Single-nuclei RNA Profiling Reveals Disruption of Adipokine and Inflammatory Signaling in Adipose Tissue of Burn Patients

OBJECTIVE

We conducted a large-scale investigation of the systemic and adipose tissue-specific alterations in a clinical population of burn patients to identify factors that may influence hypermetabolism.

BACKGROUND

Previous research has identified chronic disturbances in adipose tissue inflammation, lipolysis, and browning, which may drive the perpetuation of hypermetabolism following the severe adrenergic stress of a burn injury. Given that adipose tissue is thought to be a central node in the regulation of systemic metabolism, we believe that systematically delineating the pathologic role of adipose tissue postburn, will lead to the identification of novel interventions to mitigate morbidity and mortality from severe burns.

METHODS

This was a single-institution cohort study, which obtained plasma and subcutaneous adipose tissue samples from severely burn adult patients over various time points during acute hospitalization. Whole-body clinical, metabolic, and inflammatory mediators were assessed in plasma, while genetic analyses through RT-qPCR and single-nuclei RNA sequencing were conducted in adipose tissue.

RESULTS

Systemic inflammation and adrenergic stress increase IL-6 signaling, lipolysis, browning, and adipokine dysfunction in the adipose tissue of adult burn patients, which may further propagate the long-term hypermetabolic response. Moreover, using single-nuclei RNA sequencing, we provide the first comprehensive characterization of alterations in the adipose tissue microenvironment occurring at acute and chronic stages postburn.

CONCLUSION

We provide novel insight toward the effect of burns on adipokine release, inflammatory signaling pathways, and adipose heterogeneity over the trajectory of acute and chronic stages.

Propranolol Normalizes Metabolomic Signatures Thereby Improving Outcomes After Burn

OBJECTIVE AND BACKGROUND

Propranolol, a nonselective beta-receptor blocker, improves outcomes of severely burned patients. While the clinical and physiological benefits of beta-blockade are well characterized, the underlying metabolic mechanisms are less well defined. We hypothesized that propranolol improves outcomes after burn injury by profoundly modulating metabolic pathways.

METHODS

In this phase II randomized controlled trial, patients with burns ≥20% of total body surface area were randomly assigned to control or propranolol (dose given to decrease heart rate <100 bpm). Outcomes included clinical markers, inflammatory and lipidomic profiles, untargeted metabolomics, and molecular pathways.

RESULTS

Fifty-two severely burned patients were enrolled in this trial (propranolol, n=23 and controls, n=29). There were no significant differences in demographics or injury severity between groups. Metabolomic pathway analyses of the adipose tissue showed that propranolol substantially alters several essential metabolic pathways involved in energy and nucleotide metabolism, as well as catecholamine degradation ( P <0.05). Lipidomic analysis revealed that propranolol-treated patients had lower levels of proinflammatory palmitic acid ( P <0.05) and saturated fatty acids ( P <0.05) with an increased ratio of polyunsaturated fatty acids ( P <0.05), thus shifting the lipidomic profile towards an anti-inflammatory phenotype after burn ( P <0.05). These metabolic effects were mediated by decreased activation of hormone-sensitive lipase at serine 660 ( P <0.05) and significantly reduced endoplasmic reticulum stress by decreasing phospho-JNK ( P <0.05).

CONCLUSION

Propranolol's ability to mitigate pathophysiological changes to essential metabolic pathways results in significantly improved stress responses.

Lactate shuttling drives the browning of white adipose tissue after burn

High levels of plasma lactate are associated with increased mortality in critically injured patients, including those with severe burns. Although lactate has long been considered a waste product of glycolysis, it was recently revealed that it acts as a potent inducer of white adipose tissue (WAT) browning, a response implicated in mediating postburn cachexia, hepatic steatosis, and sustained hypermetabolism. Despite the clinical presentation of hyperlactatemia and browning in burns, whether these two pathological responses are linked is currently unknown. Here, we report that elevated lactate plays a causal signaling role in mediating adverse outcomes after burn trauma by directly promoting WAT browning. Using WAT obtained from human burn patients and mouse models of thermal injury, we show that the induction of postburn browning is positively correlated with a shift toward lactate import and metabolism. Furthermore, daily administration of l-lactate is sufficient to augment burn-induced mortality and weight loss in vivo. At the organ level, increased lactate transport amplified the thermogenic activation of WAT and its associated wasting, thereby driving postburn hepatic lipotoxicity and dysfunction. Mechanistically, the thermogenic effects of lactate appeared to result from increased import through MCT transporters, which in turn increased intracellular redox pressure, [NADH/NAD+], and expression of the batokine, FGF21. In fact, pharmacological inhibition of MCT-mediated lactate uptake attenuated browning and improved hepatic function in mice after injury. Collectively, our findings identify a signaling role for lactate that impacts multiple aspects of postburn hypermetabolism, necessitating further investigation of this multifaceted metabolite in trauma and critical illness.NEW & NOTEWORTHY To our knowledge, this study was the first to investigate the role of lactate signaling in mediating white adipose tissue browning after burn trauma. We show that the induction of browning in both human burn patients and mice is positively correlated with a shift toward lactate import and metabolism. Daily l-lactate administration augments burn-induced mortality, browning, and hepatic lipotoxicity in vivo, whereas pharmacologically targeting lactate transport alleviates burn-induced browning and improves liver dysfunction after injury.

