Hypothalamic-pituitary-adrenal axis response to sustained stress after major burn injury in children

Pathophysiology of Severe Burn Injuries: New Therapeutic Opportunities From a Systems Perspective

Severe burn injury elicits a profound stress response with the potential for high morbidity and mortality. If polytrauma is present, patient outcomes appear to be worse. Sex-based comparisons indicate females have worse outcomes than males. There are few effective drug therapies to treat burn shock and secondary injury progression. The lack of effective drugs appears to arise from the current treat-as-you-go approach rather than a more integrated systems approach. In this review, we present a brief history of burns research and discuss its pathophysiology from a systems' perspective. The severe burn injury phenotype appears to develop from a rapid and relentless barrage of damage-associated molecular patterns, pathogen-associated molecular patterns, and neural afferent signals, which leads to a state of hyperinflammation, immune dysfunction, coagulopathy, hypermetabolism, and intense pain. We propose that if the central nervous system control of cardiovascular function and endothelial-glycocalyx-mitochondrial coupling can be restored early, these secondary injury processes may be minimized. The therapeutic goal is to switch the injury phenotype to a healing phenotype by reducing fluid leak and maintaining tissue O2 perfusion. Currently, no systems-based therapies exist to treat severe burns. We have been developing a small-volume fluid therapy comprising adenosine, lidocaine, and magnesium (ALM) to treat hemorrhagic shock, traumatic brain injury, and sepsis. Our early studies indicate that the ALM therapy holds some promise in supporting cardiovascular and pulmonary functions following severe burns. Future research will investigate the ability of ALM therapy to treat severe burns with polytrauma and sex disparities, and potential translation to humans.

The impact of burn injury on the central nervous system

Burn injuries can be devastating, with life-long impacts including an increased risk of hospitalization for a wide range of secondary morbidities. One area that remains not fully understood is the impact of burn trauma on the central nervous system (CNS). This review will outline the current findings on the physiological impact that burns have on the CNS and how this may contribute to the development of neural comorbidities including mental health conditions. This review highlights the damaging effects caused by burn injuries on the CNS, characterized by changes to metabolism, molecular damage to cells and their organelles, and disturbance to sensory, motor and cognitive functions in the CNS. This damage is likely initiated by the inflammatory response that accompanies burn injury, and it is often long-lasting. Treatments used to relieve the symptoms of damage to the CNS due to burn injury often target inflammatory pathways. However, there are non-invasive treatments for burn patients that target the functional and cognitive damage caused by the burn, including transcranial magnetic stimulation and virtual reality. Future research should focus on understanding the mechanisms that underpin the impact of a burn injury on the CNS, burn severity thresholds required to inflict damage to the CNS, and acute and long-term therapies to ameliorate deleterious CNS changes after a burn.

Surviving Sepsis After Burn Campaign

INTRODUCTION

The Surviving Sepsis Campaign was developed to improve outcomes for all patients with sepsis. Despite sepsis being the primary cause of death after thermal injury, burns have always been excluded from the Surviving Sepsis efforts. To improve sepsis outcomes in burn patients, an international group of burn experts developed the Surviving Sepsis After Burn Campaign (SSABC) as a testable guideline to improve burn sepsis outcomes.

METHODS

The International Society for Burn Injuries (ISBI) reached out to regional or national burn organizations to recommend members to participate in the program. Two members of the ISBI developed specific "patient/population, intervention, comparison and outcome" (PICO) questions that paralleled the 2021 Surviving Sepsis Campaign [1]. SSABC participants were asked to search the current literature and rate its quality for each topic. At the Congress of the ISBI, in Guadalajara, Mexico, August 28, 2022, a majority of the participants met to create "statements" based on the literature. The "summary statements" were then sent to all members for comment with the hope of developing an 80% consensus. After four reviews, a consensus statement for each topic was created or "no consensus" was reported.

RESULTS

The committee developed sixty statements within fourteen topics that provide guidance for the early treatment of sepsis in burn patients. These statements should be used to improve the care of sepsis in burn patients. The statements should not be considered as "static" comments but should rather be used as guidelines for future testing of the best treatments for sepsis in burn patients. They should be updated on a regular basis.

CONCLUSION

Members of the burn community from the around the world have developed the Surviving Sepsis After Burn Campaign guidelines with the goal of improving the outcome of sepsis in burn patients.

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.

Researches on cognitive sequelae of burn injury: Current status and advances

Burn injury is a devastating disease with high incidence of disability and mortality. The cognitive dysfunctions, such as memory defect, are the main neurological sequelae influencing the life quality of burn-injured patients. The post-burn cognitive dysfunctions are related to the primary peripheral factors and the secondary cerebral inflammation, resulting in the destruction of blood-brain barrier (BBB), as is shown on Computed Tomography (CT) and magnetic resonance imaging examinations. As part of the neurovascular unit, BBB is vital to the nutrition and homeostasis of the central nervous system (CNS) and undergoes myriad alterations after burn injury, causing post-burn cognitive defects. The diagnosis and treatment of cognitive dysfunctions as burn injury sequelae are of great importance. In this review, we address the major manifestations and interventions of post-burn cognitive defects, as well as the mechanisms involved in memory defect, including neuroinflammation, destruction of BBB, and hormone imbalance.

