Outcome measures
postoperative pulmonary complications
SECONDARY
The primary outcomes were the incidence and severity of postoperative pulmonary complications (PPCs). PPCs were diagnosed using the scoring standard that has been used and continuously optimized since 1992 [Baseline characteristics and surgical dataThe incidence and severity of PPCs were evaluated every day after surgery until discharge, and the highest score during hospitalization was the final score. The assessment and diagnosis were made by the ICU or respiratory physician, and the dates were recorded. The final scores and type of PPCs in each group were recorded.The secondary outcomes were as follows. (1) Postoperative recovery time (time from the end of anesthesia to eye opening), extubation time (time from the end of anesthesia to the removal of the endotracheal tube), and length of ICU and postoperative hospital stay. (2) Pulmonary function evaluation indexes [alveolar arterial oxygen partial pressure difference (A-aDO