Lung ultrasound score-based assessment of postoperative atelectasis in obese patients according to inspired oxygen concentration: A prospective, randomized-controlled study

Abstract

Background: According to a recent meta-analysis, in patients with a body mass index (BMI) ≥ 30, a high fraction of inhaled oxygen (FiO2) did not increase postoperative atelectasis. However, a high FiO2generally increases the risk of postoperative atelectasis. Therefore, this study aimed to evaluate the effect of FiO2on the development of atelectasis in obese patients using the modified lung ultrasound score (LUSS). Methods: Patients were assigned to 4 groups: BMI ≥ 30: group A (n = 21) and group B (n = 20) and normal BMI: group C (n = 22) and group D (n = 21). Groups A and C were administered 100% O2during preinduction and emergence and 50% O2during anesthesia. Groups B and D received 40% O2for anesthesia. The modified LUSS was assessed before and 20 min after arrival to the postanesthesia care unit (PACU). Results: The difference between the modified LUSS preinduction and PACU was significantly higher in group A with a BMI ≥ 30 (P =.006); however, there was an insignificant difference between groups C and D in the normal BMI group (P =.076). Conclusion: High FiO2had a greater effect on the development of atelectasis in obese patients than did low FiO2; however, in normal-weight individuals, FiO2did not have a significant effect on postoperative atelectasis.