Adverse childhood experiences and burn pain: a review of biopsychosocial mechanisms that may influence healing

Adverse childhood experiences (ACEs) affect over half of the adults in the United States and are known to contribute to the development of a wide variety of negative health and behavioral outcomes. The consequences of ACE exposure have been studied in patient populations that include individuals with gynecologic, orthopedic, metabolic, autoimmune, cardiovascular, and gastrointestinal conditions among others. Findings indicate that ACEs not only increase risks for chronic pain but also influence emotional responses to pain in many of these individuals. A growing body of research suggests that these effects may be the result of long-lasting changes induced by ACEs in neurobiological systems during early development. However, one area that is still largely unexplored concerns the effects of ACEs on burn patients, who account for almost 450,000 hospitalizations in the United States annually. Patients with severe burns frequently suffer from persistent pain that affects their well-being long after the acute injury, but considerable variability has been observed in the experience of pain across individuals. A literature search was conducted in CINAHL and PubMed to evaluate the possibility that previously documented ACE-induced changes in biological, psychological, and social processes might contribute to these differences. Findings suggest that better understanding of the role that ACEs play in burn outcomes could lead to improved treatment strategies, but further empirical research is needed to identify the predictors and mechanisms that dictate individual differences in pain outcomes in patients with ACE exposure and to clarify the role that ACE-related alterations play in early healing and recovery from burn injuries.

Sleep Quality Among Burn Survivors And The Importance Of Intervention: A Systematic Review And Meta-Analysis

Burn survivors undergo a plethora of physiologic disturbances which can greatly affect quality of life (QOL) and healing processes. This review aimed to systematically examine sleep quality among individuals with burns and to explore the effectiveness of interventions using a meta-analytic approach. A systematic review of the literature was conducted by searching for articles using various databases. Titles and abstracts were screened and full texts of retained articles were assessed based on eligibility criteria. Methodological quality was ascertained in all articles using various scales. Overall, 5,323 articles were screened according to titles and abstracts and 25 articles were retained following full-text screening. Of the twenty-five articles, 17 were assessed qualitatively while 8 were included in the meta-analysis. Based on the qualitative analysis, sleep was found to be negatively affected in burn patients. The subsample of 8 articles included in the meta-analysis showed an overall weighted mean effect size (Hedges's g) of 1.04 (SE = 0.4, 95% CI, z = 3.0; p < 0.01), indicating a large, positive effect of intervention on sleep quality for burn patients. This review was able to demonstrate the detrimental effects of burn injury on sleep quality. Several interventions have been examined throughout the literature and have shown to be beneficial for sleep quality. However, there is great heterogeneity between existing interventions. The results from this review suggest that further research is needed before recommendations can be made as to which intervention is most effective at improving sleep in patients suffering from burn injuries.

The Ambivalent Role of Skin Microbiota and Adrenaline in Wound Healing and the Interplay between Them

After skin injury, wound healing sets into motion a dynamic process to repair and replace devitalized tissues. The healing process can be divided into four overlapping phases: hemostasis, inflammation, proliferation, and maturation. Skin microbiota has been reported to participate in orchestrating the wound healing both in negative and positive ways. Many studies reported that skin microbiota can impose negative and positive effects on the wound. Recent findings have shown that many bacterial species on human skin are able to convert aromatic amino acids into so-called trace amines (TAs) and convert corresponding precursors into dopamine and serotonin, which are all released into the environment. As a stress reaction, wounded epithelial cells release the hormone adrenaline (epinephrine), which activates the β2-adrenergic receptor (β2-AR), impairing the migration ability of keratinocytes and thus re-epithelization. This is where TAs come into play, as they act as antagonists of β2-AR and thus attenuate the effects of adrenaline. The result is that not only TAs but also TA-producing skin bacteria accelerate wound healing. Adrenergic receptors (ARs) play a key role in many physiological and disease-related processes and are expressed in numerous cell types. In this review, we describe the role of ARs in relation to wound healing in keratinocytes, immune cells, fibroblasts, and blood vessels and the possible role of the skin microbiota in wound healing.

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.

Procalcitonin kinetics early after severe burn injury and its value in diagnosis of sepsis

PURPOSE

To investigate the clinical significance of procalcitonin (PCT) kinetics early after burn and the perioperative period, and to assess its diagnostic performance for sepsis in major burn patients.

METHODS

This retrospective study on major burn patents (≥40% total body surface area) admitted from 2014 to 2019 was conducted in Southwest Hospital, Chongqing, China. A total of 321 patients were included. The kinetics of PCT was analyzed during the 1st week after burn, the perioperative period, and at the onset of clinical suspected sepsis.

RESULTS

Serum PCT concentration rose immediately after burn injury. Factors associated with increased PCT level in the 1st week after burn include greater burn area (>70% TBSA) and lower age (≤14 years). Correlations between PCT kinetics after burn and the risk of early development of sepsis and mortality were observed. At the onset of sepsis, serum PCT increased significantly compared to its basal level in the 48 h before diagnosis. The area under the receiver operating characteristics curve of PCT concentration and its kinetic changes was 0.788 and 0.826, respectively. PCT kinetics showed better accuracy than PCT concentration in discrimination of Gram-positive sepsis. The optimal diagnostic thresholds for PCT concentration and its kinetics were 1.41 ng/mL, and a 1.34-fold elevation compared to the baseline level.

CONCLUSIONS

PCT kinetics in the early stage after burn was a prognostic factor for sepsis and mortality among major burn patients. Serum PCT levels could be a diagnostic biomarker for sepsis in major burn patients.

