Inclusion and exclusion criteria
SEVERE OBESITY
The following were the inclusion criteria: patients who were undergoing laparoscopic gynecological surgery under general anesthesia, aged 18–65 years, height of 155–167 cm, nonsmokers, expected anesthesia duration of ≤ 3 h, and an American Society of Anesthesiologists physical status of class I–II. The following were the exclusion criteria: patients with severe obesity (body mass index ≥ 30 kg/m