T HERE IS DOCUMENTATION in the literature of severe, sometimes life-threatening complications during and after anesthesia and surgery in hypothyroid patients.“5Anesthetic considerations in these patients include: Extreme sensitivity to depressant drugs; hypodynamic cardiovascular system with decreased cardiac output secondary to a reduction of heart rate and stroke volume; slowed biotransformation of drugs, particularly narcotics; unresponsive baroreceptor reflexes; decreased intravascular volume; impaired ventilatory response to arterial hypoxemia and/or alterations of the partial pressure of carbon dioxide; delayed gastric emptying; impaired clearance of free water; hypothermia; anemia; hypoglycemia; and, primary adrenal insufficiency.6 These patients are of greater-than-average risk for anesthesia and surgery. They have an increased sensitivity to anesthetic drugs and their postoperative course may be complicated by delayed awakening, coma, cardiovascular crisis, impaired thermoregulation, problems with diuresis, ileus, and a higher incidence of infections.“’ Increased receptor sensitivity and decreased drug metabolism are present and are attributable to the deficiency of thyroid hormone in the target tissues. Other, non-drug-related adverse effects are probably due to the multi-system pathology in this disease.’ Hypothyroid patients with co-existent cardiac disease represent an interesting pathophysiologic group.8*9 Although cardiac operations are now performed in this patient group, the number of cardiac operations in patients with documented hypothyroidism is relatively small.9~‘o One reason might be that hypothyroid patients with coronary artery disease have a lower incidence of angina and myocardial infarc-