CLASSIC IL-6 SIGNALING IS ASSOCIATED WITH POOR OUTCOMES IN BURN PATIENTS

ABSTRACT

Background: Interleukin (IL)-6 is a multifunctional cytokine with both a proinflammatory and anti-inflammatory role. In many studies, IL-6 increases rapidly after burn injury and is associated with poor outcomes. However, there are two aspects to IL-6; it can signal via its soluble IL-6 receptor (sIL-6R), which is referred to as trans-signaling and is regarded as the proinflammatory pathway. The role of sIL-6R postburn injury has yet to be explored in its entirety. We hypothesized that patients with a lower ratio of IL-6 to sIL-6R would have worse outcomes. Methods: Patients admitted to our burn center within 7 days of injury were included in this study. Patients were divided into two groups based on IL-6 and sIL-6R levels measured within the first 7 days postburn injury. Patients were in the high ratio group if their IL-6/sIL-6R ratio was ≥0.185. Clinical outcomes included organ biomarkers, morbidities, and hospital length of stay. Groups were compared using Student's t test, Mann-Whitney U , and Fisher's exact test as appropriate; a P value of <0.05 was considered statistically significant. Results: We studied 86 patients with a median age of 50 years (36-66 years) and a median total body surface area burn of 18% (10-31). There were 40 patients categorized with a low IL-6/sIL-6R ratio and 46 patients with a high IL-6/sIL-6R ratio. Patients in the high IL-6/sIL-6R ratio group had a significantly greater total body surface area burn ( P < 0.001) and a significantly greater proportion of patients with inhalation injury ( P = 0.001). Levels of IL-6 were significantly higher in patients with a high IL-6/sIL-6R ratio ( P < 0.0001). However, levels of sIL-6R were not significantly different among the low and high groups ( P = 0.965). Mortality was significantly greater in the high IL-6/sIL-6R ratio group (3% vs. 26%; P = 0.002). Conclusions: Interestingly, patients with a higher ratio of IL-6/sIL-6R had significantly greater mortality. Using sIL-6R as a marker for the proinflammatory immune response, we expected patients with a lower IL-6/sIL-6R ratio to have poor outcomes, typically associated with a hyperinflammatory or exaggerated immune response. However, the absolute value of sIL-6R did not differ. This suggests that classical signaling of IL-6 via its membrane-bound receptor, with an anti-inflammatory function, is important.

Outbreak of Carbapenemase-Producing Enterobacteriaceae in a Regional Burn Center

Antimicrobial resistance is an increasing problem in hospitals worldwide; however, the prevalence of carbapenemase-producing Enterobacteriaceae (CPE) in our region is low. Burn patients are vulnerable to infection because of the loss of the protective skin barrier, thus burn centers prioritize infection prevention and control (IP&C). This report describes a CPE outbreak in a regional burn center. In a period of 2.5 months, four nosocomial cases of CPE were identified, three containing the Klebsiella pneumoniae carbapenemase (KPC) gene and one Verona integrin-encoded metallo-β-lactamase (VIM) gene. The first two cases were identified while there was no CPE patient source on the unit. CPE KPC gene was then isolated in sink drains of three rooms. In addition to rigorous IP&C practices already in place, we implemented additional outbreak measures including restricting admissions to patients with complex burns or burns ≥10% TBSA, admitting patients to other in-patient units, and not permitting elective admissions. We began cohorting patients using nursing team separation for CPE-positive and -negative patients and geographical separation on the unit. Despite aggressive IP&C measures already in place, hospital-acquired CPE colonization/infection occurred. Given that CPE contaminated sinks of the same enzyme were identified, we believe hospital sink drains may the source. This highlights the importance of sink design and engineering solutions to prevent the formation of biofilm and reduce splashing. CPE infections are associated with poor outcomes in patients and significant health system costs due to a longer length of stay and additional institutional resources.

Time to surgical closure of complex infectious wounds: a single-center retrospective cohort study

INTRODUCTION

Surgical management of NSTIs can result in complex wounds, and closure of these wounds is often difficult or complicated. Although surgical factors influencing mortality and LOS have been well described, little is known about patient, wound, and surgical factors associated with time to closure.

OBJECTIVE

The purpose of this study is to identify patient, wound, and surgical factors that may influence time to closure of NSTIs.

MATERIALS AND METHODS

The records of patients who presented to a tertiary care center over an 11-year period (2007-2017) with an NSTI requiring surgical closure were retrospectively reviewed.

RESULTS

Forty-seven patients met the inclusion criteria. The average time to closure was 31.1 days, with an average of 4.8 procedures. Most patients were middle aged (mean, 50.3 years; range, 20-81 years), immunocompetent, and nondiabetic upon admission. Closure was achieved mainly with autograft. The percent TBSA was described in 19 cases (40%). There was no association between substance use (alcohol, smoking, or other), anticoagulant medication use, or medical comorbidities and time to closure. On multivariable analysis, flap closure (P =.02) and increased number of surgical procedures (P =.003)-the latter reflecting the need for an increased number of debridements-were associated with increased time to closure.

CONCLUSIONS

The data in this study suggest that use of local flaps for wound closure and increased number of surgical procedures (particularly debridements) may be predictors of time to closure in patients with an NSTI.

EVALUATING SEPSIS CRITERIA IN DETECTING ALTERATIONS IN CLINICAL, METABOLIC, AND INFLAMMATORY PARAMETERS IN BURN PATIENTS

ABSTRACT

Sepsis has become the leading cause of death in burn patients. Furthermore, sepsis and septic complications result in significant morbidities and longer hospitalization, which has profound impacts on the healthcare system. Despite this, sepsis in burn patients is surprisingly poorly understood and characterized. This retrospective, single-institution cohort study aimed to increase our understanding of the septic response after burns. We hypothesized that different sepsis definitions will results in distinctive septic trajectories and biochemical patterns after injury. Sepsis was defined by our burn center-specific prospective definition, the American Burn Association criteria, Sepsis-3 criteria, and the Mann-Salinas criteria. Applying these definitions, we compared clinical, metabolic, and inflammatory markers in septic and nonseptic burn patients. We found that the Sepsis-3 criteria are the most reliable screening tool used before clinical diagnoses for detecting sepsis trajectories and biochemical patterns. Moreover, we characterized distinct temporal alterations in biomarkers during the pre- and post-septic periods in burn patients, which may be incorporated into future sepsis definitions to improve the accuracy of a sepsis diagnosis in burn patients.

