Actual Burn Nutrition Care Practices: An Update:

Burn Patient Metabolism and Nutrition

Following severe burns, patients have unique metabolic derangements that make adequate nutritional support imperative for their survival and recovery. Patients with burns have persistent and prolonged hypermetabolic states that lead to increased catabolism following injury. During rehabilitation, catabolism leads to increased muscle wasting and cachexia. Failure to adequately meet the patient's increased nutritional requirements can lead to poor wound healing, increased infections, and overall organ dysfunction. Because of these risks, adequate assessment and provision of nutritional needs are imperative to care for these patients.

An investigation of early enteral nutrition provision in major burn patients in Australia and New Zealand

AIMS

Early enteral nutrition (provided within 24 h of admission) is the optimal form of nutritional support for major burn injuries. The aim of this study was to (i) audit early enteral nutrition practices, (ii) identify characteristics of patients who received early enteral nutrition, and (iii) investigate whether early enteral nutrition was associated with in-hospital outcomes.

METHODS

An analysis of prospectively collected data from the Burns Registry of Australia and New Zealand was conducted. Specifically, this study focused on major burns patients (defined as burns affecting more than 20% and 15% total body surface area for adult paediatric patients, respectively) admitted to a specialist burn service between 1 July 2016 and 30 June 2019.

RESULTS

Data from 474 major burns patients (88 paediatric patients) revealed 69% received early enteral nutrition. Paediatric patients who received early enteral nutrition were younger than their counterparts who did not receive the same support (p = 0.04). Adult patients who received early enteral nutrition sustained larger burns (p < 0.001). Early enteral nutrition was not associated with in-hospital mortality following major burn injury in adult patients in either unadjusted (p = 0.77) or confounder-adjusted (p = 0.69) analyses.

CONCLUSIONS

Approximately two-thirds of patients with major burn injuries received early enteral nutrition. Early enteral nutrition was not associated with in-hospital mortality following major burn injury. Further research should focus on modifiable reasons why major burns patients do not receive enteral nutrition within 24 h of admission.

Validation of the modified NUTrition Risk Score (mNUTRIC) in mechanically ventilated, severe burn patients: A prospective multinational cohort study

BACKGROUND

Whether nutrition therapy benefits all burn victims equally is unknown. To identify patients who will benefit the most from optimal nutrition, the modified Nutrition Risk in Critically Ill (mNUTRIC) Score has been validated in the Intensive Care Unit. However, the utility of mNUTRIC in severe burn victims is unknown. We hypothesized that a higher mNUTRIC (≥5) will be associated with worse clinical outcomes, but that greater nutritional adequacy will be associated with better clinical outcomes in patients with higher mNUTRIC score.

METHODS

This prospective study included data from mechanically ventilated, severe burn patients (n = 359) from 51 Burn Units worldwide included in a randomized trial. Our primary and secondary outcomes were hospital mortality and the time to discharge alive (TTDA) from hospital. We described the association between nutrition performance and clinical outcomes.

RESULTS

Compared to low mNUTRIC (n = 313), the high mNUTRIC group (n = 46) had higher mortality (61% vs. 19%, p = 0.001), and longer TTDA (>90 [87->90] vs. 64 [38-90] days, p = <0.0001). Only in the high mNUTRIC group, increased calorie intake (per 20% increase) was associated with lower mortality and a faster TTDA.

CONCLUSIONS

The mNUTRIC score identifies those with poor clinical outcomes and may identifies those mechanically ventilated, severe burn patients in whom optimal nutrition therapy may be more advantageous.

The impact of serum zinc normalization on clinical outcomes in severe burn patients

INTRODUCTION

Patients with thermal burns become zinc deficient due to exudative losses, increased urinary excretion, and reduction of carrier proteins which results in impaired immunity, wound healing and glucose control. Previous trials have demonstrated improved wound healing utilizing fixed zinc supplementation, but none have assessed the potential benefits associated with normalizing serum zinc concentrations. The objective of this study was to compare the impact of zinc normalization on clinical outcomes in patients with severe thermal burns.

METHODS

This retrospective, single-center study of patients with at least 10% total body surface area (TBSA) burn and three serum zinc concentrations compared the ratio of hospital length of stay (LOS) over TBSA burned (LOS/TBSA index) between those with normal (≥60 mcg/mL) and non-normal (<60 mcg/mL) serum zinc concentrations; delineated by the third measurement. Secondary outcomes were time to 90% epithelialization, infection incidence, and percentage of blood glucose values greater than 180 mg/dL. Data are reported as median [25-75% interquartile range] for continuous variables and frequency (percent) for categorical variables.

