Effects of phentolamine on tissue perfusion in pediatric cardiac surgery

Objective: To evaluate whether the deleterious effects of cardiopulmonary b ypass (CPB) can be overcome by phentolamine-induced pharmacologic vasodilat ion in pediatric patients with congenital heart disease. Design: Prospective, randomized, clinical study. Setting: Single university hospital. Participants: Forty-three pediatric patients undergoing open cardiac surger y for repair of congenital heart disease. Interventions: Patients were randomly allocated into two groups. Patients i n group 1 (n = 22) received 0.2 mg/kg of phentolamine during the cooling an d rewarming periods of CPB. Group 2 patients (n = 21) did not receive phent olamine. 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 (2.2 4 +/- 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 degrees C +/- 0.92 degrees C) were lower than group 2 (-0.58 degre es C +/- 1.84 degrees C) values (p < 0.05). Central-peripheral temperature gradients of group 1 obtained at the end of the CPB period (N-R = 2.18 degr ees C +/- 0.69 degrees C; N-P = 7.84 degrees C +/- 1.54 degrees C; R-P = 5. 66 degrees C +/- 1.70 degrees C) were significantly lower than the values o f group 2 (N-R = 2.80 degrees C +/- 0.91 degrees C, N-P = 9.97 degrees C +/ - 2.02 degrees C; R-P = 7.18 degrees C +/- 2.10 degrees C; p < 0.05; p < 0. 001; p < 0.05). At the end of the operation values of group 1 (N-R = 0.48 d egrees C +/- 0.31 degrees C; N-P = 6.30 degrees C +/- 1.23 degrees C; R-P = 5.82 degrees C +/- 1.16 degrees C) were significantly lower than the value s of group 2 (N-R 0.94 degrees C +/- 0.56 degrees C; N-P = 8.69 degrees C /- 0.28 degrees C; R-P = 7.75 degrees C +/- 2.15 degrees C; p < 0.05; p < 0 .001; p < 0.001). The systemic oxygen consumption values of group 1 were hi gher 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 afte r 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. Copyright (C) 1999 by W.B. Saunders Company.