563 Fire safety in homeless encampments

Introduction

It is well known that people experiencing homelessness are at a greater risk for burn injury. Our burn centre saw an increase in admissions of homeless individuals during the pandemic. Typically, we partner with our hospital’s communications staff to share burn prevention public service announcements. But our usual method of broadcasting information through media like newspapers, blog posts, Facebook, or Instagram was not necessarily going to reach people sleeping rough. This report describes the development of a partnership between a burn centre, outreach workers, and people with lived experience of homelessness to improve fire safety in encampments.

Methods

Our goal was to create a Fire Safety Manual and hold Fire Safety Training Sessions. We conducted surveys that asked encampment residents questions like, “What do you use fires for?” “What fire hazards do you see at encampments?” and “How do you think fires could best be prevented?”. We used the results of this survey to guide the training manual and held workshops to engage encampment residents and incorporate feedback into the manual.

Results

The manual uses harm reductions strategies and focuses on real-life situations encountered by folks living outdoors—the manual outlines how to safely start a fire and what to do if a fire occurs. The reality is that people are trying to survive freezing winters while sleeping outside; this means that some safety standards are not possible, and the guide had to reflect that. For example, we practiced fire escape plans during training sessions and had to think about obstacles like tents with only one way out. A solution was to keep a utility knife inside and outside the tent in case one had to cut through to escape or free someone. An encampment resident suggested hiding the knives so they would not be used as weapons. We purchased fire extinguishers, fire blankets, and first aid kits that we distributed during training.

Conclusions

Education is critical to prevent burn injuries. Burn centre staff may be experts on burn prevention, but we are not experts on surviving outside. We have to be accountable to this community. This means listening, building trust, and partnering with people living outdoors. People who did training sessions were empowered to start fire brigades in their encampments. Crucial concepts are to meet people where they are and always to include people with lived experience: “Nothing about us without us.”

43 Mapping the Hypermetabolic Response in Burn Patients

Introduction

Hypermetabolism, characterized by drastic increases in whole-body catabolism and resting energy expenditure (REE), is a hallmark response to a severe burn injury. This is believed to be driven in part by alterations in adipose tissue metabolism. We proposed to define the hypermetabolic response in adipose tissue from burn patients and create a roadmap of markers indicative of hypermetabolism to improve prognosis. We hypothesized that catabolic markers, such as uncoupling protein-1 (Ucp1) and growth differentiation factor-15 (Gdf15), would positively correlate with increasing days post-burn and REE.

Methods

Adult burn patients (n=65) admitted to our burn center between 2011—2019 were included in this study. Subcutaneous white adipose tissues (sWAT) from the site of injury (n=85) and plasma were collected from severely burned patients ( ³20% total body surface area). Gene expression and circulating cytokine levels were measured by RT-qPCR and multiplex assays, respectively.

Results

We found a significant correlation between increasing Ucp1 gene expression and days post-burn (p< 0.0001). Moreover, when samples were stratified into acute (1-3 days post-burn), moderate (4-9 days post-burn), and long-term ( >10 days post-burn) timepoints, a significant increase in Ucp1 gene expression was detected only in adipose tissues from long-term time points in comparison to non-burned control tissues (p< 0.01). However, we found that REE remained stagnant throughout hospital stay after a burn injury in our patient cohort. Thus, we did not detect a significant correlation between Ucp1 gene expression and REE. Further, while Gdf15 expression was most pronounced, albeit statistically insignificant, during the moderate timepoints, we did not detect any significant differences when correlated with days post-burn. Additionally, we determined that circulating levels of IL-6, IL-10, and monocyte chemoattractant protein-1 (MCP-1) were greatly elevated within the first seven days post-burn and gradually decreased over time, while vascular endothelial growth factor (VEGF) concentrations followed a similar pattern to Ucp1 gene expression.

Conclusions

While Gdf15 expression may not accurately reflect catabolism in the adipose tissues of burn patients, Ucp1 gene expression may be used as a marker indicating a peak hypermetabolic period after ten days post-burn. This may also be reflected by circulating concentrations of VEGF. Moreover, IL-6, IL-10 and MCP-1 may be used as early determinants before the onset of hypermetabolism.

700 Use of Antibiograms and Changes in Bacterial Resistance Patterns

Introduction

Infection is a leading cause of death in burn patients. With an increase in resistance patterns, management of these infections has become progressively difficult. Antibiograms, a summary of susceptibilities to bacteria in a given institution or area, are often used to guide empiric treatment of infections. However, inappropriate prescribing and use of empiric antimicrobials may greatly impact the incidence of resistance. Currently, we do not know the patterns of antibiotic use since the introduction of institutional antibiograms or associated changes in antibiotic resistance. The objective of this study is to describe trends in antibiotic susceptibilities in burn patients in Canada pre- (PrA) and post-introduction (PoA) of antibiograms.

Methods

We performed a retrospective review of patients admitted to an ABA-verified Burn Centre 2 years pre- (2013-2014) and post-introduction (2016-2017) of institutional antibiograms and started on broad-spectrum antibiotics (meropenem, piperacillin-tazobactam, and/or vancomycin).

