Pathophysiology of burns

Dexmedetomidine on the interplay of IL-6 and STAT3 pathways in adrenal gland damage-induced scalding burns in rats

Scalding burns are a common form of thermal injury that often leads to systemic complications. Pro-inflammatory cytokines like interleukin-6 (IL-6) and the activation of signal transducer and activator of transcription 3 (STAT3) pathways have been linked to the pathophysiology of organ damage caused by burns. This study aimed to investigate the potential therapeutic effects of dexmedetomidine, an α2-adrenergic receptor agonist with anti-inflammatory properties, on the interplay of IL-6 and STAT3 pathways in adrenal gland damage following scalding burns in rats. Twenty-eight rats were divided randomly into four groups. Rats in group 1 (n=7, control) were given only 0.9% intraperitoneal (i.p.) NaCl. Rats in group 2 (n=7, DEX) were exposed to 25°C water for 17 s on day 1 and received 100 mcg/kg/day dexmedetomidine i.p. for 3 days; for rats in group 3 (n=7, Burn), boiling water of 94°C was applied inside for 17 s. Rats in group 4 (n=7, Burn+DEX) were exposed to 94°C water for 17 s and received 100 mcg/kg/day dexmedetomidine i.p. for 3 days. Adrenal gland tissues were histopathological examined, and STAT3, IL-6, and TUNEL staining were performed using immunohistochemically. Our results revealed that scalding burns increased IL-6 and STAT3 expression in the adrenal glands of rats. Histological analysis demonstrated that dexmedetomidine administration ameliorated adrenal gland damage and reduced inflammatory cell infiltration. Our findings suggest that dexmedetomidine protects the adrenal glands in scalding burns. This protection appears to be mediated, at least in part, by its modulation of IL-6 and STAT3 pathways.

Beyond the burn: An observational study of cardiovascular risk in burn survivors in the north of Iran

Burn survivors experience profound physiological changes following injury, which may have lasting implications for cardiovascular health. This study aims to investigate the cardiovascular risk profile among burn survivors treated at a burn center in northern Iran. This observational study was conducted from 2022 to 2023 at the burn centre affiliated with Guilan University of Medical Sciences, Rasht, Iran. This study assessed a cohort study of 210 burn survivors, focusing on individuals with ≥20% TBSA burn injuries who had recovered and returned to their daily lives. This study assessed patients' lipid profiles, Framingham General Cardiovascular Risk Score (FGCRS) and risk factors, including demographics, clinical variables and physical activity. Statistical analysis employed descriptive and inferential statistics. The mean age was 49.23 years, and the mean TBSA burned was 37.06%. The risk of cardiovascular disease in 66% of the study population was less than 10%, and in 13%, it was more than 20%. Significant associations were identified between CVD risk and sex, diabetes, hypertension, BMI, TBSA burned, years after burn, physical activity level and LDL. Of the lipid profile measures, LDL, triglycerides and TC/HDL exceeded the desirable levels. This research highlights the heightened cardiovascular risk in burn survivors, emphasizing the necessity for targeted interventions and regular monitoring. Identifying modifiable risk factors enables healthcare practitioners to develop tailored strategies, enhancing cardiovascular health in this vulnerable population and improving overall outcomes and quality of life.

Unforeseen Heat: An Accidental Superficial Partial-Thickness Hand Burn Utilizing a New Convection Oven

Thermal burns remain a significant public health concern, and it is crucial to understand the potential risks associated with everyday activities involving heated objects or surfaces. It has been found that males have a higher susceptibility to hand burns, but when it comes to burns caused by hot liquids, females tend to be more frequently affected. Cooking remains the predominant activity associated with a higher incidence of accidental hand burns. Prompt medical attention and appropriate management are essential in mitigating the severity of burn injuries. This case report presents a previously healthy 55-year-old female that sustained a superficial partial-thickness burn to the dorsal aspect of her right hand while preparing a meal in her kitchen with her brand-new convection oven. This was her first time using a convection oven, unaware of the fans and rapidly circulating hot air within the oven. We discuss the need for a comprehensive approach to wound care, including topical antimicrobial agents, dressings, pain management, and monitoring for potential complications to achieve favorable outcomes and minimize long-term sequelae. Prevention remains the cornerstone in reducing burn injuries. Awareness campaigns, safety guidelines, and educational initiatives aimed at promoting responsible handling of hot objects should be implemented. Simple preventive measures, such as using appropriate protective equipment such as oven mitts, being mindful of oven temperatures, and maintaining a safe distance from heated surfaces, can significantly reduce the risk of household thermal burns.

Role of medicinal herbs and phytochemicals in post burn management

Burn management is a natural and distinctly programmed process involving overlapping phases of hemostasis, inflammation, proliferation and remodeling. Burn wound healing involves initiation of inflammation, re-epithelialization, granulation, neovascularization and wound contraction. Despite the availability of multiple preparations for management of burn wound, there is dire need for efficacious alternative agents. Current approaches for burn wound management include pharmaceutical agents and antibiotics. However, high cost of synthetic drugs and accelerated resistance to antibiotics is challenging for both developed and developing nations. Among alternative options, medicinal plants have been a biocompatible, safe and affordable source of preventive/curative approaches. Due to cultural acceptance and patient compliance, there has been a focus on the use of botanical drugs and phytochemicals for burn wound healing. Keeping in consideration of medicinal herbs and phytochemicals as suitable therapeutic/adjuvant agents for burn wound management, this review highlights therapeutic potential of 35 medicinal herbs and 10 phytochemicals. Among these, Elaeis guineensis, Ephedra ciliate and Terminalia avicennioides showed better burn wound healing potential with varied mechanisms such as modulation of TNF-alpha, inflammatory cytokines, nitric oxide, eicosanoids, ROS and leukocyte response. Phytochemicals (oleanolic acid, ursolic acid, kirenol) also showed promising role in burn wound management though various pathways involving such as down regulation of TNF-alpha, IL-6 and inflammatory mediators including plasma proteases and arachidonic acid metabolites. This review provides a pavement for therapeutic/adjuvant use of potential botanical drugs and novel druggable phyto-compounds to target skin burn injury with diverse mechanisms, affordability and safety profile.

