Michele M. Gottschlich

Differential Effects of Three Enteral Dietary Regimens on Selected Outcome Variables in Burn Patients

A modular tube feeding recipe (MTF) was designed to meet the unique nutritional needs of burn patients, applying principles previously documented in our burned guinea pig model. MTF, a high-protein, low-fat, linoleic acid-restricted formulation is enriched with omega-3 fatty acids, arginine, cysteine, histidine, vitamin A, zinc, and ascorbic acid. Fifty patients, 3 to 76 years of age with burns ranging from 10 to 89% total body surface area were prospectively randomized into three groups which blindly compared MTF to two enteral regimens widely utilized in the nutritional support of burns. Age, percent total and third-degree burn, resting energy expenditure, and calorie and protein intake were similar in all groups. Data analysis demonstrated significant superiority of MTF in the reduction of wound infection (p less than 0.03) and length of stay/percent burn (p less than 0.02). MTF was also associated with a decreased incidence of diarrhea, improved glucose tolerance, lower serum triglycerides, reduced total number of infectious episodes and trends toward improved preservation of muscle mass, although statistical significance was not achieved. Seventy percent of deaths occurred in the group supported with an inherently large dose of fat and linoleic acid. Combining these observations, it is believed that MTF is effective in modulating an improved response to burn injury.

Enteral feeding during operative procedures in thermal injuries

Multiple surgical procedures necessitated by thermal trauma traditionally require withholding nutritional support during the perioperative period. Significant caloric deficits develop with subsequent catabolism of body tissues to provide energy and amino acids for the synthesis of protein. Eighty patients, matched for age and total body surface area burn, were enrolled in a study to evaluate the safety and efficacy of providing enteral support throughout operative procedures. All patients had duodenal feeding tubes placed under fluoroscopy and were provided with isonitrogenous nutritional support calculated to meet measured energy needs (indirect calorimetry). Forty patients received enteral support throughout 161 surgical procedures, and 40 had enteral support withheld during 129 procedures. Age, incidence of inhalation injury, percentage of total body surface area, and postburn day of admission were similar in both groups. Nutritional parameters, calorie counts, and infectious complications were recorded during the first 4 weeks after burn. No patient in either group experienced aspiration. The unfed group demonstrated a significant caloric deficit (p < 0.006) and increased incidence of wound infection (p < 0.02) and required more albumin supplementation to maintain serum levels at a minimum of 2.5 gm/dl (p < 0.04). Enteral nutrition can be provided safely during the perioperative period and provides the additional benefits of reducing caloric deficits, wound infections, and exogenous albumin supplementation.

Significance of obesity on nutritional, immunologic, hormonal, and clinical outcome parameters in burns☆

OBJECTIVE The potential additive effect of obesity on selected nutritional, immunologic, hormonal, and clinical outcome parameters was evaluated. DESIGN Fifteen obese patients were randomly matched for age, percentage of burn, percentage of third-degree burn, and inhalation injury to 15 nonobese patients. SETTING Subjects were admitted to Shriners Burns Institute or University Hospital in Cincinnati, Ohio. RESULTS The results of this study established a significant relationship between obesity and morbidity. Incidence of infection was greatest in the obese group (P < .03). Bacteremia (P < .008) and clinical sepsis (P < .005) occurred concomitant with obesity. The obese group required significantly (P < .05) more days on mechanical ventilatory support. Exogenous insulin supplementation (obese = 14.5 +/- 5.3 days, nonobese = 6.2 +/- 2.2 days) and antibiotic therapy (obese = 8.5 +/- 2.3 days, nonobese = 3.4 +/- 1.5 days) were required more than twice as many days in the obese group, although these trends did not reach statistical significance. Resting energy expenditure measurements were significantly higher in the obese group during weeks 1 (P < .0006) and 2 (P < .02), and the trend continued into weeks 3 and 4. Transferrin values for the obese group remained suppressed throughout the first 4 weeks after the burn, whereas the transferrin levels of the nonobese group were normal by week 4. Compared with normal-weight burn patients, obese burn patients had markedly lower alpha 2-macroglobulin values and higher glucagon levels throughout the study period. APPLICATIONS/CONCLUSIONS The data demonstrate the many metabolic and biochemical aberrations associated with obesity, distinct from the burn injury itself, and suggest that the overweight burn patient is at increased risk of morbidity. Given the prevalence of obesity in the United States, greater attention clearly needs to be given to its prevention and management.

The 2002 Clinical Research Award. An evaluation of the safety of early vs delayed enteral support and effects on clinical, nutritional, and endocrine outcomes after severe burns.

