Persistence of muscle catabolism after severe burn

Cutaneous burn injury represents a major risk factor for the development of traumatic ectopic bone formation following blast-related extremity injury

Blast-related traumatic heterotopic ossification (tHO) impacts clinical outcomes in combat-injured patients, leading to delayed wound healing, inflammatory complications, and reduced quality of life. Blast injured patients often have significant burns. This study investigated whether a partial thickness thermal burn injury exacerbates blast-related tHO in a clinically relevant polytrauma animal model. Adult male Sprague Dawley rats were subjected to an established model involving a whole-body blast overpressure exposure (BOP), complex extremity trauma followed by hind limb amputation (CET) followed by the addition of a 10 % total body surface area (TBSA) second degree thermal burn (BU). Micro-CT scans on post-operative day 56 showed a significant increase in HO volume in the CET + BU as compared to the CET alone injury group (p < .0001; 22.83 ± 3.41 mm3 vs 4.84 ± 5.77 mm3). Additionally, CET + BU concomitant with BOP significantly increased HO (p < .0001; 34.95 ± 7.71 mm3) as compared to CET + BU alone, confirming BOP has a further synergistic effect. No HO was detectable in rats in the absence of CET. Serum analysis revealed similar significant elevated (p < .0001) levels of pro-inflammatory markers (Cxcl1 and Il6) at 6 h post-injury (hpi) in the CET + BU and BOP + CET + BU injury groups as compared to naïve baseline values. Real-time qPCR demonstrated similar levels of chondrogenic and osteogenic gene expression in muscle tissue at the site of injury at 168 hpi in both the CET + BU and BOP+CET + BU injury groups. These results support the hypothesis that a 10 % TBSA thermal burn markedly enhances tHO following acute musculoskeletal extremity injury in the presence and absence of blast overpressure. Furthermore, the influence of BOP on tHO cannot be accounted for either in regards to systemic inflammation induced from remote injury or inflammatory-osteo-chondrogenic expression changes local to the musculoskeletal trauma, suggesting that another mechanism beyond BOP and BU synergistic effects are at play. Therefore, these findings warrant future investigations to explore other mechanisms by which blast and burn influence tHO, and testing prophylactic measures to mitigate the local and systemic inflammatory effects of these injuries on development of HO.

Effect of anti-gravity treadmill (Alter G) training on gait characteristics and postural stability in adult with healed burns: A single blinded randomized controlled trial

BACKGROUND

Burns constitute one of the foremost contributors to premature mortality and morbidity, and the recovery process from burn injuries is characterized by its intricate and protracted nature.

OBJECTIVE

The principal aim of this study was to assess the influence of an anti-gravity treadmill (Alter G) training program on both gait characteristics and postural stability indices (PSI) in adult individuals who have recovered from burns.

DESIGN

This study followed a single-blind, randomized, controlled design.

METHODS

A total of 45 adults, aged 18-35 years, with healed lower extremity burns that were circumferential and encompassed 35-50% of their total body surface area (TBSA) were randomly allocated to either the anti-gravity treadmill (Alter G) Training group (n = 22) or the traditional physical therapy program (TPTP) group (n=23). The TPTP group received conventional physical therapy, while the anti-gravity treadmill (Alter G) training group engaged in anti-gravity treadmill exercises alongside the traditional physical therapy program. The primary outcome measures, evaluated at both baseline and the conclusion of the 12-week intervention, included gait characteristics assessed using the GAITRite system and PSI measured by the Biodex Balance System (BBS).

RESULTS

The anti-gravity treadmill (Alter G) training group exhibited significantly greater enhancements than the TPTP group in terms of mean values and percentage changes in gait characteristics and PSI. Specifically, the percentage changes for the Alter G group were as follows: stride length (20.57%), step time (22.58%), step length (20.47%), velocity (15.67%), cadence (23.28%), and double support time (29.03%). In contrast, the TPTP group's percentage changes were: 6.73%, 8.19%, 7.65%, 7.75%, 8.89%, and 9.37%, respectively. Concerning PSI, the Alter G group exhibited percentage changes of 55.17% for the medio-lateral stability index (MLI), 48.21% for antero-posterior stability index (API), and 48.48% for the overall stability index (OSI). The TPTP group's corresponding percentage changes were 20%, 14.03%, and 16.41%.

CONCLUSIONS

The amalgamation of anti-gravity treadmill training with the traditional physical therapy program yields greater efficacy than TPTP in isolation. Consequently, the findings underscore the efficiency of anti-gravity treadmill (Alter G) Training as a valuable tool for rehabilitating patients with burn injuries.

The Efficacy of Whole-Body Vibration in Managing Postburn Victims' Complications: A Systematic Review

Burn injury is a complicated traumatic event with both systemic and local consequences. These complications include long periods of bed rest, pain, muscle weakness, vitamin D deficiency, and bone mineral density loss. Whole-body vibration demonstrated effectiveness in improving muscle power and bone mineral density in various musculoskeletal populations. This systematic review of randomized controlled trials aims to assess evidence for the effectiveness of using whole-body vibration on postburn survivors with at least 1% total body surface area on sensory and motor outcomes. A systematic search was conducted across six databases, which are, PubMed, Cochrane, PEDro, Scopus, Web of Science, and Google Scholar, from inception till March 2022. Retrieved studies were screened by title and abstract and full-text in two stages using Rayyan web-based. Included studies were assessed for risk of bias using the Cochrane risk of bias tool ROB 2.0. Six randomized controlled trials with 203 participants were included. Five of the included studies demonstrated an overall high risk of bias. Compared to conventional physiotherapy programs, whole-body vibration demonstrated improvement in functional mobility and balance using timed up and go and Biodex balance assessment, respectively. However, there were no differences between whole-body vibration and conventional physiotherapy program alone in bone mineral density and muscle power. Although the current evidence of whole-body vibration is limited, whole-body vibration combined with traditional physical therapy programs may improve functional mobility and balance in postburn survivors compared to physical therapy programs alone.

Systemic immune response of burns from the acute to chronic phase

Immune responses that occur following burn injury comprise a series of reactions that are activated in response to damaged autologous tissues, followed by removal of damaged tissues and foreign pathogens such as invading bacteria, and tissue repair. These immune responses are considered to be programmed in living organisms. Developments of modern medicine have led to the saving of burned patients who could not be cured previously; however, the programmed response is no longer able to keep up, and various problems have arisen. This paper describes the mechanism of immune response specific to burn injury and the emerging concept of persistent inflammation, immunosuppression, and catabolism syndrome.

Effects of exercise training on muscle wasting, muscle strength and quality of life in adults with acute burn injury

OBJECTIVES

Exercise training during the acute phase of burns is difficult to implement but offers potential benefits. This multicenter trial explored the effects of an exercise program on muscular changes and quality of life during burn center stay.

METHODS

Fifty-seven adults with burns ranging between 10% and 70% TBSA were allocated to receive either standard of care (n = 29), or additionally exercise (n = 28), consisting of resistance and aerobic training, commenced as early as possible according to safety criteria. Muscle wasting (primary outcome), quantified by ultrasound-derived quadriceps muscle layer thickness (QMLT) and rectus femoris cross-sectional area (RF-CSA), muscle strength and quality of life (Burn Specific Health Scale-Brief (BSHS-B) and EQ-5D-5L) were assessed at baseline, four and eight weeks later, or hospital discharge. Mixed models were used to analyze between-group changes over time with covariates of interest added in stepwise forward modeling.

RESULTS

The addition of exercise training to standard of care induced significant improvements in QMLT, RF-CSA, muscle strength and the BSHS-B subscale hand function (ß-coefficient. 0.055 cm/week of QMLT, p = 0.005). No added benefit was observed for other quality-of-life measures.

CONCLUSIONS

Exercise training, administered during the acute phase of burns, reduced muscle wasting, and improved muscle strength throughout burn center stay.

