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

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) 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 vent) during SBT and reventilation periods. The study aimed to investigate patient or respirator factors influencing P as well as the association of P 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 cmHO) and PEEP (5 cmHO). 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 mean values were significantly higher for extubation failures and SBT failures compared to successful extubations (p < 0.001). Delta P ((P reventilation - P SBT)/ P SBT) was significantly different according to whether extubation was a success or a failure: 0.21 (0.02-0.62) cm HO vs. P vs. 1.12 (0.54-2.38) cm HO; 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) cmHO vs. 0.80 (0.54; 1.28) cmHO respectively (p = 0.003). Noteworthy, P values were influenced by airway humidification systems (0.92 (0.57; 1.54) cmHO with humidification vs. 1.27 (0.91; 2.24) cmHO without, p = 0.003).

CONCLUSION

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