Automatic continuous P0.1 measurements during weaning from mechanical ventilation: a clinical study.

Abstract

Background: 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.

Patients and methods: 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 cmH₂O) and PEEP (5 cmH₂O). Data included patient characteristics, ventilator parameters and extubation outcomes.

Results: 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 H₂O vs. P_{0.1 vent} vs. 1.12 (0.54-2.38) cm H₂O; 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) cmH₂O vs. 0.80 (0.54; 1.28) cmH₂O respectively (p = 0.003). Noteworthy, P_{0.1 vent} values were influenced by airway humidification systems (0.92 (0.57; 1.54) cmH₂O with humidification vs. 1.27 (0.91; 2.24) cmH₂O without, p = 0.003).

Conclusion: The delta of P_0.1vent 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.