Frequency, complications, and mortality of inhalation injury in burn patients: A systematic review and meta-analysis protocol.

INTRODUCTION: Burns are tissue traumas caused by energy transfer and occur with a variable inflammatory response. The consequences of burns represent a public health problem worldwide. Inhalation injury (II) is a severity factor when associated with burn, leading to a worse prognosis. Its treatment is complex and often involves invasive mechanical ventilation (IMV). The primary purpose of this study will be to assess the evidence regarding the frequency and mortality of II in burn patients. The secondary purposes will be to assess the evidence regarding the association between IIs and respiratory complications (pneumonia, airway obstruction, acute respiratory failure, acute respiratory distress syndrome), need for IMV and complications in other organ systems, and highlight factors associated with IIs in burn patients and prognostic factors associated with acute respiratory failure, need for IMV and mortality of II in burn patients. METHODS: This is a systematic literature review and meta-analysis, according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). PubMed/MEDLINE, Embase, LILACS/VHL, Scopus, Web of Science, and CINAHL databases will be consulted without language restrictions and publication date. Studies presenting incomplete data and patients under 19 years of age will be excluded. Data will be synthesized through continuous (mean and standard deviation) and dichotomous (relative risk) variables and the total number of participants. The means, sample sizes, standard deviations from the mean, and relative risks will be entered into the Review Manager web analysis software (The Cochrane Collaboration). DISCUSSION: Despite the extensive experience managing IIs in burn patients, they still represent an important cause of morbidity and mortality. Diagnosis and accurate measurement of its damage are complex, and therapies are essentially based on supportive measures. Considering the challenge, their impact, and their potential severity, IIs represent a promising area for research, needing further studies to understand and contribute to its better evolution. The protocol of this review is registered on the International prospective register of systematic reviews platform of the Center for Revisions and Disclosure of the University of York, United Kingdom (https://www.crd.york.ac.uk/prospero), under number RD42022343944.

Fire deaths in Cape Town, South Africa: A retrospective review of medico-legal and toxicological findings (2006 - 2018).

BACKGROUND: In South Africa, fire-related deaths are common, particularly within dense informal housing settlements. Published data on deaths from fire incidents in Cape Town is sparse. Additionally, little emphasis has been placed on the role of toxicological investigations in these deaths, despite the known risk of alcohol and drug impairment to burn injury. METHODS: A retrospective, descriptive analysis of post-mortem case reports from Salt River Mortuary was conducted to investigate all deaths in which fires were involved in the west metropole of Cape Town, between 2006 to 2018. Demographic, circumstantial, and toxicological data were analyzed using R software. RESULTS: In total 1370 fire deaths occurred over 13 years, with a mean of 106 (SD ± 18) cases per annum (≈3% of the annual caseload and a mortality rate of 5.5 per 100,000). Males (70.4%), adults (mean=30.7 years), and toddlers (1-4 years old) were notably at risk. Deaths typically occurred in the early morning (00h00 - 06h00) (45.7%), during winter (32.1%), and in lower socioeconomic areas with highly dense informal settlements (65.6%), with 29% of deaths occurring in multi-fatality incidents. Ethanol was detected (≥0.01 g/100 mL) in 55.1% of cases submitted for analysis (71.5%), with a mean of 0.18 g/100 mL, and with 93.8% of positive cases > 0.05 g/100 mL. Carboxyhaemoglobin (COHb) analysis was requested in 76.4% of cases, with 57% of cases having a %COHb of ≥ 20%. Toxicology results (for drugs other than ethanol) from the national laboratory were outstanding in 34.4% of the cases at the conclusion of the study. BAC and %COHb were significantly higher in deaths from burns and smoke inhalation (usually accidents) than deaths from combined trauma and burns (typically homicides). Fire deaths with high COHb levels were more likely to display cherry-red discoloration (OR=3.1) and soot in the airways (OR=2.7) at autopsy. CONCLUSION: This article provides an updated description of fire deaths in the west metropole of Cape Town. The importance of BAC and COHb testing in these cases was noted, and the authors call for an investigation of the role of drug impairment (specifically frequently misused drugs methamphetamine and methaqualone) as a risk factor in these deaths. Areas of high-density informal settlements, where open flames are used to heat, light, and cook, were noted as high risk.

Hyperbaric Oxygen and Mortality in Burns With Inhalation Injury: A Study of the National Burn Repository.

