Bench Assessment of Work of Breathing During a Spontaneous Breathing Trial on Zero Pressure Support and Zero PEEP Compared to T-Piece.

BACKGROUND

Analysis of observational data suggests that both a T-piece and zero pressure support ventilation (PSV) and zero PEEP impose work of breathing (WOB) during a spontaneous breathing trial (SBT) similar to what a patient experiences after extubation. The aim of our study was to compare the WOB imposed by the T-piece with zero PSV and zero PEEP. We also compared the difference in WOB when using zero PSV and zero PEEP on 3 different ventilators.

METHODS

This study was conducted by using a breathing simulator that simulated 3 lung models (ie, normal, moderate ARDS, and COPD). Three ventilators were used and set to zero PSV and zero PEEP. The outcome variable was WOB expressed as mJ/L of tidal volume.

RESULTS

An analysis of variance showed that WOB was statistically different between the T-piece and zero PSV and zero PEEP on all the ventilators (Servo-i, Servo-u, and Carescape R860). The absolute difference was lowest for the Carescape R860, which increased WOB by 5-6%, whereas the highest for Servo-u, which reduced the WOB by 15-21%.

CONCLUSIONS

Work may be imposed or reduced during spontaneous breathing on zero PSV and zero PEEP when compared to T-piece. The unpredictable nature of how zero PSV and zero PEEP behaves on different ventilators makes it an imprecise SBT modality in the context of assessing extubation readiness.

Informations de copyright

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Déclaration de conflit d'intérêts

Mr Chatburn discloses relationships with IngMar Medical, Vyaire, Inovytec, Aires, ProMedic, AutoMedx, and Elsevier. Dr Hatipoğlu discloses relationships with UpToDate and COPD. Dr Sameed has disclosed no conflicts of interest.