array:23 [ "pii" => "S030028962200494X" "issn" => "03002896" "doi" => "10.1016/j.arbres.2022.07.008" "estado" => "S300" "fechaPublicacion" => "2023-01-01" "aid" => "3151" "copyright" => "The Author(s)" "copyrightAnyo" => "2022" "documento" => "simple-article" "crossmark" => 1 "subdocumento" => "crp" "cita" => "Arch Bronconeumol. 2023;59:61-2" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:1 [ "total" => 0 ] "itemSiguiente" => array:18 [ "pii" => "S0300289622004975" "issn" => "03002896" "doi" => "10.1016/j.arbres.2022.07.011" "estado" => "S300" "fechaPublicacion" => "2023-01-01" "aid" => "3154" "copyright" => "SEPAR" "documento" => "simple-article" "crossmark" => 1 "subdocumento" => "crp" "cita" => "Arch Bronconeumol. 2023;59:63-5" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:1 [ "total" => 0 ] "en" => array:10 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Scientific Letter</span>" "titulo" => "Iatrogenic Adrenal Insufficiency Following Post COVID-19 Organizing Pneumonia" "tienePdf" => "en" "tieneTextoCompleto" => "en" "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "63" "paginaFinal" => "65" ] ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1338 "Ancho" => 2091 "Tamanyo" => 182796 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">Hospital glucocorticoid withdrawal protocol.</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Esther Palones, Elena Curto, Anna Pelegrí, Marina Arilla, Ingrid Solanes, Astrid Crespo-Lessmann" "autores" => array:6 [ 0 => array:2 [ "nombre" => "Esther" "apellidos" => "Palones" ] 1 => array:2 [ "nombre" => "Elena" "apellidos" => "Curto" ] 2 => array:2 [ "nombre" => "Anna" "apellidos" => "Pelegrí" ] 3 => array:2 [ "nombre" => "Marina" "apellidos" => "Arilla" ] 4 => array:2 [ "nombre" => "Ingrid" "apellidos" => "Solanes" ] 5 => array:2 [ "nombre" => "Astrid" "apellidos" => "Crespo-Lessmann" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0300289622004975?idApp=UINPBA00003Z" "url" => "/03002896/0000005900000001/v3_202311210639/S0300289622004975/v3_202311210639/en/main.assets" ] "itemAnterior" => array:18 [ "pii" => "S0300289622004902" "issn" => "03002896" "doi" => "10.1016/j.arbres.2022.07.004" "estado" => "S300" "fechaPublicacion" => "2023-01-01" "aid" => "3147" "copyright" => "SEPAR" "documento" => "simple-article" "crossmark" => 1 "subdocumento" => "crp" "cita" => "Arch Bronconeumol. 2023;59:59-60" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:1 [ "total" => 0 ] "en" => array:9 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Scientific Letter</span>" "titulo" => "Risk Factors for Acute Exacerbations of Fibrotic Hypersensitivity Pneumonitis—Is Exposure a Trigger That We’re Missing?" "tienePdf" => "en" "tieneTextoCompleto" => "en" "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "59" "paginaFinal" => "60" ] ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "David Barros Coelho, Vanessa Santos, André Terras Alexandre, Helder Novais e Bastos, Patrícia Caetano Mota, António Morais, Natália Melo" "autores" => array:7 [ 0 => array:2 [ "nombre" => "David Barros" "apellidos" => "Coelho" ] 1 => array:2 [ "nombre" => "Vanessa" "apellidos" => "Santos" ] 2 => array:2 [ "nombre" => "André Terras" "apellidos" => "Alexandre" ] 3 => array:2 [ "nombre" => "Helder Novais e" "apellidos" => "Bastos" ] 4 => array:2 [ "nombre" => "Patrícia Caetano" "apellidos" => "Mota" ] 5 => array:2 [ "nombre" => "António" "apellidos" => "Morais" ] 6 => array:2 [ "nombre" => "Natália" "apellidos" => "Melo" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0300289622004902?idApp=UINPBA00003Z" "url" => "/03002896/0000005900000001/v3_202311210639/S0300289622004902/v3_202311210639/en/main.assets" ] "en" => array:13 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Scientific Letter</span>" "titulo" => "A Simple Procedure to Measure the Tidal Volume Delivered by Mechanical Ventilators: A Tool for Bedside Verification and Quality Control" "tieneTextoCompleto" => true "saludo" => "To the Director," "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "61" "paginaFinal" => "62" ] ] "autores" => array:1 [ 0 => array:4 [ "autoresLista" => "Ramon Farré, Antonio Artigas, Antoni Torres, Guillermo M. Albaiceta, Anh Tuan Dinh-Xuan, David Gozal" "autores" => array:6 [ 0 => array:4 [ "nombre" => "Ramon" "apellidos" => "Farré" "email" => array:1 [ 0 => "rfarre@ub.edu" ] "referencia" => array:4 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] 2 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">c</span>" "identificador" => "aff0015" ] 3 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">*</span>" "identificador" => "cor0005" ] ] ] 1 => array:3 [ "nombre" => "Antonio" "apellidos" => "Artigas" "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">d</span>" "identificador" => "aff0020" ] ] ] 2 => array:3 [ "nombre" => "Antoni" "apellidos" => "Torres" "referencia" => array:3 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">c</span>" "identificador" => "aff0015" ] 2 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">e</span>" "identificador" => "aff0025" ] ] ] 3 => array:3 [ "nombre" => "Guillermo M." "apellidos" => "Albaiceta" "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">f</span>" "identificador" => "aff0030" ] ] ] 4 => array:3 [ "nombre" => "Anh Tuan" "apellidos" => "Dinh-Xuan" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">g</span>" "identificador" => "aff0035" ] ] ] 5 => array:3 [ "nombre" => "David" "apellidos" => "Gozal" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">h</span>" "identificador" => "aff0040" ] ] ] ] "afiliaciones" => array:8 [ 0 => array:3 [ "entidad" => "Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain" "etiqueta" => "a" "identificador" => "aff0005" ] 1 => array:3 [ "entidad" => "CIBER de Enfermedades Respiratorias, Madrid, Spain" "etiqueta" => "b" "identificador" => "aff0010" ] 2 => array:3 [ "entidad" => "Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain" "etiqueta" => "c" "identificador" => "aff0015" ] 3 => array:3 [ "entidad" => "Corporació Sanitària Universitària Parc Tauli, I3PT, Universitat Autònoma de Barcelona, Sabadell, Spain" "etiqueta" => "d" "identificador" => "aff0020" ] 4 => array:3 [ "entidad" => "Servei de Pneumologia, Hospital Clinic, Universitat de Barcelona, IDIBAPS, Barcelona, Spain" "etiqueta" => "e" "identificador" => "aff0025" ] 5 => array:3 [ "entidad" => "Unidad de Cuidados Intensivos Cardiológicos. Hospital Universitario Central de Asturias, Oviedo, Spain" "etiqueta" => "f" "identificador" => "aff0030" ] 6 => array:3 [ "entidad" => "Service de Physiologie-Explorations Fonctionnelles, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France" "etiqueta" => "g" "identificador" => "aff0035" ] 7 => array:3 [ "entidad" => "Department of Child Health, The University of Missouri School of Medicine, Columbia, MO, USA" "etiqueta" => "h" "identificador" => "aff0040" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0005" "etiqueta" => "⁎" "correspondencia" => "Corresponding author." ] ] ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 2272 "Ancho" => 1258 "Tamanyo" => 217261 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">(A) Diagram of the method described for directly measuring the tidal volume (<span class="elsevierStyleItalic">V<span class="elsevierStyleInf">T</span></span>) delivered by a mechanical ventilator. A lung test, consisting of an orifice-type resistor (R) and a compliant bag enclosed in a water chamber open to the atmosphere through a vertical tube, is connected to the inspiratory and expiratory lines of the mechanical ventilator. The <span class="elsevierStyleItalic">V<span class="elsevierStyleInf">T</span></span> introduced into the bag induces an increase in the height (Δ<span class="elsevierStyleItalic">h</span>) of water level in the tube, from end-expiration (blue) to end-inspiration (red). (B): Example of low-cost implementation of the measuring setting. The chamber was made with 15-cm diameter PVC drainpipe fittings. One of the cylinder bases was a screw cap to allow replacing the bag. The transparent vertical tube has an internal diameter of 7.4<span class="elsevierStyleHsp" style=""></span>cm (section: 43.01<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleSup">2</span>), hence <span class="elsevierStyleItalic">V<span class="elsevierStyleInf">T</span></span> (in mL)<span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>43.01 x h (in cm).</p>" ] ] ] "textoCompleto" => "<span class="elsevierStyleSections"><p id="par0005" class="elsevierStylePara elsevierViewall">Mechanical ventilation is the most extensively employed life support intervention among patients with severe respiratory failure of different etiologies. In this context, consistent delivery of the most suitable tidal volume (<span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span>) to the patient is critical to achieving personalized mechanical ventilation. Indeed, in addition to its contribution to minute volume for optimization of blood gas exchange, appropriate <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> strategies are critical to avoid ventilator-induced lung injury in the general context of lung-protective ventilation<a class="elsevierStyleCrossRef" href="#bib0055"><span class="elsevierStyleSup">1</span></a> and when specifically applying ultra-low tidal volume ventilation.<a class="elsevierStyleCrossRef" href="#bib0060"><span class="elsevierStyleSup">2</span></a> Additionally, <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> is required to compute respiratory system compliance or ventilatory ratio, useful indices in the classification of patient phenotype and estimation of prognosis.<a class="elsevierStyleCrossRefs" href="#bib0065"><span class="elsevierStyleSup">3,4</span></a></p><p id="par0010" class="elsevierStylePara elsevierViewall">Whereas measuring the pressures characterizing mechanical ventilation (e.g., peak inspiratory or positive end-expiratory pressures) is direct and straightforward using pressure transducers, actual <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> measurements are complex since several computations are required. First, correct calibration values are required for the flow measuring device (usually a pneumotachograph) according to the oxygen fraction being used. For instance, to avoid a 12.5% volume overestimation when changing ventilation from room air to oxygen, the ventilator should automatically correct for the change in pneumotachograph resistance caused by the changes in gas viscosity.