Effects of intraoperative PEEP on postoperative arterial oxygenation.

Previous studies have suggested that early postoperative hypozemia may be due to a reduction of functional residual capacity (FRC) during anesthesia and surgery. Positive end-expiratory pressure (PEEP) has been recommended as a means of maintaining FRC and improving arterial oxygenation. Fifteen selected patients undergoing peripheral surgical procedures were anesthetized with one of three types of ventilatory patterns: (1) spontaneous respiration; (2) controlled ventilation; and (3) controlled ventilation with 10 cm. of water PEEP. Pao2 were sampled at selected preoperative, intraoperative, and postoperative periods. Patients receiving PEEP maintained the highest mean Pao2 intraoperatively. However, the beneficial effect of intraoperative PEEP was not sustained in the recovery room, where all patients experienced the same degree of arterial hypoxemia.