OBJECTIVE: The purpose of this study was to investigate any potential 
hemodynamic effect of intravenously administered triiodothyronine in patients 
undergoing coronary artery bypass surgery.
EXPERIMENTAL DESIGN: Thirty patients were randomized in this single-blind, 
placebo-controlled trial. Hemodynamic parameters including heart rate, stroke 
volume index, cardiac index, pulmonary wedge pressure, pulmonary vascular 
resistances, systemic vascular resistances, and mean blood pressure, were 
compared between the two groups preoperatively, before the initiation 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 removal of the aortic cross-clamp, (0.15 microgram/kg), before the 
end of CPB (0.1 microgram/kg), 4 hours after the end of CPB (0.1 microgram/kg), 
9 hours after CPB (0.1 microgram/kg), and 14 hours after CPB (0.1 microgram/kg). 
Patients received inotropes, vasodilators, and diuretics only if specifically 
indicated.
RESULTS: Plasma FT3 levels were higher in the T3 group, but within 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 adverse reactions were noted with 
triiodothyronine administration.
CONCLUSION: Triiodothyronine administration in patients undergoing 
cardiopulmonary bypass surgery is safe, may lessen the need for pharmacological 
(vasodilator) therapy, but may increase heart rate.