Designing and characterization of curcumin-loaded nanotechnological dressings: A promising platform for skin burn treatment

Burns affect the skin and appendages, impair their function, and become favorable regions for bacterial infections. Owing to time-consuming and costly treatments, burns have been considered a public health problem. The limitations of the treatments used for burns have motivated the search for more efficient alternatives. Curcumin has several potential properties such as anti-inflammatory, healing, and antimicrobial activities. However, this compound is unstable and has low bioavailability. Therefore, nanotechnology could offer a solution for its application. This study aimed to develop and characterize dressings (or gauzes) impregnated with curcumin nanoemulsions that were prepared using two different techniques as a promising platform for skin burn treatment. In addition, the effect of cationization on curcumin release from the gauze was evaluated. Nanoemulsions were successfully prepared using two methods, ultrasound and a high-pressure homogenizer, with sizes of 135 nm and 144.55 nm, respectively. These nanoemulsions exhibited a low polydispersity index, adequate zeta potential, high encapsulation efficiency, and stability for up to 120 d. In vitro assays demonstrated a controlled release of curcumin between 2 and 240 h. No cytotoxicity was observed at concentrations of curcumin up to 75 µg/mL, and cell proliferation was observed. The incorporation of nanoemulsions in the gauze was successfully achieved, and the evaluation of curcumin release showed a faster release from cationized gauzes, whereas the non-cationized gauze promoted a more constant release.

Impact of licorice root on the burn healing process: A double-blinded randomized controlled clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Due to the known side effects of many synthetic drugs, the use of herbal and natural substances in treating diseases such as burns has been considered. licorice is a herbal medicine whose stem and underground roots are used in traditional medicine in many countries, including Iran, for anti-inflammatory, stomach ulcer healing, and antimicrobial purposes.

AIM OF THE STUDY

This study investigated the healing effect of hydroalcoholic extract of licorice root on the wound healing process caused by second-degree burns.

METHODS

The hydroalcoholic extract of licorice was prepared in ethanol solvent, and then the licorice hydrogel product was designed using gelling compounds. Then, in a double-blinded randomized clinical trial, 50 patients with second-degree burns were selected based on inclusion criteria from the patients referred to Yazd Hospital and Isfahan Hospital. Participants were randomly divided into two groups: the control group receiving hydrogel without extract and the intervention group receiving hydrogel containing licorice root hydroalcoholic extract. The intervention lasted for 15 days, and during this period, the wound-healing process was evaluated on days 1, 3, 6, 10, and 15. Data were analyzed using SPSS software with independent T-test and Mann-Whitney U tests with a maximum error of 5 %.

RESULTS

The rate of inflammation (From the 3rd day to the 10th day), redness (From the 6th day to the 15th day), pain (on the 3rd day), and burning (From the 3rd day to the 15th day) of the wound in the group that used the hydrogel-containing hydroalcoholic extract of licorice root was significantly lower than in the control group (P < 0.05), and the healing process was significantly faster than the control group.

CONCLUSION

Hydroalcoholic extract of licorice root can accelerate the healing process of second-degree burns.

The effect of Tarantula cubensis D6 on zone of stasis in a rat burn model

AIM

Burn injuries are one of the most devastating injuries. Saving the zone of stasis decreases burn size, morbidity, and mortality. Tarantula cubensis (TC) increases epithelization of wounds, and increases wound contraction. In this study, we investigated the effects of TC on the stasis zone.

MATERIALS AND METHODS

36 Wistar albino female rats were divided into 3 groups. Using brass comb burn model, at days 0 and 3, physiological serum solution in group 2, TC injection in group 3and no injection in group 1 was applied. Thermal and normal images were taken on day 10 and rats were sacrificed for histopathological examination.

RESULTS

We found a statistically significant difference between the 1st and 3rd group, 2nd and 3rd group regarding viable wound areas (p < 0.05), temperature difference (body-stasis zone) and mean body temperature (p < 0.05). We found no statistically significant difference between groups regarding neovascularization, inflammatory density, and vital cutaneous appendages. We found a statistically significant difference in epithelial layer thickness between the1st and 3rd groups, 2nd and 3rd groups(p < 0.05).

CONCLUSION

TC increases stasis zone viability macroscopically, increases epithelial layer thickness histopathologically, thus it promotes wound healing in burn wounds. This increase in stasis zone viability was also established with thermal imaging.

The Potential of Medicinal Plants and Natural Products in the Treatment of Burns and Sunburn-A Review

Treating burns remains a challenge for modern medicine, especially in developing countries that cannot afford expensive, advanced therapies. This review article summarises clinical and animal model studies of botanical preparations and their mixtures in treating burn wounds and sunburn. Articles available in electronic databases such as PubMed, Scopus, Web of Science, Science Direct and Google Scholar, published in English in 2010-2022, were considered. In the described clinical trials, it was shown that some herbal preparations have better effectiveness in treating burn wounds, including shortening the healing time and reducing inflammation, than the conventional treatment used hitherto. These herbal preparations contained extracts from Albizia julibrissin, Alkanna tinctoria, Aloe vera, Arnebia euchroma, Betula pendula and Betula pubescens, Centella asiatica, Hippophaë rhamnoides, Juglans regia, Lawsonia inermis, and mixtures of Matricaria chamomilla and Rosa canina. Research on animal models shows that many extracts may potentially benefit the treatment of burn wounds and sunburn. Due to the diverse mechanism of action, antibacterial activity, the safety of use and cost-effectiveness, herbal preparations can compete with conventional treatment. The growing interest in alternative medicine and herbal medicine encourages further research. Not only single preparations but also their mixtures should be taken into account because the research conducted so far often suggests a synergistic effect of the ingredients.

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.

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.

Catecholamines Induce Endoplasmic Reticulum Stress Via Both Alpha and Beta Receptors

Severely burned patients suffer from a hypermetabolic syndrome that can last for years after the injury has resolved. The underlying cause of these metabolic alterations most likely involves the persistent elevated catecholamine levels that follow the surge induced by thermal injury. At the cellular level, endoplasmic reticulum (ER) stress in metabolic tissues is a hallmark observed in patients following burn injury and is associated with several detrimental effects. Therefore, ER stress could be the underlying cellular mechanism of persistent hypermetabolism in burned patients. Here, we show that catecholamines induce ER stress and that adreno-receptor blockers reduce stress responses in the HepG2 hepatocyte cell line. Our results also indicate that norepinephrine (NE) significantly induces ER stress in HepG2 cells and 3T3L1 mouse adipocytes. Furthermore, we demonstrate that the alpha-1 blocker, prazosin, and beta blocker, propranolol, block ER stress induced by NE. We also show that the effects of catecholamines in inducing ER stress are cell type-specific, as NE treatment failed to evoke ER stress in human fibroblasts. Thus, these findings reveal the mechanisms used by catecholamines to alter metabolism and suggest inhibition of the receptors utilized by these agents should be further explored as a potential target for the treatment of ER stress-mediated disease.

