To the Editor.
—Killip's Editorial1 is very timely. He states that anesthesia is safe and that postoperative risk can be reasonably predicted from preoperative findings that include general physical state and cardiovascular status. He suggests that perioperative Holter monitoring for prolonged periods of time may be of help.However, thorough evaluation of perioperative body temperature alterations has not been extensively considered as a possible contribution to perioperative mortality and morbidity. It is well known that in major abdominal, thoracic, and urological surgery open body cavities or an irrigated bladder may lead to extensive decreases in body temperature in cold operating room environments, especially in the elderly. Postoperatively, rewarming is often associated with shivering, a marked increase in total body oxygen consumption, and frequently an increase in the heart rate. These effects may be intensified by the accompanying pain and anxiety on awakening, and hypoxia due to respiratory center depression