The pulmonary and hemodynamic effects of two different recruitment maneuvers after cardiac surgery

The aim of our study was to evaluate the pulmonary and hemodynamic effects of two different recruitment maneuvers after open heart surgery.

Sixty patients undergoing coronary artery bypass surgery were randomized into three groups after operation: recruitment maneuver with continuous positive airway pressure (CPAP) (CPAP-40 group, n = 20), recruitment by positive end-expiratory pressure (PEEP) (PEEP-20 group, n = 20), and 5 cm H2O PEEP (PEEP-5 group, n = 20). In the CPAP-40 group, 40 cm H2O peak inspiratory pressure was applied for 30 s, then PEEP was reduced to 20 cm H2O and ventilation was continued with baseline variables with PEEP decreased until the best Pao2 was achieved. In the PEEP-20 group, 20 cm H2O PEEP was set for 2 min, tidal volume was adjusted to achieve a peak inspiratory airway pressure of 40 cm H2O during the maneuver, then PEEP was decreased until the best Pao2 had been achieved. In the PEEP-5 group, 5 cm H2O PEEP was applied postoperatively.

The mean arterial blood pressure of the CPAP-40 group was lower than that of the PEEP-20 (P < 0.01) and PEEP-5 groups (P < 0.01) during the interventions. Oxygenation was higher in both recruitment groups than in the PEEP-5 group during the mechanical ventilation period. There was no significant difference among the groups beyond that period. The atelectasis score of the PEEP-5 group (1.3 +/- 0.9) on postoperative day 1 was higher than that of the CPAP-40 (0.65 +/- 0.6; P = 0.01) and PEEP-20 (0.65 +/- 0.5; P = 0.01) groups.

The recruitment techniques with postmaneuver PEEP increased oxygenation and decreased atelectasis equally, whereas PEEP-20 provided more stable hemodynamic conditions than the CPAP maneuver.