Mortality in burn injury is primarily influenced by three factors: age, percent burn (%TBSA), and presence of inhalation injury. Numerous modalities have been tried in an attempt to treat those patients with burns and inhalation injury, including the use of hyperbaric oxygen (HBO). The aim of our study was to find the national prevalence of HBO for burns with inhalation injury, and whether HBO influenced mortality in these often severely injured patients. This retrospective study used the National Burn Repository (NBR) to identify hospital admissions of patients with both cutaneous burn and inhalation injuries. After applying exclusion criteria, a total of 13,044 patients were identified. Variables included in the multivariate regression analysis included age, sex, race, payer, mechanism of burn injury, TBSA group, total procedure number, mechanical ventilator days, and treatment with HBO. The main outcome variable was mortality. Of the 13,044 patients, 67 had HBO therapy. The HBO patients were older (mean age 51.7 vs 42.8 years, P < .001), but had smaller burns and thus a similar Baux score (66.6 vs 65.2, P = .661). The HBO patients had a higher mortality (29.9% vs 17.5%, P = .01). On multivariate regression analysis, HBO was an independent predictor of mortality (odds ratio = 2.484, P = .004). Other significant predictors of mortality included age, black race, Medicaid or uninsured patients, and %TBSA. The use of HBO for patients with burns and inhalation injury is uncommon in this database. It is unclear whether that reflects low prevalence or if individual centers do not all impute HBO into the NBR. For those patients in this database, HBO is an independent predictor of mortality. It can be difficult to determine the severity of inhalation injury in the NBR, so those patients receiving HBO could theoretically have more severe inhalation injury.

High molecular weight sodium hyaluronate improves survival of syndecan-1-deficient septic mice by inhibiting neutrophil migration.

METHODS: Sepsis was induced by cotton smoke inhalation followed by intranasal administration of Pseudomonas aeruginosa in female (> 6 months) Balb/c and syndecan-1 knockout mice. Survival of mice, lung capillary endothelial glycocalyx integrity, lung water content, and vascular hyper-permeability were determined with or without HMW-SH treatment in these mice. Effects of HMW-SH on endothelial permeability and neutrophil migration were tested in in vitro setting. RESULTS: In septic wildtype mice, we found a severely damaged pulmonary microvascular endothelial glycocalyx and elevated levels of shed syndecan-1 in the circulation. These changes were associated with significantly increased pulmonary vascular permeability. In septic syndecan-1 knockout mice, extravascular lung water content was higher, and early death was observed. The administration of HMW-SH significantly reduced mortality and lung water content in septic syndecan-1 knockout mice, but not in septic wildtype mice. In in vitro setting, HMW-SH inhibited neutrophil migration and reduced cultured endothelial cell permeability increases. However, these effects were reversed by the addition of recombinant syndecan-1 ectodomain. CONCLUSIONS: HMW-SH reduced lung tissue damage and mortality in the absence of syndecan-1 protein, possibly by reducing vascular hyper-permeability and neutrophil migration. Our results further suggest that increased shed syndecan-1 protein levels are linked with the inefficiency of HMW-SH in septic wildtype mice.

Inpatient and Postdischarge Outcomes Following Inhalation Injury Among Critically Injured Burn Patients.

Inhalation injury is associated with high inpatient mortality, but the impact of inhalation injury after discharge and on non-mortality outcomes is poorly characterized. To address this gap, we evaluated the effect of inhalation injury on postdischarge morbidity, mortality, and hospital readmissions among patients who sustained burn injury, as well as on in-hospital outcomes for context. This was a retrospective cohort study of patients with cutaneous fire/flame burns admitted to a burn center intensive care unit from January 1, 2009 to December 31, 2015, with or without inhalation injury. Records were linked to statewide hospital admission and vital statistics databases to assess postdischarge outcomes. Mixed-effects Poisson regression was used to assess mortality, complications, and readmissions. The overall cohort included 830 patients with cutaneous burns; of these, 201 patients had inhalation injury. In-hospital mortality was 31% among inhalation injury patients vs 6% in patients without inhalation injury (adjusted OR 2.35; 95% CI 1.66-3.31). Inhalation injury was also associated with an increased risk of in-hospital pneumonia and tracheostomy (P < .05 for all). Inhalation injury was not associated with greater postdischarge mortality, all-cause readmission, readmission for pulmonary diagnosis, or readmission requiring intubation. Among the subset of patients with bronchoscopy-confirmed inhalation injury (n = 124; 62% of inhalation injuries), a higher injury grade was not associated with greater inpatient or postdischarge mortality. Inhalation injury was associated with increased early morbidity and mortality, but did not contribute to postdischarge mortality or readmission. These findings have implications for shared decision making with patients and families and for estimating healthcare utilization after initial hospitalization.

