ENERGY-EXPENDITURE IN CHILDREN WITH CONGENITAL HEART-DISEASE, BEFORE AND AFTER CARDIAC-SURGERY

Failure to thrive is a common feature of children,vith congenital hear t disease. Whether this is the result of poor nutrition or an abnormal ly high basal metabolic rate is unknown, yet the state of nutrition ha s a profound effect on the metabolic response to injury and strongly i nfluences the outcome of surgical treatment. The aim of this study was therefore to measure the preoperative and postoperative energy requir ements of children with congenital heart disease. Eighteen children (a ged 4 to 33 months) were given two oral doses of doubly labeled water ((H2O)-O-18 and (H2O)-H-2), the first 1 week before operation and the second 6 hours after the end of cardiac surgery. By measuring the rela tive loss of each isotope from the body water pool, we were able to ca lculate the rate of carbon dioxide production and therefore total ener gy expenditure. In live patients, energy expenditure was clearly eleva ted, suggesting that a raised basal metabolic rate is an important fac tor in the observed failure to thrive in at least a proportion of such children. Postoperatively, energy expenditure fell to values below no rmal for healthy children (not having an operation), which suggests th at the stress of surgery leads to smaller energy requirements than hav e previously been thought.