Oral thyroxin supplementation in infants undergoing cardiac surgery: A double-blind placebo-controlled randomized clinical trial.

Background: Decreases in serum total thyroxin and total triiodothyronine occurs after cardiopulmonary bypass, and is reflected as poor immediate outcome. We studied effects of oral thyroxin supplementation in infants who underwent open-heart surgery. Methods: In this prospective study, 100 patients were randomized into 2 groups: 50 in the thyroxin group (TH) and 50 in the placebo group (PL). Patients in the TH group received oral thyroxin (5 mg/kg) 12 hours before surgery and once daily for the remainder of their intensive care unit (ICU) stay. Data on intraoperative and postoperative variables were recorded. Cardiac index (CI) was measured. Perioperative serum thyroid hormone levels and serum interleukin-6 and tumor necrosis factor-a were measured. Secondary analysis was performed by dividing patients into simple and complex subcategories. Results: Results of the primary analysis indicated a higher CI in the TH compared with the PL. In the complex category, the mean duration of mechanical ventilation was 3.85 +/- 0.93 and 4.66 +/- 1.55 days in the TH and PL, respectively (P =.001). Mean ICU stay was 6.79 +/- 2.26 and 8.33 +/- 3.09 days (P =.03), and mean hospital stay was 15.70 +/- 4.77 and 18.90 +/- 4.48 days (P =.01) in the TH and PL, respectively. There were no significant differences between the TH and the PL in the simple category. CI was higher in the TH at all time points (P =.004). The average therapeutic intervention scoring system scores for the first 2 days were higher in the PL in the complex category. Conclusions: Oral thyroxin supplementation improves the CI and reduces the inotropic requirement. In addition, it reduces the duration of mechanical ventilation, ICU and hospital stay, and therapeutic intervention scoring system in infants after surgery for complex congenital heart defects.