<a class="elsevierStyleCrossRef" href="#bib0075"><span class="elsevierStyleSup">5</span></a> Second, correction for the compressibility of the ventilator circuit is essential since a fraction of the inspiratory volume measured at the ventilator outlet is shunted by compression and thus not delivered to the patient. For a typical value of ventilator circuit compliance (2<span class="elsevierStyleHsp" style=""></span>mL/cmH<span class="elsevierStyleInf">2</span>O)<a class="elsevierStyleCrossRef" href="#bib0080"><span class="elsevierStyleSup">6</span></a> and an inspiratory pressure of 25<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O, the volume of shunted air is 50<span class="elsevierStyleHsp" style=""></span>mL (≈10% of the typical <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span>). Remarkably, changes in the circuit compliance (e.g. inadvertent modification of tubing or humidifier dimensions) must be taken into account for correction, otherwise, these may result in substantial <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> errors. Third, correction of <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> according to the gas physical conditions is also needed since the inspiratory volume primarily measured by the ventilator corresponds to the device temperature and humidity, which are different from those within the patient lung (37<span class="elsevierStyleHsp" style=""></span>°C and 100% relative humidity). Indeed, there is a 12.3% increase in <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> when comparing dry air at 20<span class="elsevierStyleHsp" style=""></span>°C in a ventilator and the corresponding <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> in the patient lung.<a class="elsevierStyleCrossRef" href="#bib0085"><span class="elsevierStyleSup">7</span></a></p><p id="par0015" class="elsevierStylePara elsevierViewall">Therefore, knowing the actual <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> in the patient's lungs is contingent on the implementation of ventilator algorithms to compute the three aforementioned corrective steps, each potentially amounting to more than 10% variance in the actual vs. calculated <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span>. In many instances, the clinicians will be unaware of whether and how the ventilator algorithms operate because they are commonly proprietary and generally undisclosed, and their implementation and results may differ among manufacturers.<a class="elsevierStyleCrossRef" href="#bib0090"><span class="elsevierStyleSup">8</span></a> In other situations, and regardless of the ventilator type being used, errors in measured <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> occur even in a priori well-maintained devices<a class="elsevierStyleCrossRef" href="#bib0095"><span class="elsevierStyleSup">9</span></a> and are particularly frequent in low- and middle-income countries (LMIC).<a class="elsevierStyleCrossRef" href="#bib0100"><span class="elsevierStyleSup">10</span></a> Assessment of the actual <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> values delivered by the ventilator can be carried out by commercially available systems specially designed for this purpose. However, such devices are based on measuring <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> using a pneumotachograph and a built-in microprocessor. Therefore, they are relatively expensive and require periodic servicing/recalibration as indicated by their manufacturer's instructions, prompting their limited use in low-resource medical centers. Thus, having an inexpensive and straightforward procedure for verifying the <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> delivered by the ventilator at the bedside would be very useful for regular checks and quality controls in both resource-rich and resource-poor ICUs. Moreover, such capability can be particularly helpful when alternative ventilators must be rapidly set up, such as during the critical months of the COVID-19 pandemic.