[Hypoxemia during cesarean section--evaluation of venous air embolism by transesophageal echocardiography].

We studied the incidence and cause of hypoxemia during Cesarean section under general anesthesia. Arterial oxygen desaturation (< or = 95%) occurred in 6 of 28 patients (21%). Venous air embolism (VAE) was detected in 7 of 28 subjects (25%), but the severity of which was mild and was not associated with oxygen desaturation. While, there were significant differences in obesity index, preoperative respiratory function, and PaO2 after the induction of anesthesia between the patients with and without oxygen desaturation. Our results suggest that hypoxemia may occur frequently during Cesarean section under general anesthesia, but is not caused by VAE, and is related with the physiological changes associated with pregnancy.