Airway closure and fiberoptic evidence of bronchial collapse during the acute respiratory distress syndrome
Airway closure affects approximatively one-third of patients with acute respiratory distress syndrome (ARDS) undergoing mechanical ventilation in the absence of spontaneous breathing [1, 2]. When this phenomenon is present, airways collapse during expiration; therefore, end-expiratory pressure at airway opening (although measured during an end-expiratory occlusion) is not equilibrated with alveolar pressure, and tidal inflation starts only when an airway opening pressure (AOP) is overcome. Airway closure leads to misinterpretation of static respiratory mechanics and makes actual end-expiratory alveolar pressure (and end-expiratory lung volume) independent from set PEEP, if this is lower than the AOP . Moreover, airway opening and closing may yield bronchiolotrauma, which can contribute to lung injury [1, 4, 5].
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Conflicts of interest
DLG has received payments for travel expenses by Maquet, Getinge and Air Liquide, and supported by grants from ESICM (2017 Draeger Award) and SIAARTI (2017 MSD award). MA has received payments for Board participation from Maquet, Air Liquide and Chiesi. DLG and MA disclose a research Grant by GE healthcare. All the other authors declare that no confict of interest exists regarding the material discussed in the manuscript.