RESULTS

A total of 56 patients were included for evaluation (11 normal and 45 non-normal). Burn size was 20.5% TBSA [11-29] for those with normal zinc and 27.3% [22-36] for non-normal; number of grafts for each group was 1 [0-1] vs 2 [1-3] respectively. LOS/TBSA index did not differ significantly between groups (1.10 normal vs. 1.21 non-normal, unadjusted p = 0.69; p = 0.75 adjusting for number of grafts). Time to 90% epithelialization was reduced in the normal group (27.5 vs. 57 days, p = 0.02), but this did not remain statistically significant after adjustment for %TBSA and number of grafts (p = 0.18). The groups did not differ significantly in incidence of infection or hyperglycemia in either unadjusted or adjusted analyses.

CONCLUSIONS

This was the first study, to our knowledge, to assess the clinical impact of normalizing serum zinc levels in patients with severe burns. Our results suggest the normalization of serum zinc levels through individualized zinc supplementation is not associated with improvement in clinical outcomes during hospitalization and therefore fixed-dose zinc supplementation without acquisition of serum zinc measurements should be considered.

High-Carbohydrate vs High-Fat Nutrition for Burn Patients

Nutrition is an essential component of the healing and recovery process after severe burn injury. For many burn patients, nutrition support is necessary to meet nutrition goals. The ratio of carbohydrates and fat is particularly important for burn patients, as an essential fatty acid deficiency can contribute to poor wound healing. However, there is evidence to suggest that diets containing more carbohydrates and less fat may result in better patient outcomes. A literature search was conducted to identify studies related to nutrition support and macronutrient ratios in burn patients. Eleven published papers were found that considered macronutrient use in enteral and parenteral nutrition therapies among 9 different burn patient samples. No negative outcomes associated with lower fat, higher carbohydrate nutrition for severely burned patients were found in the literature. Conversely, the literature review revealed improved outcomes among severely burned patients receiving lower fat, higher carbohydrate nutrition to include fewer incidences of pneumonia, wound infections, acute respiratory distress syndrome, fatty liver, and sepsis. These patients also experienced shorter hospital length of stay and shorter wound healing times, as well as lower spleen and kidney weights, lower urinary nitrogen losses, improved nitrogen balance, higher insulin levels, higher insulin-like growth factor-1, lower cortisol, and less muscle protein breakdown. The evidence available to date supports the clinical use of nutrition support providing ≤15% fat and ≥60% carbohydrate for critically ill burn patients.

Energy Expenditure and Protein Requirements Following Burn Injury

Severe burn injuries have long been known to have a profound effect on metabolic equilibrium that can persist after resolution of the cutaneous injuries. Following burn injury, metabolism is a dynamic state resulting in the need for frequent interval reassessment over the course of the care continuum. The acute phase of injury transitions to chronic alterations in macronutrient utilization characterized by futile energy cycling and disproportionate catabolism of skeletal muscle. Protein supplementation appears to be preferentially distributed to the burn wound rather than the skeletal muscle pool. Accurate assessment of caloric and protein requirements is extremely difficult in these patients but is an essential step in efforts to attenuate functional impairment. Indirect calorimetry should be utilized to determine caloric requirements, but trophic feeding strategies are preferred in the initial resuscitative phase to prevent overfeeding while maintaining enteric and immune function. Controversy persists regarding optimal protein targets, and weight-based estimates remain the norm. Exogenous protein and caloric provision performed in isolation is insufficient to optimize outcomes and should be incorporated within a multidisciplinary approach to include muscle loading and pharmaceutical adjuncts.

Trace element repletion following severe burn injury: A dose-finding cohort study

BACKGROUND & AIMS

Major burn patients are characterized by large exudative losses of Cu, Se and Zn. Trace element (TE) repletion has been shown to improve clinical outcome. Having increased the TE doses over time, the study aimed at analysing if our repletion protocol corrected TE plasma concentrations and if the necessity for continuous renal replacement therapy (CRRT) might increase the TE needs.

METHODS

Retrospective analysis of prospectively collected data in burn patients requiring intensive care (ICU) between 1999 and 2015.

