Anabolic effects of oxandrolone after severe burn.

OBJECTIVE: To explore the hypothesis that oxandrolone may reverse muscle catabolism in cachectic, critically ill pediatric burn patients. SUMMARY BACKGROUND DATA: Severe burn causes exaggerated muscle protein catabolism, contributing to weakness and delayed healing. Oxandrolone is an anabolic steroid that has been used in cachectic hepatitis and AIDS patients. METHODS: Fourteen severely burned children were enrolled during a 5-month period in a prospective cohort analytic study. There was a prolonged delay in the arrival of these patients to the burn unit for definitive care. This neglect of skin grafting and nutritional support resulted in critically ill children with significant malnutrition. On arrival, all patients underwent excision and skin grafting and received similar clinical care. Subjects were studied 5 to 7 days after admission, and again after 1 week of oxandrolone treatment at 0.1 mg/kg by mouth twice daily or no pharmacologic treatment. Muscle protein kinetics were derived from femoral arterial and venous blood samples and vastus lateralis muscle biopsies during a stable isotope infusion. RESULTS: Control and oxandrolone subjects were similar in age, weight, and percentage of body surface area burned. Muscle protein net balance decreased in controls and improved in the oxandrolone group. The improvement in the oxandrolone group was associated with increased protein synthesis efficiency. Muscle protein breakdown was unchanged. CONCLUSIONS: In burn victims, oxandrolone improves muscle protein metabolism through enhanced protein synthesis efficiency. These findings suggest the efficacy of oxandrolone in impeding muscle protein catabolism in cachectic, critically injured children.

Persistence of muscle catabolism after severe burn.

BACKGROUND: The hypermetabolic response to severe burn is characterized by muscle protein catabolism. Current opinion states that the hypermetabolic state resolves soon after complete wound closure. Clinically, we have witnessed that burned children appear to be hypermetabolic and catabolic long after full healing of their wounds. Our goal in this study was to determine scientifically if burn-associated hypermetabolism persists after full wound healing. METHODS: To determine the duration of muscle catabolism and systemic hypermetabolism after severe burn in children, patients with > 40% total body surface area burns were enrolled in a prospective, longitudinal study; resting energy expenditure was measured by indirect calorimetry, muscle protein kinetics were determined by using stable isotopic methodology, and body composition was measured by dual-energy x-ray absorptiometry imaging. Data were collected at 6, 9, and 12 months after injury. RESULTS: The mean total body surface area burned was 65% +/- 13%, and the mean age was 7.6 +/- 1. 5 years. Resting energy expenditure was elevated above the predicted age-matched levels from the Harris-Benedict equation and incrementally declined throughout the 12-month study. The net protein balance and lean mass reflected catabolic persistence at 6 and 9 months after severe burn. Between 9 and 12 months, protein breakdown decreased, net protein balance improved, and lean body mass increased. CONCLUSIONS: In severely burned children, hypermetabolism and catabolism remain exaggerated for at least 9 months after injury. This suggests that therapeutic attempts to manipulate the catabolic and hypermetabolic response to severe injury should be continued long after injury.

Gut epithelial apoptosis after severe burn: effects of gut hypoperfusion.

BACKGROUND: Severe cutaneous burn causes transient mesenteric vasoconstriction and altered gut mucosal integrity. We recently showed that burn also increases gut epithelial cell death by apoptosis. The goal of this study was to determine whether changes in gut perfusion after burn contribute to burn-associated gut apoptosis. STUDY DESIGN: We first correlated superior mesenteric artery blood flow with measurement of gut perfusion at the tissue level by laser doppler in four nonburned rats before, during, and after arterial clamping to validate our measurements of gut perfusion. We then characterized gut perfusion sequentially over time after burn; gut perfusion was measured 3 cm from the ligament of Treitz before burn and hourly for 6 hours. A group of control rats underwent the exact same protocol without the burn to exclude effects of anesthesia and laparotomy on tissue perfusion (n = 4). We studied a third group of rats with hypoperfusion of the same duration and magnitude induced mechanically without burn (n = 7). Sections of the proximal gut from all three groups (control without burn, burn, and hypoperfusion without burn) were examined for epithelial apoptosis. RESULTS: Linear regression analysis demonstrated a strong correlation between superior mesenteric artery blood flow and intestinal tissue perfusion measured by laser doppler under both low and high flow conditions (r = 0.85). Laser doppler measurements of gut perfusion after burn showed deceased gut perfusion that was maximal at 2 hours postburn (p < 0.05), and that persisted for 4 hours (p < 0.05). By 6 hours, gut perfusion returned to baseline. Apoptosis increased significantly in the burn group (2.11 +/- 0.17%) compared with control (0.52 +/- 0.2%) and the mechanically decreased perfusion group (0.51 +/- .03) (p < 0.001). CONCLUSIONS: We conclude that burn-induced gut hypoperfusion is insufficient to cause burn-related increased gut epithelial apoptosis. We speculate that the signal for increased gut epithelial apoptosis is primarily related to proinflammatory mediators induced by the burn wound.

