Win Ratio approach for the composite outcome of postoperative pulmonary complications: Secondary analysis of a harmonised and pooled database of three randomised clinical trials.

Background: The win ratio analysis method might provide new insight on the impact of positive end-expiratory pressure (PEEP) on clinical outcomes.

Objective: The aim is to re-analyse the results of the 'Re-evaluation of the effects of high PEEP with recruitment manoeuvres vs. low PEEP without recruitment manoeuvres during general anaesthesia for surgery' (REPEAT) study using the win ratio analysis.

Design: Individual patient data meta-analysis.

Setting: Three international multicentre randomised trials.

Participants: Patients undergoing general anaesthesia for surgery.

Intervention: High vs. low PEEP.

Main outcome measure: Hierarchical composite endpoint of: all-cause hospital mortality; hospital length of stay; need for postoperative mechanical ventilation; severe pulmonary complications; and mild pulmonary complications.

Results: A total of 3774 patients undergoing general anaesthesia for surgery were included in this analysis. The median (interquartile range [IQR]) age was 57 [45 to 68] years and 2077 (55%) were women. A total of 3 560 720 comparison pairs were produced. The high PEEP group had a higher percentage of losses than wins in hospital mortality (1.1 vs. 0.9%) and hospital length of stay (33.8 vs. 33.2%), comparable percentages of losses and wins in postoperative invasive mechanical ventilation (0.2 vs. 0.2%), a higher percentage of wins in severe complications (2.5 vs. 2.1%) and a higher percentage of ties in mild complications (18.7 vs. 3.9% wins vs. 3.3% losses). The win ratio for high PEEP compared with low PEEP group was 1.00 (95% CI 0.92 to 1.09).

Conclusion: No beneficial effects of high PEEP compared with low PEEP were found in this win ratio analysis.

Registration: Clinicaltrials.gov (study identifier NCT03937375).