Total and free thyroid hormone concentrations after elective surgery

Changes in thyroid hormone concentration and distribution and plasma cortisol levels have been followed in 11 patients undergoing elective cholocystectomy. A significant rise in total and free thyroxine (T4) and fall in total and free triiodothyronine (T3) were noted after surgery. Reverse T3 concentrations rose substantially, suggesting that peripheral conversion of T4 to T3 is diminished and that there is preferential formation of reverse T3. Serum thyroid stimulating hormone concentrations did not change. There was no direct correlation between the change in cortisol and the change in thyroid hormone or reverse T3 concentrations.