Nutrition
Sustained hyper metabolism, hormone elevations, and muscle wasting following severe burn injury all contribute to the clinical outcome, with magnitude and duration that are unique to burns. Accordingly, reducing the impact of a hyper metabolic state and providing adequate nutrition are key factors that affect burn wound healing and recovery as has been reviewed elsewhere. There is a difficult balance between the additional caloric needs to meet the demand from hyper metabolism and the consequences of nutrient overconsumption. Nutritional support following a burn injury is a complex issue. For example, early excision and aggressive feeding in children does not diminish energy expenditure but is associated with decreased muscle protein catabolism, a decreased rate of burn sepsis, and significantly lower bacterial counts from excised tissue. In adults, early nutritional support is correlated with shorter stays, accelerated wound healing, and decreased risk of infection .
Several nutritional factors must be considered. For example, excess carbohydrate consumption may lead to hyperglycemia that can exacerbate systemic inflammation and muscle degradation. Furthermore, excess fat consumption may exaggerate the immunosuppressed state; and since major burn injuries may also result in immunosuppressant, this exaggeration may increase the risk for infection and sepsis. Carbohydrate and fat intake must therefore be closely monitored in burn patients. Guidelines for nutritional support of burn patients vary, but consensus recommendations have been given by the American Burn Association and the American Society for Parenteral and Enteral Nutrition for carbohydrates, proteins, and fats.
In addition to support with amino acids and vitamins, administration of insulin has been shown to decrease healing time by reducing protein catabolism and increasing skeletal muscle protein synthesis. More research is needed to optimize insulin delivery, as many recombinant growth factors, such as epidermal growth factor and transforming growth factor, are often cost prohibitive. Other anabolic agents, such as oxandrolone, have been shown to increase lean body mass recovery, decrease length of stay, and improve overall outcomes, including wound healing . Additionally, while conventional theory suggests that hemoglobin levels must be maintained above 10 g/dl to promote wound healing, preliminary evidence suggests that mild to moderate anemia has no effect on graft success if perfusion is maintained with proper circulatory volume. The results of a multicenter, randomized, controlled trial (ClinicalTrials.gov NCT01079247) comparing blood transfusion with lower volumes (target hemoglobin of 7 to 8 g/dl) and conventional volumes (target hemoglobin >10 g/dl) for a large cohort of patients are expected soon and will allow for more definitive clinical guidelines on blood transfusion volumes.