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The effects of two levels of protein intake on protein metabolism in six severely burned adult patients were studied (means of 70% BSA burned). A crossover experimental design enabled the authors to study each patient at the end of two three-day dietary regimens. All diets were isocaloric and provided approximately 25% more calories than the measured energy expenditure (means = 40.8 Kcal/kg X day). In one regimen, each patient received 2.2 g protein/kg X day, while during the other treatment period they received 1.4 g protein/kg X day. The patients were studied in the fed state and after 10 to 12 hours of fasting. Leucine kinetics were determined by means of the primed-constant infusion of [1--13C]--leucine. The authors were able to distinguish the oxidation of plasma leucine from the oxidation of leucine derived from intracellular protein at the site of the deamination of leucine (predominantly muscle) by simultaneously determining both leucine and alpha-ketoisocaproic acid enrichment. Also, rates of whole-body protein synthesis and catabolism were calculated from the leucine flux and oxidation data. Net protein synthesis was also calculated by means of another stable-isotope technique involving the infusion of [15N2]--urea. Finally, a third means of estimating net protein catabolism based on urinary N-excretion data was used at the same time that the isotopic studies were performed. The 13C leucine-data and the N-excretion data indicated that a balance between protein synthesis and catabolism could be achieved with a protein intake of 1.4 protein/kg X day. When protein intake was increased to 2.2 g protein/kg X day, neither isotopic method indicated a further beneficial effect on net protein synthesis, although the absolute rates of protein synthesis and catabolism were stimulated. The N-excretion data, on the other hand, indicated a significant improvement in net protein synthesis with higher protein intake. Regardless of the level of protein intake, the underlying alterations in protein metabolism that occurred as a response to burn injury persisted.

Total enteric nutritional support of thermally injured patients is a safe, effective means of providing adequate caloric and nitrogen requirements and avoiding the usual weight loss associated with burns. Protein and vitamin supplements and tube feeding, when indicated, are necessary adjuncts to the standard high protein, high calorie hospital diet. A team approach, consisting of physicians, nurses, dietitians, and patients, and careful daily monitoring of all parameters is essential to the success of this method.

The metabolic response to injury is one of marked catabolic hormonal predominance resulting in hypermetabolism and protein wasting. Energy expenditure increases with increasing severity of injury, but reaches a maximum of twice resting energy expenditure when 50 per cent TBSA is burned. We agree with the nutritional recommendations of the group at the Boston Shriner's Burn Institute and the Massachusetts General Hospital. These include providing calories at twice the resting energy expenditure, as predicted by the Harris-Benedict equations, for patients with greater than 30 per cent BSAB; protein is provided at 2.5 gm per kg per day based on ideal body weight. It is important to recognize that these are optimal goals, but their attainment must be governed by safety considerations for the patient. It is probably safe to supplement intake with a multivitamin and vitamin C, as well as zinc, but our understanding of micronutrient therapy for stressed patients is rudimentary.

Much research effort has been devoted to determination of caloric and protein requirements in burn patients. Although it is generally accepted that trace mineral requirements increase concomitantly with caloric and protein needs, little research has been conducted to document that assumption. Our survey was undertaken to assess current practice and identify research needs. One hundred ninety-six survey questionnaires were sent to burn units in North America. Forty percent (78) were returned. Ninety percent of respondents prescribe or recommend trace mineral supplements in their facilities. "Higher risk" was the single criterion most often mentioned as a basis for supplementation (54 [77%] of 70 respondents), with 49 of them indicating that they provide trace mineral supplements to patients receiving total parenteral nutrition support. Fifty-six respondents provided detailed information concerning trace mineral supplementation. Of that group, 88% prescribe zinc supplements, 75% prescribe iron supplements, and 26% prescribe chromium supplements. Thirteen percent supplement selenium. Less than 2% supplement molybdenum or vanadium and do so only when administering total parenteral nutrition. Many respondents expressed concern about the lack of guidelines for trace mineral supplementation in the burn patient, leading to the conclusion that further research in that area would benefit burn-injured patients and the health care providers who care for them.

