American Burn Association Presidential Address 2006 on Nutrition: Yesterday, Today, and Tomorrow

An objective measure for the assessment and management of fluid shifts in acute major burns

BACKGROUND

Major burns are life threatening. Fluid resuscitation is required for survival to maintain intravascular volumes and prevent hypovolemic shock. Bioimpedance spectroscopy (BIS) has been recognised as a potential method of monitoring fluid shifts after burn and in other disease states. The aims of this study were to examine the reliability of BIS across different dressing conditions and electrode positions, establish the influence of Acticoat™ on BIS variable measures and determine the validity of whole-body BIS to assess net fluid shift in the presence of moderate to major burns.

METHODS

An observational longitudinal cohort study was conducted from December 2014 to February 2016. Patients with over 15% total body surface area (TBSA) burns and injury less than 48 h were enrolled in the study. BIS triplicate measures were collected in an open wound and with an ActicoatTM dressing (at 5 half hour intervals). Standard and alternate electrode placements were utilised for the reliability analysis and standard placement only for determining the validity of BIS in moderate to major burns. The ImpediMde SFB7 was used to collect whole-body and segmental BIS measures. Stata statistical software, release 14 was utilised to analyse all results. Descriptive analyses were performed and were reported using the means and standard deviations (SD).

RESULTS

BIS-repeated measures established BIS raw resistance (R), and predicted volume variables were reliable in any condition (intra-class correlation coefficient (ICC) 0.996-0.999, 95% confidence intervals (CI) 0.996-0.999) without a systematic difference. Acticoat™ dressings significantly influenced all BIS-predicted volumes (p ≤ 0.01) as determined by multilevel mixed effects (MLME) linear regression analysis. Validity of BIS was demonstrated by resistance variables significantly decreasing with increasing net ionic fluid shift and increased TBSA (severity of injury) and calculated fluid volumes increasing with increasing net fluid shift and TBSA. BIS resistance also decreased with time as oedema reduced. For clinical use, a calculator was developed to adjust BIS variables when an Acticoat™ dressing is in situ, thus facilitating BIS variable change estimates in real time, with dressings intact.

CONCLUSION

BIS may be used clinically to monitor fluid volume change in major acute burns.

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.

The use of a dermal substitute for simultaneous flap delay and donor site coverage in two cases

OBJECTIVE

Lower extremity traumatic wounds can be difficult to treat owing to limb ischaemia and large zones of injury. Often, muscle or fasciocutaneous flaps are used in the presence of severe open orthopaedic injuries with soft tissue defects. Sometimes local flaps may be the preferred or only option, but may not tolerate being rotated or advanced owing to resulting flap ischaemia. One well-studied technique that can increase the survival of various flaps involves the delay phenomenon.

METHOD

In these case reports, Integra Dermal Regeneration template was used to simultaneously create delayed flaps and to cover the wound and flap donor site so that the donor site could be skin grafted at the time of flap inset.

RESULTS

These cases demonstrate that use of Integra can enhance the delay phenomenon while simultaneously providing coverage of soft tissue defects in preparation for ultimately insetting delayed flaps and better covering donor areas.

CONCLUSION

This technique may be applicable to many different flaps in many different anatomic locations and should be considered an option when reconstructing complicated wounds.

DECLARATION OF INTEREST

none.

Immunonutrition as an adjuvant therapy for burns

BACKGROUND

With burn injuries involving a large total body surface area (TBSA), the body can enter a state of breakdown, resulting in a condition similar to that seen with severe lack of proper nutrition. In addition, destruction of the effective skin barrier leads to loss of normal body temperature regulation and increased risk of infection and fluid loss. Nutritional support is common in the management of severe burn injury, and the approach of altering immune system activity with specific nutrients is termed immunonutrition. Three potential targets have been identified for immunonutrition: mucosal barrier function, cellular defence and local or systemic inflammation. The nutrients most often used for immunonutrition are glutamine, arginine, branched-chain amino acids (BCAAs), omega-3 (n-3) fatty acids and nucleotides.

