Murzi B, Iervasi G, Masini S, Moschetti R, Vanini V, Zucchelli G, Biagini A
Institute of Clinical Physiology, National Research Council, Pisa, Italy.
Ann Thorac Surg. 1995 Feb;59(2):481-5. doi: 10.1016/0003-4975(94)00879-c.
The concentrations of thyroid hormones were measured in 14 pediatric patients before, during, and after cardiopulmonary bypass. The ages of the patients ranged between 18 months and 14 years. Patients were kept normothermic, or moderate or deep hypothermia was induced depending on the specific pathologic condition involved. A marked reduction in the levels of total triiodothyronine, total thyroxine, free triiodothyronine, and thyroid-stimulating hormone, and in the ratio of free triiodothyronine to free thyroxine was detected during the time frame of the study. The minimum levels of each hormone were reached between 12 and 48 hours after cardiopulmonary bypass, indicating that changes in thyroid function and in the conversion of thyroxine to triiodothyronine are triggered by cardiopulmonary bypass and represent specific phenomena, and that these changes are progressively exacerbated during the post-operative period. The thyroid-stimulating hormone level was markedly reduced versus its baseline values (24% +/- 0.13%), despite low levels of both total (40% +/- 18%) and free (39% +/- 20%) triiodothyronine: it returned to its preoperative level by the third postoperative day, but both the total (75% +/- 10%) and free (74% +/- 3%) triiodothyronine levels remained below their baseline values for 7 days postoperatively. Neither hemodilution nor hypothermia was responsible for the alteration observed. We conclude that pediatric patients undergoing cardiopulmonary bypass manifest changes in hormone metabolism similar to those seen in adult patients. These changes increase progressively during the postoperative period, and are still present 7 days postoperatively. The exact mechanism responsible for causing these changes is not thoroughly understood. Whether triiodothyronine replacement therapy is beneficial or deleterious remains controversial.
在14名儿科患者体外循环前、体外循环期间和体外循环后测量了甲状腺激素浓度。患者年龄在18个月至14岁之间。根据所涉及的具体病理情况，患者保持正常体温，或诱导中度或深度低温。在研究期间，检测到总三碘甲状腺原氨酸、总甲状腺素、游离三碘甲状腺原氨酸和促甲状腺激素水平显著降低，以及游离三碘甲状腺原氨酸与游离甲状腺素的比值降低。每种激素的最低水平在体外循环后12至48小时达到，这表明体外循环引发了甲状腺功能和甲状腺素向三碘甲状腺原氨酸转化的变化，代表了特定现象，并且这些变化在术后期间逐渐加剧。尽管总三碘甲状腺原氨酸（40%±18%）和游离三碘甲状腺原氨酸（39%±20%）水平较低，但促甲状腺激素水平相对于其基线值显著降低（24%±0.13%）：术后第三天恢复到术前水平，但总三碘甲状腺原氨酸（75%±10%）和游离三碘甲状腺原氨酸（74%±3%）水平在术后7天仍低于其基线值。观察到的改变既不是由血液稀释也不是由低温引起的。我们得出结论，接受体外循环的儿科患者表现出与成年患者相似的激素代谢变化。这些变化在术后期间逐渐增加，并且在术后7天仍然存在。导致这些变化的确切机制尚未完全了解。三碘甲状腺原氨酸替代疗法是有益还是有害仍存在争议。
