Individual FiO2 guided by SPO2 prevents hyperoxia and reduces postoperative atelectasis in colorectal surgery: A randomized controlled trial

To determine whether individualized fraction of inspired oxygen (iFiO2) improves pulmonary atelectasis after elective laparoscopic colorectal surgery relative to 60 % FiO2. This was a single-center, prospective, randomized study. This study was conducted in a single tertiary care hospital in China. A total of 84 eligible inpatients who underwent elective laparoscopic colorectal surgery between August 2021 and May 2022 were included in the study. The patients were randomly assigned to receive either a fixed fraction of inspiration oxygen (fFiO2 group) or individualized FiO2 based on physiological SpO2 (iFiO2 group). The primary outcome was the lung ultrasound score (LUS) at 30 min after extubation. Secondary outcomes included the length of hospital stay, admission to the intensive care unit, the length of post-anesthetic care unit stay, the ratio of lung capacity on the third day after surgery compared with before surgery, the incidence of nausea and vomiting, and surgical site infections after surgery. Additionally, the airway plate pressure, airway peak pressure, pulmonary dynamic compliance, PaO2, oxygenation index, alveolar-arterial oxygen tension gradient (A-aDO2), and pulmonary shunt fraction (Qs/Qt) were considered. The LUS was significantly lowered in the iFiO2 group (5 [4, 7]) compared with the fFiO2 group (8 [4, 10]) (P = 0.03). Based on the criterion for determining atelectasis, 25 patients (62.5 %) in the fFiO2 group experienced significant atelectasis compared with 15 patients (37.5 %) in the iFiO2 group (P = 0.025). At the end of surgery, PaO2, A-aDO2, and Qs/Qt were significantly reduced in patients in the iFiO2 group compared with those in the fFiO2 group. The use of iFiO2 during operation significantly reduces the LUS and pulmonary atelectasis in patients undergoing laparoscopic colorectal surgery under general anesthesia. ChiCTRT2100049615.