Nutrition and anabolic agents in burned patients

Review of History of Basic Principles of Burn Wound Management

Thermal energy is an essential and useful resource to humans in modern society. However, a consequence of using heat carelessly is burns. Burn injuries have various causes, such as exposure to flame, radiation, electrical, and chemical sources. In this study, we reviewed the history of burn wound care while focusing on the basic principles of burn management. Through this review, we highlight the need for careful monitoring and customization when treating burn victims at each step of wound care, as their individual needs may differ. We also propose that future research should focus on nanotechnology-based skin grafts, as this is a promising area for further improvement in wound care.

Anabolic and anticatabolic agents used in burn care: What is known and what is yet to be learned

Major thermal injury induces profound metabolic derangements secondary to an inflammatory "stress-induced" hormonal environment. Several pharmacological interventions have been tested in an effort to halt the hypermetabolic response to severe burns. Insulin, insulin growth factor 1, insulin growth factor binding protein 3, metformin, human growth hormone, thyroid hormones, testosterone, oxandrolone, and propranolol, among others, have been proposed to have anabolic or anticatabolic effects. The aim of this broad analysis of pharmacological interventions was to raise awareness of treatment options and to help establishing directions for future clinical research efforts. A PubMed search was conducted on the anabolic and anticatabolic agents used in burn care. One hundred and thirty-five human studies published between 1999 and 2017 were included in this review. The pharmacological properties, rationale for the treatments, efficacy considerations and side effect profiles are summarized in the article. Many of the drugs tested for investigational purposes in the severely thermally injured are not yet gold-standard therapies in spite of their potential benefit. Propranolol and oxandrolone have shown great promise but further evidence is still needed to clarify their potential use for anabolic and anticatabolic purposes.

Relationship Between Burn Wound Location and Outcomes in Severely Burned Patients: More Than Meets the Size

We hypothesized that burn location plays an important role in wound healing, mortality, and other outcomes and conducted the following study to test this multifold hypothesis. We conducted a study to retrospectively look at patients with burns ≥10% TBSA. Demographics, TBSA, partial/full thickness burns (PT/FT) in various wound locations, fluids, inhalation injury, mortality, ICU duration, and hospital duration were considered. Initial wound healing rates (%/d) were also calculated as a slope from the time of the first mapping of open wound size to the time of the third mapping of open wound size. Multivariate logistic regression and operating curves were used to measure mortality prediction performance. All values were expressed as median [interquartile range]. The mortality rate for 318 patients was 17% (54/318). In general, patients were 43 years [29, 58 years] old and had a TBSA of 25% [17, 39%], PT of 16% [10, 25%], and FT of 4% [0, 15%]. Between patients who lived and did not, age, TBSA, FT, 24-hour fluid, and ICU duration were statistically different (P < .001). Furthermore, there were statistically significant differences in FT head (0% [0, 0%] vs 0% [0, 1%], P = .048); FT anterior torso (0% [0, 1%] vs 1% [0, 4%], P < .001); FT posterior torso (0% [0, 0%] vs 0% [0, 4%], P < 0.001); FT upper extremities (0% [0, 3%] vs 2% [0, 11%], P < .001); FT lower extremities (0% [0, 2%] vs 6% [0, 17%], P < .001); and FT genitalia (0% [0, 0%] vs 0% [0, 2%], P < .001). Age, presence of inhalation injury, PT/FT upper extremities, and FT lower extremities were independent mortality predictors and per unit increases of these variables were associated with an increased risk for mortality (P < .05): odds ratio of 1.09 (95% confidence interval [CI] = 1.61–1.13; P < .001) for mean age; 2.69 (95% CI = 1.04–6.93; P = .041) for inhalation injury; 1.14 (95% CI = 1.01–1.27; P = .031) for mean PT upper extremities; 1.26 (95% CI = 1.11–1.42; P < .001) for mean FT upper extremities; and 1.07 (95% CI = 1.01–1.12; P = .012) for mean FT lower extremities. Prediction of mortality was better using specific wound locations (area under the curve [AUC], AUC of 0.896) rather than using TBSA and FT (AUC of 0.873). Graphs revealed that initial healing rates were statistically lower and 24-hour fluids and ICU length of stay were statistically higher in patients with FT upper extremities than in patients without FT extremities (P < .001). Burn wound location affects wound healing and helps predict mortality and ICU length of stay and should be incorporated into burn triage strategies to enhance resource allocation or stratify wound care.

