Metabolic Response to Surgery in Infants and Children

Considerable advances have been achieved in paediatric surgery during the last two decades, which can be partly ascribed to a better understanding of the physiological response to operations and the use of that knowledge to decrease the metabolic response where appropriate. Alongside this, minimally invasive surgery is now well established for many surgical conditions in the neonate, infant and child. The metabolic response to surgery differs in neonates to that seen in adults: there is a small increase in oxygen consumption and resting energy expenditure immediately after surgery with a return to normal levels by 12-24 h. The increase in resting energy expenditure is significantly greater in infants undergoing a major operation than in those subjected to a minor procedure. The limited increase in energy expenditure may be due to diversion of energy from growth to tissue repair. There are limited data available on older children, but they appear to have a different pattern of postoperative resting energy expenditure. There is a fall in the early postoperative period, similar to data collected in adults, but no late hypermetabolism. Protein metabolism mirrors energy expenditure and contributes to the overall changes observed. Various factors affect the magnitude of the response. It seems that in children intraoperative thermoregulation and metabolism are significant drivers of many of the postoperative changes. Minimally invasive surgery may maintain preoperative metabolic processes by altering the postoperative processes on a physiological level or by maintaining thermoregulation in children. The mechanism and potential benefit of these observations need further investigation.