Effects of positive end-expiratory pressure (PEEP) in cardiac surgery patients

Abstract

The role of positive end-expiratory pressure (PEEP) in the postoperative course of cardiac surgery patients remains questionable. In this prospective study, we examined the effect of different levels of PEEP on arterial oxygenation, SvO2 and PvO2 values, and on haemodynamic indices, during the early postoperative period in cardiac surgery patients. Upon transfer to the ICU, 67 adult patients with normal preoperative respiratory status were randomly assigned to receive zero PEEP (Group A), 5 cmH2O (Group B), or 10 cmH2O PEEP (Group C) during mechanical ventilatory support. PaO2/FIO2 ratio, mixed venous PvO2 and SvO2, and cardiac index, were measured 30 min, 4 h and 8 h after application of mechanical ventilation in the ICU, just prior to extubation, half an hour after extubation, and 4 h post-extubation. We found no statistically significant differences (P = n.s.) in arterial oxygenation expressed by PaO2/FIO2 ratio, SvO2 and PvO2 values, and in cardiac index among the three groups at any study interval. We conclude that low levels of PEEP have no advantage over zero PEEP in improving gas exchange in the early postoperative course of patients following open heart surgery.

Effects of Positive End-Expiratory Pressure on Mechanical Ventilation Duration after Coronary Artery Bypass Grafting: A Randomized Clinical Trial

“…The presence of cardiac dysfunction and prolonged cardiopulmonary bypass were factors associated with an increased duration of mechanical ventilation in a study by Nozawa, et al 17) Other studies evaluating the effect of PEEP on postoperative cardiac surgery reported controversial results regarding the duration of mechanical ventilation. Michalopoulos, et al 18) compared the effects of different levels of PEEP (0, 5 and 10 cmH 2 O) on arterial oxygenation in patients undergoing cardiac surgery and showed no difference in the duration of mechanical ventilation between groups.…”

Pressão expiratória positiva na via aérea por máscara facial na hemodinâmica de pós-operatórios cardíacos

“…The prophylactic use of PEEP with levels of 10 cmH 2 O was safe, although it has not reduced chest drainage output 30 . In a study comparing the use of three levels of PEEP (0, 5 and 10 cmH 2 O) in RHS in patients with EF ≥ 45%, there were no statistical differences between groups, which led us to conclude that low levels of PEEP have no advantage over zero level of PEEP in improving gas exchange in patients RHS 31 . The effects of PEEP on respiratory mechanics and hemodynamics of patients after cardiac surgery resulted in reduced airway resistance and respiratory elastance, which may reflect an improved respiratory mechanics 6 .…”

Effects of different PEEP levels on respiratory mechanics and oxygenation after coronary artery bypass grafting

“…Michalopoulos et al [19] examined the effects of different levels of PEEP (0.5 and 10 cmH 2 O) in arterial oxygenation in patients after cardiac surgery and showed no advantage in gas exchange applying low levels of PEEP when compared to no PEEP.…”