High-carbohydrate, high-protein, low-fat versus low-carbohydrate, high-protein, high-fat enteral feeds for burns.

BACKGROUND: Severe burn injuries increase patients' metabolic needs. Aggressive high-protein enteral feeding is used in the post-burn period to improve recovery and healing. OBJECTIVES: To examine the evidence for improved clinical outcomes in burn patients treated with high-carbohydrate, high-protein, low-fat enteral feeds (high-carbohydrate enteral feeds) compared with those treated with low-carbohydrate, high-protein, high-fat enteral enteral feeds (high-fat enteral feeds). SEARCH METHODS: We searched the Cochrane Injuries Group Specialised Register (searched 28 Nov 2011), Cochrane Central Register of Controlled Trials (The Cochrane Library 2011, Issue 4), MEDLINE (Ovid) 1950 to Nov (Week 3) 2011, EMBASE (Ovid), ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED) (1970 to Nov 2011), ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S) (1990 to Nov 2011), PubMed (Searched 28 Nov 2011). Online trials registers and conference proceedings were also searched to April 2010. SELECTION CRITERIA: We included all randomized controlled trials (RCTs) comparing high-carbohydrate enteral feeds to high-fat enteral feeds for treatment of patients with 10% or greater total body surface area (TBSA) burns in the immediate post-burn period, with data for at least one of the pre-specified outcomes. DATA COLLECTION AND ANALYSIS: Two authors collected and analysed the following data: mortality, incidence of pneumonia and days on ventilator. Meta-analysis could only be performed for the outcomes mortality and incidence of pneumonia. A random-effects model was used for all comparisons. MAIN RESULTS: Two RCTs, reporting results from 93 patients, were included in this review. Patients given a high-carbohydrate feeding formula had an odds ratio (OR) of 0.12 (95% confidence interval (CI) 0.04 to 0.39) for developing pneumonia compared to patients given a high-fat enteral formula (P value = 0.0004). Patients given a high-carbohydrate formula had an OR of 0.36 (95% CI 0.11 to 1.15) for risk of death compared to patients given a high-fat enteral formula; this difference did not reach statistical significance (P value = 0.08). Risk of bias in these studies was assessed as high and moderate. AUTHORS' CONCLUSIONS: The available evidence suggests that use of high-carbohydrate, high-protein, low-fat enteral feeds in patients with at least 10% TBSA burns might reduce the incidence of pneumonia compared with use of a low-carbohydrate, high-protein, high-fat diet. The available evidence is inconclusive regarding the effect of either enteral feeding regimen on mortality. Note that the available evidence is limited to two small studies judged to be of moderate risk of bias. Further research is needed in this area before strong conclusions can be drawn.

Two days of hypoxic exposure increased ventilation without affecting performance.

The aim of this study was to test the short-term effects of using hypoxic rooms before a simulated running event. Thirteen subjects (29 +/- 4 years) lived in a hypoxic dormitory (1,800 m) for either 2 nights (n = 6) or 2 days + nights (n = 7) before performing a 1,500-m treadmill test. Performance, expired gases, and muscle electrical activity were recorded and compared with a control session performed 1 week before or after the altitude session (random order). Arterial blood samples were collected before and after altitude exposure. Arterial pH and hemoglobin concentration increased (p < 0.05) and PCO2 decreased (p < 0.05) upon exiting the room. However, these parameters returned (p < 0.05) to basal levels within a few hours. During exercise, mean ventilation (VE) was higher (p < 0.05) after 2 nights or days + nights of moderate altitude exposure (113.0 +/- 27.2 L.min) than in the control run (108.6 +/- 27.8 L.min), without any modification in performance (360 +/- 45 vs. 360 +/- 42 seconds, respectively) or muscle electrical activity. This elevated VE during the run after the hypoxic exposure was probably because of the subsistence effects of the hypoxic ventilatory response. However, from a practical point of view, although the use of a normobaric simulating altitude chamber exposure induced some hematological adaptations, these disappeared within a few hours and failed to provide any benefit during the subsequent 1,500-m run.

Nutrition support in burns--is there consistency in practice?

Nutrition support is an integral part of the multidisciplinary management of a burn. However, the large body of research has lead to some confusion regarding optimal feeding practices. This review examines nutrition support practices in six United States (U.S.) and seven Australian burns units and compares practice to common themes and options in the literature. The review focuses on the consistency of practice in: managing the hormonal and metabolic changes resulting from a burn injury and their relationship to nutrition; techniques of estimating energy requirements; changes in macronutrient requirements; the use of specialized immune enhancing nutrition; methods of optimizing nutrition support; and methods of monitoring nutritional status and progress. In general, dietitians had a good understanding of the hypermetabolic response and increased nutritional requirements of burns patients. There were several areas where consistency was not seen, such as the fat and carbohydrate content of enteral formulas, the indications for use of total parenteral nutrition, the use of immunonutrition in enteral nutrition, and the most appropriate strategies for peri-operative feeding. This is a reflection of inconclusive research outcomes. There was more consistency in the techniques used for estimation of energy requirements, although more widespread use of indirect calorimetry would be beneficial. The need for high energy and high protein enteral feeds was also recognized across all units studied. The limitations of common nutritional markers was understood and managed by the use of multiple markers.