Objectives: This study was conducted to determine if oral triiodothyronine supplementation could prevent the decrease of serum triiodothyronine levels that commonly occurs after cardiopulmonary bypass for pediatric congenital heart surgery. Secondary objectives included identifying any significant adverse effects of oral triiodothyronine supplementation, including any effects on the thyroid/pituitary axis.
Design: Randomized, placebo-controlled, doubleblind clinical trial
Setting: Operating room and ICU.
Subjects: Infants and children younger than 2 years of age undergoing congenital heart surgery using cardiopulmonary bypass (n = 43).
Interventions: Subjects were assigned to placebo (n = 15, group A) or one of two treatment groups: a low-dose group (group B, n = 14, 0.5 mcg/kg triiodothyronine orally every 24 hr for 3 d) or a high-dose group (group C, n = 14, 0.5 mcg/kg triiodothyronine orally every 12 hr for 3 d).
Measurements and Main Results: Thyroid hormone, including total and free triiodothyronine levels at predetermined time points, potential side effects indicatinghyperthyroidism, indicators of the thyroid-pituitary axis, and clinicalendpoints. Oral triiodothyronine supplementation twice-daily maintainedserum triiodothyronine levels within normal limits in groupC, whereas serum levels progressively declined in groups A and B. A statistically significant difference in triiodothyronine levels between the treatment groups occurred between 18 and 36 hourspost cross-clamp release, with the largest difference in serum levelsbetween group C and group A noted at 36 hours post cross-clamprelease (total triiodothyronine, 0.71 ± 0.15 [0.34–1.08] ng/mL [p < 0.01]; free triiodothyronine, 2.56 ± 0.49 [1.33–3.79] pg/mL [p < 0.01]). There was no evidence of hyperthyroidism or suppressionof the pituitary-thyroid axis in either treatment group
Conclusions: Oral triiodothyronine supplementation at a dose of 0.5 mcg/kg every 12 hours for 3 days can maintain total and free triiodothyronine levels within normal limits after open-heart surgery using cardiopulmonary bypass for congenitalheart disease.
1Department of Pediatric Cardiac Intensive Care and Anaesthesiology, National Cardiovascular Center Harapan Kita, Jakarta, Indonesia.
2Department of Cardiology and Vascular Medicine, National Cardiovascular Center Harapan Kita, Jakarta, Indonesia.
3Department of Pediatric Cardiac Surgery, National Cardiovascular Center Harapan Kita, Jakarta, Indonesia.
4Department of Clinical Pathology, National Cardiovascular Center Harapan Kita, Jakarta, Indonesia.
5Division of Epidemiology and Biostatistics, Department of Community Medicine, University of Indonesia, Jakarta, Indonesia.
6Department of Critical Care Medicine, The Hospital for Sick Children, University of Toronto School of Medicine, Toronto, ON, Canada.
7Department of Congenital Heart Defects, Heart and Diabetes Centre, North Rhein-Westfalia, Bad Oeynhausen, Germany.
* See also p. 725.
Supported, in part, by the National Cardiovascular Center Harapan Kita, Indonesia. We thank Dalim Biotech, Korea, for donation of oral triidothyronine used in this study.
Dr. Marwali received funding from the National Cardiovascular Center Harapan Kita (Jakarta, Indonesia). Dr. Haas served as a board member for the German Society of Pediatric Cardiology. The remaining authors have disclosed that they do not have any potential conflicts of interest.
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