体外循环心脏手术对机体甲状腺素代谢的影响及其临床意义

Effect of Cardiac Surgery under Cardiopulmonary Bypass on Thyroid Hormone

目的：明确体外循环心脏手术对机体甲状腺素代谢的影响并探讨其临床意义。方法：随机选择２１例体外循环心脏病人，用放免法分别于术前、术后 ２、２４、４８ ｈ、第七天测定血浆 Ｔ ３、Ｔ ４、ＦＴ ３、ＦＴ ４、ｒＴ ３、ＴＳＨ的含量。结果：Ｔ ３、Ｔ ４、术中明显下降，术后２ｈ开始上升，至术后第七天基本恢复正常（Ｐ＜０．００１）。ＦＴ３、ＦＴ４术中无明显改变，术后２４ｈ明显下降，至术后第七天仍未恢复（ Ｐ＜ ０． ０５）。 ｒＴ３术中下降，术后进行性升高。 ＴＳＨ无明显改变。伴有围术期并发症的患者术后 Ｔ ３恢复明显延迟。结论：（１）体外循环可导致低甲状腺素血症（以低Ｔ３尤为显著）；（２）术后Ｔ３恢复状况与预后有一定关系。

Objective: To detect the effect of cardiopulmonary bypass (CPB) on the concentration of thyroid hormone of patients suffered from heart diseases. Methods: Blood samples were obtained from 21 patients suffered from heart diseases at the following intervals: before operation, 5 minutes after the beginning of the CPB, at the lowest point of hypothermia, at the end of CPB, 2 hours postoperation, 24 hours postoperation, 48 hours postoperation, 7 days postoperation. The thyroid stimulating hormone (TSH), total triiodthyronine (T3 ), total thyroxine (T4 ), free triidothyronine (FT3 ), free thyroxine (FT4) and reverse T3(rT3) were measured by radioimmunoassay. Results: It showed significant decline of T3 and CPB (P < 0.001), but a return to normal at the 7 days postoperation. FT3, FT4 towered significantly 24 hours postoperation and without return to normal 7days postoperation (P <0. 05). A significant rise of rT3 was demonstrated at 7 days postoperation. TSH showed little change during operation. Conclusion: CPB may lead to hypothyroidism during operation (specially the low T3 concentration) and the change of T3 level closely correlate with the prognosis.