Skeletal muscle wasting after burn is regulated by a decrease in anabolic signaling in the early flow phase

Following burns a sustained catabolic stress response is activated, resulting in skeletal muscle wasting. A better understanding of the underlying mechanisms of postburn skeletal muscle wasting is essential for the development of preventive and/or therapeutic strategies. Six weeks old female rats underwent a sham, 10% or 40% total body surface area scald burn. Ten days post-injury, severely burned animals gained significantly less weight compared to sham treated and minor burned animals, reflected in a significantly lower ratio of muscle to total body weight for Soleus (SOL) and Extensor Digitorum Longus (EDL) in the severely burned group. Postburn, total fiber number was significantly lower in EDL, while in SOL the amount of type1 fibers significantly increased and type2 fibers significantly decreased. No signs of mitochondrial dysfunction (COX/SDH) or apoptosis (caspase-3) were found. In SOL and EDL, eEF2 and pAKT expression was significantly lower after severe burn. MURF1,2,3 and Atrogin-1 was significantly higher in SOL, whilst in EDL MURF1,2,3 was significantly lower postburn. In both muscles, FOXO3A was significantly lower postburn. This study identified postburn changes in muscle anthropomorphology and proteins involved in pathways regulating protein synthesis and breakdown, with more pronounced catabolic effects in SOL.

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.

Children's growth and motor development following a severe burn: a systematic review

Background

The epidemiological data on post-burn growth, body composition and motor development is ambiguous and scattered. The aim of this systematic review was therefore to summarize the current body of evidence on post-burn growth, body composition and motor development in children.

Methods

A literature search was conducted in PubMed, EMBASE and Web of Science up to March 2021. We considered observational studies that reported (1) metrics on weight, height, body composition, bone mineral content, bone mineral density or motor development, in (2) paediatric burn patients and (3) published in a peer-reviewed journal.

Results

A total of 16 studies were included. Each of the included studies used quantitative methods, but with differing methodology: prospective cohort studies (n = 8), retrospective chart reviews (n = 3), case-control studies (n = 2), cross sectional studies (n = 2) and a retrospective cohort study (n = 1). When combined, the included studies represented 2022 paediatric burn patients, with a mean age of 7.7 (±3.2) years. The average burn size was 52.8% (±12.7) of the total body surface area. Identified outcome measures included weight (n = 12), height (n = 7), muscular strength (n = 4), bone mineral content (n = 5), bone mineral density (n = 5), body mass index (n = 3), fat mass (n = 5), lean body mass (n = 7) and fine and gross motor development (n = 1).

Conclusions

Following an initial decline, patients' growth and motor development started to recover during the first or second year post-burn. Nonetheless, burns may have a profound and prolonged effect on the paediatric burn patients' muscular strength, bone mineral content and lean body mass. It should be noted that the vast majority of studies included only patients with burns covering ≥30% total body surface area. The evidence presented in this review may thus not be representative of the whole paediatric burn population.

The Role of Lyophilized Xenodermotransplants in Repairing the Atria's Structure and the Peculiarities of Regenerative Processes after Thermal Trauma in an Experiment

The effects of severe burn injuries on the cardiovascular system, specifically the atria and auricles of the heart, were investigated. The potential benefits of using lyophilized xenodermotransplants as a treatment option were also evaluated. The experiments were conducted on adult guinea pigs divided into three groups: intact animals, animals with burns, and animals with burns who underwent early necrectomy followed by wound closure with lyophilized xenodermotransplants. Third-degree burns caused significant ultrastructural changes in atrial cardiomyocytes, leading to long-term destructive changes in the structural components of the atria. However, the use of lyophilized xenodermotransplants had a positive effect on the atrial ultrastructure over time. This study highlights the complex and varied effects of burn injuries on the body and the potential benefits of lyophilized xenodermotransplants in treating severe burn injuries. By preventing destructive changes in the heart and activating regenerative processes, lyophilized xenodermotransplants can improve the condition of the heart after thermal injury. Further research and development in this area are necessary for understanding the potential of lyophilized xenodermotransplants in tissue repair and regeneration.

Acute muscle mass loss was alleviated with HMGB1 neutralizing antibody treatment in severe burned rats

Burn injury is associated with muscle wasting, though the involved signaling mechanisms are not well understood. In this study, we aimed to examine the role of high mobility group box 1 (HMGB1) in signaling hyper-inflammation and consequent skeletal muscle impairment after burn. Sprague Dawley rats were randomly assigned into three groups: (1) sham burn, (2) burn, (3) burn/treatment. Animals in group 2 and group 3 received scald burn on 30% of total body surface area (TBSA) and immediately treated with chicken IgY and anti-HMGB1 antibody, respectively. Muscle tissues and other samples were collected at 3-days after burn. Body mass and wet/dry weights of the hind limb muscles (total and individually) were substantially decreased in burn rats. Acute burn provoked the mitochondrial stress and cell death and enhanced the protein ubiquitination and LC3A/B levels that are involved in protein degradation in muscle tissues. Further, an increase in muscle inflammatory infiltrate associated with increased differentiation, maturation and proinflammatory activation of bone marrow myeloid cells and αβ CD4+ T and γδ T lymphocytes was noted in in circulation and spleen of burn rats. Treatment with one dose of HMGB1 neutralizing antibody reduced the burn wound size and preserved the wet/dry weights of the hind limb muscles associated with a control in the markers of cell death and autophagy pathways in burn rats. Further, anti-HMGB1 antibody inhibited the myeloid and T cells inflammatory activation and subsequent dysregulated inflammatory infiltrate in the muscle tissues of burn rats. We conclude that neutralization of HMGB1-dependent proteolytic and inflammatory responses has potential beneficial effects in preventing the muscle loss after severe burn injury.

Cardiometabolic disease risk markers are increased following burn injury in children

Introduction

Burn injury in children causes prolonged systemic effects on physiology and metabolism leading to increased morbidity and mortality, yet much remains undefined regarding the metabolic trajectory towards specific health outcomes.

Methods

A multi-platform strategy was implemented to evaluate the long-term immuno-metabolic consequences of burn injury combining metabolite, lipoprotein, and cytokine panels. Plasma samples from 36 children aged 4-8 years were collected 3 years after a burn injury together with 21 samples from non-injured age and sex matched controls. Three different ¹H Nuclear Magnetic Resonance spectroscopic experiments were applied to capture information on plasma low molecular weight metabolites, lipoproteins, and α-1-acid glycoprotein.

Results

Burn injury was characterized by underlying signatures of hyperglycaemia, hypermetabolism and inflammation, suggesting disruption of multiple pathways relating to glycolysis, tricarboxylic acid cycle, amino acid metabolism and the urea cycle. In addition, very low-density lipoprotein sub-components were significantly reduced in participants with burn injury whereas small-dense low density lipoprotein particles were significantly elevated in the burn injured patient plasma compared to uninjured controls, potentially indicative of modified cardiometabolic risk after a burn. Weighted-node Metabolite Correlation Network Analysis was restricted to the significantly differential features (q <0.05) between the children with and without burn injury and demonstrated a striking disparity in the number of statistical correlations between cytokines, lipoproteins, and small molecular metabolites in the injured groups, with increased correlations between these groups.

Discussion

These findings suggest a 'metabolic memory' of burn defined by a signature of interlinked and perturbed immune and metabolic function. Burn injury is associated with a series of adverse metabolic changes that persist chronically and are independent of burn severity and this study demonstrates increased risk of cardiovascular disease in the long-term. These findings highlight a crucial need for improved longer term monitoring of cardiometabolic health in a vulnerable population of children that have undergone burn injury.

Adjusting body weight for edema in severely burned patients

Weight loss is difficult to quantify in critically ill burn patients, as the presence of edema can mask changes in dry body weight. We sought to estimate dry body weight using measured weights adjusted for reported extremity edema. We evaluated patients with at least 20% total body surface area (TBSA) burns admitted to our intensive care unit over a 3½-year period. Body weights were collected for this analysis from admission to the time of a recorded dry weight after wound healing. Extremity edema was collected at the time of each weight measurement and was categorized into three groups: (1) no edema, (2) 1 + pitting edema, (3) 2 + or 3 + pitting edema. Logistic regression yielded the following formula for estimating dry weight (in kg): 0.66 x measured body weight + 25 - (3 for 1 + pitting edema or 4 for 2 + or 3 + pitting edema of either upper extremity) - (4 for any pitting edema to either lower extremity) (p < 0.01, R2 = 0.81). These results may allow us to better estimate dry body weight changes in our edematous patients with severe burns. Nutrition goals can be adjusted earlier, when appropriate, based on these estimated dry body weight changes.