Soluble suppression of tumorigenicity-2 predicts pneumonia in patients with inhalation injury: Results of a pilot study.

INTRODUCTION: Several mechanisms play a role in the development of pneumonia after inhalation injury. Our aim was to analyze whether higher concentrations of inflammatory markers or of biomarkers of epithelial injury are associated with a higher incidence of pneumonia in patients with inhalation injury. MATERIAL AND METHODS: Secondary analysis of a single-center prospective observational cohort pilot study, performed over a two-year period (2015-2017) at the Burns Unit of the Plastic and Reconstructive Surgery Department of Vall d'Hebron University Hospital. All patients aged 18 with suspected inhalation injury undergoing admission to the Burns Unit were included. Plasma biomarkers of the lung epithelium (RAGE and SP-D), inflammation markers (IL6, IL8), and IL33, as well as soluble suppression of tumorigenicity-2 (sST2) levels, were measured within the first 24 h of admission. RESULTS: Twenty-four patients with inhalation injury were included. Eight (33.3%) developed pneumonia after a median of 7 (4-8) days of hospital stay. Patients with pneumonia presented higher plasma concentrations of sST2 (2853 [2356-3351] ng/mL vs 1352 [865-1839] ng/mL; p < 0.001), IL33 (1.95 [1.31-2.59] pg/mL vs 1.26 [1.07-1.45] pg/mL; p = 0.002) and IL8 (325.7 [221.6-430.0] pg/mL vs 174.1 [95.2-253.0] pg/mL; p = 0.017) on day 1 of inclusion. Plasma sST2 concentration in the first 24 h demonstrated excellent diagnostic accuracy for predicting the occurrence of pneumonia in patients with smoke inhalation (AUROC 0.929 [95%CI 0.818-1.000]). A cutoff point of ≥2825 ng/mL for sST2 had a sensitivity of 75% and a specificity of 100%. The risk ratio of pneumonia in patients with sST2 ≥ 2825 ng/mL was 7.14 ([95% CI 1.56-32.61]; p = 0.016). CONCLUSIONS: Plasma sST2 in the first 24 h of admission predicts the occurrence of pneumonia in patients with inhalation injury.

A comparative study of a preclinical survival model of smoke inhalation injury in mice and rats.

Smoke inhalation injury increases morbidity and mortality. Clinically relevant animal models are necessary for the continued investigation of the pathophysiology of inhalation injury and the development of therapeutics. The goal of our research was threefold: 1) to develop a reproducible survival model of smoke inhalation injury in rats that closely resembled our previous mouse model, 2) to validate the rat smoke inhalation injury model using a variety of laboratory techniques, and 3) to compare and contrast our rat model with both the well-established mouse model and previously published rat models to highlight our improvements on smoke delivery and lung injury. Mice and rats were anesthetized, intubated, and placed in custom-built smoke chambers to passively inhale woodchip-generated smoke. Bronchoalveolar lavage fluid (BALF) and lung tissue were collected for confirmatory tests. Lung sections were hematoxylin and eosin stained, lung edema was assessed with wet-to-dry (W/D) ratio, and inflammatory cell infiltration and cytokine elevation were evaluated using flow cytometry, immunohistochemistry, and ELISA. We confirmed that our mouse and rat models of smoke inhalation injury mimic the injury seen after human burn inhalation injury with evidence of pulmonary edema, neutrophil infiltration, and inflammatory cytokine elevation. Interestingly, rats mounted a more severe immunological response compared with mice. In summary, we successfully validated a reliable and clinically translatable survival model of lung injury and immune response in rats and mice and characterized the extent of this injury. These animal models allow for the continued study of smoke inhalation pathophysiology to ultimately develop a better therapeutic.

The epidemiologic characteristics and outcomes following intentional burn injury at a regional burn center.