</p><p id="par0020" class="elsevierStylePara elsevierViewall">We herein describe an inexpensive and straightforward procedure that can be readily followed by clinical staff who are not experts in instrumentation techniques. Notably, the method does not require additional electronic sensors or complex devices. It directly measures the <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> applied by the ventilator, thereby avoiding all the corrections and uncertainties associated with flow measurement and its attendant correction algorithms. As shown in <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>A, a resistance and bag simulating a patient (test lung) is enclosed in a water-filled rigid-wall chamber. The <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> applied by the test ventilator is measured from the difference in water levels (Δ<span class="elsevierStyleItalic">h</span>) along the ventilator cycle, for instance during end-inspiration and end-expiration pauses. Indeed, <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span><span class="elsevierStyleItalic">S</span>·Δ<span class="elsevierStyleItalic">h</span>, where <span class="elsevierStyleItalic">S</span> is the internal section of the vertical tube to measure h. The <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> measured by water displacement is the <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> applied by the ventilator to the simulated patient, measured at the conditions of the ventilator air, i.e., room temperature and humidity (0% for dry air from a compressed air supply or room humidity for turbine-based ventilators). This actual <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> is the reference value to be compared with the <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> measured by the ventilator.</p><elsevierMultimedia ident="fig0005"></elsevierMultimedia><p id="par0025" class="elsevierStylePara elsevierViewall">As a practical example particularly interesting for potential users in LMIC, <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>B shows a low-cost chamber implementation made using 15-cm diameter PVC tubing components that are widely available in hardware stores. In practical terms, the test lung (<a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>A) simply plays the role of an arbitrary patient impedance subjected to ventilation. As the method described herein is aimed at comparing the <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> measured by the ventilator with its actual value measured by water displacement, the specific resistance and compliance of the simulated patient are not relevant provided they are within realistic boundaries, making it easy to choose among different options. For instance, we included a low-cost setting consisting of an orifice-type resistance (12.1<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O<span class="elsevierStyleHsp" style=""></span>s/L at 0.3<span class="elsevierStyleHsp" style=""></span>L/s; like in the Siemens-190 test lung) and a common 2-L anesthesia bag. Since the walls of this type of bag virtually do not exert elastic pressure for typical <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> values (<2<span class="elsevierStyleHsp" style=""></span>cmH<span class="elsevierStyleInf">2</span>O up to 1.5<span class="elsevierStyleHsp" style=""></span>L), the effective compliance of the simulated patient is very close to the compliance (<span class="elsevierStyleItalic">C</span>) corresponding to the increasing pressure (Δ<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span><span class="elsevierStyleItalic">ρ</span>·<span class="elsevierStyleItalic">g</span>·Δ<span class="elsevierStyleItalic">h</span>; <span class="elsevierStyleItalic">ρ</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>1<span class="elsevierStyleHsp" style=""></span>g/mL, and <span class="elsevierStyleItalic">g</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>9.8<span class="elsevierStyleHsp" style=""></span>m/s<span class="elsevierStyleSup">2</span>) applied by water to the external wall of the bag as h increases during inspiration. Specifically, as Δ<span class="elsevierStyleItalic">V</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span><span class="elsevierStyleItalic">S</span>·Δ<span class="elsevierStyleItalic">h</span>, <span class="elsevierStyleItalic">C</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>Δ<span class="elsevierStyleItalic">V</span>/Δ<span class="elsevierStyleItalic">P</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span><span class="elsevierStyleItalic">S</span>/(<span class="elsevierStyleItalic">ρ</span>·<span class="elsevierStyleItalic">g</span>). In the setting of <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>B, <span class="elsevierStyleItalic">S</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>43.01<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleSup">2</span> and hence <span class="elsevierStyleItalic">C</span><span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>43.8<span class="elsevierStyleHsp" style=""></span>mL/cmH<span class="elsevierStyleInf">2</span>O, a figure within the range of respiratory compliance in adult patients.