OBJECTIVES

To assess the effects of a diet with added immunonutrients (glutamine, arginine, BCAAs, n-3 fatty acids (fish oil), combined immunonutrients or precursors to known immunonutrients) versus an isonitrogenous diet (a diet wherein the overall protein content is held constant, but individual constituents may be changed) on clinical outcomes in patients with severe burn injury.

SEARCH METHODS

The search was run on 12 August 2012. We searched the Cochrane Injuries Group's Specialised Register, The Cochrane Library, MEDLINE (OvidSP), Embase (OvidSP), ISI WOS SCI-EXPANDED & CPCI-S and four other databases. We handsearched relevant journals and conference proceedings, screened reference lists and contacted pharmaceutical companies. We updated this search in October 2014, but the results of this updated search have not yet been incorporated.

SELECTION CRITERIA

Randomised controlled trials comparing the addition of immunonutrients to a standard nutritional regimen versus an isonitrogenated diet or another immunonutrient agent.

DATA COLLECTION AND ANALYSIS

Two review authors were responsible for handsearching, reviewing electronic search results and identifying potentially eligible studies. Three review authors retrieved and reviewed independently full reports of these studies for inclusion. They resolved differences by discussion. Two review authors independently extracted and entered data from the included studies. A third review author checked these data. Two review authors independently assessed the risk of bias of each included study and resolved disagreements through discussion or consultation with the third and fourth review authors. Outcome measures of interest were mortality, hospital length of stay, rate of burn wound infection and rate of non-wound infection (bacteraemia, pneumonia and urinary tract infection).

MAIN RESULTS

We identified 16 trials involving 678 people that met the inclusion criteria. A total of 16 trials contributed data to the analysis. Of note, most studies failed to report on randomisation methods and intention-to-treat principles; therefore study results should be interpreted with caution. Glutamine was the most common immunonutrient and was given in seven of the 16 included studies. Use of glutamine compared with an isonitrogenous control led to a reduction in length of hospital stay (mean stay -5.65 days, 95% confidence interval (CI) -8.09 to -3.22) and reduced mortality (pooled risk ratio (RR) 0.25, 95% CI 0.08 to 0.78). However, because of the small sample size, it is likely that these results reflect a false-positive effect. No study findings suggest that glutamine has an effect on burn wound infection or on non-wound infection. All other agents investigated showed no evidence of an effect on mortality, length of stay or burn wound infection or non-wound infection rates.

AUTHORS' CONCLUSIONS

Although we found evidence of an effect of glutamine on mortality reduction, this finding should be taken with care. The number of study participants analysed in this systematic review was not sufficient to permit conclusions that recommend or refute the use of glutamine. Glutamine may be effective in reducing mortality, but larger studies are needed to determine the overall effects of glutamine and other immunonutrition agents.

Complications of chlorine inhalation in a pediatric chemical burn patient: a case report

The majority of burn injuries in the pediatric population occur at home, and a significant proportion are the result of exposure to household cleaning products. A common injury-causing agent is bleach, which has the potential to release chlorine gas, a potent respiratory irritant that leads to the added risk of inhalation injury. The survival of pediatric patients with chemical burns is extremely high, and the 3 strongest predictors of mortality are large burn size, age <48 months, and the presence of inhalation injury. The authors present a rare case of a pediatric fatality from a chemical bleach burn that resulted in acute respiratory distress syndrome as well as hemodynamic and pulmonary instability that required extracorporeal membrane oxygenation. The authors critically appraised the management of this patient to determine the possible effect certain events had on the unexpected and poor outcome of this patient, including fluid resuscitation, the effect of the chemical inhalation injury, sedation, and the need for invasive extracorporeal membrane oxygenation life support.