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.

Persistent Systemic Inflammation in Patients With Severe Burn Injury Is Accompanied by Influx of Immature Neutrophils and Shifts in T Cell Subsets and Cytokine Profiles

Severe burn injury causes local and systemic immune responses that can persist up to months, and can lead to systemic inflammatory response syndrome, organ damage and long-term sequalae such as hypertrophic scarring. To prevent these pathological conditions, a better understanding of the underlying mechanisms is essential. In this longitudinal study, we analyzed the temporal peripheral blood immune profile of 20 burn wound patients admitted to the intensive care by flow cytometry and secretome profiling, and compared this to data from 20 healthy subjects. The patient cohort showed signs of systemic inflammation and persistently high levels of pro-inflammatory soluble mediators, such as IL-6, IL-8, MCP-1, MIP-1β, and MIP-3α, were measured. Using both unsupervised and supervised flow cytometry techniques, we observed a continuous release of neutrophils and monocytes into the blood for at least 39 days. Increased numbers of immature neutrophils were present in peripheral blood in the first three weeks after injury (0.1–2.8 × 10⁶/ml after burn vs. 5 × 10³/ml in healthy controls). Total lymphocyte numbers did not increase, but numbers of effector T cells as well as regulatory T cells were increased from the second week onward. Within the CD4⁺ T cell population, elevated numbers of CCR4⁺CCR6^- and CCR4⁺CCR6⁺ cells were found. Altogether, these data reveal that severe burn injury induced a persistent innate inflammatory response, including a release of immature neutrophils, and shifts in the T cell composition toward an overall more pro-inflammatory phenotype, thereby continuing systemic inflammation and increasing the risk of secondary complications.

Overexpressing of caveolin-1 in mesenchymal stem cells promotes deep second-degree burn wound healing

Burn injury is one of the most common physical injuries in clinic. It is a big challenge to find an ideal treatment for burn injury. Mesenchymal stem cells (MSCs) have been suggested as a promising candidate for wound healing. However, it is critical to improve the therapeutic efficiency of MSCs for treatment of burn injury. Here, we demonstrated that overexpression of caveolin-1, the main component of the caveolae plasma membranes, promoted the proliferation of MSCs both in vitro and in vivo. Moreover, transplantation of MSCs overexpressing caveolin-1 facilitated the expression of various growth factors and immunoregulatory cytokines and accelerated deep second-degree burn wound healing in a rat model of burn injury. Our results suggest that overexpression of caveolin-1 can improve the therapeutic efficiency of MSCs, which may be a promising strategy for the treatment of deep second-degree burn injury in clinic.

Pathological Responses of Cardiac Mitochondria to Burn Trauma

Despite advances in treatment and care, burn trauma remains the fourth most common type of traumatic injury. Burn-induced cardiac failure is a key factor for patient mortality, especially during the initial post-burn period (the first 24 to 48 h). Mitochondria, among the most important subcellular organelles in cardiomyocytes, are a central player in determining the severity of myocardial damage. Defects in mitochondrial function and structure are involved in pathogenesis of numerous myocardial injuries and cardiovascular diseases. In this article, we comprehensively review the current findings on cardiac mitochondrial pathological changes and summarize burn-impaired mitochondrial respiration capacity and energy supply, induced mitochondrial oxidative stress, and increased cell death. The molecular mechanisms underlying these alterations are discussed, along with the possible influence of other biological variables. We hope this review will provide useful information to explore potential therapeutic approaches that target mitochondria for cardiac protection following burn injury.

Burn-Induced Cardiac Mitochondrial Dysfunction via Interruption of the PDE5A-cGMP-PKG Pathway

Burn-induced heart dysfunction is a key factor for patient mortality. However, the molecular mechanisms are not yet fully elucidated. This study sought to understand whether burn-induced heart dysfunction is associated with cardiac mitochondrial dysfunction and interruption of the PDE5A-cGMP-PKG pathway. Sixty percent total body surface area (TBSA) scald burned rats (±sildenafil) were used in this study. A transmission electron microscope (TEM), real-time qPCR, O2K-respirometer, and electron transport chain assays were used to characterized molecular function. Cardiac mitochondrial morphological shapes were disfigured with a decline in mitochondrial number, area, and size, resulting in deficiency of cardiac mitochondrial replication. Burn induced a decrease in all mitDNA encoded genes. State 3 oxygen consumption was significantly decreased. Mitochondrial complex I substrate-energized or complex II substrate-energized and both of respiratory control ratio (RCRs) were decreased after burn. All mitochondrial complex activity except complex II were decreased in the burn group, correlating with decreases in mitochondrial ATP and MnSOD activity. Sildenafil, a inhibitor of the PDE5A-cGMP-PKG pathway, preserved the mitochondrial structure, respiratory chain efficiency and energy status in cardiac tissue. Furthermore, sildenafil treatment significantly restored ADP-conjugated respiration in burned groups. In conclusion, cardiac mitochondrial damage contributes to burn-induced heart dysfunction via the PDE5A-cGMP-PKG pathway.

Epidemiology of Burn Wounds Arriving to a Level 1 Trauma Center in Israel

Burn injuries have grave consequences for patients and impose a heavy economic burden on healthcare services. Studies on the epidemiology of burn injury in Israel are sparse and outdated, and improved understanding of current trends can help experts plan prevention campaigns and design effective treatment paradigms. This study sought to assess the background, clinical, and treatment characteristics of adult patients admitted with burn injury to a level 1 trauma center in Israel in 2005 to 2017. Data were retrospectively retrieved from the hard copy and electronic files as follows: patient sex and age; burn type, degree, and etiology; percentage total BSA (%TBSA) affected; and type of treatment and length of hospital stay (LOS). The cohort included 734 patients of mean age 41.79 years and a male-to-female ratio of 1.8:1. Thermal factors, particularly hot liquids, were the most common cause; second-degree burns were the most common. Mean %TBSA was 5.39%; mean LOS was 11.81 days; and mean LOS/%TBSA was 4.65. Advanced dressings alone yielded satisfactory outcome in 74.2% of patients. The relatively younger patient age and male predominance of our cohort were in line with published findings. The LOS was similar to previous studies in Israel but lower than in Europe. The LOS/%TBSA was higher than in the literature, with a decrease over time suggesting an increased effectiveness of treatment. There appears to be a decline in the rate of surgery for burn injury and increased expertise in the use of advanced dressings. National prevention campaigns should focus on scalds rather than flame-induced burns.

