Objectives: To determine whether hypothermic cardiopulmonary bypass (CPB) per se causes an increase in angiotensin II (A-II) concentration in infants and to investigate the relationship between A-II concentration and gut mucosal perfusion. Design: Prospective, open, nonrandomized, observational study. Setting: Children's teaching hospital. Participants: Thirty acyanotic infants requiring CPB. Interventions: A-II concentrations were measured on six occasions before, during, and after CPB. An orogastric tonometer allowed intermittent calculations of gastric intramucosal pH (pHi). Gastric mucosal blood flow (flux) was monitored using a laser Doppler flowmeter. Ten infants acted as controls (group 1); 10 infants received captopril, 0.9 mg/kg orally, 45 minutes before induction of anesthesia (group 2), and 10 infants received enalaprilat, 0.06 mg/kg intravenously, just before CPB (group 3). Measurements and Main Results: A-II concentrations were abnormally high in 28 of 30 patients before CPB (median, 450 pg/mL (range, 83 to 5,787 pg/mL). A-II concentrations in groups 1 and 2 decreased during CPB, but values remained at twice normal levels throughout surgery (median, 171 to 198 pg/mL post-CPB). A-II concentrations remained normal (range, 52 to 120 pg/mL) during and after CPB in patients receiving enalaprilat (group 3). The authors found no significant correlation between A-II concentration and phi or flux before, during, or after surgery. Conclusions: Acyanotic infants requiring cardiac surgery may have high perioperative concentrations of A- II. Hypothermic CPB is associated with a decrease in A-II concentration. Reductions in gut mucosal perfusion seen in some infants during hypothermic CPB are not related to increases in A-II concentrations.
CITATION STYLE
Booker, P. D., Davis, A. J. M., Diver, M. J., & Whitehead, C. F. (1999). Angiotensin II concentrations and gut mucosal perfusion in infants undergoing cardiopulmonary bypass. Journal of Cardiothoracic and Vascular Anesthesia, 13(4), 446–450. https://doi.org/10.1016/S1053-0770(99)90218-5
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