Early enteral support is believed to improve gastrointestinal, immunological, nutritional, and metabolic responses to critical injury; however, this premise is in need of further substantiation by definitive data. The purpose of this prospective study was to examine the effectiveness and safety of early enteral feeding in pediatric patients who had burns in excess of 25% total body surface area. Seventy-seven patients with a mean percent total body surface area burn of 52.5 +/- 2.3 (range 26-91), percent full thickness injury of 44.7 +/- 2.8 (range 0-90), and age ranging from 3.1 to 18.4 (mean 9.3 +/- 0.5) were randomized to two groups: early (feeding within 24 hours of injury) vs control (feeding delayed at least 48 hours postburn). Nutrient intake was measured daily, indirect calorimetry was performed biweekly, and blood and urine samples were obtained for the assay of cortisol, glucagon, insulin, gastrin, epinephrine, norepinephrine, dopamine, triiodothyronine, tetraiodothyronine, albumin, transferrin, prealbumin, retinol-binding protein, glucose, nitrogen balance, and 3-methylhistidine throughout the study period. Three protocol violations occurred, and two patients were transferred to another hospital; these patients were excluded from the study. No patient in either group experienced tube feeding aspiration. No differences were evident in infection, diarrhea, hospital length of stay, or mortality outcomes. A higher incidence of reportable adverse events coincided with early feeding (22 vs 8%), but this was not statistically significant. The delayed feeding group demonstrated a significant caloric deficit during postburn week (PBW) 1 (P <.0001) and PBW2 (P =.0022). Serum insulin (P =.0004) and triiodothyronine (P =.0162) were higher in the early fed group during PBW1. A decrease in 3-methylhistidine output (suggesting a decrease in protein breakdown) was also evident during PBW1 (P =.0138). No other significant trends in study outcome variables were noted. In conclusion, provision of enteral nutrients shortly after burn injury reduces caloric deficits and may stimulate insulin secretion and protein retention during the early phase postburn. These data, however, do not necessarily reaffirm the safety of early enteral feeding, nor do they associate earlier feeding with a direct improvement in endocrine status or a reduction in morbidity, mortality, hypermetabolism, or hospital stay. Future studies are needed to establish precise feeding implementation times that maximize clinical benefit while minimizing morbidity in the critically injured burn patient.

Diarrhea in tube-fed burn patients: incidence, etiology, nutritional impact, and prevention.

The hypermetabolic state observed in thermally injured patients warrants aggressive nutritional management. Enteral support is the preferred route of nutrient delivery, however diarrhea is reported to be a persistent complication of continuous nasogastric or nasoduodenal hyperalimentation. Diarrhea adds to problems in patient care, disturbs fluid and electrolyte balance, and worsens nutritional status. There has been the impression that tube feeding hyperosmolality, antibiotics, and low serum albumin induce diarrhea. However, in view of the sparsity of published work, a prospective study was undertaken to determine the incidence of diarrhea and to define factors associated with its cause. Of the 50 patients studied, 16 (32%) developed diarrhea. Stool cultures were negative for pathogenic organisms. Although the risk of diarrhea was associated with antibiotics (p less than 0.005), several nutrients also had an impact. Results demonstrated a significant relationship between dietary lipid content (p less than 0.05) or vitamin A intake (p less than 0.001) and diarrhea. Implementation of tube feeding within 48 hrs postburn was also associated with a decreased incidence of diarrhea (p less than 0.001). This paper describes a modular tube feeding program in which diarrheal frequency is lessened (p less than 0.0001). Surprisingly, tube feeding osmolality, drugs used to prevent stress ulcers, or hypoalbuminemia did not have an adverse effect on intestinal absorption. The cause of diarrhea in burn patients is obviously multifactorial. It is concluded that a low fat (less than 20% of caloric intake), vitamin A enriched (greater than 10,000 IU/day), early enteral support program maximizes conditions which promote tube feeding tolerance while minimizing nutrient malabsorption during the nutritional rehabilitation of thermal injury.

Review of Evidenced-Based Practice for the Prevention of Pressure Sores in Burn Patients

Pressure ulcers represent a complex clinical problem, with a reported incidence of 2.7% to 29.5% in hospitalized patients and an etiology that is multifactorial. The prevention of pressure sores in the burn patient population is clearly an area of practice in need of guidelines for care. A multidisciplinary group of advanced burn care professionals have compiled, critiqued, and summarized herein the current evidence of practice in nursing, nutrition, and rehabilitation as it pertains to the prevention of pressure sores after burn injuries. A broad overview of risk factors and assessment scales is described, and current intervention practices and recommendations for care are provided based, whenever possible, on research findings. In addition, research questions are generated in an attempt to move the specialty of burns toward the formal investigation of pressure sores with the ultimate goal being the development of evidence-based practice guidelines.

The 1994 Clinical Research Award. A prospective clinical study of the polysomnographic stages of sleep after burn injury.

