The Effects Of ECC Surgery On Thyroid Hormone For Infants Weighting Less Than 10kg

Objective: To observe the tendency and law of thyroid hormone perioperatively, and explore the effects of ECC on thyroid hormone metabolism in low weight infants undergoing ECC surgeries.Methods: 21 infants weighting less than 10kg undergoing ventricular septal defect(VSD) repair surgeries on ECC was investigated. The venous blood samples were collected at five time points: before ECC, after ECC, 1 day, 2 day, and 4 day post-operatively. The concentration of serum thyroid hormone triiodothyronine(T3), tetraiodothyronine(T4) and thyroid stimulating hormone(TSH) ware assayed by Microparticle Enzyme Immunoassay (MEIA).Results: The concentration of T3 decreased significantly after ECC, from 1.05±0.35ng/ml to 0.83±0.19ng/ml, which was 21% less than that before ECC, and went on decreasing by 49% on the first day post-operatively and 61% on the second day post-operatively to 0.83±0.19ng/ml, which reached the lowest point. Then it began to recovery, but didn't reach the level before ECC yet, 21% lower than that before ECC; The concentration of T4 didn't decrease obviously after ECC and the first day post-operatively, but decreased from 7.65±1.73ug/dl to 5.81±1.30ug/dl on the second day after ECC, and recovered to the level before ECC on the fourth day. The concentration of TSH increased rather than decreased after ECC, but decreased obviously on the first and second day after operation, from 1.71±1.34uIU/L to 0.38±0.24uIU/L and 0.57±0.54uIU/L, which was 78% and 66% lower. Then it recovered to the level before ECC on the fourth day.Conclusion: ECC surgery in infants is a definite risk factor related to Euthyroid Sick Syndrome, especially for low birth weight infants. Infants weighting less than 10kg undergoing ECC surgeories could develop type II Euthyroid Sick Syndrome perioperatively and the concentrations of T3, T4 and TSH decreases at different time points. ECC surgery has great effects on the level and function of thyroid hormone of infants, especially for low birth weight infants, so it makes great sense to monitor the thyroid hormone level of the infants perioperatively and supplement thyroid hormone early after surgery.