Results

A total of 864 patients were admitted during the study period (n=420 PrA and n=444 PoA). Average age, % total body surface area (%TBSA), and length of stay were similar between cohorts. Administration of empiric meropenem increased (43.2% vs. 56.8%) and piperacillin-tazobactam decreased (60.6% vs. 39.4%), which was significant (p=0.002). The use of vancomycin was unchanged. There was a significant decrease in the overall use of empiric antibiotics (p=0.002) since the inception of antibiograms, with a significant improvement in culture and sensitivity (C&S) testing within 5 days of starting empiric antibiotics (p=0.002). There was no significant difference in use of targeted antibiotics pre- or post-antibiogram introduction.

Conclusions

Our study demonstrates that since the inception of antibiograms, there has been a significant decrease in overall use of empiric antibiotics and improvement in acquiring C&S within 5 days. However, these antibiotics were not always targeted to the appropriate organism and therefore may contribute to multi-drug resistant organisms in a burn population.

Identifying risk factors that increase analgesic requirements at discharge among patients with burn injuries

Patients with burn injuries require large doses of opioids and gabapentinoids to achieve pain control and are often discharged from hospital with similar amounts. This study aimed to identify patient risk factors that increase analgesic requirements among patients with burn injuries and to determine the relationship between opioid and gabapentinoid use. Patient charts from July 1, 2015 - 2018 were reviewed retrospectively to determine analgesic requirements 24 hours before discharge. Linear mixed regression models were performed to determine patient risk factors (age, gender, history of substance misuse, total body surface area of burn, length of stay in hospital, history of psychiatric illness, or surgical treatment) that may increase analgesic requirements. This study found that patients with a history of substance misuse (p = 0.01) or who were managed surgically (p = 0.01) required higher doses of opioids at discharge. Similarly, patients who had undergone surgical debridement required more gabapentinoids (p < 0.001). For every percent increase in TBSA, patients also required 14 mg more gabapentinoids (p = 0.01). In contrast, older patients (p = 0.006) and those with a longer hospital stay (p = 0.009) required fewer amounts of gabapentinoids before discharge. By characterizing factors that increase analgesic requirements at discharge, burn care providers may have a stronger understanding of which patients are at greater risk of developing chronic opioid or gabapentinoid misuse. The quantity and duration of analgesics prescribed at discharge may then be tailored according to these patient specific risk factors.

Admission creatinine is associated with poor outcomes in burn patients

INTRODUCTION

Renal failure is the most common organ failure in severely burned patients. However, defining acute kidney injury and renal failure is very challenging. This study was designed to determine the relationship between a biomarker commonly measured on admission, serum creatinine, and outcomes in burn patients.

METHODS

We conducted a retrospective cohort study of adult patients (≥ 18 years) with a burn ≥ 5% total body surface area (TBSA) and a serum creatinine level measured within the first 72 h after injury. Patients were admitted over an 11-year period and divided into two groups based on creatinine levels measured within the first 72 h after injury. Patients were categorized in the high creatinine group if they had a measured creatinine ≥107 μmol/L (≥1.21 mg/dL); this value was chosen as the threshold for creatinine based on our institution's reference range. Clinical outcomes included morbidities, hospital length of stay, and mortality. Multivariable logistic regression was used to model the association between high admission creatinine and each outcome, adjusting for patient and injury characteristics.

RESULTS

We studied 923 patients, mean age 47 ± 18 years and median 13% (IQR 8-24) TBSA burned. There were 718 patients categorized with low admission creatinine and 205 patients with high admission creatinine. After adjustment for patient and injury characteristics, high admission creatinine was associated with a significantly higher rate of sepsis (OR 3.44; 95% CI 2.11-5.59), pneumonia (OR 4.56; 95% CI 1.8-11.53), and mortality (OR 3.59; 95% CI 1.91-6.75).

CONCLUSIONS

Elevated creatinine on admission is associated with an increased risk of morbidity and mortality. We suggest that admission creatinine can be used as a "red flag" to identify patients at a higher risk for poor outcomes.

Comparison of clinical outcomes of lower extremity burns in diabetic and non-diabetic patients: a retrospective analysis

Diabetes mellitus is an increasingly prevalent chronic disease that leads to long-term health consequences. Some long-term clinical sequelae of diabetes include coronary artery disease, peripheral vascular disease, peripheral neuropathy, and impaired wound healing. These can increase hospital stay and complications such as wound infections and amputations among patients with lower extremity burns. A retrospective analysis was performed of all isolated lower extremity burns from a single tertiary burn care centre from 2006-2017. Patients were stratified by diabetic status and the incidence of lower extremity amputations was the primary outcome. Multivariable regression was used to model the association between diabetes and amputations, adjusting for patient and injury characteristics. A total of 198 patients were identified as meeting inclusion criteria, 160 were non-diabetic and 38 were diabetic. Age was significantly different between non-diabetic and diabetic patients; mean age was 46 ± 18 years versus 62 ± 17 years (p<0.0001). Length of stay was also significantly different, median length of stay was 11 (IQR 7-15) versus 18 (IQR 12-24) (p<0.001), with diabetic patients staying longer. There was a significantly greater proportion of diabetic patients that had an amputation (control 4% versus diabetic 29%; p<0.0001). After adjustment for patient and injury characteristics, there was a significant association between diabetes and amputation (p=0.002). Among patients with isolated lower extremity burns, those with a pre-existing condition of diabetes had a longer hospitalization and increased amputations, despite similar size of burn. Diabetes is an important risk factor to acknowledge in patients with these injuries to optimize care.

