufactures have developed dedicated NIV ventilators, particularly oriented towards leakage management and comfort. Some bench studies have observed that dedicated turbine-driven NIV ventilators allow a better patient–ventilator synchrony than ICU and transport ventilators.8,9 The results our study suggest that the type of humidification circuit, beyond the ventilatory settings and leak compensation algorithms, can influence the flow and volume delivered to the patient. In our study, FP and RP circuits have better flow performance compared to IT. The linear wire jointly with an inner diameter of 22mm in the IT circuit may generate turbulence flow specially in situations of increase flow demand or leak compensation, making the ventilation less effective. Due to the use of a passive lung simulator it is not possible to infer directly from the results of the study the possibility of generating flow asynchronies. However, the differences observed in the peak inspiratory flow between the different circuits, with a fixed rise time, give an idea that the behaviour of the inspiratory flow is different as a consequence of variations in the internal diameter of the circuits. The fact that one of the circuits has a greater resistance to flow could influence the synchronization, even if the patient did not present a high inspiratory effort.

Limitations

Bearing in mind that this is a pilot study that was performed under ideal conditions, the hygrometric and respiratory values obtained may be different to those obtained in real conditions. Moreover, we evaluated respiratory mechanics in a continuous mandatory ventilation model, and the results can differ from those obtained either in a spontaneous ventilation model or with patients. It is interesting to note that we evaluated normal ventilatory conditions with a RR of 12, that is not usual in patients with respiratory failure treated with NIV, and this can limit our results when extrapolating them in real conditions. However, we think that in clinical conditions the differences between the three circuits, in terms of ventilatory parameters, would be the same, although it would be necessary to confirm this point with clinical studies. Other limitation is related to the ventilator use in our study. This ventilator does not identify the resistances and compliance of the circuit. Newer ventilators can calibrate the resistances and compliance of the circuit and therefore modify the pressurization according to these. This fact could limit the differences in the values identified for each circuit if we had evaluated such type of ventilators.

In our study, we did not evaluate the effect of the nasopharyngeal conditioning system on temperature and humidity, which in real terms during NIV partially contributes to conditioning inspired gas. It is important to mention that ventilatory parameters measurements in our study were obtained under ideal conditions without leaks and may therefore differ to those obtained in clinical practice. It would be necessary to conduct clinical studies to ascertain the impact of heated circuits in patient's respiratory mechanics and asynchronies generation.

Conclusions

This study is the first to undertake an in vitro evaluation of humidification and respiratory mechanics performance of three different SHWC. From the analysis of the results it can be seen that the type of circuit used, influences both humidification values and ventilatory variables. The FP circuit was the most reliable in terms of two factors combined: stable humidification values independently from changes in ventilator settings and, low resistance to flow tested with the BiPAP Vision compared to the other two circuits. This study suggests that heated circuits can affect humidification and ventilator performance.

Funding

This study was conducted at Centro de Simulación Clínica Avanzada (CESIMAV), Meliana (Spain) and was supported by institutional funds.

Conflict of interests

The authors declare no conflict of interests.