Effect of small molecular weight soybean protein-derived peptide supplementation on attenuating burn injury-induced inflammation and accelerating wound healing in a rat model

The populations most afflicted by burn injuries have limited abilities to support the significant specialized requirements and costs for acute and long-term burn injury care. This article describes the results of optimizing the use of readily absorbed small molecular weight soybean protein enzymolysis-derived peptide to attenuate rat burn injury-induced inflammation and accelerate wound healing. A major full-thickness 30% total body surface area burn-injury rat model was utilized and the systemic white blood cell (WBC) counts, the relative level of stimulation index of respiratory burst, and the inflammatory markers procalcitonin (PCT), tumor necrosis factor-α (TNF-α), chemokine (C–C motif) ligand 3 (CCL-3), chemokine (C–C motif) ligand 11 (CCL-11) and interleukin-10 (IL-10) were assessed. The burn injury-induced neutrophil and macrophage immune cell infiltration of the cutaneous tissues was detected by immunohistochemical analysis of the protein markers myeloperoxidase (MPO) and cluster of differentiation 68 (CD-68). The local induction of the burn injury-induced toll-like receptor 4/nuclear factor kappa-light-chain-enhancer of activated B (TLR4/NF-κB) signaling pathway in the effected cutaneous tissues was determined by the quantification of the protein expression of TLR4 and phosphorylated NF-κB/p65 using Western blots. In addition, burn wound size and healing rate were assessed biweekly for 8 weeks by imaging and measuring the burn wound surface area, and the angiogenesis protein marker of cluster of differentiation 31 (CD-31) expression in cutaneous tissues was also detected by immunohistochemical analysis. The results showed that nutrient supplementation with optimized readily absorbed small molecular weight soybean protein-derived peptide resulted in a dramatic anti-inflammatory effect as evidenced by the significant increase in the burn injury-induced systemic white blood cell counts and their relative level of stimulation index of respiratory burst, reduction in the burn injury-induced activation of NF-κB transcriptional signaling pathways, significant reduction in the local burn injury-induced cutaneous infiltration of neutrophils and macrophages at all measured time points, reduction in wound size and improved rate of burn injury wound healing with increased CD-31 protein expression. These results indicated that dietary supplementation with small molecular weight soybean-derived peptides could be used as an adjunct therapy in burn injury management to reduce inflammation and improve overall patient outcomes.

The populations most afflicted by burn injuries have limited abilities to support the significant specialized requirements and costs for acute and long-term burn injury care.

Fluid Restriction for Treatment of “Fluid Creep” after Acute Burn Resuscitation

Objective

Fluid creep in patients recovering from acute burns still exists, despite the use of a more treatment conservative approach. Most of our severe burn patients develop fluid overload and body weight increase after acute fluid resuscitation. How to quickly return patients to their pre-injury body weight is an important issue.

Methods

Right after acute fluid resuscitation, we applied a “total fluid requirement” volume (usually 1/2 to 2/3 of initial 24 hour volume) and strictly monitored patients' hourly urine (between 0.5-1 ml/kg/hr). Patients' responses (body weight, enteric feeding amount, pulmonary condition, etc.) were also closely monitored and frequent adjustments of fluid volume administration were performed simultaneously.

Results

Most patients regained their pre-injury body weight within 2-3 weeks. Enteric feeding also improved markedly. No patients had severe oedema-related complications.

Conclusions

Stricter fluid administration after acute burn fluid resuscitation is advised for allowing patients to reduce body weight to their pre-injury weight or at least close to it. We use pre-injury body weight, enteric feeding and urine output as our guides. (Hong Kong j.emerg.med. 2014;21:222-229)

Burn wound healing and treatment: review and advancements

Burns are a prevalent and burdensome critical care problem. The priorities of specialized facilities focus on stabilizing the patient, preventing infection, and optimizing functional recovery. Research on burns has generated sustained interest over the past few decades, and several important advancements have resulted in more effective patient stabilization and decreased mortality, especially among young patients and those with burns of intermediate extent. However, for the intensivist, challenges often exist that complicate patient support and stabilization. Furthermore, burn wounds are complex and can present unique difficulties that require late intervention or life-long rehabilitation. In addition to improvements in patient stabilization and care, research in burn wound care has yielded advancements that will continue to improve functional recovery. This article reviews recent advancements in the care of burn patients with a focus on the pathophysiology and treatment of burn wounds.