INTRODUCTION: Intentional burn injury outcomes are usually more severe, have a high mortality and are seen more often in low and middle-income countries. This study will examine the epidemiological characteristics of intentional burn injury patients and mortality outcomes at a regional Burn Center. METHODS: This is a retrospective study of 11,977 patients admitted to a regional Burn center from 2002 to 2015.Variables analyzed were basic demographics (sex, age, and race), total body surface area of burn (%TBSA), presence of inhalation injury, Charlson comorbidity index, intent of injury, mortality, and hospital and ICU length of stay (LOS). Chi-square tests, bivariate analysis and logistic regression models were utilized to determine the effect of burn intent on outcomes. RESULTS: Eleven thousand eight hundred and twenty-three (n = 11,823) adult and pediatric patients from 2002 to 2015 were included in the study. Three hundred and forty-eight (n = 348, 2.9%) patients had intentional burn injuries (IBI). Patients with IBI were younger, 26.5 ± 20 years compared to the non-intentional burn injury (NIBI) group (32 ± 22 years, p < 0.001). Mean %TBSA was significantly higher in the IBI vs. NIBI group at 14.6 ± 20 vs. 6.4 ± 10%, p < 0.001, respectively. Overall, Non-whites (n = 230, 66%) were more likely to have IBI, p < 0.001. Inhalation injury and mortality were statistically significant in the IBI group compared to the NIBI group, (n = 54,16%) vs. (n = 30, 9%) and (n = 649,6%) vs. (n = 329,2.9%), p < 0.001, respectively. Multivariate logistic regression did not show any significant increase in odds of mortality based on burn intent. In subgroup analysis of self-inflicted (SIB) vs. assault burns, SIB patients were significantly older, 38 years (±14.7) vs. 22.4 years (±20.5), p < 0.001 and had a higher %TBSA, 26.5 (±29.6) vs. 10.3 (±13.6), p < 0.001. Seventy three percent (n = 187, 73%) of assault burn patients were Nonwhite and Whites were more likely to incur self-inflicted burns, (n = 53% p < 0.001). CONCLUSION: We show that patients with intentional burn injuries have an associated increased %TBSA and inhalation injury without increased adjusted odds for mortality. Intentional burns increase health care expenditures. Violence prevention initiatives and access to mental health providers may be beneficial in reducing intentional burn injury burden.

Characteristics and outcomes of patients with inhalation injury treated at a military burn center during U.S. combat operations.

BACKGROUND: The purpose of this study was to examine risk factors for mortality in burned patients with inhalation injury (II). We further sought to compare a cohort of burned military service members to civilian patients with II. METHODS: We identified patients treated at our burn center over a 10-year period. Demographics, injury characteristics, and outcomes were compared between patients with and without II. Logistic regression analysis was performed to determine the impact of patient characteristics and II grade on mortality. RESULTS: 3791 patients treated at our burn center met study inclusion criteria. 424 (11.2%) patients were diagnosed with II [II(+)]. Age, % total body surface area (TBSA) burned, % full thickness burned, intensive care unit (ICU) days, hospital days, and mortality were all greater in II(+) patients. Separating the II(+) patients into military and civilian groups, there was a higher incidence of grade 4 II and higher mortality for grades 2-4 II in military patients. Analyses demonstrated that military service was associated with increased mortality in II(+) patients. The bronchoscopic grade of II did not have an association with mortality in this population. CONCLUSIONS: II(+) patients were older, had larger burns, needed more ICU and hospital days, and had higher mortality rates. Among II(+) patients, military affiliation was associated with more severe II and increased mortality. Establishment of an objective grading system for II that is associated with mortality is a meaningful future research endeavor.

Early patient deaths after transfer to a regional burn center.