INCLUSION CRITERIA

Admission on day 1, full treatment, burned surface area (TBSA) ≥20% and ≥1 TE plasma determination during the stay. Four groups were constituted according to protocol changes. Period 1 (P1): 1999-2000, P2: 2001-2005, P3: 2006-2010, P4: 2011-2015. Changes consisted in increasing TE repletion doses and duration. Demographic data, daily TE intakes and weekly plasma concentrations were retrieved for the first 21 ICU-days. Data as median (IQR).

RESULTS

139 patients completed the criteria, aged 37 (28) years, burned on 35 (25) % TBSA. As a result of prescription, Cu, Se and Zn intakes increased significantly between P1 and P4, resulting in normalization of plasma Cu (16 μmol/l) since P3 and Zn (13.5 μmol/l) since P2. Median plasma Se were above reference range (1400 nmol/l) during P3 and P4. CRRT patients required higher doses of Cu for maintenance within normal ranges.

CONCLUSION

This dose finding study shows that the latest repletion protocol is safe and normalizes Cu and Zn concentrations. Se doses result in supra-normal Se concentrations, suggesting prescription reduction. CRRT patients are at high risk of Cu depletion and require specific monitoring.

Nutrition and metabolism in burn patients

Severe burn causes significant metabolic derangements that make nutritional support uniquely important and challenging for burned patients. Burn injury causes a persistent and prolonged hypermetabolic state and increased catabolism that results in increased muscle wasting and cachexia. Metabolic rates of burn patients can surpass twice normal, and failure to fulfill these energy requirements causes impaired wound healing, organ dysfunction, and susceptibility to infection. Adequate assessment and provision of nutritional needs is imperative to care for these patients. There is no consensus regarding the optimal timing, route, amount, and composition of nutritional support for burn patients, but most clinicians advocate for early enteral nutrition with high-carbohydrate formulas.

Nutritional support must be individualized, monitored, and adjusted throughout recovery. Further investigation is needed regarding optimal nutritional support and accurate nutritional endpoints and goals.

Nutrition and metabolism in burn patients

Severe burn causes significant metabolic derangements that make nutritional support uniquely important and challenging for burned patients. Burn injury causes a persistent and prolonged hypermetabolic state and increased catabolism that results in increased muscle wasting and cachexia. Metabolic rates of burn patients can surpass twice normal, and failure to fulfill these energy requirements causes impaired wound healing, organ dysfunction, and susceptibility to infection. Adequate assessment and provision of nutritional needs is imperative to care for these patients. There is no consensus regarding the optimal timing, route, amount, and composition of nutritional support for burn patients, but most clinicians advocate for early enteral nutrition with high-carbohydrate formulas. Nutritional support must be individualized, monitored, and adjusted throughout recovery. Further investigation is needed regarding optimal nutritional support and accurate nutritional endpoints and goals.

Skin Regeneration Symposium Cambridge, 12-13 April 2016

The Annual Skin Regeneration Symposium, held in Cambridge, UK, 12-13 April 2016, explored the latest advancements in skin repair, regeneration and restoration, and the impact this has on patients. With over 140 delegates from the disciplines of burn and trauma care, chronic wounds and esthetic medicine, the symposium sparked lively debate and the sharing of results from interesting case studies, clinical trials and basic research to support the use of a Regenerative Epithelial Suspension produced using the ReCell(®) technology. Furthermore, it enabled delegates and speakers alike to share ideas and discuss how to improve the quality of care for patients.

Amino Acid Availability Regulates the Effect of Hyperinsulinemia on Skin Protein Metabolism in Pigs

The effects of amino acid supply and insulin infusion on skin protein kinetics (fractional synthesis rate (FSR), fractional breakdown rate (FBR), and net balance (NB)) in pigs were investigated. Four-month-old pigs were divided into four groups as follows: control, insulin (INS), amino acid (AA), and INS + AA groups based on the nutritional and hormonal conditions. l-[ring-(13)C6]Phenylalanine was infused. FBR was estimated from the enrichment ratio of arterial phenylalanine to intracellular free phenylalanine. Plasma INS was increased (p < 0.05) in the INS and INS + AA groups. Plasma glucose was maintained by infusion of glucose in the groups receiving INS. The interventions did not change the NB of skin protein. However, the interventions affected the FSR and FBR differently. An infusion of INS significantly increased both FSR and FBR, although AA infusion did not. When an AA infusion was added to the infusion of insulin (INS + AA group), FSR and FBR were both lower when compared with the INS group. Our data demonstrate that in anesthetized pigs INS infusion did not exert an anabolic effect, but rather it increased AA cycling into and out of skin protein. Because co-infusion of AAs with INS ameliorated this effect, it is likely that the increased AA cycling during INS infusion was related to AA supply. Although protein kinetics were affected by both INS and AAs, none of the interventions affected the skin protein deposition. Thus, skin protein content is closely regulated under normal circumstances and is not subject to transient changes in AAs or hormonal concentrations.