Biobrane versus 1% silver sulfadiazine in second-degree pediatric burns.

Partial-thickness burns in children have been treated for many years by daily, painful tubbing, washing, and cleansing of the burn wound, followed by topical application of antimicrobial creams. Pain and impaired wound healing are the main problems. We hypothesized that the treatment of second-degree burns with Biobrane is superior to topical treatment. Twenty pediatric patients were prospectively randomized in two groups to compare the efficacy of Biobrane versus 1% silver sulfadiazine. The rest of the routine clinical protocols were followed in both groups. Demographic data, wound healing time, length of hospital stay, pain assessments and pain medication requirements, and infection were analyzed and compared. Main outcome measures included pain, pain medication requirements, wound healing time, length of hospital stay, and infection. The application of Biobrane to partial-thickness burns proved to be superior to the topical treatment. Patients included in the biosynthetic temporary cover group presented with less pain and required less pain medication. Length of hospital stay and wound healing time were also significantly shorter in the Biobrane group. None of the patients in either group presented with wound infection or needed skin autografting. In conclusion, the treatment of partial-thickness burns with Biobrane is superior to topical therapy with 1% silver sulfadiazine. Pain, pain medication requirements, wound healing time, and length of hospital stay are significantly reduced.

Sensitivity and specificity of bronchoalveolar lavage and protected bronchial brush in the diagnosis of pneumonia in pediatric burn patients.

BACKGROUND: Infection is still one of the leading causes of death in burn patients. The diagnosis of respiratory tract infection in critically ill burn patients is still difficult. The diagnostic technique of choice remains uncertain, especially because of the lack of a criterion standard by which other diagnostic methods can be compared. HYPOTHESIS: Bronchoalveolar lavage (BAL) and protected bronchial brush (PBB) cultures are not efficacious for the diagnosis of pneumonia in critically ill burn patients. DESIGN: All pediatric patients with burns who died at Shriners Burns Hospital, Galveston, Tex, in the past 10 years were studied. We compared the clinical diagnosis of pneumonia, BAL quantitative culture results, and PBB culture results with autopsy findings. The diagnosis of pneumonia at autopsy was considered the criterion standard, and it was used to calculate the sensitivity and specificity of BAL and PBB cultures. RESULTS: Forty-three patients were studied. Pneumonia was present in 19 (44%) of the 43 autopsies. Pneumonia was diagnosed clinically in 12 (28%) of the 43 patients, and 6 (50%) of them had negative autopsy findings. The sensitivity and specificity of BAL were 56% and 28%, respectively; PBB, 55% and 61%, respectively. The same microorganisms were found at autopsy, in BAL cultures, and in PBB cultures in fewer than 10% of the patients. CONCLUSIONS: Bronchoalveolar lavage and protected bronchial brush have a low sensitivity and specificity and cannot be relied on by themselves for the diagnosis of pneumonia in critically ill burn patients. The results of these sampling techniques must be interpreted in the context of the overall clinical picture of each individual patient.

Current status of anabolic hormone administration in human burn injury.

Survival after massive burns has increased due to advances in critical care and wound closure techniques. Because of the ravages of hypermetabolism that is so prevalent in these patients, survivors are left with significant lean body mass losses that correspond to decreased strength with which to begin the rehabilitation phase. Efforts to decrease lean body mass catabolism by environmental regulation, early wound closure, and sufficient caloric provision modify the hypermetabolic response to an extent; however, further manipulations are required to optimize recovery fully. Pharmacologic intervention with hormone agonists and antagonists holds this promise. This article reviews some of the current investigations in this area and points out the future work that needs to be done to elucidate the field of anabolic hormones after severe injury.