INTRODUCTION: Patients who sustain burn injuries are frequently transferred to regional burn centers. Severely injured patients, unlikely to survive, may be transported far from home and family to die shortly after arrival. An examination of early deaths, those that happen within a week of transfer, may offer an opportunity to revise the way we think about critical burns and consider the best way to provide regional care. METHODS: This is a focused review of burn patients who survived ≤1 week after transfer to a regional center from 2013-2017. Originating location data such as city, state, population at origin were obtained. Transfer data, including mode of transport and distance traveled, as well as patient characteristics, Total Body Surface Area (TBSA) burned, inhalation injury, medical history with calculation of revised-Baux (r-Baux) score were analyzed. RESULTS: 25 patients (1.2%) met inclusion criteria. Patients were transferred from a wide geographic area with population ranges of 1000 to 279,000. 21 patients met criteria for burn resuscitation by TBSA; 4 (19%) were placed on comfort care upon arrival, 7 (33%) were placed on comfort care after discussion with the patient's family, and 10 (48%) received full resuscitation efforts. Of these 10 patients, 2 died as "full code", 8 were transitioned to comfort care after failed resuscitation or other events. Code status was not always addressed prior to the decision to transfer. Two patients were transferred after cardiac arrest in the field both of which had significant medical comorbidities in addition to their burn. CONCLUSIONS: Regional burn centers support a variety of populations. Transferring patients for which care is futile may have a profound impact on resource utilization from a variety of perspectives including transferring centers, receiving centers, regional Emergency Medical Services and families. Referring providers need to be supported in identifying these severely injured, potentially expectant patients. Transfer of patients may negatively impact families as a loved one may die far from home, before family can arrive. With our increasing ability to utilize telemedicine, transfer may not always provide the best support we can offer for providers, patients, and families. APPLICABILITY OF RESEARCH TO PRACTICE: Early deaths after transfer to a regional burn center, especially those that do not undergo a full resuscitation, should be critically examined to determine the appropriateness of transfer in a palliative, patient and family centered approach.

Influence of pre-existing medical condition and predicting value of modified Elixhauser comorbidity index on outcome of burn patients.

OBJECTIVES: To evaluate the impact of comorbidity and predicting value of the modified Elixhauser comorbidity index score on the outcome of burn patients. METHODS: A retrospective study was conducted on 5480 patients admitted during 24 h after burn to the National Burn Hospital from 1/1/2016 to 31/12/2018. Demographic data and pre-existing medical conditions were collected. Modified Elixhauser comorbidity index (ECI) score developed by Walravel et al. was calculated for each patient. The score was the weighted sum of comorbid conditions. Outcomes measured included hospitalization, complication and mortality. RESULTS: Among 5480 patients, 345(6.3%) had at least one pre-existing medical condition. Most common comorbidities were neurological disorder, diabetes, hypertension and psychoses. Pre-existing medical conditions were more common in elderly (25% vs. 4.8%; p < .001) and female (7.5% vs. 5.8%; p < .05). Moreover, significantly larger burn extent, higher rate of inhalation injury (p < .01) and complication (12.8% vs. 6.1%; p < .001), longer time of hospitalization (21.4 vs. 17.1 days; p < .001) were recorded in comorbidity group. It is noted that higher ECI score was remarkably higher in patients who developed complication (.6 vs. .3 respectively, p < .05) and death (.5 vs. .3; p < .05). Multivariate analysis indicated that apart from presence of inhalation injury, increased burn extent, full thickness burn area, ECI score was an independently predicted factor for prolonging the time of staying, for the development of complication and death. Each score of ECI results in increased probability unit of complication to .13 and probability unit of death to .11. CONCLUSION: Pre-existing medical conditions lead to more severe and worse outcomes among burn patients. Modified Elixhauser comorbidity index score should be used as a prognosis factor for outcomes of burn patients.

Association between hydroxocobalamin administration and acute kidney injury after smoke inhalation: a multicenter retrospective study.

BACKGROUND: The use of hydroxocobalamin has long been advocated for treating suspected cyanide poisoning after smoke inhalation. Intravenous hydroxocobalamin has however been shown to cause oxalate nephropathy in a single-center study. The impact of hydroxocobalamin on the risk of acute kidney injury (AKI) and survival after smoke inhalation in a multicenter setting remains unexplored. METHODS: We conducted a multicenter retrospective study in 21 intensive care units (ICUs) in France. We included patients admitted to an ICU for smoke inhalation between January 2011 and December 2017. We excluded patients discharged at home alive within 24 h of admission. We assessed the risk of AKI (primary endpoint), severe AKI, major adverse kidney (MAKE) events, and survival (secondary endpoints) after administration of hydroxocobalamin using logistic regression models. RESULTS: Among 854 patients screened, 739 patients were included. Three hundred six and 386 (55.2%) patients received hydroxocobalamin. Mortality in ICU was 32.9% (n = 243). Two hundred eighty-eight (39%) patients developed AKI, including 186 (25.2%) who developed severe AKI during the first week. Patients who received hydroxocobalamin were more severe and had higher mortality (38.1% vs 27.2%, p = 0.0022). The adjusted odds ratio (95% confidence interval) of AKI after intravenous hydroxocobalamin was 1.597 (1.055, 2.419) and 1.772 (1.137, 2.762) for severe AKI; intravenous hydroxocobalamin was not associated with survival or MAKE with an adjusted odds ratio (95% confidence interval) of 1.114 (0.691, 1.797) and 0.784 (0.456, 1.349) respectively. CONCLUSION: Hydroxocobalamin was associated with an increased risk of AKI and severe AKI but was not associated with survival after smoke inhalation. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03558646.