A review of potential biomarkers for assessing physical and psychological trauma in paediatric burns

Biological markers that evaluate physical healing as well as psychological impact of a burn are essential for effective treatment of paediatric burns. The objective of this review is to summarize the evidence supporting the use of biomarkers in children with burns. An extensive review of the literature was performed using PubMed. A total of 59 biomarkers were identified relating to burn presence, specifically relating to processes involved in inflammation, wound healing, growth and metabolism. In addition, biomarkers involved in the stress response cascade following a burn trauma were also identified. Although many biomarkers have been identified that are potentially associated with burn-related physical and psychological trauma, an understanding of burn biology is still lacking in children. We propose that future research in the field of children’s burns should be conducted using broad screening methods for identifying potential biomarkers, examine the biological interactions of different biomarkers, utilize child-appropriate biological fluids such as urine or saliva, and include a range of different severity burns. Through further research, the biological response to burn injury may be fully realized and clinically relevant diagnostic tests and treatment therapies utilizing these biomarkers could be developed, for the improvement of healing outcomes in paediatric burn patients.

Transfusion and Infections in the Burn Patient

Background: Blood product transfusion has historically been utilized after major burn injury in the resuscitative as well as the acute phase. Transfusion has been implicated in infection and immunosuppression in many disease states. Recommendations for blood product transfusion has varied, but several landmark studies have helped define optimal burn transfusion strategies with respect to infection. The purpose of this article is to review the evidence describing the relation between transfusion and infection in burn injury during different phases of burn treatment to identify optimal transfusion strategies and suggest future targets for transfusion research in burns. Methods: This article presents the history, current status, and future research directions related to blood and blood product transfusion in burn injury. Results: Patients with burns are subject to infectious complications resulting from the loss of skin and burn-related immunosuppression. The use of blood in burn treatment has varied during both the resuscitative phase and the acute treatment phase. Whole-blood use in resuscitation was replaced with crystalloid infusion. Future trials are examining the role of plasma and albumin in burn resuscitation. A randomized prospective multicenter transfusion trial was able to decrease transfusion by 50% with no change in infection. Further examination of the role of hemostatic resuscitation in burn excision may help to better define transfusion goals. Conclusions: Blood product transfusion in burn injury has varied throughout the last century. Although advances in the understanding of blood transfusion in burn injury have occurred, initiatives to define optimal care better are required.

Screening of Key Genes in Severe Burn Injury at Different Stages via Analyzing Gene Expression Data

Microarray analysis was performed to investigate the changes in gene expression profiles after severe burn injury at the early and middle stages, further discovering therapeutic targets for severe burn injury. Microarray data (GSE19743) were downloaded from Gene Expression Omnibus. First, differentially expressed genes (DEGs) at different stages were screened using limma package. Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs were then performed using DAVID. Protein-protein interaction (PPI) networks were also constructed using String database. Additionally, transcription factor binding site was detected using the Whole-Genome rVISTA. Compared with the healthy controls, 160 DEGs were identified in patients with early-stage burn injury and 261 DEGs were obtained in patients with middle-stage burn injury. Only 10 genes showed differential expression between the early and middle stages. KEGG functional analysis indicated that DEGs detected at the early stage were mainly enriched in the immune response, kinase activity, and signaling pathways and DEGs detected at the middle stage were involved in the immune response, protein and fat metabolism, and programmed cell death pathways. Three PPI networks were constructed and hub proteins with high degrees of connection were screened, such as lactotransferrin, interleukin 8, and perforin-1. Additionally, many transcription factor binding sites that may be involved in the regulation of these DEGs were also detected. A number of DEGs were identified in patients with early- and middle-stage burn injury, which helps to deepen the understanding about the molecular mechanism underlying severe burn injury.

The biochemical alterations underlying post-burn hypermetabolism

A severe burn can trigger a hypermetabolic state which lasts for years following the injury, to the detriment of the patient. The drastic increase in metabolic demands during this phase renders it difficult to meet the body's nutritional requirements, thus increasing muscle, bone and adipose catabolism and predisposing the patient to a host of disorders such as multi-organ dysfunction and sepsis, or even death. Despite advances in burn care over the last 50 years, due to the multifactorial nature of the hypermetabolic phenomenon it is difficult if not impossible to precisely identify and pharmacologically modulate the biological mediators contributing to this substantial metabolic derangement. Here, we discuss biomarkers and molecules which play a role in the induction and mediation of the hypercatabolic condition post-thermal injury. Furthermore, this thorough review covers the development of the factors released after burns, how they induce cellular and metabolic dysfunction, and how these factors can be targeted for therapeutic interventions to restore a more physiological metabolic phenotype after severe thermal injuries. This article is part of a Special Issue entitled: Immune and Metabolic Alterations in Trauma and Sepsis edited by Dr. Raghavan Raju.

Altered adrenal and gonadal steroids biosynthesis in patients with burn injury

Introduction

Burn injury inevitably leads to changes in the endogenous production of cytokines, as well as adrenal and gonadal steroids. Previous studies have reported gender-related differences in outcome following burn injury, which suggests that gonadal steroids may play a role. The aim of this study was to assess alterations in concentration of endogenous steroids in patients with burn injury.

Methods

For this single-center, prospective descriptive study, high-sensitivity liquid chromatography tandem mass spectrometry (LC-MS/MS)-based steroid quantification was used to determine longitudinal profiles of the concentrations of endogenous steroids in plasma from sixteen adult male patients with burn injury (14.5-72% of total body surface area). Steroids were extracted from plasma samples and analyzed using multiple reaction monitoring acquisition, with electrospray ionization on a triple quadruple mass spectrometer. Total protein concentration was measured in the samples using spectrophotometry.

