Weaning by gradual pressure support (PS) reduction without an initial spontaneous breathing trial (SBT) versus PS-supported SBT: a pilot study

Abstract

Background and aim: Studies on weaning strategies have yielded conflicting results regarding the superiority of different methods. The aim of this RCT was to compare the efficacy of gradual pressure support (PS) reduction without an initial spontaneous breathing trial (SBT) with PS-supported SBT.

Methods: Patients mechanically ventilated for >24h were randomized to weaning by gradual reduction of PS without an initial SBT versus once daily SBT (PS 7cm H(2)O). The primary outcomes were the rates of successful weaning trial and time to successful extubation. The secondary outcomes were the ICU and hospital length of stay, hospital mortality and the occurrence of ventilator-associated pneumonia (VAP).

Results: Of the 120 patients (61 males, median age 35 years), 58 were assigned to PS and 62 to the SBT group. The median (IQR) duration of ventilation prior to weaning was 80.2 (50.5-175.6)h. The baseline characteristics were similar in the two groups except the PaO(2)/FiO(2) ratio, which was significantly higher in SBT group. The rates of successful weaning trial (89.7% versus 69.4%) were significantly higher in the PS group. The median duration of weaning (66h versus 81.5h, P=0.05) and the median duration of ICU stay (8 days versus 9.4 days, P=0.027) were lower in the PS group. There was no difference in hospital stay, mortality rates or occurrence of VAP in the two arms. On multivariate analysis, the duration of ventilation prior to weaning, baseline SOFA score and the weaning method were predictors of successful extubation.

Conclusions: Gradual reduction of PS without an initial SBT was found to be associated with better outcomes compared to once daily PS-supported SBT.