Burns: Classification, Pathophysiology, and Treatment: A Review

Burns and their treatment are a significant medical problem. The loss of the physical barrier function of the skin opens the door to microbial invasion and can lead to infection. The repair process of the damage caused by the burn is impaired due to the enhanced loss of fluids and minerals through the burn wound, the onset of hypermetabolism with the concomitant disruption of nutrient supply, and derangements in the endocrine system. In addition, the initiated inflammatory and free radical processes drive the progression of oxidative stress, the inhibition of which largely depends on an adequate supply of antioxidants and minerals. Clinical experience and research provide more and more data to make the treatment of patients with thermal injury increasingly effective. The publication discusses disorders occurring in patients after thermal injury and the methods used at various stages of treatment.

Molecular mechanisms of post-burn muscle wasting and the therapeutic potential of physical exercise

After a severe burn injury, a systemic stress response activates metabolic and inflammatory derangements that, among other, leads to muscle mass loss (muscle wasting). These negative effects on skeletal muscle continue for several months or years and are aggravated by short-term and long-term disuse. The dynamic balance between muscle protein synthesis and muscle protein breakdown (proteolysis) is regulated by complex signalling pathways that leads to an overall negative protein balance in skeletal muscle after a burn injury. Research concerning these molecular mechanisms is still scarce and inconclusive, understanding of which, if any, molecular mechanisms contribute to muscle wasting is of fundamental importance in designing of therapeutic interventions for burn patients as well. This review not only summarizes our present knowledge of the molecular mechanisms that underpin muscle protein balance but also summarizes the effects of exercise on muscle wasting post-burn as promising strategy to counteract the detrimental effects on skeletal muscle. Future research focusing on the pathways causing post-burn muscle wasting and the different effects of exercise on them is needed to confirm this hypothesis and to lay the foundation of therapeutic strategies.

Pathological changes in the brain after peripheral burns

Brain injuries are common complications in patients with thermal burns and are associated with unpleasant outcomes. In clinical settings, it was once believed that brain injuries were not major pathological processes after burn, at least in part due to the unavailability of specific clinical manifestations. Burn-related brain injuries have been studied for more than a century, but the underlying pathophysiology has not been completely clarified. This article reviews the pathological changes in the brain following peripheral burns at the anatomical, histological, cytological, molecular and cognitive levels. Therapeutic indications based on brain injury as well as future directions for research have been summarized and proposed.

Reliability and feasibility of skeletal muscle ultrasound in the acute burn setting

OBJECTIVES

Despite the impact of muscle wasting after burn, tools to quantify muscle wasting are lacking. This multi-centre study examined the utility of ultrasound to measure muscle mass in acute burn patients comparing different methodologies.

METHODS

B-mode ultrasound was used by two raters to determine feasibility and inter-rater reliability in twenty burned adults following admission. Quadriceps muscle layer thickness (QMLT) and rectus femoris cross-sectional area (RF-CSA) were measured, comparing the use of i) a single versus average measurements, ii) a proximal versus distal location for QMLT, and iii) a maximum- versus no-compression technique for QMLT.

RESULTS

Analysis of twenty burned adults (50 years [95%CI 42-57], 32%TBSA [95%CI 23-40]) yielded ICCs of> 0.97 for QMLT (for either location and compression technique) and> 0.95 for RF-CSA, using average measurements. Relative minimal detectable changes were smaller using no-compression than maximum-compression (6.5% vs. 15%). Using no-compression to measure QMLT was deemed feasible for both proximal and distal locations (94% and 96% of attempted measurements). In 9.5% of cases maximum-compression was not feasible. 95% of RF-CSA measurements were successfully completed.

CONCLUSION

Ultrasound provides feasible and reliable values of quadriceps muscle architecture that can be adapted to clinical scenarios commonly encountered in acute burn settings.

VARIABLES INFLUENCING THE DIFFERENTIAL HOST RESPONSE TO BURNS IN PEDIATRIC AND ADULT PATIENTS

ABSTRACT

Burn injury is a significant source of morbidity and mortality in the pediatric population. Although 40,000 pediatric patients in the United States are admitted to the hospital with burn wounds annually, significant differences exist in the management and treatment of these patients, even among highly specialized burn centers. Some aspects of pediatric burn research, such as metabolic changes and nutritional support after burn injury, have been studied extensively; however, in many aspects of burn care, pediatric research lags behind the study of adult populations. This review compares and contrasts a wide array of physiologic and immune responses between children and adults after burn injury. Such a review elucidates where robust research has been conducted, where adult research is applicable to pediatric patients, and where additional pediatric burn research needs to be conducted.

DEMOGRAPHICS TO DEFINE PEDIATRIC BURN PATIENTS AT RISK OF ADVERSE OUTCOMES

ABSTRACT

Background: There is currently no standard definition of a severe burn in the pediatric patient population to identify those at higher risk of infectious complications. Our aim was to correlate total burn surface area (TBSA), burn depth, and type of burn injury to nosocomial infection rates and systemic immune system responses to better define risk factors associated with adverse outcomes. Methods: A prospective observational study at a single-center, quaternary-care, American Burn Association-verified pediatric burn center was conducted from 2016 to 2021. Blood was collected within 72 h of injury from 103 pediatric patients. Whole blood was incubated with lipopolysaccharide or phytohemagglutinin stimulation reagent to measure innate and adaptive immune response, respectively. Flow cytometry was performed on whole blood samples to measure both innate and adaptive immune cells. Unstimulated plasma was also extracted, and IL-6 and IL-10 as well as soluble proteins B- and T-lymphocyte attenuator, CD27, and T-cell immunoglobulin mucin 3 were quantified. Results: There was a significant increased risk for nosocomial infection in pediatric patients with TBSA burns of ≥20%, full-thickness burn injuries ≥5%, or flame burn injuries. There was an overall decrease in both innate and adaptive immune function in patients with TBSA burns ≥20% or full-thickness burn injuries ≥5%. Both burn injury characteristics were also associated with a significant increase in unstimulated IL-6 and IL-10 and soluble immunoregulatory checkpoint proteins. We observed a significant decrease in soluble B- and T-lymphocyte attenuator for those with a flame injury, but there were no other differences between flame injury and scald/contact burns in terms of innate and adaptive immune function. Conclusion: Burns with ≥20% TBSA or ≥5% full thickness in pediatric patients are associated with systemic immune dysfunction and increased risk of nosocomial infections.

Modulation of Burn Hypermetabolism in Preclinical Models

Severe burns elicit a state of physiological stress and increased metabolism to help the body compensate for the changes associated with the traumatic injury. However, this hypermetabolic state is associated with increased insulin resistance, cardiovascular dysfunction, skeletal muscle catabolism, impaired wound healing, and delayed recovery. Several interventions were attempted to modulate burn hypermetabolism, including nutritional support, early excision and grafting, and growth hormone application. However, burn hypermetabolism still imposes significant morbidity and mortality in burn patients. Due to the limitations of in vitro models, animal models are indispensable in burn research. Animal models provide researchers with invaluable tools to test the safety and efficacy of novel treatments or advance our knowledge of previously utilized agents. Several animal studies evaluated novel therapies to modulate burn hypermetabolism in the last few years, including recombinant human growth hormone, erythropoietin, acipimox, apelin, anti-interleukin-6 monoclonal antibody, and ghrelin therapies. Results from these studies are promising and may be effectively translated into human studies. In addition, other studies revisited drugs previously used in clinical practice, such as insulin and metformin, to further investigate their underlying mechanisms as modulators of burn hypermetabolism. This review aims to update burn experts with the novel therapies under investigation in burn hypermetabolism with a focus on applicability and translation. Furthermore, we aim to guide researchers in selecting the correct animal model for their experiments by providing a summary of the methodology and the rationale of the latest studies.

Epidemiological and Clinical Profile of Pediatric Burns in the COVID-19 Era: The Experience of a Reference Center

Pediatric burns represent a significant public health problem. We analyzed the characteristics of pediatric burns in a reference center, in order to identify better strategies for prevention and care. Burn patients admitted to the pediatric departments of our hospital from January 2020 to June 2022 were retrospectively evaluated. Age, gender, the etiology of injuries, the total burn surface area (TBSA), the degree of burns, the length of hospital stay (LOS), concomitant SARS-CoV-2 infection, and burn surface microbial colonization were analyzed. Forty-seven patients were included in the analysis (M:F = 1:0.67). Most of the cases involved patients between 0 and 4 years of age (83%). Hot liquid burns accounted for 79% of cases, flame burns for 9%, thermal burns for 6%, scald burns for 4% and chemical burns for 2%. Mean TBSA was 14 ± 11%. A second-degree lesion was detected in 79% of patients and third-degree in 21%. Mean LOS was 17 days. No additional infection risks or major sequelae were reported in patients with SARS-CoV-2 infection. Fifteen different species of bacteria plus C. parapsilosis were isolated, while no anaerobic microorganisms were detected. In the light of our experience, we recommend a carefully planned and proactive management strategy, always multidisciplinary, to ensure the best care for the burned child.

