TY - JOUR T1 - Protective Recommendations for Non-invasive Ventilation During COVID-19 Pandemic: A Bench Evaluation of the Effects of Instrumental Dead Space on Alveolar Ventilation JO - Archivos de Bronconeumología T2 - AU - Delorme,Mathieu AU - Leroux,Karl AU - Boussaid,Ghilas AU - Lebret,Marius AU - Prigent,Helene AU - Leotard,Antoine AU - Louis,Bruno AU - Lofaso,Frédéric SN - 03002896 M3 - 10.1016/j.arbres.2021.01.012 DO - 10.1016/j.arbres.2021.01.012 UR - https://archbronconeumol.org/en-protective-recommendations-for-non-invasive-ventilation-articulo-S030028962100034X AB - IntroductionWith the current COVID-19 pandemic, concerns have raised regarding the risk for NIV to promote airborne transmission. In case of hospital admission, continuation of therapy in patients undergoing chronic NIV is necessary and several protective circuit configurations have been recommended to reduce the risk of aerosol dissemination. However, all these configurations increase instrumental dead space. We therefore designed this study to evaluate their effects on the tidal volume (VTE) required to preserve stable end-tidal CO2 partial pressure (PETCO2) with constant respiratory rate. MethodsA bench consisting of a test lung connected to an adult-sized mannequin head was set up. The model was ventilated through usual domiciliary configuration (single limb circuit with facial vented mask) which was used as reference. Then, five different circuit configurations including non-vented facial mask with viral/bacterial filter, modification of leak position, and change from single to double-limb circuit were evaluated. For each configuration, pressure support (PS) was gradually increased to reach reference PETCO2. Resulting VTE was recorded as primary outcome. ResultsReference PETCO2 was 38(0)mmHg, with a PS set at 10cmH2O, resulting in a VTE of 432(2)mL. Compared to reference, all the configurations evaluated required substantial increase in VTE to preserve alveolar ventilation, ranging from +79(2) to +216(1)mL. ConclusionsModifications of NIV configurations in the context of COVID-19 pandemic result in substantial increase of instrumental dead space. Re-evaluation of treatment efficiency and settings is crucial whenever protective measures influencing NIV equipment are considered. ER -