Carbon monoxide poisoning in Denmark with focus on mortality and factors contributing to mortality.

INTRODUCTION: Carbon monoxide (CO) poisoning is frequent worldwide but knowledge regarding the epidemiology is insufficient. The aim of this study was to clarify the extent of this intoxication, its mortality and factors associated with mortality. MATERIALS AND METHODS: National databases from Statistics Denmark were used to identify individuals who suffered from CO-poisoning during 1995-2015, as well as information regarding co-morbidities, mortality and manner of death. RESULTS: During the period from 1995 to 2015, 22,930 patients suffered from CO-poisoning in Denmark, and 21,138 of these patients (92%) were hospitalized. A total of 2,102 patients died within the first 30 days after poisoning (9.2%). Among these, 1,792 (85% of 2,102) were declared dead at the scene and 310 (15% of 2,102) died during hospitalization. Deaths due to CO-poisoning from smoke were intentional in 6.3% of cases, whereas deaths due to CO containing gases were intentional in 98.0% of cases. Among patients who survived >30 days, there was no significant difference in survival when comparing hyperbaric oxygen therapy (HBO) treatment with no HBO treatment after adjustment for age and co-morbidities such as drug abuse, psychiatric disease, stroke, alcohol abuse, arterial embolism, chronic obstructive pulmonary disease, cerebrovascular disease and atrial fibrillation. Several co-morbidities predicted poorer outcomes for patients who survived the initial 30 days. CONCLUSIONS: Poisoning from smoke and/or CO is a frequent incident in Denmark accounting for numerous contacts with hospitals and deaths. Both intoxication and mortality are highly associated with co-morbidities interfering with cognitive and physical function. Treatment with HBO was not seen to have an effect on survival.

Using the injury severity score to adjust for comorbid trauma may be double counting burns: implications for burn research.

BACKGROUND: The injury severity score considers burn size and inhalation injury in estimating overall anatomical injury severity. Models that adjust for injury severity score in addition to total burn size and inhalation injury may therefore be double counting the risk from these individual burn characteristics, and obscuring (or overemphasizing) the contribution of risk from each source. The primary aim of this study was to compare differences in the estimated mortality risk of burn trauma using the traditional injury severity score (ISS) calculation and the non-burn injury severity score (NBISS) to examine how separating out the risk attributable to the burn injury versus other trauma changes the interpretation and clinical assessment. METHODS: Among U.S. casualties sustaining burns during combat operations in Iraq and Afghanistan from March 2003 to October 2013, we performed a retrospective cohort study. Unadjusted, adjusted, and weighted Cox proportional hazards models were performed to estimate the risk of age, burn injury severity, and non-burn injury severity on mortality. Weighted hazard ratios and adjusted survival curves were performed using non-parametric inverse probability weighting. RESULTS: Our final sample consisted of 902 service members with a mortality proportion of 5.7% (n=51). Adjusting for non-burn trauma with traditional ISS attenuated the risk of percent total body surface area burned (%TBSA) by 20% when modeled continuously [HR (95% CI): 1.27 (1.10-1.32) vs. 1.07 (0.99-1.15]. However, the adjusted model using NBISS only attenuated the associated mortality risk of burn size by 5% [HR (95% CI): 1.22 (1.12-1.34)] and had a similar model fit (AIC: 484.2 vs. 478.6). For the weighted Cox proportional hazards models, the risk from a large burn (%TBSA≥60) was also attenuated when adjusting for ISS [HR (95% CI): 2.80 (1.18-6.64)] compared to the model adjusting for NBISS [HR (95% CI): 5.63 (2.79-11.35)]. CONCLUSION: Our analysis comparing the use of traditional ISS and NBISS to measure comorbid non-burn trauma resulted in different interpretations for the effect of %TBSA on subsequent mortality. Our results suggest that the association of %TBSA with death can be obscured by the inclusion of traditional ISS. Therefore, we recommend using NBISS when constructing statistical models in this patient population.

Tracheostomy and mortality in patients with severe burns: A nationwide observational study.