Results

Steroid and total protein concentration distributions were compared to reference intervals characteristic of healthy adult men. Concentrations of the following steroids in plasma of burn injured patients were found to correlate positively to the area of the burn injury: cortisol (r = 0.84), corticosterone (r = 0.73), 11-deoxycortisol (r = 0.72), androstenedione (r = 0.72), 17OH-progesterone (r = 0.68), 17OH-pregnenolone (r = 0.64) and pregnenolone (r = 0.77). Concentrations of testosterone decreased during the acute phase and were up to ten-times lower than reference values for healthy adult men, while concentrations of estrone were elevated. By day 21 after injury, testosterone concentrations were increased in younger, but not older, patients. The highest concentrations of estrone were observed on day 3 after the injury and then declined by day 21 to concentrations comparable to those observed on the day of the injury.

Conclusion

Burn injury alters endogenous steroid biosynthesis, with decreased testosterone concentrations and elevated estrone concentrations, during the first 21 days after the injury. Concentrations of glucocorticoids, progestagens and androgen precursors correlated positively with the area of burn injury. The finding of increased estrone following burn injury needs to be confirmed in a larger hypothesis-driven study.

Glucocorticoid receptor expression and binding capacity in patients with burn injury

BACKGROUND

Burn injuries are associated with strong inflammation and risk of secondary sepsis which both may affect the function of the glucocorticoid receptor (GR). The aim of this study was to determine GR expression and binding capacity in leucocytes from patients admitted to a tertiary burn center.

METHODS

Blood was sampled from 13 patients on admission and days 7, 14 and 21, and once from 16 healthy subjects. Patients were grouped according to the extent of burn and to any sepsis on day 7. Expression and binding capacity of GR were determined as arbitrary units using flow cytometry.

RESULTS

GR expression and binding capacity were increased compared to healthy subjects in most circulating leucocyte subsets on admission irrespective of burn size. Patients with sepsis on day 7 displayed increased GR expression in T lymphocytes (51.8%, P < 0.01) compared to admission. There was a negative correlation between GR binding capacity in neutrophils and burn size after 14 days (P < 0.05).

CONCLUSIONS

GR expression and binding capacity are increased in most types of circulating leucocytes of severely burned patients on their admission to specialized burn care. If sepsis is present after 1 week, it is associated with higher GR expression in T lymphocytes and NK cells.

Suspected adrenal insufficiency in critically ill burned patients: etomidate-induced or critical illness-related corticosteroid insufficiency?-A review of the literature

Adrenal insufficiency (AI), whether etomidate-induced or secondary to critical illness-related corticosteroid insufficiency (CIRCI), is a common and under appreciated problem in the intensive care unit intensive care unit (ICU). However, AI is often difficult to identify and diagnose in the critically ill. The pathophysiology and ideal management of etomidate-induced AI and CIRCI, especially in burn patients, is unknown. Many studies, however, have examined the prevalence of and risk factors for developing AI in critically ill populations as well as the effect of AI on morbidity and mortality. Observing a seemingly increased number of patients with suspected AI in our burn ICU, we sought to evaluate and summarize the current literature relating to adrenal insufficiency in the critically ill. We performed an electronic literature search on the PubMed and Ovid Medline databases using the key words "etomidate," "adrenal insufficiency," "CIRCI," and "burn injury." Relevant studies from the current burn and ICU era were selected to be included in this review of the literature. Among the critically ill, burn patients are at increased risk for developing adrenal insufficiency and the risk is greatest for elderly patients with large burns and inhalation injury. Both CIRCI and etomidate-induced AI are associated with high morbidity and mortality, therefore avoiding preventable causes of AI, such as choosing alternatives to etomidate for rapid sequence intubation (RSI) in the severely burn injured patient should be encouraged. Further research is indicated to investigate the biological relationship between AI and associated morbidity and mortality, whether etomidate-induced or secondary to critical illness; as well as how best to identify and diagnose patients with suspected adrenal insufficiency in the burn intensive care unit.

Intraoperative target-controlled infusion anesthesia application using remifentanil hydrochloride with etomidate in patients with severe burn as monitored using Narcotrend

OBJECTIVE

This study aims to evaluate the feasibility of intraoperative composite target-controlled infusion (TCI) anesthesia application using remifentanil hydrochloride with etomidate in patients with severe burns, as monitored by Narcotrend.

METHODS

A total of 40 patients with severe burns with eschar excisions and skin grafts were randomly and equally grouped into the etomidate (E) and the propofol groups (P). Anesthesia was induced and maintained by a remifentanil hydrochloride TCI combined with etomidate or propofol. The depth of anesthesia and other relevant indicators were recorded through intraoperative electroencephalogram monitoring using a Narcotrend monitor.

RESULTS

No statistically significant differences were observed between the drug withdrawal times, eye opening requirements, or orientation recoveries of the two groups (P>0.05). The cortisol and aldosterone levels in group E were significantly lower than those in group P 24h post operation (P<0.05). No significant differences between the number of operations, hospitalization duration, mean arterial pressure, heart rate, and postoperative adverse reaction incidence of the two groups were observed at each time point (P>0.05).

CONCLUSION

The application of a composite remifentanil hydrochloride combined with etomidate TCI is feasible for the early eschar excision in patients with severe burns.

The endocrine response to severe burn trauma

The endocrine system is frequently altered after a major burn trauma. Besides the endocrine response to stress characterized by hypercortisolism, several hypothalamus-hypophysis-target gland axes are rapidly perturbed within a few days. These alterations can persist in the long term and deserve an appropriate treatment. Disturbances in water clearance and glucidic metabolism are also common and need to be diagnosed and corrected to decrease morbidity in such patients. Bone and mineral metabolism is deeply compromised and requires correction of mineral abnormalities in order to improve symptoms and prevent bone loss. No large prospective and/or intervention trials are available to date to elaborate age-related, evidence-based recommendations to monitor and treat burn-related endocrine alterations.