Although subjective evidence suggests that patients with burns are deprived of sleep, previous clinical studies have been limited to observational data and have not to date included electroencephalographic or polysomnographic recordings. The purpose of this study was to characterize the sleep pattern of patients suffering from thermal injury. Biweekly 24-hour polysomnographic measurements (electromyography, electrooculography, and electroencephalography) were performed with 12 leads. This measuring permitted continuous recording of intrinsic electrical activity in skeletal muscles via chin electrodes, eye movement via outer canthal electrodes, and brain wave activity with the other bipolar electrodes. Determinations were obtained on 11 patients with thermal injuries for a total of 43 24-hour periods. The patients had a mean age of 8.31 +/- 1.5 years (range 1.4 to 16 years), a mean total body surface area burn of 55.1% +/- 16.5% (range 17.5% to 90.5%), and a mean full-thickness burn of 48.5% +/- 8.1% (range 10.5% to 90.5%). Although mean total sleep time was seemingly adequate (625.1 +/- 31.6 min/patient/24 hrs), large aberrations in sleep stage distribution were noted. Significant decreases in stage 3 + 4 and in rapid eye movement (deep sleep) and increases in stages 1 and 2 (light sleep) were noted, suggesting a cycling back to stages 1 or 2 after disruption of sleep. Overall, in 43 runs 40% of the subjects were completely lacking stage 3 + 4, and 19% were missing rapid eye movement during an entire 24-hour run.(ABSTRACT TRUNCATED AT 250 WORDS)

Invited Review: Selection of Optimal Lipid Sources in Enteral and Parenteral Nutrition

: The manipulation of dietary fat intake can affect the response to disease, injury, and infection. These effects include enhancement or inhibition of immune function, altered susceptibility to cardiovascular disease, promotion or maintenance of gut integrity, and prevention of total parenteral nutrition-induced hepatic dysfunction. These effects may occur as a result of changes in the fatty acid composition of biomembranes or changes in concentrations of lipid moieties such as prostaglandins or leukotrienes. Those fats that have been shown to affect physiologic function include long-chain, medium-chain, and short-chain fatty acids and omega-3 and omega-6 fatty acids. Currently available enteral and parenteral products used for nutrition support contain widely varied amounts of these different fatty acids. Therefore, the selection of the most appropriate product or nutrition support regimen for an individual patient requires an understanding of the metabolism of these different fat substrates, their therapeutic indications, and the contraindications and controversies that surround their use. This article reviews these issues and also focuses on several alternate lipid sources such as short-chain fatty acids, medium-chain fatty acids, omega-3 fatty acids, and blended and structured lipids.

Evaluation of Predicted and Measured Energy Requirements in Burned Children

OBJECTIVE The energy predictions of nine calculations for pediatric patients were compared with measured resting energy expenditure (MREE) by means of indirect calorimetry to determine the optimal means of energy projection in the burn population younger than 3 years of age. METHODOLOGY Nutritional sufficiency and maintenance of preburn weight were factors in the confirmation of energy needs. Demographic factors were also studied: preburn weight, percent burn, percent third-degree burn, and age. Group 1 consisted of 24 patients younger than 3 years of age (range = 7 months to 2.6 years) with a percent burn of 30.6 +/- 2.0 and percent third-degree burn of 21.9 +/- 2.6. Group 2, consisting of 24 patients 5 to 10 years old matched by percent burn and percent third-degree burn, was included to determine whether differences between actual and projected needs were evident in older, prepubescent patients. STATISTICAL ANALYSIS Analysis of variance was used to ascertain the most reliable multiplier for MREE needed to maintain at least 95% of preburn weight at discharge while ensuring adequate nutrition. Multiple regression analysis was used to determine the relationship between energy requirement and body weight, percent burn, and age. RESULTS An additional 30% of MREE provided a consistent ratio of actual energy intake to required intake. MREE x 1.3 was used as a guide to study the existing calculations. For both groups, the four equations that predicted energy in healthy children most often underestimated MREE x 1.3, whereas the five formulas for children with burns tended to overpredict energy. Regression analysis yielded two new sets of equations using age, preburn weight, and percent burn (< 3 years = Mayes 1 [r2 = .71], 5 to 10 years = Mayes 3 [r2 = 70] or percent third-degree burn (< 3 years = Mayes 2 [r2 = .68], 5 to 10 years = Mayes 4 [r2 = .67]). CONCLUSIONS The application of a 30% factor to MREE is supported in burn patients younger than 10 years of age. Standard energy projections do not provide an accurate assessment of energy needs in the pediatric burn population; thus, two sets of equations that more closely predict energy needs are proposed.

Outcome and socioeconomic aspects of suspected child abuse scald burns

Fifty-two children suffering from abuse-related scald burns were admitted between January 1, 1986, and June 30, 1991. Their clinical and socioeconomic aspects were compared with those of 50 nonabused scalded children. Patients were matched for age, total body surface area burn, and percentage of full-thickness burn. Patient characteristics and initial nutritional parameters were similar except for race; a higher percentage of black children were in the abused group. A significantly longer length of hospital stay was found in the abused children after using analyses of covariance to control for percentages of total and full-thickness body surface area burn. The number of operations and frequency of complications were increased in the abused group, but not significantly so. Several significant differences were found in the socioeconomic characteristics of the two groups. Children suspected of being scalded intentionally were more likely to be part of a broken home, belong to a single parent, and have a younger mother than were children in the control group. The majority of the parents of abused children were unemployed, and all but two earned less than