Effect of lung volume preservation during spontaneous breathing trial on successful extubation among patients receiving mechanical ventilation. Study protocol for a multi-center clinical trial.

Abstract Background: the best spontaneous breathing test (SBT) during weaning from mechanical ventilation is a 30-min test with pressure support ventilation (PSV) 8 cmH2O without positive end expiratory pressure (PEEP). There is a debate about the possible collapse of some alveolar units during such SBT and during extubation with continuous suctioning. A few experiences showed extubation without suctioning as feasible and safe. Lung ultrasound is an excellent tool to determine the level of lung aeration. We hypothesize that preserving lung volume during SBT and extubation can yield higher rates of successful extubation. Methods: Primary objective: To determine the rates of successful extubation in two extubation approaches aiming at different levels of lung volume preservation: standard SBT (30-min PSV8 without PEEP followed by extubation with continuous suctioning) versus experimental SBT (30-min PSV8 + PEEP5 followed by extubation without suctioning). Secondary objectives: To determine reintubation rate, ICU and hospital stays, the lung volume aeration using modified lung ultrasound score (LUS) before and after successful or failed SBT, diaphragm and intercostal thickness and thickening fraction by ultrasound (US) before and after successful or failed SBT. Design: Multi-center, randomized clinical trial. Eligible patients will be randomly assigned to a two opposing extubation strategies. The follow-up period will be 90-days after randomization. Discussion: A representative group of mechanically ventilated patients ready to be liberated from the ventilator will be studied in order to provide comprehensive data on the potential impact of preserving lung volume during weaning. Ethics and registration: The study has been approved by the Board Research Committee (CEIm) of the Fundació Unió Catalana d'Hospitals with the code CEI 22/67 and 23/26. Already registered on ClinicalTrials.gov Identifier: NCT05526053 on August 2023.