This study was performed to investigate the mechanism whereby immediate enteral feeding after burn injury reduces postburn hypermetabolism and hypercatabolism. Fifty-seven burned guinea pigs (30% TBSA) were divided into three groups: A (N = 19), given 175 kcal/kg/day beginning 2 hours after burn; B (N = 20), given 175 kcal/kg/day with an initial 72-hour adaptation period; and C (N = 18), given 200 kcal/kg/day with the same adaptation period as B. Resting metabolic expenditure (RME) on PBD 13 was lowest in group A (109% of preburn level), compared with group B (144%, p less than 0.001) and group C (137%, p less than 0.01). On PBD 1, group A had the greatest jejunal mucosal weight and thickness (p less than 0.001), and mucosal weight had negative correlations with plasma cortisol (r = 0.829, p less than 0.001) and glucagon (r = 0.888, p less than 0.001). Two weeks after burn, urinary vanillyl mandelic acid (VMA) excretion, plasma cortisol, and glucagon were lowest in group A (p less than 0.05 to p less than 0.01). These hormones also significantly correlated with RME (p less than 0.01 to p less than 0.001). These findings suggest that immediate postburn enteral feeding can prevent hypermetabolism via preservation of gut mucosal integrity and prevention of excessive secretion of catabolic hormones.

So that the efficacy of route of nutrient administration in thermal injury could be determined, a comparison was made between immediate enteral vs parenteral feedings in burned guinea pigs. Thirty-five guinea pigs underwent both catheter gastrostomy and jugular vein catheterization. On postoperative day 8, burned animals [30% total body surface area (TBSA)] were divided into an intragastrically (ig) fed group (N = 14) and a parenterally (iv) fed group (N = 14). Animals in each group received 175 kcal/kg/day with a solution of identical nutrient value beginning 2 hr after burn. The body weight change until postburn day (PBD) 8 and the average nitrogen balance were significantly better in the ig group than in the iv group. Values were also higher for the iv group than for the ig group in the early postburn period for urinary vanillyl mandelic acid (VMA) (p less than 0.05), plasma cortisol (p less than 0.05), and plasma glucagon (p less than 0.05). Also, the iv group showed reduced mucosal weight and thickness compared to the ig group on PBD 1 (p less than 0.02). There were significant negative correlations between VMA excretion and body weight change, and between plasma cortisol and jejunal mucosal structure (thickness and weight). These findings suggest that immediate postburn enteral nutrition can provide better nutritional support than parenteral nutrition through the maintenance of gut mucosal integrity and the prevention of increased secretion of catabolic hormones.

The effects of different types of dietary lipids were tested in burned guinea pigs. All diets were identical except for the type of lipid, with total energy intake from lipids equaling 10%. All animals received a 30% total body surface area (TBSA) flame burn and were fed identically by pump-controlled gastrostomy feedings for 14 days. When compared to safflower oil (74% linoleic acid) as well as linoleic acid alone, fish oil (18% eicosapentaenoic acid or EPA) administration resulted in less weight loss, better skeletal muscle mass, lower resting metabolic expenditure, better cell mediated immune responses, better opsonic indices, higher splenic weight, lower adrenal weight, higher serum transferrin, and lower serum C3 levels. With the exception of better cell mediated immune responses in the animals fed linoleic acid, the administration of indomethacin made little difference. These findings can be explained by a reduction in the synthesis of the dienoic prostaglandins that are derived from the omega 6 series of fatty acids, some of which are significantly immunosuppressive. Regulation of dietary lipids may be an important therapeutic advance in nutritional support after burn injury, and controlled trials should be considered.

REE in children with MMC is variable when compared to predicted values. TEE was found to be lower in children with MMC than predicted values and EI was similar to predicted values in this group of seven children. BCM is reduced in children with MMC when compared to expected values.