Glucose intolerance induced by glucocorticoid excess is further impaired by co-administration with β-hydroxy-β-methylbutyrate in rats

Glucocorticoid (GC) excess alters glucose homeostasis and promotes modifications in murinometric and anthropometric parameters in rodents and humans, respectively. β-hydroxy-β-methylbutyrate (HMB), a leucine metabolite, has been proposed as a nutritional strategy for preventing muscle wasting, but few data regarding its effects on glucose homeostasis are available. Here, we analyzed whether the effects of GC excess on glucose homeostasis may be attenuated or exacerbated by the concomitant ingestion of HMB. Adult Wistar rats (90-days-old) were assigned to four groups: (1) vehicle treated (Ctl), (2) dexamethasone (DEX) treated (Dex), (3) HMB treated (Hmb), and (4) DEX plus HMB treated (DexHmb). Dex groups received DEX (1 mg·kg body weight (BW)−1, intraperitoneal) for 5 consecutive days. HMB groups ingested HMB (320 mg·kg BW−1, oral gavage) for the same 5 days. HMB ingestion did not attenuate the effects of DEX on food intake and body weight loss, changes in masses of several organs, insulin resistance, and glucose intolerance (p > 0.05). In fact, in DexHmb rats, there was increased fasting glycemia and exacerbated glucose intolerance with the main effect attributed to DEX treatment (p < 0.05). HMB exerted no attenuating effect on plasma triacylglycerol levels from DexHmb rats, but it seems to attenuate the lipolysis induced by β-adrenergic stimulation (20 μmol·L−1isoproterenol) in fragments of retroperitoneal adipose tissue from DexHmb rats. Therefore, HMB does not attenuate the diabetogenic characteristics of GC excess. In fact, the data suggest that HMB may exacerbate GC-induced glucose intolerance.

The role of diminishing appetite and serum nesfatin-1 level in patients with burn wound infection

BACKGROUND

The burn wound represents a susceptible site for opportunistic colonization by organisms of endogenous and exogenous origin. Diminishing appetite is known to occur in patients with burn infection, yet its underlying reason is not fully understood. We have examined the levels of nesfatin 1, a protein that we consider to be a potential new treatment target for the solution of appetite and nutrition problem in patients with burn infection.

OBJECTIVES

The aim of the present study was therefore to examine nesfatin levels in patients with burn infection.

MATERIAL AND METHODS

Laboratory values, medication and dietary records, and patient notes with diagnostic information of burn wounds patients who were admitted to the Division of Burn Treatment Center were obtained from the Erzurum Region Education and Research Hospital electronic database. Post-burn wound infection was objectively assessed by culturing wound homogenates from skin tissue. The main immediate inflammatory stress response parameters assessed were serum CRP concentrations, WBC counts, and blood nesfatin concentrations.

RESULTS

Scalding was the predominant cause of burns in both categories of patients. In 19 (61.3%) burn wound infection patients, the burns were due to a scald. A significant difference was found for the nesfatin, CRP, and WBC levels between the patients and the control group (P = 0.000). A significant difference was also determined between the nesfatin, CRP, and WBC figures at the time of hospitalization and at discharge from the hospital (P = 0.000). The most predominant bacterial isolate was Pseudomonas aeruginosa 16 (51.6%) followed by Methicilline resistant Staphylococcus aureus (MRSA) 7 (22.6%).

CONCLUSIONS

We showed that the serum nesfatin 1 level was significantly lower in the patients with burn than in the control group in our study. We considered that the central nesfatin 1 system should be taken into consideration, rather than the peripheric nesfatin 1 system, when considering the regulation of appetite in patients with burns and particularly those accompanied by infection. In other explanation of the observed negative correlation between nesfatin 1 and burn wound infection suggests that nesfatin 1 may indicate the possible contribution of nesfatin 1 to the energy homeostasis.

Serum immunoglobulin levels in pediatric burn patients

Infections remain the leading cause of death in burn patients. Immune responses play an important role in patient's defense mechanism against infection and decreasing morbidity and mortality associated with burn. Our goal was to determine serum immunoglobulin levels in pediatric burn patients in order to understand role of humoral immune defense in these patients. During this analytic cross sectional study from January 2011 to February 2012, all patients with burn and younger than 6 years old that were referred to Shahid Motahari burn and reconstruction center were enrolled. Patients had no inhalation injury or sepsis. Immunoglobulin levels were measured once on 3-5 days after burn. The burn size in 12 patients (24%) was less than 30%, in 30 patients (60%) were between 30% and 50% and in the remained 8 patients (16%) were more than 50%. In 45 patients (90%) depth and severity of burn were 2nd degree (superficial and deep) and in the remaining 5 patients (10%), it was 3rd or 4th degree. In 28 (56%), 1 (2%), 3 (6%), 35 (70%), 48 (96%), 19 (38%) and 6 (12%) patients IgG, IgM, IgA, IgG1, IgG2, IgG3 and IgG4 were lower than normal values, respectively. No significant correlation was seen between burn size (TBSA) and value of immunoglobulin (P>0.05). Although the drop in the serum concentration of immunoglobulins is irrespective to the burn size, more severe burn is associated with more decrease in the serum levels of IgA, IgM, IgG and its subclasses. However, further studies are needed to provide complementary data on this issue.

