Effects of pulsatile perfusion on plasma catecholamine levels and hemodynamics during and after cardiac operations with cardiopulmonary bypass

Abstract

Thirty patients scheduled for elective coronary artery bypass grafting were studied in two groups. Group A had standard cardiopulmonary bypass with nonpulsatile perfusion and group B had pulsatile perfusion. Measurements of plasma epinephrine, norepinephrine, granulocyte elastase, and hemodynamic parameters including mean arterial pressure total peripheral resistance, cardiac index, and pulmonary capillary wedge pressure were made before and after anesthesia induction, after surgical incision, during cardiopulmonary bypass, and 2, 4, and 24 hours after the operation. The venous compliance of the total body venous bed was measured at the end of the operation. In all patients the total net fluid balance was determined during bypass and in the postoperative period. In both groups plasma catecholamine levels increased 5 minutes after institution of bypass (epinephrine 176 +/- 56 to 611 +/- 108 pg/ml and norepinephrine 231 +/- 48 to 518 +/- 100 pg/ml in group A; epinephrine 168 +/- 40 to 444 +/- 100 pg/ml and norepinephrine 162 +/- 44 to 267 +/- 52 pg/ml in group B). The maximum catecholamine level was measured between the end of bypass and 2 hours after the end of bypass (epinephrine 1489 +/- 169 pg/ml and norepinephrine 1542 +/- 108 pg/ml in group A; epinephrine 990 +/- 134 pg/ml and norepinephrine 934 +/- 197 pg/ml in group B). During the same period mean arterial pressure and total peripheral resistance were also significantly higher in group A than in group B mean arterial pressure, 61.4 +/- 3 versus 53.6 +/- 3, p less than 0.06; total peripheral resistance, 1055 +/- 60 versus 899 +/- 45, p less than 0.01). The venous compliance was significantly higher in group A than in group B (2.4 +/- 0.3 versus 1.2 +/- 0.3 ml/mm Hg/kg body weight). The intraoperative and perioperative net fluid balance were significantly higher in group A than in group B (p less than 0.005). The average postoperative tracheal intubation time was also significantly longer in group A than in group B (4.6 +/- 1.2 hours versus 2.7 +/- 0.8 hours, p less than 0.001). No significant difference was detected in either hemoglobin or plasma free hemoglobin content between the two groups postoperatively. The results suggest that pulsatile perfusion, when compared with nonpulsatile perfusion, can attenuate the catecholamine stress response to cardiopulmonary bypass, reduce the fluid overloading of patients, and improve the postoperative recovery period as evaluated by tracheal intubation time.