The effect of inspired oxygen concentration on postoperative pulmonary atelectasis in obese patients undergoing laparoscopic cholecystectomy: a randomized-controlled double-blind study

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

“…In obese patients, when a high inhaled oxygen concentration (90%) was administered, more atelectasis was observed than when low inhaled oxygen (40%) was administered; however, no significant difference was found. [15] The results of comparing the difference in the incidence of atelectasis by chest radiography performed on the first postoperative day were consistent with the results of this study in that there was no significant difference between the obese and normal-weight patient groups. The influence of ventilator setting and inspired oxygen concentration is prone to overlap because patient factors or other factors influence patient prognosis much more.…”

“…[6,11] Contrary to the fact that obese patients are more prone to atelectasis due to decreased functional residual capacity, [12][13][14] many recent studies have shown that the rate of atelectasis in obese patients does not increase significantly even if a high inhaled oxygen concentration is administered. [15][16][17] The increase in body mass index (BMI) promotes cyclic airway closure, which in turn interferes with preoxygenation and alveolar ventilation, resulting in nitrogen retention. It can be explained that these alveoli are resistant to atelectasis, preventing atelectasis formation during preoxygenation and ventilator-assisted anesthesia.…”

“…[16] However, this meta-analysis did not consider the degree of atelectasis of the obese patient prior to anesthesia, and the various durations of exposure to different concentrations of oxygen and various types of surgeries were included. [12,13,[15][16][17] Therefore, this study was designed to target patients undergoing surgery that does not affect lung dynamics, to avoid exposure to high concentrations of oxygen even for a short period of time in the group receiving a low FiO 2 , and to examine the effect of inhaled oxygen concentration on the development of atelectasis by differentiating obese and normal-weight patients.…”

“…Previous research [12,15,16,18,19] on factors affecting the formation of atelectasis have evaluated atelectasis using computed tomography (CT), which is considered the gold standard for lung imaging. It is unsuitable for a regular examination of perioperative atelectasis because of the inconvenience and risk of radiation exposure.…”

“…[16] However, this meta-analysis did not consider the degree of atelectasis of the obese patient prior to anesthesia, and the various durations of exposure to different concentrations of oxygen and various types of surgeries were included. [12,13,15–17]…”