Sepsis Definitions in Burns

Background: Sepsis is the leading cause of death in burns. Despite its importance, sepsis lacks a proper definition. An established definition will lead to early and accurate diagnosis, prompt treatment, and a reduced mortality rate. The aim of this work is to discuss current definitions and to look ahead at novel definitions with clinical implications. Method: A review of the current understanding of sepsis definitions in burns. Results: Adaptation of sepsis definitions in the general population and specific burn definitions have gotten better but still need improvements and, potentially, incorporation of molecular, laboratory, patient-specific, and clinical factors. This work includes the history, evolution, and predictive value of current definitions of sepsis in burns. A review of current and future markers of sepsis and potentially useful definitions are presented. Conclusions: Sepsis definitions have evolved over the last decades and will continue to do so. We believe the best definition in burn patients is the Sepsis-3 that was developed originally for critically ill patients. However, there are several studies investigating more specific definitions with better sensitivity and specificity.

Prescribing patterns of opioids and adjunctive analgesics for patients with burn injuries

PURPOSE

Large quantities of analgesics are prescribed to control pain among patients with burn injuries and may lead to chronic use and dependency. This study aimed to determine whether patients are overprescribed analgesics at discharge and to identify factors that influence prescribing patterns.

MATERIAL AND METHODS

A retrospective review of patient charts (n = 199) between July 1, 2015-2018 were reviewed from a registry at a single burn center. Opioid, neuropathic pain agent, acetaminophen, and ibuprofen quantities given before and at discharge were compared. Linear mixed regression models were used to identify factors that increased the amount of analgesics prescribed.

RESULTS

On average, patients were prescribed significantly more analgesics at discharge compared to what was consumed pre-discharge (p < 0.0001). Specifically, on average, providers did not overprescribe the daily dose, but overprescribed the duration of pain medications required. For every increase in percent TBSA, 14 MEQ more opioids, 203 mg more neuropathic pain agents, 843 mg more acetaminophen, and 126 mg more ibuprofen were prescribed (p < 0.05). Surgery was a predictor for higher opioid and neuropathic pain agent prescriptions (p = 0.03), while length of stay was associated with fewer neuropathic pain agents prescribed (p = 0.04). Fewer ibuprofen were given to patients with a history of substance misuse (p = 0.01).

CONCLUSIONS

The quantity of analgesics prescribed at discharge varied widely and often prescribed for long durations of time. Standardized prescribing guidelines should be developed to optimize how analgesics are prescribed at discharge.

Allogeneic mesenchymal stem cells for treatment of severe burn injury

The most important determinant of survival post-burn injury is wound healing. For decades, allogeneic mesenchymal stem cells (MSCs) have been suggested as a potential treatment for severe burn injuries. This report describes a patient with a severe burn injury whose wounds did not heal with over 18 months of conventional burn care. When treated with allogeneic MSCs, wound healing accelerated with no adverse treatment complications. Wound sites showed no evidence of keloids or hypertrophic formation during a 6-year follow-up period. This therapeutic use of allogeneic MSCs for large non-healing burn wounds was deemed safe and effective and has great treatment potential.

The Impact of Introducing a Physical Medicine and Rehabilitation Consultation Service to an Academic Burn Center

Prior retrospective studies suggest that physical medicine and rehabilitation (PM&R) acute care consultation improves outcome and reduces acute care length of stay (ACLOS) in trauma patients. There have not been prospective studies to evaluate this impact in burn patients. This cohort study compared outcomes before and after the introduction of a PM&R consultation service to the acute burn program, and the inpatient rehabilitation program, at a large academic hospital. The primary outcome measures were length of stay (LOS) in acute care and during subsequent inpatient rehabilitation. For the acute care phase, there were 194 patients in the preconsultation group and 114 who received a consultation. There was no difference in age, Baux score, or LOS in these patients. For the rehabilitation phase, there were 109 patients in the prephysiatrist group and 104 who received PM&R care. The LOS was significantly shorter in the latter group (24 days vs 30 days, P = .002). Functional independence measure (FIM) change, unexpected readmission, and discharge destination were not significantly different. The addition of a burn physiatrist did not influence ACLOS. However, there was a significant reduction in inpatient rehabilitation LOS.

Acute and long-term clinical, neuropsychological and return-to-work sequelae following electrical injury: a retrospective cohort study

OBJECTIVE

To determine acute and long-term clinical, neuropsychological, and return-to-work (RTW) effects of electrical injuries (EIs). This study aims to further contrast sequelae between low-voltage and high-voltage injuries (LVIs and HVIs). We hypothesise that all EIs will result in substantial adverse effects during both phases of management, with HVIs contributing to greater rates of sequelae.

DESIGN

Retrospective cohort study evaluating EI admissions between 1998 and 2015.

SETTING

Provincial burn centre and rehabilitation hospital specialising in EI management.

PARTICIPANTS

All EI admissions were reviewed for acute clinical outcomes (n=207). For long-term outcomes, rehabilitation patients, who were referred from the burn centre (n=63) or other burn units across the province (n=65), were screened for inclusion. Six patients were excluded due to pre-existing psychiatric conditions. This cohort (n=122) was assessed for long-term outcomes. Median time to first and last follow-up were 201 (68-766) and 980 (391-1409) days, respectively.

OUTCOME MEASURES

Acute and long-term clinical, neuropsychological and RTW sequelae.