The effect of ketoconazole on post-burn inflammation, hypermetabolism and clinical outcomes

Background

Hypercortisolemia has been suggested as a primary hormonal mediator of whole-body catabolism following severe burn injury. Ketoconazole, an anti-fungal agent, inhibits cortisol synthesis. We, therefore, studied the effect of ketoconazole on post-burn cortisol levels and the hyper-catabolic response in a prospective randomized trial (block randomization 2∶1).

Methodology/Principal Findings

Fifty-five severely burned pediatric patients with >30% total body surface area (TBSA) burns were enrolled in this trial. Patients were randomized to receive standard care plus either placebo (controls, n = 38) or ketoconazole (n = 23). Demographics, clinical data, serum hormone levels, serum cytokine expression profiles, organ function, hypermetabolism measures, muscle protein synthesis, incidence of wound infection sepsis, and body composition were obtained throughout the acute hospital course. Statistical analysis was performed using Fisher’s exact test, Student’s t-test, and parametric and non-parametric two-way repeated measures analysis of variance where applicable. Patients were similar in demographics, age, and TBSA burned. Ketoconazole effectively blocked cortisol production, as indicated by normalization of the 8-fold elevation in urine cortisol levels [F(1, 376) = 85.34, p<.001] with the initiation of treatment. However, there were no significant differences in the inflammatory response, acute-phase proteins, body composition, muscle protein breakdown or synthesis, or organ function between groups.

Conclusions

Both groups were markedly hypermetabolic and catabolic throughout the acute hospital stay. Normalization of hypercortisolemia with ketoconazole therapy had no effect on whole-body catabolism or the post-burn inflammatory or hypermetabolic response, suggesting that hypercortisolemia does not play a central role in the post-burn hypermetabolic catabolic response.

Trial Registration

ClinicalTrials.gov NCT00675714; and NCT00673309

The protective role of ascorbic acid in burn-induced testicular damage in rats

OBJECTIVE

To investigate the ability of ascorbic acid to protect the testes from damage in severe burns.

DESIGN

Experimental study.

SETTING

University of Lagos Medical School, Department of Anatomy.

ANIMALS

28 adult male Wistar rats (250-300 g).

INTERVENTION

Third degree burn was induced on 40% body surface area of rats and they were given ascorbic acid at 4 mg/kg over 8 weeks.

MAIN OUTCOME MEASURED

Weight of reproductive organs and epididymal sperm parameters were measured. Oxidative status was assayed and a semi-quantitative assessment of histologic changes was also carried out.

RESULTS

Burn caused severe seminiferous tubular damage, especially germ cell loss (p<0.05). This was matched by significant reduction in sperm density and morphology (p<0.05). Burn also increased oxidative stress, with elevated malondialdehyde (MDA) levels (p<0.01) and changes in catalase and superoxide dismutase enzyme levels. Ascorbic acid prevented the changes in all sperm parameters. It normalized MDA levels (p<0.01) and attenuated changes in the levels of catalase and superoxide dismutase. Ascorbic acid treatment also significantly reduced histologic damage to seminiferous tubules.

CONCLUSION

This study shows that severe thermal injury causes significant testicular damage and impairs spermatogenesis. It also shows that ascorbic acid protects the testis from such damage and therefore has the potential to be a useful adjunct therapy during treatment of young males with severe burns.

Analgesia and sedation for children undergoing burn wound care

Standard care of burn wounds consists of cleaning and debridement (removing devitalized tissue), followed by daily dressing changes. Children with burns undergo multiple, painful and anxiety-provoking procedures during wound care and rehabilitation. The goal of procedural sedation is safe and efficacious management of pain and emotional distress, requiring a careful and systematic approach. Achieving the best results needs understanding of the mechanisms of pain and the physiologic changes in burn patients, frequent evaluation and assessment of pain and anxiety, and administration of suitable pharmacological and nonpharmacological therapies. Pharmacological therapies provide the backbone of analgesia and sedation for procedural pain management. Opioids provide excellent pain control, but they must be administered judiciously due to their side effects. Sedative drugs, such as benzodiazepines and propofol, provide excellent sedation, but they must not be used as a substitute for analgesic drugs. Ketamine is increasingly used for analgesia and sedation in children as a single agent or an adjuvant. Nonpharmacological therapies such as virtual reality, relaxation, cartoon viewing, music, massage and hypnosis are necessary components of procedural sedation and analgesia for children. These can be combined with pharmacological techniques and are used to limit the use of drugs (and hence side effects), as well as to improve patient participation and satisfaction. In this article, we review the pathophysiologic changes associated with major thermal injury in children, the options available for sedation and analgesia for wound care procedures in these children and our institutional guidelines for procedural sedation.

The evaluation of the adrenal and thyroid axes and glucose metabolism after burn injury in children

INTRODUCTION

Burn injury is an important trauma and can cause many hormonal and metabolic changes in the human body. In contrast to the situation with adults, there are inadequate number of studies on children with this condition. Our aim in this study was to determine the changes in the adrenal, thyroid axes and glucose metabolism in the acute and subacute period and relation to the percent total body surface area (TBSA) burned in children with major burn injury.

PATIENTS AND METHOD

A total of 90 hospitalized children aged 0-13 years (mean: 3.44 +/- 2.90 years) with major fluid burn injury were included in this study. Serum ACTH, cortisol, fasting glucose and insulin and thyroid hormones (free T3 and T4, TSH) were evaluated in the first 24 hours after the burn injury and on day 3 and month 3 consequently in all of the cases. An ACTH stimulation test was performed when necessary. Continuous variables were compared with analysis of variance and categorical variables were compared with the chi-square test. The Pearson correlation was used to determine the relation between ACTH and cortisol and between blood glucose and insulin (on day 1 and 3 and month 3). Also the correlation with the TBSA burned and the hormonal values were evaluated. A p value <0.05 was considered statistically significant.

