Investigation of the relationship between heat loss and nitrogen excretion in elderly patients undergoing major abdominal surgery under general anaesthetic

Abstract

Summary: An attempt was made to reduce heat loss in elderly patients undergoing major abdominal surgery. Two groups were studied. In one group, efforts were made to minima heat loss by using a hot-water humidifier in the anaesthetic circuit, a hot-water circulating mattress under the patient and warming all i.v. fluids. Otherwite, the surgical and anaesthetic techniques were comparable. The same anaesthetic technique of nitrous oxide, oxygen, pancuronium and fentanyl with intermittent positive pressure ventilation was used in all cases. Nitrogen loss was measured in urine collected over 48 h from an indwelling urinary catheter inserted soon after induction of anaesthesia. Prevention of heat loss during anaesthesia and postoperative recovery caused a significant reduction in nitrogen loss. © 1982 The Macmillan Press Ltd.