Effects of phentolamine on tissue perfusion in pediatric cardiac surgery

Abstract

Objective: To evaluate whether the deleterious effects of cardiopulmonary bypass (CPB) can be overcome by phentolamine-induced pharmacologic vasodilation in pediatric patients with congenital heart disease. Design: Prospective, randomized, clinical study. Setting: Single university hospital. Participants: Forty-three pediatric patients undergoing open cardiac surgery for repair of congenital heart disease. Interventions: Patients were randomly allocated into two groups. Patients in group 1 (n = 22) received 0.2 mg/kg of phentolamine during the cooling and rewarming periods of CPB. Group 2 patients (n = 21) did not receive phentolamine. Temperature measurements (rectal [R], nasopharyngeal [N], and toe [P]) and serum lactate values were obtained before, during, and after CPB; systemic oxygen consumption was evaluated during CPB. Measurements and Main Results: At the end of the CPB period and at the end of the operation, lactate values of group 1 (1.87 ± 0.37 and 1.8 ± 0.39 mmol/L, respectively) were significantly lower than values of group 2 (2.24 ± 0.28 and 2.33 ± 0.33 mmol/L; p < 0.05 and p < 0.05, respectively). At the beginning of the rewarming period N-R temperature gradients of group 1 (0.14°C ± 0.92°C) were lower than group 2 (−0.58°C ± 1.84°C) values ( p < 0.05). Central-peripheral temperature gradients of group 1 obtained at the end of the CPB period (N-R = 2.18°C ± 0.69°C; N-P = 7.84°C ± 1.54°C; R-P = 5.66°C ± 1.70°C) were significantly lower than the values of group 2 (N-R = 2.80°C ± 0.91°C, N-P = 9.97°C ± 2.02°C; R-P = 7.18°C ± 2.10°C; p < 0.05; p < 0.001; p < 0.05). At the end of the operation values of group 1 (N-R = 0.48°C ± 0.31°C; N-P = 6.30°C ± 1.23°C; R-P = 5.82°C ± 1.16°C) were significantly lower than the values of group 2 (N-R = 0.94°C ± 0.56°C; N-P = 8.69°C ± 0.28°C; R-P = 7.75°C ± 2.15°C; p < 0.05; p < 0.001; p < 0.001). The systemic oxygen consumption values of group 1 were higher than group 2 (6.26 ± 1.82 v 5.17 ± 1.05 mL/min/kg; p < 0.05) after complete rewarming. Mean arterial pressure (MAP) values of group 1 (58.9 ± 6.4 mmHg) were lower than group 2 (63.4 ± 6.7 mmHg) at the period after CPB ( p = 0.03). Conclusion: The results suggest that the use of phentolamine during CPB is associated with limited systemic anaerobic metabolism and more uniform body perfusion.