Proceedings of the 2021 American Burn Association State and Future of Burn Science Meeting

Periodically, the American Burn Association (ABA) has convened a State of the Science meeting on various topics representing multiple disciplines within burn care and research. In 2021 at the request of the ABA President, meeting development was guided by the ABA's Burn Science Advisory Panel (BSAP) and a subgroup of meeting chairs. The goal of the meeting was to produce both an evaluation of the current literature and ongoing studies, and to produce a research agenda and/or define subject matter-relevant next steps to advance the field(s). Members of the BSAP defined the topics to be addressed and subsequently solicited for nominations of expert speakers and topic leaders from the ABA's Research Committee. Current background literature for each topic was compiled by the meeting chairs and the library then enhanced by the invited topic and breakout discussion leaders. The meeting was held in New Orleans, LA on November 2nd and 3rd and was formatted to allow for 12 different topics, each with two subtopics, to be addressed. Topic leaders provided a brief overview of each topic to approximately 100 attendees, followed by expert-lead breakout sessions for each topic that allowed for focused discussion among subject matter experts and interested participants. The breakout and topic group leaders worked with the participants to determine research needs and associated next steps including white papers, reviews and in some cases collaborative grant proposals. Here, summaries from each topic area will be presented to highlight the main foci of discussion and associated conclusions.

Adjunctive effect of pulsed electromagnetic field therapy on quadriceps muscle strength after burn injury

Purpose. This study was conducted to examine the effect of pulsed electromagnetic field therapy on quadriceps muscle strength after burn injury. Methods. From April 2021 to June 2022, sixty male patients who suffered from second degree lower limb thermal burn injury and Total body surface area (TBSA) from 25% to 35% participated in this study. Their ages ranged from (20-40) years. They were randomly assigned in two groups, a study group composed of 30 patients who received (PEMF) over thigh area before strengthening exercise for quadriceps muscle and a control group composed of 30 patients who received strengthening exercise for quadriceps muscle. Patients of both groups received traditional physical therapy program.. Evaluation tool was isokinetic dynamometer to measure the quadriceps muscle peak torque before the treatment and after 8 weeks of treatment for both groups. Results. There was no significant difference between both group (study and control) in mean values of quadriceps peak torque pre-treatment (P > 0.05). There was a significant increase in the mean values of quadriceps peak torque after 8 weeks of treatment in both groups (p < 0.05) while there was a significant difference in post treatment mean values of quadriceps peak torque in the study group when compared with control group (p < 0.05). Conclusion. Pulsed electromagnetic field therapy is an effective modality that can be used for improving muscle strength and performance in patients with lower limb burn when applied prior to strengthening exercise.

The role of biodegradable temporizing matrix in the management of a patient with major burns and anorexia nervosa

Severe malnutrition secondary to anorexia nervosa results in deeper burns and significantly impacts wound healing, which represents a major challenge to burn management. The use of acellular dermal matrices, such as biodegradable temporizing matrix (BTM), is a valuable tool to overcome the surgical limitations. We describe a case of a 36-year-old female with a background of anorexia nervosa (body mass index of 12.3) presenting with a 30% total burns surface area (TBSA) burn. All of her burns were excised down to fascia due to the absence of subcutaneous fat. Her thin skin and depleted nutritional status significantly impacted reconstructive options. BTM was utilized to create a neodermis and provide adequate time to optimize the nutritional status before autologous skin resurfacing 3 weeks later, which yielded robust coverage with minimal donor site morbidity. Despite initial surgical and nutritional challenges, excellent outcomes were achieved in terms of wound healing, scar contractures and mobility.

The involvement of the adrenergic nervous system in activating human brown adipose tissue and browning

Obesity is a chronic condition of multifactorial etiology characterized by excessive body fat due to a calorie intake higher than energy expenditure. Given the intrinsic limitations of surgical interventions and the difficulties associated with lifestyle changes, pharmacological manipulation is currently one of the main therapies for metabolic diseases. Approaches aiming to promote energy expenditure through induction of thermogenesis have been explored and, in this context, brown adipose tissue (BAT) activation and browning have been shown to be promising strategies. Although such processes are physiologically stimulated by the sympathetic nervous system, not all situations that are known to increase adrenergic signaling promote a concomitant increase in BAT activation or browning in humans. Thus, a better understanding of factors involved in the thermogenesis attributed to these tissues is needed to enable the development of future therapies against obesity. Herein we carry out a critical review of original articles in humans under conditions previously known to trigger adrenergic responses-namely, cold, catecholamine-secreting tumor (pheochromocytoma and paraganglioma), burn injury, and adrenergic agonists-and discuss which of them are associated with increased BAT activation and browning. BAT is clearly stimulated in individuals exposed to cold or treated with high doses of the β3-adrenergic agonist mirabegron, whereas browning is certainly induced in patients after burn injury or with pheochromocytoma, as well as in individuals treated with β3-adrenergic agonist mirabegron for at least 10 weeks. Given the potential effect of increasing energy expenditure, adrenergic stimuli are promising strategies in the treatment of metabolic diseases.

Carry That Weight! The Challenge of Managing Weight Changes During Inpatient Admission for Patients With Burn Injuries ≥20% TBSA

The hypermetabolic state of patients with ≥20% total body surface area (TBSA) causes loss of muscle mass and compromised immune function with delayed wound healing. Weight loss is most severe in patients with ≥20% TBSA with initial weight gain due to fluid resuscitation. The American Burn Association (ABA) proposed quality measures for burn injury admissions, including weight loss from admission to discharge. We assessed how our outcomes adhere to these measures and if they correlate with previously described results. We retrospectively reviewed adult admissions with ≥20% TBSA burn injuries from 2016 to 2021. Four groups were established based on %TBSA: 20% to 29% (Group 1), 30% to 39% (Group 2), 40% to 59% (Group 3), and ≥60% (Group 4). We assessed weight changes from admission to discharge and performed multivariate analyses to account for age, sex, total surgeries, and length of stay. Data from 123 patients revealed 40 with 20% to 29% TBSA, 29 with 30% to 39% TBSA, 33 with 40% to 59% TBSA, 21 with ≥60% TBSA. A significant difference in weight loss was observed when comparing Groups 1 and 2 and Groups 3 and 4 (Group 1: −3.63%, Group 2: −2%, Group 3: −9.28%, Group 4: −13.85%; P-value ≤ .05). Groups 3 and 4 had significantly longer lengths of stay compared to Groups 1 and 2 (Group 1: 32.16, Group 2: 37.5, Group 3: 71.13, Group 4: 87.18; P-value ≤ .01). Most patients that experienced weight loss during their admission had &lt;15% weight loss. We found no significant difference in outcomes for patients receiving oxandrolone vs not. The mean weight change was −11% for patients with an overall weight loss and +5% for patients with an overall weight gain. The significant difference between the two groups was admission body mass index (BMI; loss: 30.4 kg/m2, gain: 26.0 kg/m2; P-value ≤ .05). Patients with ≥20% TBSA suffer weight changes, likely due to metabolic disturbances. Increased length of stay and higher %TBSA may be associated with greater weight loss. Patients experiencing weight gain had lower admission BMI suggesting that patients with higher BMI are more prone to weight loss. Our findings support that patients with %TBSA ≥40 are unique, requiring specialized nutritional protocols and metabolic analysis.

