In critically ill patients, weaning from mechanical ventilation (MV) includes spontaneous breathing trial (SBT) usually followed by a reventilation period in order to recover from the alveolar derecruitement induced by the SBT. The measurement of occlusion pressure during the first 100 ms of an airway occlusion (P _0.1 ) one of the non-invasive tools available for estimating the respiratory drive, is a determinant of patient respiratory effort. This clinical study explores the use of non-invasive continuous monitoring of occlusion pressure automatically calculated by ventilators in the first 100 ms of airway occlusion (P _0.1 vent ) during SBT and reventilation periods. The study aimed to investigate patient or respirator factors influencing P _{0.1 vent} as well as the association of P _{0.1 vent} values with extubation success or failure.

This prospective observational study, conducted from February 2022 to April 2023, included adult patients intubated for more than 24 h and screened for extubation weaning. SBTs were performed for one hour with zero pressure support and zero end-expiratory pressure (PS0 ZEEP). Reventilation followed for an hour with pressure support (8–12 cmH ₂ O) and PEEP (5 cmH ₂ O). Data included patient characteristics, ventilator parameters and extubation outcomes.

The study involved 224 measurements from 212 patients, with 157 successful extubations, 46 extubation failures at day 7 and 21 SBT failures. P _{0.1 vent} mean values were significantly higher for extubation failures and SBT failures compared to successful extubations ( p   <  0.001). Delta P _{0.1 vent} ((P _{0.1 vent} reventilation - P _{0.1 vent} SBT)/ P _{0.1 vent} SBT) was significantly different according to whether extubation was a success or a failure: 0.21 (0.02–0.62) cm H ₂ O vs. P _{0.1 vent} vs. 1.12 (0.54–2.38) cm H ₂ O; p   <  0.0001 respectively. Values significantly differed in both the SBT and the reventilation periods whether or not patients had previous ARDS: 1.08 (0.70; 2.02) cmH ₂ O vs. 0.80 (0.54; 1.28) cmH ₂ O respectively ( p  = 0.003). Noteworthy, P _{0.1 vent} values were influenced by airway humidification systems (0.92 (0.57; 1.54) cmH ₂ O with humidification vs. 1.27 (0.91; 2.24) cmH ₂ O without, p  = 0.003).

The delta of P _0.1 vent values between SBT and reventilation are higher for patients who fail extubation, especially for those who had ARDS. While elevated P _{0.1 vent} values were associated with extubation failure, the overlap in values limits its usefulness as a reliable predictor.