Thermal injury activates the eEF2K-dependent eEF2 pathway in pediatric patients

BACKGROUND

Burn induces a hypermetabolic state characterized by alterations in protein metabolism, which is associated with increased morbidity and mortality. Eukaryotic elongation factor 2 (eEF2) plays a crucial role in regulating protein synthesis in many diseases, but whether it participates in burn-induced hypermetabolism is unclear. The aim of this study was to determine the expression of eEF2 and the upstream eEF2-inactivating kinase, eEF2K, in severely burned pediatric patients.

METHODS

Eight pediatric patients (> 40% total body surface area) and 3 nonburned pediatric volunteers were enrolled. Muscle and skin biopsies were collected at early (0-10 days postburn [dpb]), middle (11-49 dpb), and late (50-365 dpb) time points. Resting energy expenditure (REE), body composition, and muscle protein fractional synthesis rate (FSR) were measured. Proteins were extracted and analyzed by Western blotting. To further investigate the protein synthesis pathway, microarray data from muscle and skin were examined from 22 nonburned and 20 burned children.

RESULTS

Burn patients exhibited a profound hypermetabolic response, as seen by a significant increase in REE (P < .05) and loss of lean body mass without altered muscle FSR, indicating a shift to catabolism after thermal injury. In muscle, the phosphorylation of eEF2K-dependent eEF2 was down regulated early and middle postburn. Similar changes in eEF2K and eEF2 levels occurred in skin at the early time point. Total amounts of eEF2 and eEF2K were not altered.

CONCLUSION

Burn induces prolonged activation of eEF2K and eEF2. Alterations in these mediators may contribute to profound hypermetabolism in severely burned patients.

Burns: what are the pharmacological treatment options?

BACKGROUND

Many advances have been made in the understanding and management of burn injury, dramatically increasing pharmacological decision options for burn care professionals. Since burn injury is so multi-faceted, these advances cross many injury processes, both acute and chronic.

OBJECTIVE

The purpose of this review was to highlight the advances and decision options across the entire scope of the burn injury process. The burn-related processes with the most significant pharmacological options of approved products are highlighted.

METHODS

The scope of the current research is the most pertinent literature, which has been summarized with the addition of a personal perspective.

RESULTS/CONCLUSIONS

Many advances over the past decade in multiple fields have made pharmacological options plentiful in burn care. That said, there are many problems for the burn patient which persist, making burn injury still the most severe form of trauma. These issues range from management of a catabolic state with involuntary weight loss in the critical burn to severe itching in the rehabilitating patient. There are also many more treatment options available today. Two key reasons stand out as the most prominent. One reason is the fact that burn care has become much more proactive, by searching out new approaches to solve old problems. Now the treatment approach is altering its focus on manipulating the course of a burn. Examples include the use of temporary skin substitutes in partial thickness or second degree burns, decreasing pain and increasing the healing rate. Another is the use of slow release silver dressing as the topical burn wound antimicrobial of choice, markedly reducing discomfort, the need for dressing changes and an overall decrease in infection. In larger, deeper burns, the approach has changed from the chronic management of an open burn wound to rapid excision and wound closure, eliminating the burn as a source of complications. In addition, there has been a very aggressive approach to controlling the profound hypermetabolic, catabolic response to burns, rather than simply treating the outcome of this predictable post-burn complication. Approaching psychosocial stress again by prevention rather than treatment of established problems is another example. The second reason for increased options and differences in management involves the mindset of those individuals taking care of burns. Tremendous differences in experience are involved in decision-making. Different opinions are based on the expertise and also the personal preferences of those managing the burn.

Management of blast injuries and shock lung

PURPOSE OF REVIEW

Blast injuries have always occurred both in civilian life and as acts of war or terrorism. Nowadays, the risk of being involved in an explosion has increased even for those living in countries with no previous experience of such events. It is our intention that this review is of assistance to those providing emergency/critical care to patients who have sustained blast injuries.

RECENT FINDINGS

Exposure to blast may indirectly produce physiological insults such as bradycardia, hypotension, tissue hypoxia and oxidative stress. The use of early goal-directed therapy might be important in minimizing such insults. Explosions in an enclosed environment are associated with increased risk of pulmonary blast injury and also air and fat embolism. Mechanical ventilation after pulmonary blast injury is associated with barotrauma and the use of lung protective strategies previously recommended in acute lung injury may be beneficial.

SUMMARY

The potential for blast to cause injury depends on the nature of the explosive and environment in which the blast occurs. Soft tissue injury with environmental contamination is frequent. Optimal antimicrobial cover and strategies such as selective digestive decontamination may be advantageous. Early surgery should follow the principles of 'damage control'. Blast injury often leads to severe sepsis/systemic inflammatory response, multiple organ dysfunction and prolonged critical illness. In this clinical scenario, recent studies have shown improved outcome with the use of activated protein C, steroid replacement and aggressive control of blood glucose but have been less convincing regarding the use of immuno-nutrition.