Burn injury

Burn injuries are under-appreciated injuries that are associated with substantial morbidity and mortality. Burn injuries, particularly severe burns, are accompanied by an immune and inflammatory response, metabolic changes and distributive shock that can be challenging to manage and can lead to multiple organ failure. Of great importance is that the injury affects not only the physical health, but also the mental health and quality of life of the patient. Accordingly, patients with burn injury cannot be considered recovered when the wounds have healed; instead, burn injury leads to long-term profound alterations that must be addressed to optimize quality of life. Burn care providers are, therefore, faced with a plethora of challenges including acute and critical care management, long-term care and rehabilitation. The aim of this Primer is not only to give an overview and update about burn care, but also to raise awareness of the ongoing challenges and stigmata associated with burn injuries.

A Systematic Review and Meta-Analysis Examining the Impact of Sleep Disturbance on Postoperative Delirium

OBJECTIVES

Basic science and clinical studies suggest that sleep disturbance may be a modifiable risk factor for postoperative delirium. We aimed to assess the association between preoperative sleep disturbance and postoperative delirium.

DATA SOURCES

We searched PubMed, Embase, CINAHL, Web of Science, and Cochrane from inception until May 31, 2017.

STUDY SELECTION

We performed a systematic search of the literature for all studies that reported on sleep disruption and postoperative delirium excluding cross-sectional studies, case reports, and studies not reported in English language.

DATA EXTRACTION

Two authors independently performed study selection and data extraction. We calculated pooled effects estimates with a random-effects model constructed in Stata and evaluated the risk of bias by formal testing (Stata Corp V.14, College Station, TX), DATA SYNTHESIS:: We included 12 studies, from 1,238 citations that met our inclusion criteria. The pooled odds ratio for the association between sleep disturbance and postoperative delirium was 5.24 (95% CI, 3.61-7.60; p < 0.001 and I = 0.0%; p = 0.76). The pooled risk ratio for the association between sleep disturbance and postoperative delirium in prospective studies (n = 6) was 2.90 (95% CI, 2.28-3.69; p < 0.001 and I = 0.0%; p = 0.89). The odds ratio associated with obstructive sleep apnea and unspecified types of sleep disorder were 4.75 (95% CI, 2.65-8.54; p < 0.001 and I = 0.0%; p = 0.85) and 5.60 (95% CI, 3.46-9.07; p < 0.001 and I = 0.0%; p = 0.41), respectively. We performed Begg's and Egger's tests for publication bias and confirmed a null result for publication bias (p = 0.371 and 0.103, respectively).

CONCLUSIONS

Preexisting sleep disturbances are likely associated with postoperative delirium. Whether system-level initiatives targeting patients with preoperative sleep disturbance may help reduce the prevalence, morbidity, and healthcare costs associated with postoperative delirium remains to be determined.

Risk factors and the associated limit values for abnormal elevation of extravascular lung water in severely burned adults

BACKGROUND

Increased extravascular lung water (EVLW) correlates with pulmonary morbidity and mortality in critical illness. The extravascular lung water index (EVLWI), which reflects the degree of EVLW in an individual, increases in the fluid reabsorption stage rather than the initial resuscitation stage in severe burn cases. While many factors contribute to EVLWI variation, the risk factors contributing to its abnormal elevation in severe burns remain unclear. The aim of this study was to identify the risk factors and associated limit values for abnormal elevation of EVLWI during the fluid reabsorption stage in a cohort of severely burned adults.

METHOD

This prospective, single-center study included only adults with burn sizes≥50% of the total body surface area (TBSA) who were admitted within 24h after burn. Demographic data were collected, and transpulmonary thermodilution (TPTD) measurements and blood biochemistry tests were performed upon admission and up to day (PBD) 9. Risk factors for abnormal EVLWI were analyzed by logistic regression. Receiver operating characteristic (ROC) curves were constructed to determine the optimal cut-offs for each risk factor.

RESULTS

Seventy-two patients were ultimately enrolled, with a mean age of 40.3 years and mean burn size of 69.4% TBSA. EVLWI began to abnormally increase (>7ml/kg) on day 3 and up to PBD 9, indicating that a supranormal EVLWI developed in the fluid reabsorption stage. Several relevant factors were considered, including patient age, burn size, intrathoracic blood volume index (ITBVI), pulmonary vascular permeability index (PVPI), cardiac index (CI), systemic vascular resistance index (SVRI), serum albumin, time of first excision and grafting, and number of operations and daily fluid administration. Among these factors, we found that only burn size and ITBVI were significantly correlated with EVLWI variation and were further identified as the independent risk factors for EVLWI abnormality. ROC analysis showed that the limits for predicting a supranormal EVLWI during the fluid reabsorption stage were 65.5% TBSA for burn size and 845ml/m² for ITBVI. Patients with burn sizes or ITBVIs higher than the limit showed significantly longer mechanical ventilation time and substantially higher occurrences of acute respiratory distress syndrome (ARDS) and pneumonia within two weeks after burn.

CONCLUSIONS

Burn size and ITBVI are the independent risk factors for EVLWI abnormality during the fluid reabsorption stage in severely burned adults. The limit values for predicting a supranormal EVLWI in those patients are 65.5% TBSA for burn size and 845ml/m² for ITBVI.

Mesenchymal Stromal Cell Preconditioning: The Next Step Toward a Customized Treatment For Severe Burn

Over the last century, the clinical management of severe skin burns significantly progressed with the development of burn care units, topical antimicrobials, resuscitation methods, early eschar excision surgeries, and skin grafts. Despite these considerable advances, the present treatment of severe burns remains burdensome, and patients are highly susceptible to skin engraftment failure, infections, organ dysfunction, and hypertrophic scarring. Recent researches have focused on mesenchymal stromal cell (MSC) therapy and hold great promises for tissue repair, as reported in several animal studies and clinical cases. In the present review, we will provide an up-to-date outlook of the pathophysiology of severe skin burns, clinical treatment modalities and current limitations. We will then focus on MSCs and their potential in the burn wound healing both in in vitro and in vivo studies. A specific attention will be paid to the cell preconditioning approach, as a means of improving the MSC efficacy in the treatment of major skin burns. In particular, we will debate how several preconditioning cues would modulate the MSC properties to better match up with the burn pathophysiology in the course of the cell therapy. Finally, we will discuss the clinical interest and feasibility of a MSC-based therapy in comparison to their paracrine derivatives, including microvesicles and conditioned media for the treatment of major skin burn injuries.

