Effect of perioperative use of oral triidothyronine for infants undergoing complex congenital cardiac surgeries under cardiopulmonary bypass: A double-blinded randomised controlled study

Abstract

Background: Thyroid hormone metabolism disrupts after cardiopulmonary bypass both in adults and pediatric patients. This is known as Euthyroid sick syndrome, and it is more evident in pediatric patients who were undergoing complex cardiac surgeries compared to adults. This decrease in serum T3 levels increases the incidence of low cardiac output, requirement of inotropes, prolonged mechanical ventilation, and prolonged intensive care unit (ICU) stay. Aims and Objectives: The primary objective was to compare the mean Vasoactive-inotropic score (VIS) at 72 hours postoperatively between T3 and Placebo groups. Materials and Methods: One hundred patients were screened, and 88 patients were included in the study. Triidothyronine 1 mic/kg 10 doses 8 th hourly was given orally postoperatively to cases and sugar sachets to controls. The blood samples for analysis of FT3, FT4, and TSH were taken every 24 hours postoperatively, and baseline values were taken after induction. Mean VIS scores, ejection Fraction (EF), Left ventricular outflow tract velocity time integral (LVOT VTi), hemodynamics and partial pressure of oxygen/ fraction of inspired oxygen(PaO2/FiO2) were recorded daily. Results: The Mean VIS scores at 72 Hours postoperatively were significantly less in the T3 group (5.49 ± 6.2) compared to the Placebo group (13.6 ± 11.7). The PaO2/FiO2 ratios were comparatively more in the T3 group than the Placebo group. The serum levels of FT3 FT4 were significantly higher in the T3-supplemented group than the Placebo group. The VIS scores were significantly lower from 48 hours postoperatively in children < 6 months of age. Conclusion: In this study, we observed that supplementing T3 postoperatively decreases the ionotropic requirement from 72 hours postoperatively. This is more useful in children <6 months of age undergoing complex cardiac surgeries.

The use of triiodothyronine during critical illness

“…A similar study was conducted in an Indian hospital, where 88 infants undergoing complex cardiac surgery were randomized to receive T3 (1 μg/kg 8 hourly) or placebo for 80 h [14]. The primary outcome was a vasoactive-inotrope score, however it is unclear how this score was derived, or how the investigators determined the study sample size.…”