RESULTS

Acute clinical complications included infections (14%) and amputations (13%). HVIs resulted in greater rates of these complications, including compartment syndrome (16% vs 4%, p=0.007) and rhabdomyolysis (12% vs 0%, p<0.001). Rates of acute neuropsychological sequelae were similar between voltage groups. Long-term outcomes were dominated by insomnia (68%), anxiety (62%), post-traumatic stress disorder (33%) and major depressive disorder (25%). Sleep difficulties (67%) were common following HVIs, while the LVI group most frequently experienced sleep difficulties (70%) and anxiety (70%). Ninety work-related EIs were available for RTW analysis. Sixty-one per cent returned to their preinjury employment and 19% were unable to return to any form of work. RTW rates were similar when compared between voltage groups.

CONCLUSIONS

This is the first investigation to determine acute and long-term patient outcomes post-EI as a continuum. Findings highlight substantial rates of neuropsychological and social sequelae, regardless of voltage. Specialised and individualised early interventions, including screening for mental health concerns, are imperative to improvingoutcomes of EI patients.

The effect of diabetes on burn patients: a retrospective cohort study

BACKGROUND

Hyperglycemia during the acute phase after burn is associated with increased morbidity and mortality. There is little knowledge regarding the effect of pre-existing hyperglycemia in the form of diabetes on the outcomes after severe burns. The objective is to determine the impact of diabetes on clinical outcomes after burns.

METHODS

Single-center cohort study where adult diabetic (n = 76) and non-diabetic (n = 1186) burn patients admitted between 2006 and 2016 were included. Diabetic patients were stratified into those with well-controlled diabetes (n = 24) and poorly controlled diabetes (n = 33) using a HbA1c of 7% as a cutoff; additionally, diabetics were divided into well-controlled glycemia (n = 47) and poorly controlled glycemia (n = 22) based on daily blood glucose measurements during hospitalization.

RESULTS

On univariate analysis, diabetics had a significantly increased median length of stay per percent total body surface area burn (2.1 vs. 1.6 days; p = 0.0026) and a greater number of overall morbidity (1.39 ± 1.63 vs. 0.8 ± 1.24; p = 0.001). After adjustment for patient characteristics, diabetics were associated with significantly increased total morbidity (RR 1.5; 95% CI 1.1-1.9). At discharge, almost two thirds of diabetics needed an escalation of anti-diabetic medication and a quarter had newly developed insulin dependency. There were no differences in morbidity or mortality in the diabetic subgroups.

CONCLUSIONS

Diabetics had a longer hospitalization and increased morbidity, regardless of the quality of their anti-diabetic therapy prior to injury. Additionally, diabetes in burn patients is associated with an increased risk of total morbidity.

Burn injury and multiple sclerosis: A retrospective case-control study

OBJECTIVES

The purpose of this study was to determine whether having a previous diagnosis of multiple sclerosis (MS) changed acute care needs in burn-injured patients.

METHODS

This was a retrospective case-control study that included adult (aged ≥18years) patients with an acute burn injury. Control patients were matched with eleven patients with a history of MS at a 4:1 ratio. Outcomes included fluid resuscitation volumes, temperature, heart rate, mean arterial pressure, in-hospital complications, and hospital length of stay (LOS).

RESULTS

There were fifty-five patients included and of those, eleven had a documented history of MS. Fluid resuscitation volumes, temperature, heart rate, and mean arterial pressure were similar between groups during the resuscitation period (p>0.05). LOS was similar between both groups (12, IQR: 2-17 vs. median 16, IQR: 12-21; p=0.090). However, when normalized to % TBSA burn, patients with MS had a significantly higher median LOS/% TBSA burned (1.2, IQR: 0.7-2.0 vs. 2.1, IQR: 1.1-7.1; p=0.031).

CONCLUSIONS

Patients with concurrent burn injuries and MS have a significantly longer LOS/% TBSA burn suggesting that more time is required to heal their wounds. Surprisingly, there were no other significant differences in the after the burn acute phase between these two cohorts.

Contributors to the length-of-stay trajectory in burn-injured patients

OBJECTIVES

Burn patients have a highly variable length-of-stay (LOS) due to the complexity of the injury itself. The LOS for burn patients is estimated as one day per percent total body surface area (TBSA) burn. To focus care expectation and prognosis we aimed to identify key factors that contribute to prolonged LOS.

METHODS

This was a retrospective cohort-study (2006-2016) in an adult burn-centre that included patients with ≥10% TBSA burn. Patients were stratified into expected-LOS (<2 days LOS/%TBSA) and longer-than-expected-LOS (≥2 days LOS/%TBSA). We assessed demographics, comorbidities, and in-hospital complications. Logistic regression and propensity matching was utilized.

RESULTS

Of the 583 total patients, 477 had an expected-LOS whereas 106 a longer-than-expected-LOS. Non-modifiable factors such as age, 3rd degree TBSA%, inhalation injuries and comorbidities were greater in the exceeded LOS patients. Subsequent matched analysis revealed factors like number of procedures performed, days ventilated and in-hospital complications (bacteremia, pneumonia, sepsis, graft loss, and respiratory failure) were significantly increased in the longer-than-expected-LOS group.

CONCLUSIONS

Progress has been made to update the conventional one day/%TBSA to better aid health care providers in giving appropriate outcomes for patients and their families and to supply intensive care units with valuable data to assess quality of care and to improve patient prognosis.

Sepsis criteria versus clinical diagnosis of sepsis in burn patients: A validation of current sepsis scores

BACKGROUND

Sepsis remains an ongoing diagnostic challenge in burns, especially with the signs of sepsis being ubiquitously present during the acute period after injury. We aimed to determine the predictive validity of 3 current sepsis criteria in the burn population. The criteria of interest included the American Burn Association sepsis criteria, Mann-Salinas et al predictors of sepsis, and the Sepsis-3 consensus definition.