The effect of informational feedback on the protein and caloric consumption of burn patients was investigated using a multiple-baseline across subjects. The patients were four severely burned adult males who failed to consume sufficient foods to achieve prescribed levels of protein or kilocalories via standard burn unit procedures during recovery. Feedback consisted of informing patients of (a) their prescribed levels of protein and kilocalories, (b) the protein and kilocalorie content of hospital foods and beverages, and (c) their actual intake of protein and kilocalories. Following the provision of feedback, there was an increase in protein and kilocalorie intakes and in the number of days during which prescribed levels for protein and kilocalories were achieved. These results suggest that the informational feedback was effective for improving the oral caloric intake of burn patients.

A regime involving the dietary management of 8 severely burned patients has been described, the main feature of this diet being the high egg intake. The eggs were given in a variety of forms without any untoward effects and without any distaste being developed. No pathological levels of serum lipoproteins or cholesterol were attained. Serum proteins from an initial low level reached normal values within a relatively short time. It is felt that a high egg diet is a valuable and safe addition in the management of severely burned patients.

The greatly increased nutritional demands of the severely burned patient frequently require the use of tube feeding for enternal hyperalimentation. At a time when general patient morale is low and motivation needs to be maximally maintained, there is nothing so dispiriting as the distress of a painful perianal region and uncontrollable liquid stools. Attempts to control the diarrhea which frequently accompanies tube feeding by changing the formula or the method of administration or a wide variety of constipating drugs have all met with very limited success. Based on the clinical observation of a noted gastroenterologist (Bockus), we have administered a mucilagenous hydrophilic colloid bulk laxative (Metamucil) to patients on tube feeding formulae. The dosage and frequency are adjusted to individual patient needs, but average 7 g per liter of liquid formula. The results have been dramatic; namely, the virtual elimination of the diarrhea problem in our burn patients on enteral hyperalimentation by gastric tube feeding. Colonic transit time increases. The stools become formed but soft, cohesive but not adhesive. Perianal irritation does not occur. Neither does soilage of wound, dressings, or bed. No rebound constipation or obstructive symptoms have been encountered. We attribute this response to the same water binding mechanism that allows these colloids to prevent chronic constipation. Our patients may be given as much as 5,000 to 6,000 calories of tube feeding per day. Our patients are not distressed by diarrhea. Our nursing staff is relieved of the burden that entails.

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.

Eight severely burned young patients were maintained on an oral hyperalimentation regimen of about 7,000 calories--including 314 proteins, 600 g carbohydrates and 336 g fats, containing greater than 8 g cholesterol--based mainly on a daily ingestion of 35 eggs. Serum cholesterol and protein, and plasma lipoprotein levels were measured during period of 30 days on the diet. The mean serum cholesterol level prior to the egg-rich diet was low [108 +/- 42 (SD) mg/dl] and it remained within the normal range during the study. The initial mean serum total protein level of 4.1 +/- 0.5 (SD) rose to 6.5 +/- 0.7 g/dl by the 19th day and stayed high throughout the remainder of the study. Plasma lipoprotein levels, assessed by nephelometry and reported as concentrations of large, medium and small particles, were not increased. It is assumed that the high demand for energy during recovery from burns prevented abnormal rises in plasma lipid levels on fat-rich diet.

Adequate nutritional support for the critically ill patient has evolved over the past 150 years from a time when starvation was accepted practice for patients with fever. Three to four thousand calories and other essential nutrients can now be safely provided each day to patients with infection or other critical illness. Nutrients may be provided in meals, administered by specialized enteral feedings, or infused intravenously. Nutrient mixtures with a high proportion of carbohydrate and protein appear the best dietary therapy to maintain body protein and support other organ systems and and cellular functions. New products and formulas offer the physician a wide variety of techniques for providing adequate nutrition to all patients with critical illness.