[Intraoperative changes in blood lactate level and body temperature in younger and elderly adults]

Sequential changes in arterial blood lactate concentration and central-peripheral temperature gradient during anesthesia were measured in 10 younger patients (46-63 yr) and 10 elderly patients (66-92 yr) undergoing abdominal surgery. A central temperature probe was attached at the rectum and peripheral probe on the palm of the hand. Anesthesia was induced with thiopental and succinylcholine and maintained with isoflurane and nitrous oxide in oxygen. There was a marked increase in lactate values intraoperatively in the elderly as compared to the younger patients. Difference between central and peripheral temperature increased significantly in the elderly patients, while there was no change in the temperature gradient in the younger patients. Central-peripheral temperature gradient is an indicator of peripheral circulation, and the results imply the presence of anaerobic oxidation in elderly patients during operation. In elderly patients, the functional reserve of organ system and the tolerance to surgical stress are considered to be reduced. Intraoperative elevation of blood lactate levels might be caused either by impairment of peripheral circulation or by metabolic deficit due to age-related decline in hepatic function.