FINDINGS

ACTH and Cortisol level increased in first 24 hours and decreased significantly by time. The change of ACTH and Cortisol level with time was significantly related to the TBSA burned. ACTH and cortisol levels were found significantly correlated in each time-point, but the correlation was highest in 3rd month. The glucose level in the first 24 hours was significantly higher than day 3 and month 3 levels in all of the children. There was again a significant increase in the serum insulin level in the first 24 hours. However there was no difference between day 1 and 3 serum insulin levels. A correlation was found between serum glucose and insulin on the first day but not on day 3 or month 3. Free T3 and T4 levels increased by time. Pairwise comparisons indicated that 1st day free T3 and T4 level was significantly lower than both 3rd day and 3rd month levels.

CONCLUSION

ACTH, Cortisol and fasting blood glucose level increased significantly however serum insulin level was slightly higher in first 24 hours after burns in children. Thyroid hormones were found to be decreased acute period following burns but staying in normal levels.

Measurement of tissue cortisol levels in patients with severe burns: a preliminary investigation

Introduction

The assessment of adrenal function in critically ill patients is problematic, and there is evidence to suggest that measurement of tissue glucocorticoid activity may be more useful than estimation of plasma cortisol concentrations. Interstitial cortisol concentrations of cortisol represent the available pool of glucocorticoids able to enter the cell and bind to the glucocorticoid receptor. However the concentrations of plasma cortisol may not accurately reflect interstitial concentrations. We elected to perform a preliminary study into the feasibility of measuring interstitial cortisol by microdialysis, and to investigate the relationship between total plasma cortisol, free plasma cortisol and interstitial cortisol in patients with severe burns.

Methods

A prospective observational study carried out in a tertiary intensive care unit. Ten adult patients with a mean total burn surface area of 48% were studied. Interstitial cortisol was measured by microdialysis from patient-matched burnt and non-burnt tissue and compared with that of 3 healthy volunteers. Plasma sampling for estimations of total and free cortisol concentrations was performed concurrently.

Results

In the burn patients, mean total plasma and free plasma cortisol concentrations were 8.8 +/- 3.9, and 1.7 +/- 1.1 mcg/dL, (p < 0.001), respectively. Mean subcutaneous microdialysis cortisol concentrations in the burn and non-burn tissue were 0.80 +/- 0.31 vs 0.74 +/- 0.41 mcg/dL (p = 0.8), respectively, and were significantly elevated over the mean subcutaneous microdialysis cortisol concentrations in the healthy volunteers. There was no significant correlation between total plasma or free plasma and microdialysis cortisol concentrations. Plasma free cortisol was better correlated with total burn surface area than total cortisol.

Conclusions

In this preliminary study, interstitial cortisol concentrations measured by microdialysis in burnt and non-burnt skin from patients with severe thermal injury are significantly elevated over those from healthy volunteers. Plasma estimations of cortisol do not correlate with the microdialysis levels, raising the possibility that plasma cortisol may be an unreliable guide to tissue cortisol activity.

Bench-to-bedside review: Burn-induced cerebral inflammation--a neglected entity?

Severe burn injury remains a major burden on patients and healthcare systems. Following severe burns, the injured tissues mount a local inflammatory response aiming to restore homeostasis. With excessive burn load, the immune response becomes disproportionate and patients may develop an overshooting systemic inflammatory response, compromising multiple physiological barriers in the lung, kidney, liver, and brain. If the blood–brain barrier is breached, systemic inflammatory molecules and phagocytes readily enter the brain and activate sessile cells of the central nervous system. Copious amounts of reactive oxygen species, reactive nitrogen species, proteases, cytokines/chemokines, and complement proteins are being released by these inflammatory cells, resulting in additional neuronal damage and life-threatening cerebral edema. Despite the correlation between cerebral complications in severe burn victims with mortality, burn-induced neuroinflammation continues to fly under the radar as an underestimated entity in the critically ill burn patient. In this paper, we illustrate the molecular events leading to blood–brain barrier breakdown, with a focus on the subsequent neuroinflammatory changes leading to cerebral edema in patients with severe burns.

Stress-mediated increases in systemic and local epinephrine impair skin wound healing: potential new indication for beta blockers

BACKGROUND

Stress, both acute and chronic, can impair cutaneous wound repair, which has previously been mechanistically ascribed to stress-induced elevations of cortisol. Here we aimed to examine an alternate explanation that the stress-induced hormone epinephrine directly impairs keratinocyte motility and wound re-epithelialization. Burn wounds are examined as a prototype of a high-stress, high-epinephrine, wound environment. Because keratinocytes express the beta2-adrenergic receptor (beta2AR), another study objective was to determine whether beta2AR antagonists could block epinephrine effects on healing and improve wound repair.