<a class="elsevierStyleCrossRef" href="#bib0065"><span class="elsevierStyleSup">3</span></a> As it is readily apparent, the dimensions of the setting in <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>B can be reduced if the aim is focused on assessing <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> in pediatric ventilators. Interestingly, the precision in measuring volume emerges as being inversely proportional to section S of the vertical tube. Assuming the 1-mm resolution in the common ruler for assessing h in the setting in <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>B, resolution in <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> measurement is 4.3<span class="elsevierStyleHsp" style=""></span>mL, which corresponds to 0.43% and 0.86% for maximum and typical <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> values of 1000 and 500<span class="elsevierStyleHsp" style=""></span>mL, respectively. Such precision is by far sufficient to detect any potential real-life errors when <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> is measured by mechanical ventilators.<a class="elsevierStyleCrossRefs" href="#bib0090"><span class="elsevierStyleSup">8–10</span></a> The practical suitability and usefulness of the simple method proposed herein should be assessed in future studies evaluating mechanical ventilators by comparison with gold standard volume sensors.</p><p id="par0030" class="elsevierStylePara elsevierViewall">In conclusion, we describe the concept and implementation of a simple and inexpensive method to measure the tidal volume delivered by a mechanical ventilator. As the procedure is straightforward and does not require complex equipment, clinical staff can perform such estimates in the ICU at the patient's bedside. The method can help verify the accuracy of <span class="elsevierStyleItalic">V</span><span class="elsevierStyleInf"><span class="elsevierStyleItalic">T</span></span> in otherwise well-serviced settings and can be a realistic and easily implementable quality control procedure in LMIC regions where routine maintenance of medical devices is not necessarily widely available.</p></span>" "pdfFichero" => "main.pdf" "tienePdf" => true "multimedia" => array:1 [ 0 => array:7 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 2272 "Ancho" => 1258 "Tamanyo" => 217261 ] ] "descripcion" => array:1 [ "en" => "<p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">(A) Diagram of the method described for directly measuring the tidal volume (<span class="elsevierStyleItalic">V<span class="elsevierStyleInf">T</span></span>) delivered by a mechanical ventilator. A lung test, consisting of an orifice-type resistor (R) and a compliant bag enclosed in a water chamber open to the atmosphere through a vertical tube, is connected to the inspiratory and expiratory lines of the mechanical ventilator. The <span class="elsevierStyleItalic">V<span class="elsevierStyleInf">T</span></span> introduced into the bag induces an increase in the height (Δ<span class="elsevierStyleItalic">h</span>) of water level in the tube, from end-expiration (blue) to end-inspiration (red). (B): Example of low-cost implementation of the measuring setting. The chamber was made with 15-cm diameter PVC drainpipe fittings. One of the cylinder bases was a screw cap to allow replacing the bag. The transparent vertical tube has an internal diameter of 7.4<span class="elsevierStyleHsp" style=""></span>cm (section: 43.01<span class="elsevierStyleHsp" style=""></span>cm<span class="elsevierStyleSup">2</span>), hence <span class="elsevierStyleItalic">V<span class="elsevierStyleInf">T</span></span> (in mL)<span class="elsevierStyleHsp" style=""></span>=<span class="elsevierStyleHsp" style=""></span>43.01 x h (in cm).</p>" ] ] ] "bibliografia" => array:2 [ "titulo" => "References" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "bibs0015" "bibliografiaReferencia" => array:10 [ 0 => array:3 [ "identificador" => "bib0055" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Acute respiratory distress syndrome: advances in diagnosis and treatment" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "E. Fan" 1 => "D. Brodie" 2 => "A.S. 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Scientific Letter
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A Simple Procedure to Measure the Tidal Volume Delivered by Mechanical Ventilators: A Tool for Bedside Verification and Quality Control
Ramon Farréa,b,c,
, Antonio Artigasb,d, Antoni Torresb,c,e, Guillermo M. Albaicetab,f, Anh Tuan Dinh-Xuang, David Gozalh
Corresponding author
a Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
b CIBER de Enfermedades Respiratorias, Madrid, Spain
c Institut Investigacions Biomediques August Pi Sunyer, Barcelona, Spain
d Corporació Sanitària Universitària Parc Tauli, I3PT, Universitat Autònoma de Barcelona, Sabadell, Spain
e Servei de Pneumologia, Hospital Clinic, Universitat de Barcelona, IDIBAPS, Barcelona, Spain
f Unidad de Cuidados Intensivos Cardiológicos. Hospital Universitario Central de Asturias, Oviedo, Spain
g Service de Physiologie-Explorations Fonctionnelles, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
h Department of Child Health, The University of Missouri School of Medicine, Columbia, MO, USA
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A Simple Procedure to Measure the Tidal Volume Delivered by Mechanical Ventilators: A Tool for Bedside Verification and Quality Control
Ramon Farré, Antonio Artigas, Antoni Torres, Guillermo M. Albaiceta, Anh Tuan Dinh-Xuan, David Gozal
10.1016/j.arbres.2022.07.008Arch Bronconeumol. 2023;59:61-2