Minimizing ICU Neurological Dysfunction with Dexmedetomidine-induced Sleep (MINDDS): protocol for a randomised, double-blind, parallel-arm, placebo-controlled trial

INTRODUCTION

Delirium, which is prevalent in postcardiac surgical patients, is an acute brain dysfunction characterised by disturbances in attention, awareness and cognition not explained by a pre-existing neurocognitive disorder. The pathophysiology of delirium remains poorly understood. However, basic science and clinical studies suggest that sleep disturbance may be a modifiable risk factor for the development of delirium. Dexmedetomidine is a α-2A adrenergic receptor agonist medication that patterns the activity of various arousal nuclei similar to sleep. A single night-time loading dose of dexmedetomidine promotes non-rapid eye movement sleep stages N2 and N3 sleep. This trial hypothesises dexmedetomidine-induced sleep as pre-emptive therapy for postoperative delirium.

METHODS AND ANALYSIS

The MINDDS (Minimizing ICU Neurological Dysfunction with Dexmedetomidine-induced Sleep) trial is a 370-patient block-randomised, placebo-controlled, double-blinded, single-site, parallel-arm superiority trial. Patients over 60 years old, undergoing cardiac surgery with planned cardiopulmonary bypass, will be randomised to receive a sleep-inducing dose of dexmedetomidine or placebo. The primary outcome is the incidence of delirium on postoperative day 1, assessed with the Confusion Assessment Method by staff blinded to the treatment assignment. To ensure that the study is appropriately powered for the primary outcome measure, patients will be recruited and randomised into the study until 370 patients receive the study intervention on postoperative day 0. Secondary outcomes will be evaluated by in-person assessments and medical record review for in-hospital end points, and by telephone interview for 30-day, 90-day and 180-day end points. All trial outcomes will be evaluated using an intention-to-treat analysis plan. Hypothesis testing will be performed using a two-sided significance level (type I error) of α=0.05. Sensitivity analyses using the actual treatment received will be performed and compared with the intention-to-treat analysis results. Additional sensitivity analyses will assess the potential impact of missing data due to loss of follow-up.

ETHICS AND DISSEMINATION

The Partners Human Research Committee approved the MINDDS trial. Recruitment began in March 2017. Dissemination plans include presentations at scientific conferences, scientific publications and popular media.

TRIAL REGISTRATION NUMBER

NCT02856594.

Topically administered rhGM-CSF affects PPARβ expression in the stasis zone

Using a rat comb thermal damage model, we investigated the effects of topically administered recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on peroxisome proliferator-activated receptor PPARβ expression. We created bilateral comb scald models on the backs of fifty Sprague-Dawley rats. The left sides of the backs served as the experimental group and the right sides served as the control group. The experimental group received topically applied rhGM-CSF hydrogel and the control group did not. The survival situations of the stasis zones were compared between the experimental and control groups on the 1st, 3rd, 7th, 14th and 21st post-burn days. Tissues from the surviving stasis zones of both groups were collected at different time-points. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting were used to detect the PPARβ mRNA and protein expression levels. Immunohistochemical methods were applied to detect the localization of PPARβ protein expression. The results showed that, first, the tissue viability numbers for the stasis zones of the experimental group were significantly increased compared with those of the control group. Second, RT-PCR revealed that the PPARβ mRNA expression first increased and then gradually declined in both groups. At all time-points, the expression level in the experimental group was increased compared with that in the control group and the highest expression levels were observed in both groups on the 3rd post-burn day. Third, western blot analysis revealed that the PPARβ protein expression in both groups increased after thermal damage and then gradually decreased. PPARβ protein expression in the experimental group was greater than that in the control group, and the highest expression quantities in both groups were observed on the 3rd post-burn day. In conclusion, rhGM-CSF hydrogel effectively promotes the expression of PPARβ, and the hydrogel had a specific protective effect for the stasis zone.

Neutrophil extracellular traps coincide with a pro-coagulant status of microcirculatory endothelium in burn wounds

Burn-induced tissue loss is partly related to secondary expansion of necrosis into vital dermis neighboring the initial burn injury. An important factor herein is the severe loss of perfusion of the burn wound, probably caused by microvascular damage induced by the intense local inflammatory responses as well as burn-induced hypercoagulation. We hypothesize that the formation of neutrophilic extracellular traps (NETs) play an important role in this. The purpose of this study was to investigate postburn intravascular thrombosis, NETs formation and the coagulant state in the microvasculature of burns in both animal models and patients. We used two in vivo burn wound models: rats and pigs. In rats, the entire wound was excised at day 14 postburn and in pigs burn wound biopsies were collected at different time points up to 60 days postburn. To confirm the data in patients, eschar from the burn wound was obtained from burn wound patients at different time points after wounding. The number of intravascular thrombi, the presence of intravascular NETs and the number of tissue factor (TF) positive blood vessels in the burn wound was determined. In rats, a significant increase in intravascular thrombi and TF expression was observed 14 days postburn, that in majority coincided with NETs. In pigs, a significant increase in intravascular thrombi and TF expression was found over time up to 60 days postburn, that in majority coincided with NETs too. Also in eschar of burn wound patients, a significant increase in intravascular thrombi was noted, that in majority coincided with NETs, already 0.5 days postburn and remained elevated up to 46 days postburn. This study shows the presence of NETosis in microcirculatory thrombosis of burn wounds and a switch in the microcirculatory endothelium toward a procoagulant phenotype.

Propranolol kinetics in plasma from severely burned adults

OBJECTIVES

The aim of this study was to determine the appropriate propranolol dosing strategy for reducing heart rate in severely burned adults.

METHODS

A total of 26 patients (≥18 years) with burns covering ≥30% of the total body surface area were included in this IRB-approved study. Plasma propranolol concentrations were determined in a placebo group (n=10) or following one of three dosing strategies: Q6 (n=4), Q8 (n=6), and Q24 (n=6). Blood was collected just before dosing and at regular intervals over two dosing periods with corresponding heart rate and blood pressure recordings. Statistical significance was determined by one-way ANOVA followed by the appropriate post-hoc test.

RESULTS

Heart rate was 86±2 bpm for Q6, 93±3 bpm for Q8, and 90±4 bpm for Q24. The Q8 group had a significantly higher heart rate than the Q6 group (p=0.0001). Plasma propranolol concentrations were significantly higher in the Q6 dosing strategy than in the Q8 dosing strategy (p=0.02).

