Failure of positive end-expiratory pressure to decrease postoperative bleeding after cardiac surgery

To determine whether the application of positive end-expiratory pressure (PEEP) in the postoperative period after cardiac operation would reduce postoperative blood loss, the number of transfusions required, or the rate of reoperation for bleeding, we conducted a prospective study of 83 patients who underwent elective coronary revascularization. These patients were randomly assigned to receive either PEEP (10 cm H2O) or no PEEP (zero end-expiratory pressure). All other aspects of their care were identical. There was no statistically significant reduction in the amount of bleeding in patients treated with PEEP at 8 or 24 hours postoperatively. There was no significant difference in hematocrit between the groups preoperatively or postoperatively. There was no statistically significant difference in the number of reexplorations for bleeding. Finally, there was no significant difference between the groups in the amount of blood administered. On the basis of our results, we conclude that the application of PEEP in the postoperative period of cardiac operation did not reduce the amount of blood loss, the need for reexploration for bleeding, or the blood requirements in this group of patients.