Topical nystatin powder in severe burns: a new treatment for angioinvasive fungal infections refractory to other topical and systemic agents.

Angioinvasive fungal infections have a significant morbidity and mortality in the immunocompromised host. Massive burns produce a profound derangement in cellular immunity along with a loss of cutaneous barrier function. Treatment of fungal burn wound infections poses a difficult therapeutic challenge. We present a new method of treatment for angioinvasive fungal infections with nystatin powder at a concentration of 6,000,000 units/g. It proved to be efficacious in four consecutive severely burned patients affected by massive angioinvasive fungal infection. Both superficial and deep tissue infections were eradicated without any other therapeutic interventions or adverse effects on wound healing.

Thermal injury.

Intensive care management of severely burned patients demands expertise in several areas. These include airway management, fluid resuscitation, support of the hypermetabolic response, infection control, and treatment of smoke inhalation injury. Surgical management of the burn wound, plastic reconstruction, and long-term rehabilitation are also essential aspects of modern burn care.

Muscle protein catabolism after severe burn: effects of IGF-1/IGFBP-3 treatment.

OBJECTIVE: To determine the effects of recombinant human insulin-like growth factor-1 (IGF-1) complexed with its principal binding protein, IGFBP-3, on skeletal muscle metabolism in severely burned children. SUMMARY BACKGROUND DATA: Severe burns are associated with a persistent hypermetabolic response characterized by hyperdynamic circulation and severe muscle catabolism and wasting. Previous studies showed that nutritional support and pharmacologic intervention with anabolic agents such as growth hormone and insulin abrogated muscle wasting and improved net protein synthesis in the severely burned. The use of these agents, however, has several adverse side effects. A new combination of IGF-1 and IGFBP-3 is now available for clinical study. METHODS: Twenty-nine severely burned children were prospectively studied before and after treatment with 0.5, 1, 2, or 4 mg/kg/day IGF-1/IGFBP-3 to determine net balance of protein across the leg, muscle protein fractional synthetic rates, and glucose metabolism. Another group was studied in a similar fashion without IGF-1/IGFBP-3 treatment as time controls. RESULTS: Seventeen of 29 children were catabolic before starting treatment. The infusion of 1.0 mg/kg/day IGF-1/IGFBP-3 increased serum IGF-1, which did not further increase with 2.0 and 4.0 mg/kg/day. IGF-1/IGFBP-3 treatment at 1 to 4 mg/ kg/day improved net protein balance and increased muscle protein fractional synthetic rates. This effect was more pronounced in catabolic children. IGF-1/IGFBP-3 did not affect glucose uptake across the leg or change substrate utilization. CONCLUSIONS: IGF-1/IGFBP-3 at doses of 1 to 4 mg/kg/day attenuates catabolism in catabolic burned children with negligible clinical side effects.

Comparison of wound culture and bronchial lavage in the severely burned child: implications for antimicrobial therapy.

BACKGROUND: The relationship of the burn wound flora to microbial pathogens in the tracheobronchial tree has important implications for antimicrobial therapy in the severely burned patient. Management of septic complications is bolstered by surveillance quantitative wound cultures (QWC) and bronchial lavage fluid (BLF) cultures. OBJECTIVES: To compare the organisms present in BLF with those found in QWC and to determine if QWC can predict BLF results. DESIGN: Results of BLF cultures from all patients who underwent bronchial lavage from January 1, 1996, to December 31, 1996, at our institution were compared with QWC data from the same date. Criteria for a positive match included an identical antibiotic susceptibility pattern and biotype. Match rates were calculated qualitatively and quantitatively. RESULTS: In 30 (48%) of the 62 BLF cultures, there was a match between the organism identified in the BLF and the QWC. When strict quantitative criteria were applied, the match rate was only 9 (14%) of 62. Burn size and inhalation injury had no significant effect on match rate. CONCLUSIONS: Whereas the microbial pathogens were similar in the QWC and BLF, linear regression showed no value of QWC in predicting BLF culture results. The difference between qualitative and quantitative match rates suggests cross-colonization between the burn wound and tracheobronchial tree, but little to no cross-infection. The QWC and BLF cultures must be performed independently in determining antimicrobial specificity in the burned patient.