CONCLUSIONS

Heart rate can be decreased to a similar degree with Q6 and Q24 dosing strategies, with the Q8 dosing strategy being less effective. Q6 dosing is recommended to maintain reduced heart rate throughout dosing periods.

Polytrauma-induced hepatic stress response and the development of liver insulin resistance

Insulin resistance and metabolic dysfunction are common following injury. Polytrauma is defined as combined injuries to more than one body part or organ system, and is common in modern warfare, as well as automobile and industrial accidents. Polytrauma can include any combination of burn injury, fracture, hemorrhage, trauma to the extremities, and blunt or penetrating trauma. Multiple minor injuries are often more deleterious than a more severe single injury. To investigate the mechanisms of development of insulin resistance following injury, we have developed a rat model of polytrauma which combined soft tissue trauma with burn injury and penetrating gastrointestinal (GI) trauma. Male Sprague-Dawley rats were subjected to a laparotomy plus either a 15-18% total body surface area scald burn or a single puncture of the cecum (CLP) with a G30 needle, or the combination of both burn and CLP injuries (polytrauma). We examined the effects of polytrauma which increased markers of hepatic endoplasmic reticulum (ER) stress, and increased hepatic Trib3 mRNA levels coincident with reduced insulin-inducible insulin signaling. Phosphorylation/activation of the insulin receptor (IR) and AKT were decreased at 24, but not 6h following polytrauma. These results demonstrate a complex, time-dependent development of hepatic ER-stress and a diminished response to insulin, which were among the pathological sequelae following polytrauma.

The role of complement in the acute phase response after burns

Severe burns induce a complex systemic inflammatory response characterized by a typical prolonged acute phase response (APR) that starts approximately 4-8h after-burn and persists for months up to a year after the initial burn trauma. During this APR, acute phase proteins (APPs), including C-reactive protein (CRP) and complement (e.g. C3, C4 and C5) are released in the blood, resulting amongst others, in the recruitment and migration of inflammatory cells. Although the APR is necessary for proper wound healing, a prolonged APR can induce local tissue damage, hamper the healing process and cause negative systemic effects in several organs, including the heart, lungs, kidney and the central nervous system. In this review, we will discuss the role of the APR in burns with a specific focus on complement.

A mathematical model for the simulation of the contraction of burns

A continuum hypothesis-based model is developed for the simulation of the contraction of burns in order to gain new insights into which elements of the healing response might have a substantial influence on this process. Tissue is modeled as a neo-Hookean solid. Furthermore, (myo)fibroblasts, collagen molecules, and a generic signaling molecule are selected as model components. An overview of the custom-made numerical algorithm is presented. Subsequently, good agreement is demonstrated with respect to variability in the evolution of the surface area of burns over time between the outcomes of computer simulations and measurements obtained in an experimental study. In the model this variability is caused by varying the values for some of its parameters simultaneously. A factorial design combined with a regression analysis are used to quantify the individual contributions of these parameter value variations to the dispersion in the surface area of healing burns. The analysis shows that almost all variability in the surface area can be explained by variability in the value for the myofibroblast apoptosis rate and, to a lesser extent, the value for the collagen molecule secretion rate. This suggests that most of the variability in the evolution of the surface area of burns over time in the experimental study might be attributed to variability in these two rates. Finally, a probabilistic analysis is used in order to investigate in more detail the effect of variability in the values for the two rates on the healing process. Results of this analysis are presented and discussed.

Spatiotemporal Dynamics of Dexmedetomidine-Induced Electroencephalogram Oscillations

An improved understanding of the neural correlates of altered arousal states is fundamental for precise brain state targeting in clinical settings. More specifically, electroencephalogram recordings are now increasingly being used to relate drug-specific oscillatory dynamics to clinically desired altered arousal states. Dexmedetomidine is an anesthetic adjunct typically administered in operating rooms and intensive care units to produce and maintain a sedative brain state. However, a high-density electroencephalogram characterization of the neural correlates of the dexmedetomidine-induced altered arousal state has not been previously accomplished. Therefore, we administered dexmedetomidine (1mcg/kg bolus over 10 minutes, followed by 0.7mcg/kg/hr over 50 minutes) and recorded high-density electroencephalogram signals in healthy volunteers, 18–36 years old (n = 8). We analyzed the data with multitaper spectral and global coherence methods. We found that dexmedetomidine was associated with increased slow-delta oscillations across the entire scalp, increased theta oscillations in occipital regions, increased spindle oscillations in frontal regions, and decreased beta oscillations across the entire scalp. The theta and spindle oscillations were globally coherent. During recovery from this state, these electroencephalogram signatures reverted towards baseline signatures. We report that dexmedetomidine-induced electroencephalogram signatures more closely approximate the human sleep onset process than previously appreciated. We suggest that these signatures may be targeted by real time visualization of the electroencephalogram or spectrogram in clinical settings. Additionally, these signatures may aid the development of control systems for principled neurophysiological based brain-state targeting.

The impact of non-severe burn injury on cardiac function and long-term cardiovascular pathology

Severe burn injury significantly affects cardiovascular function for up to 3 years. However, whether this leads to long-term pathology is unknown. The impact of non-severe burn injury, which accounts for over 80% of admissions in developed countries, has not been investigated. Using a rodent model of non-severe burn injury with subsequent echocardiography we showed significantly increased left ventricular end systolic diameter (LVESD) and ventricular wall thickness at up to 3 months post-injury. Use of propranolol abrogated the changes in cardiac measures observed. Subsequently we investigated changes in a patient cohort with non-severe injury. Echocardiography measured at baseline and at 3 months post-injury showed increased LVESD at 3 months and significantly decreased posterior wall diameter. Finally, 32 years of Western Australian hospital records were used to investigate the incidence of cardiovascular disease admissions after burn injury. People who had experienced a burn had increased hospital admissions and length of stay for cardiovascular diseases when compared to a matched uninjured cohort. This study presents animal, patient and population data that strongly suggest non-severe burn injury has significant effects on cardiovascular function and long-term morbidity in some burn patients. Identification of patients at risk will promote better intervention and outcomes for burn patients.

