Increased energy expenditure and glucose oxidation during acute nontraumatic skin pain in humans

Background and objective Tissue injury is accompanied by pain and results in increased energy expenditure, which may promote catabolism. The extent to which pain contributes to this sequence of events is not known. Methods In a cross-over design, 10 healthy volunteers were examined on three occasions; first, during self-controlled nontraumatic electrical painful stimulus to the abdominal skin, maintaining an intensity of 8 on the visual analogue scale (0-10). Next, the electrical stimulus was reproduced during local analgesia and, finally, there was a control session without stimulus. Indirect calorimetry and Mood and urine sampling was done in order to calculate energy expenditure and substrate utilization. Results During pain stimulus, energy expenditure increased acutely and reversibly by 62% (95% confidence interval, 43-83), which was abolished by local analgesia. Energy expenditure paralleled both heart rate and blood catecholamine levels. The energy expenditure increase was fuelled by all energy sources, with the largest increase in glucose utilization. Conclusion The pain-related increase in energy expenditure was possibly mediated by adrenergic activity and was probably to a large extent due to increased muscle tone. These effects may be enhanced by cortical events related to the pain. The increase in glucose consumption favours catabolism. Our findings emphasize the clinical importance of pain management. Eur J Anaesthesiol 26:311-317 (c) 2009 European Society of Anaesthesiology.