Cardiopulmonary Bypass and Serum Thyroid Hormone Profile in Pediatric Patients with Congenital Heart Disease

摘要

Objective: To study the effect of cardiopulmonary bypass (CPB) on serum thyroid hormone profile in children undergoing open-heart surgery. Design: Prospective cross-sectional study. Setting: Multispecialty tertiary level referral center. Patients: One hundred consecutive patients (age 15.9±14.6 months, weight 6.7±2.5kg) undergoing open-heart surgery under CPB. Interventions: None. Outcome Measures: Levels and trends of serum total thyroxine (TT4), free thyroxine (FT4), total tri-iodothyronine (TT3), free tri-iodothyronine (FT3) and thyroid stimulating hormone (TSH), survival, inotropic score, duration of mechanical ventilation, postoperative complications. Results: TT4 levels were 9.08±3.6, 6.4±2.5, 6.24±2.1, 6.43±2.4, 7.20±3.0μg/dL at baseline and at 1, 24, 48 and 72 hours; FT4 levels were 1.82±0.5, 1.49±0.3, 1.29±0.3, 1.32±0.4, and 1.43±0.5ng/dL; TT3 levels were 1.81±0.4, 1.31±0.3, 0.99±0.2, 1.0±0.37, and 1.17±0.48ng/ml; FT3 levels were 4.09±1.0, 3.02±0.8, 2.21±0.6, 2.22±0.7, and 2.66±1.05pg/ml; TSH levels were 5.40±3.8, 2.0±3.1, 1.24±1.1, 2.90±3.3, and 4.03±3.4mIU/L. There was significant fall (29.1% for FT4, 32.1% for TT4, 77% for TSH, 46% for FT3 and 45% for TT3, p<0.0001). When area under curve (AUC) TT4 was compared between survivors (n = 87) and nonsurvivors (n=12), significantly larger AUC was seen in survivors (492.81±158.6) than nonsurvivors (360.75±179.6 p=0.0125). In survivors >72 hours, AUC TT4 was larger in patients with uneventful postoperative course versus those with postoperative complications (516.48±18.6 vs. 394.78±29.9, p=0.001). AUC TT4 showed significant inverse correlation with inotropic score and borderline inverse correlation with duration of mechanical ventilation. Conclusion: Children undergoing surgery under CPB showed significant fall in thyroid hormones. Because TT4 level is modifiable, prophylactic administration of TT4 for improving outcomes needs to be studied further.