Fig. 3

Forest Plot of Multivariate Cox Regression Model. 1 We treated postoperative positive airway pressure use as a time-dependent variable in the multivariate Cox regression model. The PAP variable for patients who received postoperative PAP was coded as zero until the start of PAP and as one thereafter. 2 10-year increase. 3 Chronic obstructive pulmonary disease. 4 60-min increase