Preventive efficacy of oral small-dose thyroid hormone tablet premedication for a short time on euthyroid sick syndrome in children undergoing open heart surgery under cardiopulmonary bypass

Abstract

Objective To evaluate the preventive efficacy of oral small-dose thyroid hormone tablet premedication for a short time on euthyroid sick syndrome (ESS) in children undergoing open heart surgery under cardiopulmonary bypass (CPB) .Methods Forty ASA Ⅰ or Ⅱ children aged 3-12 yr, weighing 10-30 kg, scheduled for elective congenital heart disease surgery under CPB, were randomly allocated into 2 groups ( n = 20 each):placebo group (group P) and thyroid hormone tablet group (group T). Group T received oral thyroid hormone tablets 0.4 mg/kg every day for 4 consecutive days before surgery, while group C were given placebo. CPB was routinely established, and mild hypothermia, moderate hemodilution and high flow perfusion were adopted. Blood samples were taken from radial veins before administration (baseline) and on 1st, 2nd and 4th day after surgery to detect the serum concentrations of triiodothyronine (T3), thyroxine (T4) and thyroid stimulating hormone (TSH).SP, DP and HR were recorded before administration, immediately after surgery, and on 1st and 2nd day after surgery. The endotracheal extubation time, length of ICU stay, application of positive inotropic agents and occurrence of ESS were recorded. Results No significant difference was found in hemodynamic parameters, endotracheal extubation time and length of ICU stay between the two groups ( P ＞ 0.05). As compared with the baseline values,the serum T3 levels on 1st, 2nd and 4th day after surgery, and the serum TSH levels on 1 st day after surgery were significantly decreased in the two groups, and the serum T4 levels were significantly decreased on 1 st day after surgery in group P ( P ＜ 0.05). The serum levels of T3 and T4 were significantly higher, the severity of postoperative ESS and the number of positive inotropic agent administration were significantly lower in group T than in group P (P ＜ 0.05 ). Conclusion Although oral small-dose thyroid hormone tablet premedication for 4 days (0.4 mg/kg per day) can reduce the severity of postoperative ESS, but it can not prevent the occurrence of ESS in children undergoing open heart surgery under CPB. Key words: Thyroid hormones; Euthyroid sick syndromes; Extracorporeal circulation; Cardiac surgical procedures; Child