Micronutrients after burn injury: a review

Supplementation of micronutrients after burn injury is common practice in order to fight oxidative stress, support the immune system, and optimize wound healing. Assessing micronutrient status after burn injury is difficult because of hemodilution in the resuscitation phase, redistribution of nutrients from the serum to other organs, and decreases in carrier proteins such as albumin. Although there are many preclinical data, there are limited studies in burn patients. Promising research is being conducted on combinations of micronutrients, especially via the intravenous route.

International observational study of nutritional support in mechanically ventilated patients following burn injury

INTRODUCTION

It has been proposed that nutritional therapy in critically ill patients after major burn reduces mortality. However, the actual practice of nutrient delivery, and the effect on outcome, has not been described.

STUDY OBJECTIVES

To evaluate international practices related to nutritional support and outcomes in mechanically ventilated patients with burn injury.

METHODS

Data from the International Nutrition Surveys (2007-2011) for patients with a primary diagnosis of burn were extracted and analysed.

RESULTS

Eighty-eight of 90 patients (aged 16-84 years) received enteral nutrition. The median time for initiation of enteral feeding was 17 h [range 0-65]. Fifty patients (57%) had interruptions to nutrient delivery, most often these interruptions were fasting for operative procedures. There were substantive energy and protein deficits [943 (654) kcal/day and 49 (41) g/day, respectively; mean (SD)]. Nineteen (21%) patients died within 60 days of admission, and the energy and protein deficits were greater in those that died compared with survivors [died vs. survived, energy: 1251 (742) vs. 861 (607) kcal/d; p=0.02; and protein 67(42) vs. 44(39) g/d; p=0.03]. Energy and protein deficits were associated with increased mortality with the greater the deficit, the stronger the association with death (odds ratio for death: energy deficit/100 kcal 1.10 (1.01, 1.19); p=0.028 and protein/10 g 1.16 (1.01, 1.33); p=0.037). Results were similar and remained significant after adjusting for severity of illness.

CONCLUSIONS

Mechanically ventilated patients following burn develop substantial energy and protein deficits, with lesser deficits observed in survivors.

Establishment and assessment of new formulas for energy consumption estimation in adult burn patients

OBJECTIVE

An accurate knowledge of energy consumption in burn patients is a prerequisite for rational nutrition therapy. This study sought to create a formula that accounts for the metabolic characteristics of adult burn patients to accurately estimate energy consumption of patients with different areas and extents of burn and at different times after injury.

METHODS

Resting energy expenditure (REE) data on 66 burn patients, with total body surface area (TBSA) of burns ranging from 4% to 96%, were evaluated at different times after injury. REE values were determined in patients using indirect calorimetry at days 1, 2, 3, 7, 14, 21, and 28 after injury. We then constructed a mathematical model of REE changes post-burn. Next, established two new formulas (one non-linear and the other linear) for energy consumption estimation using model-based analytical solution and regression analysis. The new formulas were compared with measured REE and commonly used formulas including those of Carlson, Xie, Curreri, and Milner to determine accuracy and reliability.

RESULTS

Comparative analysis showed that the new formulas offered significantly higher accuracy and reliability than the Milner formula, which is considered the most accurate of commonly used burn energy consumption estimate formulas. The accuracy of the new nonlinear formula (94.29%) and that of the linear formula (91.43%) were significantly higher than that of Milner formula (72.86%) when compared to measured REE (χ2  =  11.706, P  =  0.001; χ2  =  8.230, P  =  0.004, respectively). The reliabilities of the new estimation formulas were both 100% and that of Milner formula was 74.24% (χ2  =  19.513, P  =  0.000).

CONCLUSION

The new formulas constructed in this study provide reliable simulation of the impact of the degree of burn and post-burn days on energy consumption and offer notably higher accuracy and reliability than other formulas. These formulas will help determine nutritional needs of burn patients.

TRIAL REGISTRATION

The study was registered on Chinese Clinical Trial Registry as ChiCTR-TRC-13003806.