Adults with well-healed burn injuries have lower pulmonary function values decades after injury

Sub-acute (e.g., inhalation injury) and/or acute insults sustained during a severe burn injury impairs pulmonary function. However, previous work has not fully characterized pulmonary function in adults with well-healed burn injuries decades after an injury. Therefore, we tested the hypothesis that adults with well-healed burn injuries have lower pulmonary function years after recovery. Our cohort of adults with well-healed burn-injuries (n = 41) had a lower forced expiratory volume in one second (Burn: 93 ± 16 vs. Control: 103 ± 10%predicted, mean ± SD; d = 0.60, p = 0.04), lower maximal voluntary ventilation (Burn: 84 [71-97] vs. Control: 105 [94-122] %predicted, median [IQR]; d = 0.84, p < 0.01), and a higher specific airway resistance (Burn: 235 ± 80 vs. Control: 179 ± 40%predicted, mean ± SD; d = 0.66, p = 0.02) than non-burned control participants (n = 12). No variables were meaningfully influenced by having a previous inhalation injury (d ≤ 0.44, p ≥ 0.19; 13 of 41 had an inhalation injury), the size of the body surface area burned (R²  ≤ 0.06, p ≥ 0.15; range of 15%-88% body surface area burned), or the time since the burn injury (R²  ≤ 0.04, p ≥ 0.22; range of 2-50 years post-injury). These data suggest that adults with well-healed burn injuries have lower pulmonary function decades after injury. Therefore, future research should examine rehabilitation strategies that could improve pulmonary function among adults with well-healed burn injuries.

The effects of short bouts of ergometric exercise for severely burned children in intensive care: A randomized controlled trial

OBJECTIVE

To determine the effects of short bouts of ergometric exercises on the number of days in the burn intensive care unit (ICU), body mass, and functional ambulation.

DESIGN

Multi-center, randomized controlled trial.

SETTING

Burn intensive care unit.

PARTICIPANTS

Children ages 7-17 with severe burns covering over 30% total body surface area (TBSA).

INTERVENTION

All patients received standard of care (Control) with the experimental group receiving additional exercise with a cycle ergometer (Exercise).

MAIN MEASURES

The number of days in the ICU, total weight, lean body mass (LBM), and functional ambulation were taken shortly after randomization and again within one week of the scheduled hospital discharge. Results of outcomes are expressed as median ± interquartile range (IQR), unless otherwise noted (e.g. demographics).

RESULTS

Fifty-four severely burned children (n = 18 Control, n = 36 Exercise) were included. The average ± standard deviation for age was 12 ± 3 years and TBSA was 48 ± 16%. The median ± IQR ICU days for Control was 46 ± 51 days vs 31 ± 29 days for Exercise. The median total weight loss for Control was 2.2 ± 1.2 kg vs 1.8 ± 1.4 kg in Exercise. Control lost 0.75 ± 0.8 kg of LBM vs 0.46 ± 0.43 kg in Exercise. Both groups showed significant improvement in functional ambulation (p < 0.01). However, exercise did not add additional benefits.

CONCLUSION

Short bouts of ergometric exercises are feasible for severely burned patients while receiving care in the ICU but did not add additional benefits.

Evaluation of Kinesiophobia in Survivors of Major Burn Injury

Kinesiophobia, the fear of movement and re-injury, has not been described in burn injury survivors. Physical activity is a key component of burn rehabilitation programs. Yet, not all burn survivors exercise at the recommended level. This is an exploratory study examining the association of the demographics and injury characteristics of burn survivors with a fear of movement. The subjective fear of movement was measured using the Tampa Scale for Kinesiophobia (TSK). The TSK score was compared between several demographics and injury characteristics by performing the independent sample t-test. Sixty-six percent of subjects in our study (n=35), reported high levels of kinesiophobia (score 37 or above). The mean scores of the TSK were greater in males (40.7), non-White (43.0), Hispanic/Latino (41.1), age greater than 50 years (42.3), and total body surface area (TBSA) burn of >15% compared to females (36.9), White (38.5), non-Hispanic/Latino (39.3), age 50 years or less (38.1), and TBSA 15% or less (39.4) respectively. However, with the exception of time post injury, none of the mean differences were statistically significant. Subjects who had sustained a burn injury more than 12 months ago showed higher levels of kinesiophobia than the subjects who were injured within 12 months with a mean difference of 7.35 (p=.01). Thus, this study highlights the importance of (i) continued, long-term follow up for burn survivors, and (ii) appropriate educational and treatment interventions to address any underlying existing, new, or emerging medical issues that may contribute to the fear or avoidance of movement.

Metabolic Responses to Severe Burn Injury

ABSTRACT

Management of the metabolic responses to severe burn injury is recognized as a fundamental part of burn care. Definition of burn hypermetabolism is being refined to subcellular and genomic levels, and treatment concepts are need to be refined into increasingly sophisticated strategies.

Current understanding of thermo(dys)regulation in severe burn injury and the pathophysiological influence of hypermetabolism, adrenergic stress and hypothalamic regulation—a systematic review

Background

In this systematic review, we summarize the aetiology as well as the current knowledge regarding thermo(dys)regulation and hypothermia after severe burn trauma and aim to present key concepts of pathophysiology and treatment options. Severe burn injuries with >20% total body surface area (TBSA) affected commonly leave the patient requiring several surgical procedures, prolonged hospital stays and cause substantial changes to body composition and metabolism in the acute and long-term phase. Particularly in severely burned patients, the loss of intact skin and the dysregulation of peripheral and central thermoregulatory processes may lead to substantial complications.

Methods

A systematic and protocol-based search for suitable publications was conducted following the PRISMA guidelines. Articles were screened and included if deemed eligible. This encompasses animal-based in vivo studies as well as clinical studies examining the control-loops of thermoregulation and metabolic stability within burn patients

Results

Both experimental animal studies and clinical studies examining thermoregulation and metabolic functions within burn patients have produced a general understanding of core concepts which are, nonetheless, lacking in detail. We describe the wide range of pathophysiological alterations observed after severe burn trauma and highlight the association between thermoregulation and hypermetabolism as well as the interactions between nearly all organ systems. Lastly, the current clinical standards of mitigating the negative effects of thermodysregulation and hypothermia are summarized, as a comprehensive understanding and implementation of the key concepts is critical for patient survival and long-term well-being.

Conclusions

The available in vivo animal models have provided many insights into the interwoven pathophysiology of severe burn injury, especially concerning thermoregulation. We offer an outlook on concepts of altered central thermoregulation from non-burn research as potential areas of future research interest and aim to provide an overview of the clinical implications of temperature management in burn patients.

Edward F. Adolph Distinguished Lecture. It's more than skin deep: thermoregulatory and cardiovascular consequences of severe burn injuries in humans

Each year, within the United States, tens of thousands of individuals are hospitalized for burn-related injuries. The treatment of deep burns often involves skin grafts to accelerate healing and reduce the risk of infection. The grafting procedure results in a physical disruption between the injured and subsequently debrided host site and the skin graft placed on top of that site. Both neural and vascular connections must occur between the host site and the graft for neural modulation of skin blood flow to take place. Furthermore, evaporative cooling from such burn injured areas is effectively absent, leading to greatly impaired thermoregulatory responses in individuals with large portions of their body surface area burned. Hospitalization following a burn injury can last weeks to months, with cardiovascular and metabolic consequences of such injuries having the potential to adversely affect the burn survivor for years postdischarge. With that background, the objectives of this article are to discuss 1) our current understanding of the physiology and associated consequences of skin grafting, 2) the effects of skin grafts on efferent thermoregulatory responses and the associated consequences pertaining to whole body thermoregulation, 3) approaches that may reduce the risk of excessive hyperthermia in burn survivors, 4) the long-term cardiovascular consequences of burn injuries, and 5) the extent to which burn survivors can "normalize" otherwise compromised cardiovascular responses. Our primary objective is to guide the reader toward an understanding that severe burn injuries result in significant physiological consequences that can persist for years after the injury.

Prognostic Nutritional Index and Major Adverse Cardiac Events After Burn Surgery: A Propensity Score Matching Analysis

Burn injuries can cause significant malnutrition, leading to cardiovascular impairments. The prognostic nutritional index (PNI) predicts postoperative complications. We evaluated the impact of preoperative PNI on major adverse cardiac events (MACE) after burn surgery. PNI was calculated using the equation, 10×(serum albumin level)+0.005×(total lymphocyte count). Multivariable logistic regression analysis was conducted to evaluate the predictors for MACE at 6 months after burn surgery. Receiver operating characteristic curve and propensity score matching analyses were conducted. Additionally, Kaplan-Meier analysis was conducted to compare postoperative 1-year mortality between MACE and non-MACE groups. MACE after burn surgery occurred in 184 (17.5%) of 1049 patients. PNI, age, American Society of Anesthesiologists physical status, and TBSA burned were significantly related to MACE. The area under the receiver operating characteristic curve of PNI was 0.729 (optimal cutoff value = 35). After propensity score matching, the incidence of MACE in the PNI <35 group was higher than that in the PNI ≥35 group (20.1% vs 9.6%, P < .001). PNI <35 was related to an increased incidence of MACE (odds ratio = 2.373, 95% confidence interval = 1.499-3.757, P < .001). The postoperative 1-year mortality was higher in the MACE group than in the non-MACE group (54.9% vs 9.1%, P < .001). Preoperative PNI was a predictor for MACE after burn surgery. PNI <35 was significantly related to an increased incidence of MACE. Moreover, MACE was related to higher postoperative 1-year mortality.

