Metabolic and nutritional aspects of thermal injury

Branched chain amino/keto acid supplementation following severe burn injury: a preliminary report

14 severely burned patients were randomly assigned to receive one of three nasogastric feeds commencing after the resuscitation period and continuing for 15 days. Group A received a feed with a high leucine content (31% of protein as branched chain amino-acids, BCAA). Group B received a similar feed to Group A but 65% of the leucine was replaced by alpha-ketoisocaproate (KIC). Group C received a whole protein feed (16% of the protein content as BCAA), and acted as a control group. Targeted energy intake was twice the calculated Basal Metabolic Rate (BMR). Group A had significantly reduced urinary 3-methylhistidine (3-MEH) and serum urea, compared with the control group. Serum total protein, albumin and transferrin and apparent nitrogen balance were not significantly different. Group B's results did not vary significantly from controls. Leucine enrichment reduces muscle protein breakdown benefiting burn patients fed enterally when compared to a standard feed, whereas KIC enrichment does not.

Enteral hyperalimentation of burned patients: the possibility of correcting metabolic disorders by the early administration of prolonged high calorie evenly distributed tube feeds

Metabolic processes and the ways they may be treated were investigated in severely burned patients receiving prolonged high calorie evenly distributed tube feedings. It was shown that in critically ill patients the absorption of nutrients in the upper regions of the intestine was slightly impaired but the ability to absorb was preserved, which made it possible to provide prolonged evenly distributed tube feeding. For these purposes we used the nutrient mixture 'Combustal'. Restoration of nitrogen balance could be reached within about 10 days after starting tube feeding. However, the creatine excretion remained high, a manifestation of increased dystrophy of muscle tissue. Pseudocholinesterase activity in serum was also decreased, suggesting subnormal biosynthetic processes. To provide the full correction to normal of the metabolic processes the tube feeding with 'Combustal' should be given for at least a month.

Stimulation of muscle protein degradation by murine and human epidermal cytokines: relationship to thermal injury

Accelerated muscle proteolysis is a characteristic of systemic reaction following trauma, sepsis, or extensive thermal injury. The factors involved in this accelerated muscle breakdown have not been fully described. However, recently leukocytic pyrogen or interleukin 1 (IL-1) have been implicated in the induction of muscle protein degradation in septicemia or trauma. The epidermal cytokine epidermal cell-derived thymocyte activating factor (ETAF) is biochemically and functionally similar to IL-1. Injury to skin can augment ETAF activity. Using a murine model, we found that thermal injury can significantly enhance ETAF/IL-1 activity in a dose-dependent fashion. In addition, ETAF can cause net muscle protein breakdown in vitro. Thus, increased amounts of ETAF produced by thermally injured skin may contribute to the accelerated muscle breakdown in extensive thermal injury.

Water movement in red cells from burned patients. Its relationship to sodium retention and red cell filtrability

Nine burned patients were investigated. Urinary sodium retention was associated with low red cell water and reduced red cell filtrability. The red cells from patients who recovered lost less water than normal cells when suspended in hypertonic NaCl solution but the proportionality of water loss or gain found for normal cells was maintained. The red cells from fatally burned patients lost proportional behaviour in hypertonic or hypotonic media. The abnormalities are not related to the area of the burn and may be the result of varying therapy. The monitoring of red cell water and water movement under tonicity stress is a convenient measure of the metabolic state of the cell.

Nutritional support of the burned patient

Patients with major thermal injury exhibit hypermetabolism as a result of neurohormonal alterations. Thus caloric requirements are exaggerated. Failure to provide supranormal caloric intake by both enteral and parenteral routes is associated with pronounced weight loss, delayed wound healing, decreased host resistance, and cellular dysfunction. Special dietary programs delivered early in the course of treatment must be utilized to prevent these complications of acute postburn malnutrition.