METHODS AND FINDINGS

Migratory rates of normal human keratinocytes exposed to physiologically relevant levels of epinephrine were measured. To determine the role of the receptor, keratinocytes derived from animals in which the beta2AR had been genetically deleted were similarly examined. The rate of healing of burn wounds generated in excised human skin in high and low epinephrine environments was measured. We utilized an in vivo burn wound model in animals with implanted pumps to deliver beta2AR active drugs to study how these alter healing in vivo. Immunocytochemistry and immunoblotting were used to examine the up-regulation of catecholamine synthetic enzymes in burned tissue, and immunoassay for epinephrine determined the levels of this catecholamine in affected tissue and in the circulation. When epinephrine levels in the culture medium are elevated to the range found in burn-stressed animals, the migratory rate of both cultured human and murine keratinocytes is impaired (reduced by 76%, 95% confidence interval [CI] 56%-95% in humans, p < 0.001, and by 36%, 95% CI 24%-49% in mice, p = 0.001), and wound re-epithelialization in explanted burned human skin is delayed (by 23%, 95% CI 10%-36%, p = 0.001), as compared to cells or tissues incubated in medium without added epinephrine. This impairment is reversed by beta2AR antagonists, is absent in murine keratinocytes that are genetically depleted of the beta2AR, and is reproduced by incubation of keratinocytes with other beta2AR-specific agonists. Activation of the beta2AR in cultured keratinocytes signals the down-regulation of the AKT pathway, accompanied by a stabilization of the actin cytoskeleton and an increase in focal adhesion formation, resulting in a nonmigratory phenotype. Burn wound injury in excised human skin also rapidly up-regulates the intra-epithelial expression of the epinephrine synthesizing enzyme phenylethanolamine-N-methyltransferase, and tissue levels of epinephrine rise dramatically (15-fold) in the burn wounded tissue (values of epinephrine expressed as pg/ug protein +/- standard error of the mean: unburned control, 0.6 +/- 0.36; immediately postburn, 9.6 +/- 1.58; 2 h postburn, 3.1 +/- 1.08; 24 h post-burn, 6.7 +/- 0.94). Finally, using an animal burn wound model (20% body surface in mice), we found that systemic treatment with betaAR antagonists results in a significant increase (44%, 95% CI 27%-61%, p < 0.00000001) in the rate of burn wound re-epithelialization.

CONCLUSIONS

This work demonstrates an alternate pathway by which stress can impair healing: by stress-induced elevation of epinephrine levels resulting in activation of the keratinocyte beta2AR and the impairment of cell motility and wound re-epithelialization. Furthermore, since the burn wound locally generates epinephrine in response to wounding, epinephrine levels are locally, as well as systemically, elevated, and wound healing is impacted by these dual mechanisms. Treatment with beta adrenergic antagonists significantly improves the rate of burn wound re-epithelialization. This work suggests that specific beta2AR antagonists may be apt, near-term translational therapeutic targets for enhancing burn wound healing, and may provide a novel, low-cost, safe approach to improving skin wound repair in the stressed individual.

Pathophysiologic response to severe burn injury

OBJECTIVE

To improve clinical outcome and to determine new treatment options, we studied the pathophysiologic response postburn in a large prospective, single center, clinical trial.

SUMMARY BACKGROUND DATA

A severe burn injury leads to marked hypermetabolism and catabolism, which are associated with morbidity and mortality. The underlying pathophysiology and the correlations between humoral changes and organ function have not been well delineated.

METHODS

Two hundred forty-two severely burned pediatric patients [>30% total body surface area (TBSA)], who received no anabolic drugs, were enrolled in this study. Demographics, clinical data, serum hormones, serum cytokine expression profile, organ function, hypermetabolism, muscle protein synthesis, incidence of wound infection sepsis, and body composition were obtained throughout acute hospital course.

RESULTS

Average age was 8 +/- 0.2 years, and average burn size was 56 +/- 1% TBSA with 43 +/- 1% third-degree TBSA. All patients were markedly hypermetabolic throughout acute hospital stay and had significant muscle protein loss as demonstrated by a negative muscle protein net balance (-0.05% +/- 0.007 nmol/100 mL leg/min) and loss of lean body mass (LBM) (-4.1% +/- 1.9%); P < 0.05. Patients lost 3% +/- 1% of their bone mineral content (BMC) and 2 +/- 1% of their bone mineral density (BMD). Serum proteome analysis demonstrated profound alterations immediately postburn, which remained abnormal throughout acute hospital stay; P < 0.05. Cardiac function was compromised immediately after burn and remained abnormal up to discharge; P < 0.05. Insulin resistance appeared during the first week postburn and persisted until discharge. Patients were hyperinflammatory with marked changes in IL-8, MCP-1, and IL-6, which were associated with 2.5 +/- 0.2 infections and 17% sepsis.

CONCLUSIONS

In this large prospective clinical trial, we delineated the complexity of the postburn pathophysiologic response and conclude that the postburn response is profound, occurring in a timely manner, with derangements that are greater and more protracted than previously thought.

Advances in burn care

PURPOSE OF REVIEW

This article reviews and critiques new developments in the critical care of burn patients.

RECENT FINDINGS

The practice of restrictive transfusion is slowly gaining traction. Abdominal compartment syndrome is associated with resuscitation volumes of 300 ml/kg per 24 h, and percutaneous decompression may be a treatment option. Adrenal insufficiency is common, but whom and when to treat are unclear. Imaging or noninvasive monitoring may confirm renal perfusion before urine output, and the concept of permissive hypovolemia should be explored. There is progress in the laboratory in smoke inhalation and myocardial depression, but no human translation. Antibiotic pharmacokinetics in large burns are unpredictable, and so aminoglycosides (measurable concentrations) are not obsolete. Selective digestive decontamination remains controversial. Nutritional predictions by formula are inaccurate. Oxandrolone is safe and effective in promoting anabolism in large burns. Deep venous thrombosis prophylaxis remains guided only by expert opinion. Females fare worse than male patients after burns.

SUMMARY

The application of the scientific method to burn care is improving slowly. Randomized controlled trials are becoming more common. There is a need for translation of excellent animal work to the human arena.