Beta-Adrenergic Blockade in Critical Illness

Catecholamine upregulation is a core pathophysiological feature in critical illness. Sustained catecholamine β-adrenergic induction produces adverse effects relevant to critical illness management. β-blockers (βB) have proposed roles in various critically ill disease states, including sepsis, trauma, burns, and cardiac arrest. Mounting evidence suggests βB improve hemodynamic and metabolic parameters culminating in decreased burn healing time, reduced mortality in traumatic brain injury, and improved neurologic outcomes following cardiac arrest. In sepsis, βB appear hemodynamically benign after acute resuscitation and may augment cardiac function. The emergence of ultra-rapid βB provides new territory for βB, and early data suggest significant improvements in mitigating atrial fibrillation in persistently tachycardic septic patients. This review summarizes the evidence regarding the pharmacotherapeutic role of βB on relevant pathophysiology and clinical outcomes in various types of critical illness.

The effects of resistance training on children with burns: a meta-analysis

The aim of this study was to evaluate effectiveness and safety of resistance training (RT). Data were retrieved from Medline, EMBASE, PubMed, CINAHL and Cochrane Central Register of Controlled Trials (Central) databases from inception to April 2020. Quantitative studies on RT for muscle strength, lean body mass, cardiopulmonary function, metabolism, quality of life, and pain in burned children were included in this study. Twelve RCTs (379 patients) were identified. Meta-analysis showed RT significant increase in muscle strength [SMD = 2.18, 95% CI (0.79, 3.56), p = 0.002]. However, training showed no significant effect on muscle endurance [MD = 10.00, 95% CI (- 0.22, 20.22), p = 0.06]. Notably, training significantly increases total lean body mass [MD = 2.10, 95% CI (1.28, 2.92), p < 0.001]. In addition, training significantly increased leg lean body mass [MD = 2.10, 95% CI (1.28, 2.92), p < 0.001]. Moreover, training significantly increased VO₂peak [MD = 5.83, 95% CI (3.52, 8.13), p < 0.001]. Meta-analysis showed that training significantly increases gait parameters, including stride length, step length, velocity and cadence. Furthermore, training significantly increased explosive capacity of lower limb muscles (p < 0.001). Meta-analysis of 6-min walking test results showed that training significantly improves walking speed (p = 0.0008). Notably, all studies showed unclear or high risk of bias; whereas, quality of the evidence was moderate or low. Analysis showed that RT significantly improves clinical outcomes. However, more high-quality, double-blind, randomized control trials should be performed to explore the effects of RT to ensure successful implementation in rehabilitation.

Protein requirements for critically ill ventilator-dependent patients with COVID-19

Background

Recent studies indicate critically ill patients with coronavirus disease 2019 (COVID‐19) are hypermetabolic; however, protein requirements in critically ill COVID‐19 patients are unknown. Our intent was to evaluate the nitrogen accretion response to varying protein intakes for critically ill ventilator‐dependent patients with COVID‐19.

Methods

Adult patients (age ≥ 18 years) with COVID‐19, admitted to the intensive care unit (ICU) and who required mechanical ventilation were retrospectively evaluated. Patients received continuous enteral nutrition (EN), including supplemental protein boluses, and had a 24‐h urine collection for determination of nitrogen balance (NBAL). Data are expressed as mean ± SD with a P‐value < .05 as significant.

Results

Twenty‐two patients provided 29 NBAL determinations. Protein intake from EN and protein supplements was 0.9 ± 0.7 g/kg/day at the time of the NBAL with an NBAL of –12.1 ± 10.9 g/day at 7 ± 4 days in the ICU. Combined caloric intake from EN and propofol at the time of the NBAL was 12 ± 8 kcal/kg/day. Nitrogen equilibrium (NBAL of –4 g/day or better) occurred in five patients. Patients achieving nitrogen equilibrium received more protein than those with a negative NBAL (1.2 ± 0.4 g/kg/day vs 0.8 ± 0.8 g/kg/day, P = .046). The linear regression for NBAL in response to graded increases in protein intake was as follows: NBAL = 8.5 × protein intake (g/kg/day) – 18.8 (r = 0.450, P < .001).

Conclusion

Critically ill ventilator‐dependent patients with COVID‐19 exhibit significant variability in nitrogen accretion response to increases in protein intake and often have a markedly negative NBAL.

A Comparative Study of Modulation of Neuroendocrine Stress Response by Dexmedetomidine versus Fentanyl Premedication during Laparoscopic Cholecystectomy

Introduction:

Surgical stress is the systemic response to surgical injury. Analyzing these surgical stress responses and pharmacologically modulating them can be of immense use to an anesthetist for optimal patient care.

Aim:

The aim of the present study was to investigate the influence of dexmedetomidine and fentanyl premedication on the modulation of neuroendocrine stress response during laparoscopic cholecystectomy under general anesthesia.

Methods:

After obtaining approval from the institutional ethical committee [Date - 05/11/2020, Ethical Clearence Number - 133/2018], 60 patients undergoing laparoscopic cholecystectomy under general anesthesia were randomized into three study groups of 20 patients each. Group D patients were given intravenous (i.v.) dexmedetomidine 1 μg.kg⁻¹, Group F patients fentanyl 2 μg.kg⁻¹ and Group C patients 10 mL of normal saline. All patients received the same anesthetic drugs and surgical procedure. Patients were assessed for changes in hemodynamic parameters such as heart rate (H) and mean arterial pressure (MAP). Blood samples were analyzed for glucose, serum albumin, C-reactive protein (CRP), and serum cortisol levels at various time intervals.

Results:

H and MAP differed among the groups after intubation, 5 min after pneumoperitoneum (POT), and 10 min after POT. The increase in these parameters from their baseline values was less in the dexmedetomidine group when compared to other groups. Among the biological markers, the increase in serum cortisol levels and decrease in albumin levels could be detected 6 h after induction while blood glucose levels rose immediately after the incision. CRP levels started significantly rising only after 24 h of induction. All these changes were much less pronounced in patients receiving dexmedetomidine premedication as compared to other groups.

Conclusion:

i.v. dexmedetomidine 1 μg.kg⁻¹ is better than injection fentanyl 2 μg.kg⁻¹, in the modulation of neuroendocrine response in patients undergoing laparoscopic cholecystectomy under general anesthesia.

Muscle deteriorations become prominent within 24 hours after admission in severely burned adults

BACKGROUND

Severe burn injury results in profound catabolic deterioration. Although burn-related catabolism has been well stated, it is unclear when the catabolic response begins. This study characterized acute changes of muscle protein breakdown at the admission and the day after in severely burned adults.

METHODS

Twelve patients (43 ± 19 years old) with 40% ± 21% total body surface area burns were prospectively enrolled into an observational study approved by institutional review board. Urinary samples were collected on admission day and the day after (day 1). Patient demographic and clinical data of vital signs, blood gas and chemistry, and coagulation status were collected. Catabolic changes of muscle breakdown were quantified by urinary excretion of 3-methylhisitidine, determined by gas chromatography and mass spectrometry analysis.

RESULTS

Compared with admission day, burned patients had elevated mean ± SD arterial pressure (from 90 ± 5 mm Hg to 108 ± 7 mm Hg) and heart rate (from 102 ± 7 beats per minute to 119 ± 4 beats per minute both p < 0.05) after 24 hours. Their 24-hour urinary output was 1,586 ± 813 mL at admission day to 1,911 ± 1,048 mL on day 1. The 24-hour urea excretion was elevated from 172 ± 101 mg/kg per day at admission day to 302 ± 183 mg/kg per day on day 1 (both p < 0.05), with no change in creatinine excretion. Urinary 3-methylhisitidine excretion increased from 0.75 ± 0.74 mg/kg per day at admission to 1.14 ± 0.86 mg/kg per day on day 1 (p < 0.05). The estimated skeletal muscle protein breakdown was increased from 1.1 ± 1.0 g/kg per day at admission day to 1.6 ± 1.2 g/kg per day on day 1 (p < 0.05). There were no changes in prothrombin time, activated partial thromboplastin time, or platelets.