Whey feeding suppresses the measurement of oxidative stress in experimental burn injury

PURPOSE

Burns cause thermal injury to local tissue and trigger systemic acute inflammatory processes, which may lead to multiple distant organ dysfunction. We investigated the protective effect of dietary whey supplementation on distant organs in a rat model.

METHODS

Forty-eight rats were divided into six groups of eight: groups 1 and 2 were the controls, fed a standard diet and a whey-supplemented diet, respectively; groups 3 and 4 were fed a standard diet and subjected to burn injury; and groups 5 and 6 were fed a whey-supplemented diet and subjected to burn injury. We measured the oxidative stress variables, as well as glutathione in the liver and kidney, and histologically examined skin samples obtained 4 h (groups 3 and 5) and 72 h (groups 4 and 6) after burn injury.

RESULTS

Glutathione (GSH) levels remained the same in the liver but were slightly elevated in the kidneys after burn injury in the rats fed a standard diet. Whey supplementation caused a significant increase in hepatic GSH levels 4 h after burn injury. Moreover, there was a significant rebound effect in the liver and kidney GSH levels after 72 h and whey supplementation potentiated this effect. Hepatic and renal lipid peroxide levels were also increased 4 h after burn injury in the rats fed a standard diet. Whey supplementation significantly suppressed the burn-induced increase in hepatic and renal lipid peroxide levels. Histological examination revealed that although whey supplementation resulted in decreased subepidermal inflammation, the indicators of wound healing and collagen deposition were not improved.

CONCLUSION

Whey pretreatment suppressed hepatic and renal oxidative stress measurements after experimental burn injury.

Controlled study of enteral arginine supplementation in burned children: impact on immunologic and metabolic status

OBJECTIVE

We compared the effects of an arginine-supplemented diet with those of an isocaloric isonitrogenous diet on immune and metabolic response of children with burns.

METHODS

This was a double-blind, randomized, placebo-controlled trial in a burn treatment center of a pediatric hospital in Santiago, Chile. All children (1-5 y of age) admitted within 48 h of a moderate to deep burn injury covering 10% to 40% of total body surface area were evaluated. Twenty-eight children met the criteria and were randomly assigned to receive an arginine-supplemented diet (AG; n = 14) or an isocaloric isonitrogenous diet (CG; control, n = 14) for 14 d. Samples were collected at admission (baseline) and on days 7 and 14 for lymphoproliferative response to mitogens, plasma interleukins (interleukin-1, interleukin-6, tumor necrosis factor-alpha), plasma arginine and ornithine levels, serum C-reactive protein, prealbumin, albumin, glucose, and total urinary nitrogen.

RESULTS

The AG enhanced lymphoproliferative responses (analysis of variance, P < 0.05), which were 72% of normal at baseline in both groups; by day 7 responses increased to 144% in the AG group and decreased to 56% in the CG group; both groups returned to normal by day 14. Baseline interleukin-6 was significantly increased in all children. There were no differences in plasma concentrations of interleukin-1, interleukin-6, tumor necrosis factor-alpha, C-reactive protein, prealbumin, albumin, or glucose between the AG and CG groups. On day 7 plasma ornithine levels increased significantly in the AG versus CG group (P < 0.05); arginine levels showed no change.

CONCLUSIONS

An exclusively AG improves mitogen-stimulated lymphocyte proliferation in burned children. The benefits of arginine for the immune system do not appear to be related to a metabolic response. The biological significance of this finding remains to be determined.

Burn-induced alterations of chromium and the glucose/insulin system in rats

Our objective was to demonstrate a role of chromium (Cr) in response to severe burn. A third-degree burn involving 20% of total body surface was applied under anaesthesia in accord with ethical guidelines. Chromium concentrations in liver decreased progressively and were non-detectable on days 5 and 10 following injury. In quadriceps muscle, Cr concentrations increased 6h after injury and then declined significantly within the first day and remained at these levels the following 9 days. Urinary Cr losses were also increased. Changes in kidney, brain and serum Cr were not significant. Non-fasting glucose rose 6h after injury and then returned to levels measured before the burn. There was a significant rise in corticosterone reaching a maximum the first day after injury that was accompanied by significant increases in circulating insulin and glucagon that were maximal after 2 days. Changes in IGF-1 were not significant. In summary, changes in Cr concentrations were associated with an early hyperglycemia, hyperinsulinemia and increased secretion of stress hormones. These observations strongly suggest a mobilization and utilization of Cr following severe burn. Additional studies are needed to document that improved Cr status might lead to improved recovery following burn.

