Physiologic Effects of Reconnection to the Ventilator for 1 Hour Following a Successful Spontaneous Breathing Trial

Abstract

Reconnection to the ventilator for 1 hour after a successful spontaneous breathing trial (SBT) may reduce reintubation rate as compared to direct extubation. However, the physiological mechanisms leading to this effect are unclear. Does reconnection to the ventilator for 1 hour reverse alveolar derecruitment induced by SBT, and is alveolar derecruitment more pronounced with a T-piece than with pressure-support ventilation (PSV)? Ancillary study of a randomized clinical trial comparing SBT performed with a T-piece or with PSV. Alveolar recruitment was assessed using measurement of end-expiratory lung volume (EELV). Out of 25 patients analyzed after successful SBT, 11 underwent SBT with a T-piece and 14 with PSV. At the end of the SBT, EELV decreased by -30% (95% confidence interval, -37% to -23%) compared with baseline before the SBT. This reduction was greater with a T-piece than with PSV: -43% (95% CI, -51% to -35%) vs. -20% (95% CI, -26% to -13%), p<0.001. After reconnection to the ventilator for 1 hour, EELV accounted for 96% (95% CI, 92% to 101%) of baseline EELV and did not significantly differ from before the SBT (p=0.104). After 10 minutes of reconnection to the ventilator, EELV wasted at the end of the SBT was completely recovered using PSV (p=0.574) whereas it remained lower than before the SBT using T-piece (p=0.010). Significant alveolar derecruitment was observed at the end of a SBT, and was markedly more pronounced with a T-piece than with PSV. Reconnection to the ventilator for 1 hour allowed complete recovery of alveolar derecruitment. NCT04227639.