CONCLUSION

In severely burned patients, catabolic muscle protein breakdown is elevated within 24 hours after admission and before changes in coagulation. These findings suggest that early interventions may be needed to effectively attenuate the catabolic responses in burn patients.

LEVEL OF EVIDENCE

Prospective and observational study, level II.

Skeletal muscle wasting after a severe burn is a consequence of cachexia and sarcopenia

Muscle wasting is common and persistent in severely burned patients, worsened by immobilization during treatment. In this review, we posit two major phenotypes of muscle wasting after severe burn, cachexia and sarcopenia, each with distinguishing characteristics to result in muscle atrophy; these characteristics are also likely present in other critically ill populations. An online search was conducted from the PubMed database and other available online resources and we manually extracted published articles in a systematic mini review. We describe the current definitions and characteristics of cachexia and sarcopenia and relate these to muscle wasting after severe burn. We then discuss these putative mechanisms of muscle atrophy in this condition. Severe burn and immobilization have distinctive patterns in mediating muscle wasting and muscle atrophy. In considering these two pathological phenotypes (cachexia and sarcopenia), we propose two independent principal causes and mechanisms of muscle mass loss after burns: (1) inflammation-induced cachexia, leading to proteolysis and protein degradation, and (2) sarcopenia/immobility that signals inhibition of expected increases in protein synthesis in response to protein loss. Because both are present following severe burn, these should be considered independently in devising treatments. Discussing cachexia and sarcopenia as independent mechanisms of severe burn-initiated muscle wasting is explored. Recognition of these associated mechanisms will likely improve outcomes.

Muscle Homeostasis Is Disrupted in Burned Adults

Severe burn leads to substantial skeletal muscle wasting that is associated with adverse outcomes and protracted recovery. The purpose of our study was to investigate muscle tissue homeostasis in response to severe burn. Muscle biopsies from the right m. lateralis were obtained from 10 adult burn patients at the time of their first operation. Patients were grouped by burn size (total body surface area of <30% vs ≥30%). Muscle fiber size and factors of cell death and muscle regeneration were examined. Muscle cell cross-sectional area was significantly smaller in the large-burn group (2174.3 ± 183.8 µm2 vs 3687.0 ± 527.2 µm2, P = .04). The expression of ubiquitin E3 ligase MuRF1 and cell death downstream effector caspace 3 was increased in the large-burn group (P < .05). No significant difference was seen between groups in expression of the myogenic factors Pax7, MyoD, or myogenin. Interestingly, Pax7 and proliferating cell nuclear antigen (PCNA) expression in muscle tissue were significantly correlated to injury severity only in the smaller-burn group (P < .05). In conclusion, muscle atrophy after burn is driven by apoptotic activation without an equal response of satellite cell activation, differentiation, and fusion.

Population Pharmacokinetic Modeling and Simulations of Imipenem in Burn Patients With and Without Continuous Venovenous Hemofiltration in the Military Health System

Continuous venovenous hemofiltration (CVVH) is a life‐sustaining procedure in patients with severe burns and acute kidney injury. Physiologic changes from burn injury and use of CVVH may alter imipenem pharmacokinetics (PK). We aimed to compare imipenem clearance (CL) in burn patients with and without CVVH, determine the effect of burn on imipenem volume of distribution (CVVH, n = 12; no CVVH, n = 11), in combination with previously published models. Model qualification was performed with standard diagnostics and comparing predicted PK parameters/time‐concentration profiles with those in the existing literature. Monte Carlo simulations were conducted to evaluate the probability of target attainment. A 2‐compartment model best described the data. Utilizing albumin as a covariate on volume parameters and leveraging the clearance model from prior literature, our model predicted imipenem central volume and CL within a 10% margin of error across healthy, renally impaired, and burn populations. We provide direct comparison of imipenem CL in burn patients with and without CVVH. Notably, there was no significant difference. Large imipenem V_d in patients with severe burns is likely explained by increased capillary permeability, for which serum albumin may be a reasonable surrogate. Dosing 500 mg every 6 hours is adequate for burn patients on renally dosed CVVH; however, suspicion of augmented renal clearance or patients placed on CVVH without renal impairment may necessitate dosing of 1000 mg every 6 hours.

Cardiac Dysfunction in Severely Burned Patients: Current Understanding of Etiology, Pathophysiology, and Treatment

Patients who experience severe burn injuries face a massive inflammatory response resulting in hemodynamic and cardiovascular complications. Even after immediate and appropriate resuscitation, removal of burn eschar and covering of open areas, burn patients remain at high risk for serious morbidity and mortality. As a result of the massive fluid shifts following the initial injury, along with large volume fluid resuscitation, the cardiovascular system is critically affected. Further, increased inflammation, catecholamine surge, and hypermetabolic syndrome impact cardiac dysfunction, which worsens outcomes of burn patients. This review aimed to summarize the current knowledge about the effect of burns on the cardiovascular system.A comprehensive search of the PubMed and Embase databases and manual review of articles involving effects of burns on the cardiovascular system was conducted.Many burn units use multimodal monitors (e.g., transpulmonary thermodilution) to assess hemodynamics and optimize cardiovascular function. Echocardiography is often used for additional evaluations of hemodynamically unstable patients to assess systolic and diastolic function. Due to its noninvasive character, echocardiography can be repeated easily, which allows us to follow patients longitudinally.The use of anabolic and anticatabolic agents has been shown to be beneficial for short- and long-term outcomes of burn survivors. Administration of propranolol (non-selective β-receptor antagonist) or oxandrolone (synthetic testosterone) for up to 12 months post-burn counteracts hypermetabolism during hospital stay and improves cardiac function.A comprehensive understanding of how burns lead to cardiac dysfunction and new therapeutic options could contribute to better outcomes in this patient population.

Comparison of Arterial-Venous Balance and Tracer Incorporation Methods for Measuring Muscle Fractional Synthesis and Fractional Breakdown Rates

Loss of muscle mass in response to injury or immobilization impairs functional capacity and metabolic health, thus hindering rehabilitation. Stable isotope techniques are powerful in determining skeletal muscle protein fluxes. Traditional tracer incorporation methods to measure muscle protein synthesis and breakdown are cumbersome and invasive to perform in vulnerable populations such as children. To circumvent these issues, a two-bolus stable isotope amino acid method has been developed; although, measured rates of protein synthesis and breakdown have not been validated simultaneously against an accepted technique such as the arterial-venous balance method. The purpose of the current analysis was to provide preliminary data from the simultaneous determination of the arteriovenous balance and two-bolus tracer incorporation methods on muscle fractional synthesis and breakdown rates in children with burns. Five were administered a primed-constant infusion of L-[ 15N]Threonine for 180 minutes (Prime: 8 µmol/kg; constant: 0.1 µmol·kg -1·min -1). At 120 and 150 minutes, bolus injections of L-[ring- 13C6]Phenylalanine and L-[ 15N]Phenylalanine (50 µmol/kg each) were administered, respectively. Blood and muscle tissue samples were collected to assess mixed muscle protein synthesis and breakdown rates. The preliminary results from this study indicate there is no difference in either fractional synthesis rate (mean ± SD; arteriovenous balance: 0.19 ± 0.17 %/h; tracer incorporation: 0.14 ± 0.08 %/h; P = 0.42) or fractional breakdown rate (arteriovenous balance: 0.29 ± 0.22 %/h; tracer incorporation: 0.23 ± 0.14 %/h; P = 0.84) between methods. These data support the validity of both methods in quantifying muscle amino acid kinetics; however, the results are limited and adequately powered research is still required.

Burn-induced hypermetabolism and skeletal muscle dysfunction

Critical illnesses, including sepsis, cancer cachexia, and burn injury, invoke a milieu of systemic metabolic and inflammatory derangements that ultimately results in increased energy expenditure leading to fat and lean mass catabolism. Burn injuries present a unique clinical challenge given the magnitude and duration of the hypermetabolic response compared with other forms of critical illness, which drastically increase the risk of morbidity and mortality. Skeletal muscle metabolism is particularly altered as a consequence of burn-induced hypermetabolism, as it primarily provides a main source of fuel in support of wound healing. Interestingly, muscle catabolism is sustained long after the wound has healed, indicating that additional mechanisms beyond wound healing are involved. In this review, we discuss the distinctive pathophysiological response to burn injury with a focus on skeletal muscle function and metabolism. We first examine the diverse consequences on skeletal muscle dysfunction between thermal, electrical, and chemical burns. We then provide a comprehensive overview of the known mechanisms underlying skeletal muscle dysfunction that may be attributed to hypermetabolism. Finally, we review the most promising current treatment options to mitigate muscle catabolism, and by extension improve morbidity and mortality, and end with future directions that have the potential to significantly improve patient care.

