TRIIODOTHYRONINE ADMINISTRATION IN CORONARY-ARTERY BYPASS-SURGERY - EFFECT ON HEMODYNAMICS

Objective. The purpose of this study was to investigate any potential hemodynamic effect of intravenously administered triiodothyronine in p atients undergoing coronary artery bypass surgery. Experimental design . Thirty patients were randomized in this single-blind, placebo-contro lled trial. Hemodynamic parameters including heart rate, stroke volume index, cardiac index, pulmonary wedge pressure, pulmonary vascular re sistances, systemic vascular resistances, and mean blood pressure, wer e compared between the two groups preoperatively, before the initiatio n of cardiopulmonary bypass (CPB), 5 minutes after the end of CPB, and 2, 4, 10, 16, and 22 hours thereafter. Intervention. Triiodothyronine was administered as a bolus infusion over a 1 min period after remova l of the aortic cross-clamp, (0.15 mu g/kg), before the end of CPB (0. 1 mu g/kg), 4 hours after the end of CPB (0.1 mu g/kg), 9 hours after CPB (0.1 mu g/kg), and 14 hours after CPB (0.1 mu g/kg). Patients rece ived inotropes, vasodilators, and diuretics only if specifically indic ated. Results. Plasma FT3 levels were higher in the T3 group, but with in the normal range. No significant differences were noted in the pre and post CPB hemodynamics between the two groups for the most part of the study except that heart rate was increased in T3 group. A greater number of patients in the control group received vasodilators. No adve rse reactions were noted with triiodothyronine administration. Conclus ion. Triiodothyronine administration in patients undergoing cardiopulm onary bypass surgery is safe, may lessen the need for pharmacological (vasodilator) therapy, but may increase heart rate.