Nutritional care of the obese adult burn patient: a U.K. Survey and literature review

Obesity is an emerging healthcare problem and affects an increasing number of burn patients worldwide. An email survey questionnaire was constructed and distributed among the 16 U.K. burn services providing adult inpatient facilities to investigate nutritional practices in obese thermally injured patients. Responses received from all dieticians invited to participate in the study were analyzed, and a relevant literature review of key aspects of nutritional care is presented. The majority of services believe that obese patients warrant a different nutritional approach with specific emphasis to avoid overfeeding. The most common algebraic formulae used to calculate calorific requirements include the Schofield, Henry, and modified Penn State equations. Indirect calorimetry despite being considered the "criterion standard" tool to calculate energy requirements is not currently used by any of the U.K. burn services. Gastric/enteral nutrition is initiated within 24 hours of admission in the services surveyed, and a variety of different practices were noted in terms of fasting protocols before procedures requiring general anesthesia/sedation. Hypocaloric regimens for obese patients are not supported by the majority of U.K. facilities, given the limited evidence base supporting their use. The results of this survey outline the wide diversity of dietetic practices adopted in the care of obese burn patients and reveal the need for further study to determine optimal nutritional strategies.

Obesity and burns

The population of overweight patients presenting to burn facilities is expected to increase significantly over the next decades due to the global epidemic of obesity. Excess adiposity mediates alterations to key physiological responses and poses challenges to the optimal management of burns. The purpose of this study is to document the general epidemiological aspects of thermal injuries in the obese population, outline relevant physiological aspects associated with obesity, and draw attention to topics relating to the management, rehabilitation, and prognosis of burns in this emerging subpopulation of patients.

Whole body protein kinetics measured with a non-invasive method in severely burned children

Persistent and extensive skeletal muscle catabolism is characteristic of severe burns. Whole body protein metabolism, an important component of this process, has not been measured in burned children during the long-term convalescent period. The aim of this study was to measure whole body protein turnover in burned children at discharge (95% healed) and in healthy controls by a non-invasive stable isotope method. Nine burned children (7 boys, 2 girls; 54±14 (S.D.)% total body area burned; 13±4 years; 45±20 kg; 154±14 cm) and 12 healthy children (8 boys, 4 girls; 12±3 years; 54±16 kg; 150±22 cm) were studied. A single oral dose of (15)N-alanine (16 mg/kg) was given, and thereafter urine was collected for 34 h. Whole body protein flux was calculated from labeling of urinary urea nitrogen. Then, protein synthesis was calculated as protein flux minus excretion, and protein breakdown as flux minus intake. At discharge, total protein turnover was 4.53±0.65 (S.E.)g kg body weight(-1) day(-1) in the burned children compared to 3.20±0.22 g kg(-1) day(-1) in controls (P=0.02). Expressed relative to lean body mass (LBM), the rates were 6.12±0.94 vs. 4.60±0.36 g kg LBM(-1) day(-1) in burn vs. healthy (P=0.06). Total protein synthesis was also elevated in burned vs. healthy children, and a tendency for elevated protein breakdown was observed.

CONCLUSION

Total protein turnover is elevated in burned children at discharge compared to age-matched controls, possibly reflecting the continued stress response to severe burn. The oral (15)N-alanine bolus method is a convenient, non-invasive, and no-risk method for measurement of total body protein turnover.

Dietetic service provision for burn care in the United Kingdom: are nutrition support standards being met?

BACKGROUND

Catabolism and lean body mass losses in severe burn injury present an extreme challenge to the dietitian. A high level of nutritional intervention is often required, but service levels have not been described in the UK. This study aimed to identify levels of current dietetic services with respect to burns and to assess adequacy against existing nutrition support standards.

METHODS

A postal survey of 34 UK dietetic departments known to provide care to burned adult and paediatric admissions was undertaken. Data were collected on burns settings, hospital service characteristics, staffing and caseload issues, and absence cover. Comparison was made between funding and activity to National Health Service standards for the nutritional care of inpatients.

RESULTS

The response rate was 71% and data were analysed for 20 departments Clinical settings were either burn units or plastic surgery wards. Dietetic care was provided to critically ill burned patients in 16 hospitals. Most hospitals had no dietetic funding assigned for burn care. The funding deficit for critical care compared to recommendations was 5.9 full-time equivalents and no individual hospital met funding standards. Thirty-seven percent of dietitians were unable to provide daily follow up for critically ill patients. Absence cover was limited in 60% of cases. Approximately one-third of dietitians were members of a nutrition support team.

CONCLUSIONS

Compared to national guidelines for nutrition support, deficiencies of dietetic service provision exist within UK burns settings. This is further reinforced when practice is compared with existing multi-professional burns management standards.