Anesthesia for untreated hypothyroidism: report of three cases.

Two preoperatively unsuspected and one known hypothyroid patients underwent elective surgery with general anesthesia. All demonstrated unusual sensitivity to anesthetic agents. As suggested by a history of thyroid abnormalities, high serum cholesterol, and exaggerated response to anesthetic agents, the authors were led to suspect hypothyroidism, which was confirmed postoperatively by low serum thyroxine levels.