ABSTRACT
BACKGROUND: Critical illness that requires major surgery is often associated with non-thyroidal illness syndrome (NTIS). The characteristic feature of NTIS is low serum triiodothyronine (T3) levels, and in severe illness, the levels of serum thyroxine (T4) are also low in the absence of a rise in thyroid stimulating hormone (TSH). However, little is known about the changes in thyroid hormones during and after liver transplantation (LT). This study was conducted in order to evaluate the intra- or postoperative changes in thyroid hormones. METHODS: Twenty-two patients who underwent LT were enrolled. Serum levels of triiodothyronine (T3), thyroxine (T4), thyroid stimulating hormone (TSH), free T3 (FT3) and free T4 (FT4) were measured immediately after the induction of anesthesia (T1), at the end of the anhepatic period (T2), at the end of the surgical procedure (T3), and at 24 hours (T4) and 120 hours postoperatively (T5). RESULTS: The mean levels of T3, T4, FT3, FT4 and TSH were significantly decreased throughout the study when compared with the T1 value. The mean levels of T3, T4 FT3 and TSH were below the normal range from T2, T4 and T5. CONCLUSIONS: We suggest that LT may induce NTIS by at least postoperative day 5. In the future, longer follow-up studies, and the effects of thyroid hormones on the prognosis and determination of the advantages and disadvantages of T3 replacement therapy to these patients will be required.