The effectiveness of caloric value of enteral nutrition in patients with major burns

Enteral nutrition as an important component of modern treatment is mandatory for patients suffering from major burns. Regardless of the initial estimation of caloric requirements, actual daily volume of energy consumption may vary depending on the general condition of the patient and the side effects of enteral nutrition. The aim of our study was to investigate the relation between caloric value of enteral nutrition and treatment course.

METHODS

The prospective study involved 103 adult patients treated in the Hospital of Kaunas University of Medicine for 2 degrees -3 degrees burns of 10-80% body surface area from 1 January 2001 till 31 December 2003. All patients received enteral nutrition during the acute phase. After the completion of the treatment, caloric value of enteral nutrition was estimated, and patients were divided into two groups: group A received more than 30 kcal/(kg 24 h); and group B, received less than 30 kcal/(kg 24 h). We compared patients' mortality, complication rate, and hospital stay time.

RESULTS

The mortality of patients, who enterally received less than 30 kcal/(kg 24 h), was 32.6%, comparing to 5.3% mortality in patients who received 30 or more kcal/(kg 24 h) (p < 0.01). The caloric value of less than 30 kcal/(kg 24 h) increased the frequency of pneumonia by 2.0 times, and the frequency of sepsis by 1.8 times (p < 0.05). The duration of the treatment of survivors in this group was by 12.6 days longer (p = 0.01).

CONCLUSIONS

The caloric value of enteral nutrition seems to be associated with patient mortality, complication rate, and treatment duration. The results of the treatment of patients who received more or 30 kcal/(kg 24 h) were much better. Because determined relationship may not be directly causal, further study is needed to determine whether active intervention to improve nutrition could improve outcomes.

Burn-induced oxidative injury of the gut is ameliorated by the leukotriene receptor blocker montelukast

There is increasing evidence that oxidative stress has an important role in the development of multiorgan failure after major burn injury. In the present study, we investigated whether the leukotriene receptor blocker montelukast is protective against burn-induced injury of the gut. Under brief ether anaesthesia, shaved dorsum of the rats was exposed to 90 degrees C (burn group) or 25 degrees C (control group) water bath for 10 s. Montelukast (10 mg/kg) or saline was administered intraperitoneally immediately after and at the 12th hour of the burn injury. Rats were decapitated 24 h after burn injury and the skin samples, as well as tissue samples from stomach, ileum and colon, were taken for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen contents. Tissues were also examined microscopically. Tumor necrosis factor-alpha (TNF-alpha) and lactate dehydrogenase (LDH) were assayed in serum samples. Severe skin scald injury (30% of total body surface area) caused a significant decrease in GSH level, which was accompanied with significant increases in MDA level, MPO activity and collagen content of tissues. Similarly, serum TNF-alpha and LDH were elevated in the burn group as compared to control group. On the other hand, montelukast treatment reversed all these biochemical indices, as well as histopathological alterations, which were induced by thermal trauma. Findings of the present study suggest that montelukast possesses an anti-inflammatory effect on burn-induced gastrointestinal damage and protects against oxidative injury by a neutrophil-dependent mechanism.

Impact of intraoperative duodenal feeding on the oxygen balance of the splanchnic region in severely burned patients

Enteral feeding causes an increase of intestinal oxygen demand depending on the amount administered. The aim of this study presented was to evaluate, whether intraoperative duodenal feeding might put patients at risk developing splanchnic O(2)-imbalance due to an intraoperatively compromised intestinal perfusion based on stress and unrecognized hypovolemia. In 18 severely burned patients, the CO(2)-gap between the arterial and gastric CO(2), as a parameter for the intestinal O(2)-balance, was measured during the first operation. All operations were performed on day 3-5 after admission and lasted for 4-5h. Half of the patients (nine patients) were fed intraoperatively, whereas in the other nine patients feeding was suspended beginning 1h prior to surgery until 6h after surgery. CO(2)-gap measurements were carried out prior to surgery, hourly during the operation and 5h postoperatively. Measurements 3 and 4h after beginning of the operation revealed significantly higher CO(2)-gap values in the fasting group. All other measurements showed no significant difference between both groups. Therefore, intraoperative enteral nutrition, at least in the early postburn phase, is not only necessary for reducing caloric deficits, but also seems to have a protective effect on gut oxygen balance.