Complications of surgery in hypothyroid patients.

Hypothyroidism has generally been considered a contraindication to surgery. To determine the actual risks of perioperative complications in hypothyroid patients, the clinical courses of 40 hypothyroid surgical patients (serum thyroxine concentration 1.9 +/- 1.0 micrograms/dl) were retrospectively compared with those of 80 control patients matched for age, sex, and operative procedure. The two study groups were comparable in preoperative anesthetic physical class, prevalence of other medical conditions, and year of operation. During noncardiac surgery, intraoperative hypotension was encountered more frequently in the hypothyroid patients than in the control patients (61 versus 30 percent, p less than 0.05). Cardiac surgery was complicated by heart failure more often in the hypothyroid patients (29 versus 6 percent, p less than 0.05). Postoperatively, the hypothyroid patients more commonly had gastrointestinal (19 versus 1 percent, p less than 0.02) and neuropsychiatric (38 versus 18 percent, p less than 0.02) complications than control patients. Despite comparable rates of perioperative infection (38 versus 33 percent, p = NS), the hypothyroid patients less frequently manifested fever (35 versus 79 percent, p less than 0.001). There were no differences in perioperative blood loss, duration of hospitalization, or the prevalences of perioperative arrhythmia, hypothermia, hyponatremia, delayed anesthetic recovery, abnormal tissue integrity, impaired wound healing, pulmonary complications, or death. Preoperative clinical and chemical features of hypothyroidism were not useful in defining a subgroup of patients at special risk. Thus, surgery in hypothyroid patients is associated with an increased risk of several minor perioperative complications, which should be anticipated and preemptively managed in the course of their anesthetic and surgical care.