Metabolic implications of severe burn injuries and their management: a systematic review of the literature

BACKGROUND

Severe burn patients are some of the most challenging critically ill patients, with an extreme state of physiologic stress and an overwhelming systemic metabolic response. A major component of severe burn injury is a hypermetabolic state associated with protein losses and a significant reduction of lean body mass. The second prominent component is hyperglycemia. Reversal of the hypermetabolic response by manipulating the patient's physiologic and biochemical environment through the administration of specific nutrients, growth factors, or other agents, often in pharmacologic doses, is emerging as an essential component of the state of the art in severe burn management. The present review aims at summarizing the new treatment modalities established to reduce the catabolic burden of severe burn injuries, for which there is some evidence-based support.

METHODS

A systematic review of the literature was conducted. Search tools included Elsevier ScienceDirect, EMBASE.com, Medline (OVID), MedlinePlus, and PubMed. Topics searched were Nutrition and Burns, Metabolic Response and Burns, Hypermetabolism and Burns, Hyperglycemia and Burns, and several more specific topics when indicated. With a focus on the most recently published articles, abstracts were reviewed and, when found relevant, were included as references. Full text articles, whenever available, were retrieved.

RESULTS

Many issues remain unanswered. Unfortunately, the present state of our knowledge does not allow the formulation of clear-cut guidelines. Only general trends can be outlined, and these will certainly have some practical applications but above all will dictate future research in the field.

Bedside assessment of swallowing is predictive of an abnormal barium swallow examination

Adequate nutritional support after thermal burn injury is essential for achieving successful patient outcomes. Dysphagia is common in burn patients. Our objective was to analyze hospitalized burn patients referred to speech pathology for swallowing evaluation. A retrospective study of burn patients admitted to our center and evaluated by speech pathology from December 2001 through July 2006 was performed. Of the 16 patients, 5 (31%) had a normal bedside swallow examination, did not undergo a modified barium swallow study (MBSS), and were excluded. Six (55%) of the 11 included patients were men. The average age was 44 +/- 18 years. All 11 patients had a thermal burn with an average total body surface area burn of 36% +/- 16%. Facial burns were present in 91% (10 of 11) of the patients, and inhalation injury was confirmed by bronchoscopy in 55% (6 of 11) of the patients. The average length of stay was 84 +/- 45 days. Of the 11 abnormal bedside assessments performed, 10 (91%) were associated with an abnormal MBSS. One patient had evidence of oral dysphagia only and one patient had evidence of pharyngeal dysphagia only. Six patients had oral and pharyngeal dysphagia, and two patients had pharyngeal and esophageal dysphagia. One tracheal-esophageal fistula was identified. A bedside assessment of swallowing performed by a speech pathologist is predictive of an abnormal modified barium swallow in burn patients. Burn patients with facial burns, inhalation injury, pneumonia, and a prolonged ICU stay are at increased risk for dysphagia. Prospective studies are necessary to determine in which patients an MBSS adds additional relevant clinical information.

Thermal injury-plus-sepsis contributes to a substantial deletion of intestinal mesenteric lymph node CD4 T cell via apoptosis

Thermal injury (TI) with septic complications continues to be a serious clinical problem. One of the main concerns in such patients is immunosuppression related to functional derangements in intestinal CD4⁺ T lymphocytes. Extensive previous studies in thermal injury/septic patients and animal models of thermal injury/sepsis have shown decreased responsiveness of intestinal CD4⁺ T cells to antigen/mitogen. This hyporesponsiveness could significantly contribute to increase injured host susceptibility to pathogens including those translocating from host's gut lumen. Our previous studies indicated that while thermal injury or sepsis alone lead to suppressed proliferation and IL-2 production of intestinal CD4⁺ T cells, this study showed a substantial deletion via apoptosis of the Mesenteric Lymph Nodes (MLN) CD4⁺ T cells. Hence, thermal injury-plus-sepsis contributes not only to suppressed CD4⁺ T proliferation/IL-2 production but also to a substantial modulation of CD4⁺ T cell survivability. These findings allow us to conclude that while thermal injury alone can produce attenuated cell mediated responses without an overt change in CD4⁺ T cell survival, thermal injury with septic complications causes CD4⁺ T cell death and an irreversible loss of cell-mediated responses. The latter happening could be responsible for high morbidity and mortality in the injured host afflicted with thermal injury plus a critical infection.