Dopamine induces lipid accumulation, NADPH oxidase-related oxidative stress, and a proinflammatory status of the plasma membrane in H9c2 cells

Excess catecholamine levels are suggested to be cardiotoxic and to underlie stress-induced heart failure. The cardiotoxic effects of norepinephrine and epinephrine are well recognized. However, although cardiac and circulating dopamine levels are also increased in stress cardiomyopathy patients, knowledge regarding putative toxic effects of excess dopamine levels on cardiomyocytes is scarce. We now studied the effects of elevated dopamine levels in H9c2 cardiomyoblasts. H9c2 cells were cultured and treated with dopamine (200 μM) for 6, 24, and 48 h. Subsequently, the effects on lipid accumulation, cell viability, flippase activity, reactive oxygen species (ROS) production, subcellular NADPH oxidase (NOX) protein expression, and ATP/ADP and GTP/GDP levels were analyzed. Dopamine did not result in cytotoxic effects after 6 h. However, after 24 and 48 h dopamine treatment induced a significant increase in lipid accumulation, nitrotyrosine levels, indicative of ROS production, and cell death. In addition, dopamine significantly reduced flippase activity and ATP/GTP levels, coinciding with phosphatidylserine exposure on the outer plasma membrane. Furthermore, dopamine induced a transient increase in cytoplasmic and (peri)nucleus NOX1 and NOX4 expression after 24 h that subsided after 48 h. Moreover, while dopamine induced a similar transient increase in cytoplasmic NOX2 and p47^phox expression, in the (peri)nucleus this increased expression persisted for 48 h where it colocalized with ROS. Exposure of H9c2 cells to elevated dopamine levels induced lipid accumulation, oxidative stress, and a proinflammatory status of the plasma membrane. This can, in part, explain the inflammatory response in patients with stress-induced heart failure.

Time-Dependent and Organ-Specific Changes in Mitochondrial Function, Mitochondrial DNA Integrity, Oxidative Stress and Mononuclear Cell Infiltration in a Mouse Model of Burn Injury

Severe thermal injury induces a pathophysiological response that affects most of the organs within the body; liver, heart, lung, skeletal muscle among others, with inflammation and hyper-metabolism as a hallmark of the post-burn damage. Oxidative stress has been implicated as a key component in development of inflammatory and metabolic responses induced by burn. The goal of the current study was to evaluate several critical mitochondrial functions in a mouse model of severe burn injury. Mitochondrial bioenergetics, measured by Extracellular Flux Analyzer, showed a time dependent, post-burn decrease in basal respiration and ATP-turnover but enhanced maximal respiratory capacity in mitochondria isolated from the liver and lung of animals subjected to burn injury. Moreover, we detected a tissue-specific degree of DNA damage, particularly of the mitochondrial DNA, with the most profound effect detected in lungs and hearts of mice subjected to burn injury. Increased mitochondrial biogenesis in lung tissue in response to burn injury was also observed. Burn injury also induced time dependent increases in oxidative stress (measured by amount of malondialdehyde) and neutrophil infiltration (measured by myeloperoxidase activity), particularly in lung and heart. Tissue mononuclear cell infiltration was also confirmed by immunohistochemistry. The amount of poly(ADP-ribose) polymers decreased in the liver, but increased in the heart in later time points after burn. All of these biochemical changes were also associated with histological alterations in all three organs studied. Finally, we detected a significant increase in mitochondrial DNA fragments circulating in the blood immediately post-burn. There was no evidence of systemic bacteremia, or the presence of bacterial DNA fragments at any time after burn injury. The majority of the measured parameters demonstrated a sustained elevation even at 20–40 days post injury suggesting a long-lasting effect of thermal injury on organ function. The current data show that there are marked time-dependent and tissue-specific alterations in mitochondrial function induced by thermal injury, and suggest that mitochondria-specific damage is one of the earliest responses to burn injury. Mitochondria may be potential therapeutic targets in the future experimental therapy of burns.

Nutrition and anabolic pharmacotherapies in the care of burn patients

Thermal injury is a devastating injury that results in a number of pathological alterations in almost every system in the body. Hypermetabolism, muscle wasting, depressed immunity, and impaired wound healing are all clinical features of burns. Failure to address each of these specific pathological alterations can lead to increased mortality. Nutrition supplementation has been recommended as a therapeutic tool to help attenuate the hypermetabolism and devastating catabolism evident following burn. Despite the wide consensus on the need of nutrition supplementation in burn patients, controversy exists with regard to the type and amount of nutrition recommended. Nutrition alone is also not enough in these patients to halt and reverse some of the damage done by the catabolic pathways activated following severe burn injury. This has led to the use of anabolic pharmacologic agents in conjunction with nutrition to help improve patient outcome following burn injury. In this review, we examine the relevant literature on nutrition after burn injury and its contribution to the attenuation of the postburn hypermetabolic response, impaired wound healing, and suppressed immunological responses. We also review the commonly used anabolic agents clinically in the care of burn patients. Finally, we provide nutrition and pharmacological recommendations gained from prospective trials, retrospective analyses, and expert opinions based on our practice at the Ross Tilley Burn Center in Toronto, Canada.

Sunburn, Thermal, and Chemical Injuries to the Skin

Sunburn, thermal, and chemical injuries to the skin are common in the United States and worldwide. Initial management is determined by type and extent of injury with special care to early management of airway, breathing, and circulation. Fluid management has typically been guided by the Parkland formula, whereas some experts now question this. Each type of skin injury has its own pathophysiology and resultant complications. All primary care physicians should have at least a basic knowledge of management of acute and chronic skin injuries.

The evaluation and management of thermal injuries: 2014 update

Burns are among the most common injuries presenting to the emergency department. While burns, especially large ones, may be associated with significant morbidity and mortality, most are minor and can be managed by emergency practitioners and discharged home with close follow-up. In contrast, patients with large burns require aggressive management of their airway, breathing and circulation in order to reduce mortality and morbidity. While early endotracheal intubation of patients with actual or impending airway compromise and aggressive fluid resuscitation have been emphasized, it appears that the pendulum may have swung a bit too far towards the extreme. The current review will briefly cover the epidemiology, pathogenesis and diagnosis of burn injuries with greater emphasis on airway and fluid management. We will also discuss the local management of the burn wound, which is all that is required for most burn patients in the emergency department.

Animal models in burn research

Burn injury is a severe form of trauma affecting more than 2 million people in North America each year. Burn trauma is not a single pathophysiological event but a devastating injury that causes structural and functional deficits in numerous organ systems. Due to its complexity and the involvement of multiple organs, in vitro experiments cannot capture this complexity nor address the pathophysiology. In the past two decades, a number of burn animal models have been developed to replicate the various aspects of burn injury, to elucidate the pathophysiology, and to explore potential treatment interventions. Understanding the advantages and limitations of these animal models is essential for the design and development of treatments that are clinically relevant to humans. This review aims to highlight the common animal models of burn injury in order to provide investigators with a better understanding of the benefits and limitations of these models for translational applications. While many animal models of burn exist, we limit our discussion to the skin healing of mouse, rat, and pig. Additionally, we briefly explain hypermetabolic characteristics of burn injury and the animal model utilized to study this phenomena. Finally, we discuss the economic costs associated with each of these models in order to guide decisions of choosing the appropriate animal model for burn research.

