Respiratory complications in the postanesthesia care unit: A review of pathophysiological mechanisms.

General anesthesia and mechanical ventilation impair pulmonary function, even in normal individuals, and result in decreased oxygenation in the postanesthesia period. They also cause a reduction in functional residual capacity of up to 50% of the preanesthesia value. It has been shown that pulmonary atelectasis is a common finding in anesthetized individuals because it occurs in 85% to 90% of healthy adults. Furthermore, there is substantial...