Post-operative pulmonary complications with high versus standard fiO2 in adult patients undergoing major abdominal surgery: A non-inferiority trial

Despite of possible clinical benefit of high intraoperative oxygen therapy on surgical site infection, effect on postoperative respiratory function is debatable. Whether intraoperative hyperoxia, when used along with a lung protective ventilation strategy is associated with postoperative pulmonary complications, is not known. Patients and methods In this non- inferiority randomized trial, intraoperative high fiO2 of 0.8 (group H) was compared to standard fiO2 of 0.3–0.4 (group S) in adult patients undergoing major elective or emergency surgery. Lung protective ventilation strategy, that included volume control ventilation with a tidal volume of 6–8 ml/kg of predicted body weight, respiratory rate of 12 beats per minute and PEEP of 5–8 cm H2O were employed in all patients. POPC was assessed at postoperative day 3 & day 5 by Melbourne group scale. Results In this trial, n = 226 patients were randomized and n = 130 patients underwent routine surgery and rest 96 patients underwent emergency surgery. Median (interquartile range, IQR) of the patients were 48 (35–58) year and 47.3% patients were female. MGS score at postoperative day 3 [median (IQR) 2 (1–4) in group S versus 2(1–3) in group H; difference in median (95% CI) 0 (0, −1); p = 0.13] & day 5 [median (IQR) 1 (0–3) in group S versus 1(0–3) in group H; difference in median (95% CI) 0 (0, 0.5); p = 0.34] were statistically similar in both the group and upper margin was within the pre-defined margin of 1. Incidence of surgical site infection (p = 0.46), postoperative hospital stay (p = 0.29) and days alive without antibiotic therapy at postoperative day 28 (p = 0.95) were similar in both the groups. Conclusion High intraoperative fiO2 was not inferior to standard fiO2 in terms of postoperative pulmonary complications in adult patients undergoing major surgery.