The post-burn period is characterised by a hypermetabolic state with increased protein catabolism, ureagenesis, lipolysis and gluconeogenesis. Visceral protein loss, impaired antibacterial host defence and impaired wound healing will result without intervention (1). A policy of aggressive nutritional support has been shown to improve survival of burn patients (2). It has been suggested that there is a plateau in the metabolic rate where burned surface area (BSA) exceeds 50%(3). Hence application of formulae which include BSA > 50% would be inappropriate. This is substantiated by data showing the effects ofexcess glucose on increasing carbon dioxide production and the metabolic rate (4,5).

 

        The gut would appear to play a central role in the response to injury. Immediate post-burn alimentation can prevent hypersecretion of catabolic hormones via the preservation of mucosal integrity or via gut-derived hormones (6). Feeds containing arginine, glutamine or MCT have an increasing role to play in the nutritional management of the burn patient.

        All patients should be individually assessed on admission. Requirements can be estimated using a variety of formulae. The Burns Interest Group of the BDA presently recommend Schofield (1985) and Elia (1990) for adult energy requirements, and Elia (1990) or Elwyn (1980) for nitrogen. Where BSA > 20%, aim to achieve an energy: Nitrogen ratio of 100 – 120:1. Where BSA < 20% a ratio of 120 – 150: 1 is adequate. In paediatrics, aim to meet EAR’s for energy and twice the EAR’s for protein. It is often difficult to achieve the estimated requirements in view of repeated trips to theatre and time spent nil by mouth.

        Formulae do not consider burn depth, age, and antecedent nutritional status. The presence of concurrent disease should also be considered. Estimations of energy requirements have become reduced over the years due to overall improvements in burn care (treating infections, analgesia, early excision and grafting) which minimise nutritional losses and because of the
increased awareness to the dangers of overfeeding the critically ill. The aim is to meet basal energy requirements within the first 48 hours post injury.

        There is increasing evidence that early feeding initiated as early as 2 hours post burn, can benefit the patient by suppressing the hypermetabolic response, preventing bacterial translocation and maintaining gut integrity (thereby reducing the risk of gut origin sepsis), preventing paralytic ileus and permitting greater mean protein and energy intakes by day7 post burn. (6,9,10,11)

        Diet and fluids should be encouraged as soon as possible with all minor burns with the use of food snacks and supplements as required. Enteral tube feeding should be considered for all shock burn cases (> 10% BSA children, > 15% BSA adults) and be initiated in the fluid resuscitation period. The nasogastric route is most frequently used, but may be poorly tolerated in the ventilated patient receiving large doses of opiates. Consider nasojejunal feeding using dual lumen feeding and aspiration tubes – permitting both drainage of gastric contents and maintenance of enteral nutrition (EN) despite large NG aspirates. These tubes also permit feeding throughout surgery, or allow a shorter period of fasting perioperatively. Parenteral nutrition should only be considered where the gut is not accessible or functioning, but the transition to EN should occur at the earliest opportunity re infection risks. Parenteral access is often limited by the burn distribution and peripheral venous shutdown.

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