METHODS

Adult patients with an acute burn injury who were diagnosed prospectively with sepsis by the burn team using specific clinical markers were included in this cohort study. Sepsis predictors were collected from patient charts and used to calculate the results of the 3 criteria, then subsequently compared to the clinical diagnosis.

RESULTS

Of the 418 patients in the study, which took place from 2000 until 2016, 88 (21%) were septic; the mean age was 50 ± 18 years with a mean percent total body surface area burn of 30% ± 17%. Inhalation injury was present in 50%, median length of stay was 49 (29-71) days, and mortality was 19%. The American Burn Association, Mann-Salinas, and Sepsis-3 criteria were positive in 59%, 28%, and 85% respectively, P < .05. The most reliable predictors included increased oxygen requirements, altered mental status, hypothermia, hyperthermia, tachycardia, and hypotension.

CONCLUSION

The Sepsis-3 criteria was the most predictive, followed by the American Burn Association and Mann-Salinas criteria. However, no criterion alone had the accuracy to be a diagnostic standard within this burn population. We recommend sepsis is clinically assessed, diagnosed, and documented prospectively by the burn team, and not by the application of retrospective criteria.

The influence of substance misuse on clinical outcomes following burn

INTRODUCTION

Ongoing increases in the prevalence of substance misuse among burn-injured patients necessitate a contemporary analysis of the association between substance misuse and clinical outcomes in burn-injured adults.

METHODS

We conducted a retrospective cohort study of 1199 patients admitted to a regional burn center. History of substance misuse was derived from a prospective clinical registry and categorized as alcohol, illicit drug, or both. The primary outcome was hospital length of stay; association of substance misuse and inpatient complications were secondary outcomes. Multivariable logistic regression was used to model the association between categories of substance misuse and each outcome, adjusting for patient and injury characteristics.

RESULTS

The incidence of substance misuse was 34% overall. After adjustment for patient and injury characteristics, drug misuse was associated with a significantly longer length of stay (RR 1.12; 95% CI 1.00-1.25), as was alcohol misuse (RR 1.32; 95% CI 1.14-1.52), and drug/alcohol misuse (RR 1.34; 95% CI 1.16-1.56). Drug/alcohol misuse was associated with significantly higher rates of bacteremia (OR 3.84; 95% CI 1.83-8.04) and sepsis (OR 2.50; CI 1.13-5.53).

CONCLUSIONS

A history of substance misuse is associated with an increased risk of inpatient complications and longer hospital stay. Providers should be cognizant of increased complications in this cohort with a view to improving outcomes.

Burned Adults Develop Profound Glucose Intolerance

OBJECTIVES

Metabolic alterations after burn injury have been well described in children; however, in adult patients, glucose metabolism and insulin sensitivity are essentially unknown. We sought to characterize metabolic alterations and insulin resistance after burn injury and determine their magnitude and persistence at discharge.

DESIGN

Prospective, cohort study.

SETTING

Tertiary burn centre.

PATIENTS

Nondiabetic adults with an acute burn involving greater than or equal to 20% total body surface area.

INTERVENTIONS

An oral glucose tolerance test was administered at discharge.

MEASUREMENTS AND MAIN RESULTS

Glucose, insulin, and C-peptide levels were measured to derive surrogate measures of insulin resistance and β-cell function, including quantitative insulin sensitivity check index, homeostasis model assessment of β-cell function, homeostasis model assessment of insulin sensitivity, homeostasis model assessment of insulin resistance, and the composite whole-body insulin sensitivity index. Patients were grouped according to the degree of glucose tolerance: normal glucose tolerance, impaired fasting glucose/impaired glucose tolerance, or diabetes. Forty-five adults, 44 ± 15 years old and with 38% ± 14% total body surface area burned, underwent an oral glucose tolerance test at discharge. Median quantitative insulin sensitivity check index (0.348 [0.332-0.375]) and median homeostasis model assessment of insulin resistance (1.13 [0.69-1.45]) were abnormal, indicating insulin resistance and impaired insulin production at discharge. Two-thirds of patients (n = 28) met criteria for impaired fasting glucose/impaired glucose tolerance or diabetes.

CONCLUSIONS

We have demonstrated that burn-injured adults remain hyperglycemic, are insulin resistant, and express defects in insulin secretion at discharge. Patients with lower burn severity (total body surface area, 20-30%) express similar metabolic alterations as patients with larger burns (total body surface area, ≥ 30%). Glucose tolerance testing at discharge offers an opportunity for early identification of burn patients who may be at high risk of prediabetes and diabetes. Our findings demonstrated that two-thirds of burn patients had some degree of glucose intolerance. With this in mind, surveillance of glucose intolerance post discharge should be considered. As hyperglycemia and insulin resistance are associated with poor outcomes, studies should focus on how long these profound alterations persist.

Pathophysiologic Response to Burns in the Elderly

Over the last decades advancements have improved survival and outcomes of severely burned patients except one population, elderly. The Lethal Dose 50 (LD50) burn size in elderly has remained the same over the past three decades, and so has morbidity and mortality, despite the increased demand for elderly burn care. The objective of this study is to gain insights on why elderly burn patients have had such a poor outcome when compared to adult burn patients. The significance of this project is that to this date, burn care providers recognize the extreme poor outcome of elderly, but the reason remains unclear. In this prospective translational trial, we have determined clinical, metabolic, inflammatory, immune, and skin healing aspects. We found that elderly have a profound increased mortality, more premorbid conditions, and stay at the hospital for longer, p < 0.05. Interestingly, we could not find a higher incidence of infection or sepsis in elderly, p > 0.05, but a significant increased incidence of multi organ failure, p < 0.05. These clinical outcomes were associated with a delayed hypermetabolic response, increased hyperglycemic and hyperlipidemic responses, inversed inflammatory response, immune-compromisation and substantial delay in wound healing predominantly due to alteration in characteristics of progenitor cells, p < 0.05. In summary, elderly have substantially different responses to burns when compared to adults associated with increased morbidity and mortality. This study indicates that these responses are complex and not linear, requiring a multi-modal approach to improve the outcome of severely burned elderly.