The contradictory role of androgens in cutaneous and major burn wound healing

Wound healing is a complex process involving four overlapping phases: haemostasis, inflammation, cell recruitment and matrix remodeling. In mouse models, surgical, pharmacological and genetic approaches targeting androgen actions in skin have shown that androgens increase interleukin-6 and tumor necrosis factor-α production and reduce wound re-epithelization and matrix deposition, retarding cutaneous wound healing. Similarly, clinical studies have shown that cutaneous wound healing is slower in men compared to women. However, in major burn injury, which triggers not only local wound-healing processes but also systemic hypermetabolism, the role of androgens is poorly understood. Recent studies have claimed that a synthetic androgen, oxandrolone, increases protein synthesis, improves lean body mass and shortens length of hospital stay. However, the possible mechanisms by which oxandrolone regulates major burn injury have not been reported. In this review, we summarize the current findings on the roles of androgens in cutaneous and major burn wound healing, as well as androgens as a potential therapeutic treatment option for patients with major burn injuries.

Metabolism and energy prescription in critically III children

Optimal nutrition therapy can positively influence clinical outcomes in critically ill children. Accurate assessment of nutritional status, metabolic state, macronutrient requirements and substrate utilization allows accurate prescription of nutrition in this population. In response to stress and injury, the body undergoes adaptive physiologic changes leading to dysregulation of the inflammatory response and hyperactivation of the inflammatory cascade. This results in a global catabolic state with modification in oxygen consumption and macronutrient metabolism. A comprehensive understanding of the metabolic response is essential when prescribing nutritional interventions aimed to offset the burden of this adaptive stress response in the critically ill. In this narrative review we aim to provide a comprehensive review of the physiologic basis, recent literature and some emerging concepts related to energy expenditure and the practical aspects of energy delivery in the critically ill child. Based on the unique metabolic characteristics of the critically ill child, we aim to provide a pragmatic approach to providing nutrition therapy.

The pathogenesis and diagnosis of sepsis post burn injury

Burn is an under-appreciated trauma that is associated with unacceptably high morbidity and mortality. Although the survival rate after devastating burn injuries has continued to increase in previous decades due to medical advances in burn wound care, nutritional and fluid resuscitation and improved infection control practices, there are still large numbers of patients at a high risk of death. One of the most common complications of burn is sepsis, which is defined as “severe organ dysfunction attributed to host's disordered response to infection” and is the primary cause of death in burn patients. Indeed, burn injuries are accompanied by a series of events that lead to sepsis and multiple organ dysfunction syndrome, such as a hypovolaemic state, immune and inflammatory responses and metabolic changes. Therefore, clear diagnostic criteria and predictive biomarkers are especially important in the prevention and treatment of sepsis and septic shock. In this review, we focus on the pathogenesis of burn wound infection and the post-burn events leading to sepsis. Moreover, the clinical and promising biomarkers of burn sepsis will also be summarized.

The impact of catecholamines on skeletal muscle following massive burns: Friend or foe?

Profound skeletal muscle wasting in the setting of total body hypermetabolism is a defining characteristic of massive burns, compromising the patient's recovery and necessitating a protracted period of rehabilitation. In recent years, the prolonged use of the non-selective beta-blocker, propranolol, has gained prominence as an effective tool to assist with suppressing epinephrine-dependent burn-induced hypermetabolism and by extension, blunting muscle catabolism. However, synthetic β-adrenergic agonists, such as clenbuterol, are widely associated with the promotion of muscle growth in both animals and humans. Moreover, experimental adrenodemedullation is known to result in muscle catabolism. Therefore, the blunting of muscle β-adrenergic signaling via the use of propranolol would be expected to negatively impair muscle protein homeostasis. This review explores these paradoxical observations and identifies the manner by which propranolol is thought to exert its anti-catabolic effects in burn patients. Moreover, we identify potential avenues by which the use of beta-blocker therapy in the treatment of massive burns could potentially be further refined to promote the recovery of muscle mass in these critically ill patients while continuing to ameliorate total body hypermetabolism.

Hyperbaric Oxygen Therapy Attenuates Burn-Induced Denervated Muscle Atrophy

Background: Neuronal apoptosis and inflammation in the ventral horn of the spinal cord contribute to denervated muscle atrophy post-burn. Hyperbaric oxygen therapy (HBOT) exerts anti-inflammation and neuroprotection. Furthermore, hypoxia-inducible factor (HIF)-1α has been reported to promote inflammation and apoptosis. We investigated the therapeutic potential of HBOT and the role of HIF-1α post-burn. Methods: Sprague-Dawley rats were divided into three groups: a control group, an untreated burn group receiving burn and sham treatment, and a HBOT group receiving burn injury and HBOT. The burn injury was induced with 75ºC ± 5ºC at the right hindpaw. HBOT (100% oxygen at 2.5 atmosphere, 90 min/day) and sham HBOT (21% oxygen at 1 atmosphere, 90 min/day) was started on day 28 after burn injury and continued for 14 treatments (days 28-41). Incapacitance (hind limb weight bearing) testing was conducted before burn and weekly after burn. At day 42 post-burn, the gastrocnemius muscle and the spinal cord ventral horn were analyzed. Results: HBOT improved burn-induced weight bearing imbalance. At day 42 post-burn, less gastrocnemius muscle atrophy and fibrosis were noted in the HBOT group than in the untreated burn group. In the ventral horn, HBOT attenuated the neuronal apoptosis and glial activation post-burn. The increases in phosphorylated AKT/mTOR post-burn were reduced after HBOT. HBOT also inhibited HIF-1α signaling, as determined by immunofluorescence and western blot. Conclusions: HBOT reduces burn-induced neuronal apoptosis in the ventral horn, possibly through HIF-1α signaling.

Status of adult inpatient burn rehabilitation in Europe: Are we neglecting metabolic outcomes?

BACKGROUND

Hypermetabolism, muscle wasting and insulin resistance are challenging yet important rehabilitation targets in the management of burns. In the absence of concrete practice guidelines, however, it remains unclear how these metabolic targets are currently managed. This study aimed to describe the current practice of inpatient rehabilitation across Europe.

METHODS

An electronic survey was distributed by the European Burn Association to burn centres throughout Europe, comprising generic and profession-specific questions directed at therapists, medical doctors and dieticians. Questions concerned exercise prescription, metabolic management and treatment priorities, motivation and knowledge of burn-induced metabolic sequelae. Odds ratios were computed to analyse associations between data derived from the responses of treatment priorities and knowledge of burn-induced metabolic sequelae.

RESULTS

Fifty-nine clinicians with 12.3 ± 9 years of professional experience in burns, representing 18 out of 91 burn centres (response rate, 19.8%) across eight European countries responded. Resistance and aerobic exercises were only provided by 42% and 38% of therapists to intubated patients, 87% and 65% once out-of-bed mobility was possible and 97% and 83% once patients were able to leave their hospital room, respectively. The assessment of resting energy expenditure by indirect calorimetry, muscle wasting and insulin resistance was carried out by only 40.7%, 15.3% and 7.4% respondents, respectively, with large variability in employed frequency and methods. Not all clinicians changed their care in cases of hypermetabolism (59.3%), muscle wasting (70.4%) or insulin resistance (44.4%), and large variations in management strategies were reported. Significant interdisciplinary variation was present in treatment goal importance ratings, motivation and knowledge of burn-induced metabolic sequelae. The prevention of metabolic sequelae was regarded as the least important treatment goal, while the restoration of functional status was rated as the most important. Knowledge of burn-induced metabolic sequelae was linked to higher importance ratings of metabolic sequelae as a therapy goal (odds ratio, 4.63; 95% CI, 1.50-14.25; p < 0.01).

CONCLUSION

This survey reveals considerable non-uniformity around multiple aspects of inpatient rehabilitation across European burn care, including, most notably, a potential neglect of metabolic outcomes. The results contribute to the necessary groundwork to formulate practice guidelines for inpatient burn rehabilitation.