References
[1]
T.W. Evans.
International Consensus Conferences in Intensive Care Medicine: non-invasive positive pressure ventilation in acute respiratory failure. Organised jointly by the American Thoracic Society, the European Respiratory Society, the European Society of Intensive Care Medicine, and the Societe de Reanimation de Langue Francaise, and approved by the ATS Board of Directors, December 2000.
Intensive Care Med, 27 (2001), pp. 166-178
[2]
J. Masip, M. Roque, B. Sanchez, R. Fernandez, M. Subirana, J.A. Exposito.
Noninvasive ventilation in acute cardiogenic pulmonary edema: systematic review and meta-analysis.
JAMA, 294 (2005), pp. 3124-3130
[3]
R.M. Hedley, J. Allt-Graham.
Heat and moisture exchangers and breathing filters.
Br J Anaesth, 73 (1994), pp. 227-236
[4]
R.D. Restrepo, B.K. Walsh.
Humidification during invasive and noninvasive mechanical ventilation: 2012.
Respir Care, 57 (2012), pp. 782-788
[5]
R.D. Branson, M.A. Gentile.
Is humidification always necessary during noninvasive ventilation in the hospital?.
Respir Care, 55 (2010), pp. 209-216
[6]
J.M. Alonso-Iñigo, A. Almela, A. Albert, J.M. Carratala, M.J. Fas.
Active humidification with Boussignac CPAP: in vitro study of a new method.
Respir Care, 58 (2013), pp. 647-654
[7]
F. Lellouche, S.M. Maggiore, A. Lyazidi, N. Deye, S. Taille, L. Brochard.
Water content of delivered gases during non-invasive ventilation in healthy subjects.
Intensive Care Med, 35 (2009), pp. 987-995
[8]
G. Carteaux, A. Lyazidi, A. Cordoba-Izquierdo, L. Vignaux, P. Jolliet, A.W. Thille, et al.
Patient–ventilator asynchrony during noninvasive ventilation. A bench and clinical study.
Chest, 142 (2012), pp. 367-376
[9]
J. Oto, C.T. Chenelle, A.D. Marchese, R.M. Kacmarek.
A comparison of leak compensation in acute care ventilators during noninvasive and invasive ventilation: a lung model study.
Respir Care, 58 (2013), pp. 2027-2037
[10]
L. Lellouche, S. Taille, S.M. Maggiore, S. Qader, E. L’Her, N. Deye, et al.
Influence of ambient air and ventilator output temperature on performances of heated-wire humidifiers.
Am J Respir Crit Care Med, 170 (2004), pp. 1073-1079
[11]
J.D. Ricard, P. Markowicz, K. Djedaini, L. Mier, F. Coste, D. Dreyfuss.
Bedside evaluation of efficient airway humidification during mechanical ventilation of the critically ill.
Chest, 115 (1999), pp. 1646-1652
[12]
R. Williams, N. Rankin, T. Smith, D. Galler, P. Seakins.
Relationship between the humidity and the temperature of inspired gas and the function or airway mucosa.
Crit Care Med, 24 (1996), pp. 1920-1929
[13]
B.G. Carter, N. Whittington, M. Hochmann, A. Osborne.
The effect of inlet gas temperatures on heated humidifier performance.
J Aerosol Med, 15 (2002), pp. 7-13
[14]
Y. Chikata, M. Izawa, H. Imanaka, M. Okuda, M. Nishimura.
Temperature of gas delivered from ventilators.
J Intensive Care, 1 (2013), pp. 16
[15]
A.B. Lumb.
Respiratory system resistance.
Nunn's applied respiratory physiology, 7th ed., pp. 43-59
[16]
G. Ferrone, F. Cipriani, G. Spinazzola, O. Festa, A. Arcangeli, R. Proietti, et al.
A bench study of 2 ventilator circuits during helmet noninvasive ventilation.
Respir Care, 58 (2013), pp. 1474-1481
[17]
L. Vignaux, F. Vargas, J. Roeseler, D. Tassaux, A.W. Thille, M.P. Kossowsky, et al.
Patient–ventilator asynchrony during non-invasive ventilation for acute respiratory failure: a multicenter study.
Intensive Care Med, 35 (2009), pp. 840-846
[18]
S. Nava, C. Bruschi, C. Fracchia, A. Braschi, F. Rubini.
Patient–ventilator interaction and inspiratory effort during pressure support ventilation in patients with different pathologies.
Eur Respir J, 10 (1997), pp. 177-183
[19]
H. Tokioka, T. Tanaka, T. Ishizu, T. Fukushima, T. Iwaki, Y. Nakamura, et al.
The effect of breath termination criterion on breathing patterns and the work of breathing during pressure support ventilation.
Anesth Analg, 92 (2001), pp. 161-165
[20]
A.W. Thille, P. Rodriguez, B. Cabello, F. Lellouche, L. Brochard.
Patient–ventilator asynchrony during assisted mechanical ventilation.
Intensive Care Med, 32 (2006), pp. 1515-1522
Copyright © 2019. SEPAR
Archivos de Bronconeumología
Article options
Tools

Are you a health professional able to prescribe or dispense drugs?