Aquacel(®) Ag dressing versus Acticoat™ dressing in partial thickness burns: a prospective, randomized, controlled study in 100 patients. Part 1: burn wound healing

INTRODUCTION

Studies comparing contemporary silver dressings in burns are scarce.

METHODS

In a prospective, randomized, controlled study, counting 50 patients/research group, we compared two frequently used silver dressings, Acticoat™ and Aquacel(®) Ag, in the management of partial thickness burns with a predicted healing time between 7 and 21 days as assessed by laser Doppler imaging between 48 and 72h after burn. Variables investigated were related to baseline research group characteristics, wound healing, bacteriology, economics, nurse, and patient experience.

RESULTS

Both research groups were comparably composed taking into account gender, age and burn characteristics. Similar results were obtained as to healing time and bacterial control with both silver dressings. A statistically significant difference in favor of the Aquacel(®) Ag dressing was found for average ease of use (p<0.001), average ease of application (p=0.001), patient pain (p<0.001), patient comfort with the dressing (p=0.017), silver staining (p<0.001), and cost effectiveness (p<0.001).

CONCLUSION

Both silver dressings resulted in comparable healing times and bacterial control but the Aquacel(®) Ag dressing significantly increased comfort for patients as well as nurses and was significantly more cost-effective than the Acticoat™ dressing for the given indication.

Spatial frequency domain imaging of burn wounds in a preclinical model of graded burn severity

Frequent monitoring of early-stage burns is necessary for deciding optimal treatment and management. Both superficial and full thickness burns are relatively easy to diagnose based on clinical observation. In between these two extremes are superficial-partial thickness and deep-partial thickness burns. These burns, while visually similar, differ dramatically in terms of clinical treatment and are known to progress in severity over time. The objective of this study was to determine the potential of spatial frequency domain imaging (SFDI) for noninvasively mapping quantitative changes in chromophore and optical properties that may be an indicative of burn wound severity. A controlled protocol of graded burn severity was developed and applied to 17 rats. SFDI data was acquired at multiple near-infrared wavelengths over a course of 3 h. Burn severity was verified using hematoxylin and eosin histology. From this study, we found that changes in water concentration (edema), deoxygenated hemoglobin concentration, and optical scattering (tissue denaturation) to be statistically significant at differentiating superficial partial-thickness burns from deep-partial thickness burns.

Pathophysiology of white-nose syndrome in bats: a mechanistic model linking wing damage to mortality

White-nose syndrome is devastating North American bat populations but we lack basic information on disease mechanisms. Altered blood physiology owing to epidermal invasion by the fungal pathogen Geomyces destructans (Gd) has been hypothesized as a cause of disrupted torpor patterns of affected hibernating bats, leading to mortality. Here, we present data on blood electrolyte concentration, haematology and acid-base balance of hibernating little brown bats, Myotis lucifugus, following experimental inoculation with Gd. Compared with controls, infected bats showed electrolyte depletion (i.e. lower plasma sodium), changes in haematology (i.e. increased haematocrit and decreased glucose) and disrupted acid-base balance (i.e. lower CO2 partial pressure and bicarbonate). These findings indicate hypotonic dehydration, hypovolaemia and metabolic acidosis. We propose a mechanistic model linking tissue damage to altered homeostasis and morbidity/mortality.

The impact of severe burns on skeletal muscle mitochondrial function

Severe burns induce a pathophysiological response that affects almost every physiological system within the body. Inflammation, hypermetabolism, muscle wasting, and insulin resistance are all hallmarks of the pathophysiological response to severe burns, with perturbations in metabolism known to persist for several years post injury. Skeletal muscle is the principal depot of lean tissue within the body and as the primary site of peripheral glucose disposal, plays an important role in metabolic regulation. Following a large burn, skeletal muscle functions as and endogenous amino acid store, providing substrates for more pressing functions, such as the synthesis of acute phase proteins and the deposition of new skin. Subsequently, burn patients become cachectic, which is associated with poor outcomes in terms of metabolic health and functional capacity. While a loss of skeletal muscle contractile proteins per se will no doubt negatively impact functional capacity, detriments in skeletal muscle quality, i.e. a loss in mitochondrial number and/or function may be quantitatively just as important. The goal of this review article is to summarise the current understanding of the impact of thermal trauma on skeletal muscle mitochondrial content and function, to offer direction for future research concerning skeletal muscle mitochondrial function in patients with severe burns, and to renew interest in the role of these organelles in metabolic dysfunction following severe burns.

Severe burn injury, burn shock, and smoke inhalation injury in small animals. Part 1: burn classification and pathophysiology

OBJECTIVE

To review the literature related to severe burn injury (SBI), burn shock, and smoke inhalation injury in domestic animals. Current animal- and human-based research and literature were evaluated to provide an overview of thermal burn classification and the pathophysiology of burn shock and smoke inhalation injury.

ETIOLOGY

Severe burn injury, burn shock, and smoke inhalation injury may be encountered as a result of thermal injury, radiation injury, chemical injury, or electrical injury.

DIAGNOSIS

Burns can be subdivided based on the amount of total body surface area (TBSA) involved and the depth of the burn. Local burn injuries involve <20% of the TBSA whereas SBI involves >20-30% of the TBSA. The modern burn classification system classifies burns by increasing depth: superficial, superficial partial-thickness, deep partial-thickness, and full-thickness.

SUMMARY

Local burn injury rarely leads to systemic illness whereas SBI leads to significant metabolic derangements that require immediate and intensive management. SBI results in a unique derangement of cardiovascular dysfunction known as "burn shock." The physiologic changes that occur with SBI can be divided into 2 distinct phases; the resuscitation phase and the hyperdynamic hypermetabolic phase. The resuscitation phase occurs immediately following SBI and lasts for approximately 24-72 hours. This period of hemodynamic instability is characterized by the release of inflammatory mediators, increased vascular permeability, reduced cardiac output, and edema formation. The hyperdynamic hypermetabolic phase begins approximately 3-5 days after injury. This phase is characterized by hyperdynamic circulation and an increased metabolic rate that can persist up to 24 months post burn injury in people.