Comparison of the Effect of High Versus Low Fraction of Inspired Oxygen During Alveolar Recruitment on Absorption Atelectasis in Laparoscopic Bariatric Surgery Patients With Atelectasis

The incidence of obesity (defined by a body mass index (BMI) > 30 kg/m2) is increasing worldwide. In selected individuals, bariatric surgery may offer means of achieving long-term weight loss, improved health, and healthcare cost reduction. Physiological changes that occur because of obesity and general anesthesia predispose to respiratory complications following bariatric surgery.

Obesity affects many respiratory functions, including, among others, a reduction in functional residual capacity, an increase in airway resistance, and a high level of ventilation-perfusion mismatch. The combination of obesity and postoperative respiratory muscle dysfunction could promote respiratory failure.

Absorption atelectasis occurs in most patients, typically due to absorption of gas, compression of the lung tissue, and impairment of surfactant function. Additionally, during laparoscopic surgery, the increased abdominal pressure of capnoperitoneum may shift the diaphragm cranially and decrease respiratory compliance.

Compression of basal lung regions due to a stiffened diaphragm would accelerate the formation of absorption atelectasis that was already initiated during anesthesia induction.

Such deterioration is associated with pulmonary densities revealed by computed tomography. In addition to physiologic impairment, atelectasis could contribute to perioperative lung injury and PPC.