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The outcome of elderly burn management is low with reasons that remain unclear.

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Elderly have a higher mortality, more premorbid conditions and a higher incidence of multi organ failure.

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Elderly stay at the hospital for longer time.

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The incidence of infection or sepsis is not higher than young adult.

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Elderly show delayed hyper-metabolic response, increased hyperglycemic and hyperlipidemic responses.

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Elderly present inversed inflammatory response.

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Elderly show substantial delay in wound healing, predominantly due to alteration in characteristics of progenitor cells.

Despite advancements in treatment of severely burned patients, the death rate is still high in elderly. In this project, we investigate the reason behind this poor outcome. Our report highlights some of the deficiencies that we have observed in elderly patients and compare them to the young adults. Elderly have late immune responses which are necessary to fight the disease. Their body lacks some of the essential stem cells which are essential for skin healing. By learning the major deficiencies that come with this age group, we will be able to help elderly who have been subjected to burn injury.

Management of adult patients with buttock and perineal burns: The Ross Tilley Burn Centre experience

BACKGROUND

Perineal and buttock burns are challenging wounds to heal for several reasons because of the contamination risk and shear stress that is always present. Because of the nature of the wound bed, pathogens can have ready access to create systemic infections and complications. Prolonged healing times also delay the recovery for patients and add to their discomfort and psychological stress from the injury. The ideal treatment approach is not well defined, and the aims of this study were to conduct a literature review of current treatment suggestions and to look at our own patient population to determine how our center treated these challenging patients.

METHODS

This is a retrospective review of all patients treated between 2010 and 2013 at our center. Patients that received care for burns to the perineum or buttocks were evaluated. Mortalities within 24 hours of admission and transfers before completion of their care were excluded. All patients older than 18 years were included in the study. The primary outcome studied was a cause for graft revision. Secondary outcomes included benefits and risks of fecal management devices, risk of infection, and mortality.

RESULTS

The literature review did not show consensus on how to best manage this patient population. Our results however demonstrated that patients treated with the fecal management device Flexi-seal (Convatec, Skillman, NJ) were at increased risk of developing an infection involving an enteric pathogen and requiring revision procedures. The patient population that was treated with this device was also older and had larger burns. The patients within this group that were treated initially with allograft required fewer revisions when compared with patients that received autograft in this group (23% vs. 34%, p > 0.05).

CONCLUSION

After our data and the literature had been reviewed, the lack of evidence-based treatment protocols led us to create recommendations for burn surgeons with regard to the initial management of this complicated area. Certain key features include avoiding autograft at the primary excision if they have an increased revised Baux score and minimizing the amount of liquid stool contaminating the wound bed to increase success.

LEVEL OF EVIDENCE

Epidemiologic study, level IV. Therapeutic study, level V.

The efficacy of 2 doses of epidural morphine for postcesarean delivery analgesia: a randomized noninferiority trial

BACKGROUND

A single dose of epidural morphine is effective in reducing pain after cesarean delivery but is associated with adverse effects. In this study, we sought to establish whether half the traditional dose of epidural morphine, when administered as part of a multimodal analgesia regimen after cesarean delivery, was associated with noninferior analgesia and fewer adverse effects.

METHODS

Ninety term parturients undergoing cesarean delivery under epidural anesthesia were enrolled in this randomized, double-blinded, noninferiority study. Patients were randomly allocated to receive either 3 mg epidural morphine or, half this dose, 1.5 mg epidural morphine. In addition, subjects received regular systemic ketorolac and acetaminophen. Rescue analgesia (oral oxycodone) was administered for breakthrough pain. The primary outcome was the difference between groups in total opioid consumption (measured in median IV morphine equivalents) within the first 24 hours. A prespecified noninferiority margin of 3.33 mg was used. Secondary outcomes included total opioid consumption from 24 to 48 hours, numerical rating scale pain scores, time to first request for analgesics, overall pain relief, maternal satisfaction, quality of recovery, and adverse effects.

RESULTS

Data were analyzed for 87 participants. Noninferiority was demonstrated as the difference in median 24-hour opioid consumption between the 1.5 mg epidural morphine (EM) and 3 mg EM groups was 0 mg (1-sided 95% confidence interval [CI], 2.5 mg), which was less than the prespecified noninferiority margin of 3.33 mg. No significant differences were found between groups in the median 24- to 48-hour opioid consumption or the median total opioid consumption within 48 hours. Pain scores, overall pain relief, and satisfaction at 24 and 48 hours were not significantly different between groups. The 1.5 mg EM group had a lower incidence of moderate and severe pruritus at 6 and 12 hours (relative risk [RR] 0.44, 95% CI, 0.2-0.9 and RR 0.41, 95% CI, 0.2-0.8, respectively) and had less nausea and vomiting at 6 hours (RR 0.22, 95% CI, 0.05-0.9). There was no difference in average pain scores at 12 weeks between the 2 groups.

CONCLUSION

When used as part of a multimodal analgesia regimen, 1.5 mg epidural morphine provided noninferior postcesarean analgesia and caused fewer adverse effects compared with 3 mg epidural morphine.