BACKGROUND: Tracheostomy is often performed in patients with severe burns who are undergoing prolonged mechanical ventilation. However, the appropriate timing of tracheostomy and its effect on mortality remain unknown. The aim of this study was to determine whether tracheostomy can reduce mortality in patients with severe burns. METHODS: Using the Japanese Diagnosis Procedure Combination database from April 2010 to March 2014, we extracted data on adult patients with severe burns (burn index score of ≥15) who started mechanical ventilation within 3days of admission. We estimated the hazard ratio for 28-day in-hospital mortality associated with tracheotomy performed from day 5 to 28. We adjusted for baseline and time-dependent confounders using inverse probability of treatment weighting methods and fitted a marginal structural Cox proportional hazard model. RESULTS: We identified 680 eligible patients (94 in the tracheostomy group, 2289 person-days; 586 in the non-tracheostomy group, 11,197 person-days). Patients who underwent a tracheostomy had worse prognostic factors for mortality. After adjustment for these factors, the hazard ratio for 28-day mortality associated with tracheostomy compared with non-tracheostomy was 0.73 (95% confidence interval, 0.39-1.34). CONCLUSIONS: There was no significant association between 28-day in-hospital mortality and early tracheostomy in adult patients with severe burns.

Emergency Care of Pediatric Burns.

Although the overall incidence of and mortality rate associated with burn injury have decreased in recent decades, burns remain a significant source of morbidity and mortality in children. Children with major burns require emergent resuscitation. Resuscitation is similar to that for adults, including pain control, airway management, and administration of intravenous fluid. However, in pediatrics, fluid resuscitation is needed for burns greater than or equal to 15% of total body surface area (TBSA) compared with burns greater than or equal to 20% TBSA for adults. Unique to pediatrics is the additional assessment for non-accidental injury and accurate calculation of the percentage of total burned surface area (TBSA) in children with changing body proportions are crucial to determine resuscitation parameters, prognosis, and disposition.

Cyanide poisoning is a possible cause of cardiac arrest among fire victims, and empiric antidote treatment may improve outcomes.

BACKGROUND: Carbon monoxide and cyanide poisoning are important causes of death due to fire. Carbon monoxide is more regularly assessed than cyanide at the site of burn or smoke inhalation treatment due to its ease in assessment and simplicity to treat. Although several forensic studies have demonstrated the significance of cyanide poisoning in fire victims using blood cyanide levels, the association between the cause of cardiac arrest and the concentration of cyanide among fire victims has not been sufficiently investigated. This study aimed to investigate the frequency of cyanide-induced cardiac arrest in fire victims and to assess the necessity of early empiric treatment for cyanide poisoning. METHODS: This study was a retrospective analysis of fire victims with cardiac arrest at the scene who were transported to a trauma and critical care center, Kyorin University Hospital, from January 2014 to June 2017. Patients whose concentration of cyanide was measured were included. RESULTS: Five patients were included in the study; all died despite cardiopulmonary resuscitation. Three of these victims were later found to have lethal cyanide levels (>3 µg/ml). Two of the patients had non-lethal carboxyhemoglobin levels under 50% and might have been saved if hydroxocobalamin had been administered during resuscitation. CONCLUSION: According to our results, cyanide-induced cardiac arrest may be more frequently present among fire victims than previously believed, and early empiric treatment with hydroxocobalamin may improve outcomes for these victims in cases where cardiac arrest is of short duration.

The use of a simple three-level bronchoscopic assessment of inhalation injury to predict in-hospital mortality and duration of mechanical ventilation in patients with burns.

Major burn centres in Australia use bronchoscopy to assess severity of inhalation injuries despite limited evidence as to how best to classify severity of inhalational injury or its relationship to patient outcomes. All patients with burns who were admitted to the intensive care unit (ICU) at The Alfred Hospital between February 2010 and July 2014 and underwent bronchoscopy to assess inhalational injury, were reviewed. Age, total body surface area burnt, severity of illness indices and mechanisms of injury were extracted from medical histories and local ICU and burns registries. Inhalational injury was classified based on the Abbreviated Injury Score and then grouped into three categories (none/mild, moderate, or severe injury). Univariable and multivariable analyses were undertaken to examine the relationship between inhalational injury and outcomes (in-hospital mortality and duration of mechanical ventilation). One hundred and twenty-eight patients were classified as having none/mild inhalational injury, 81 moderate, and 13 severe inhalation injury. Mortality in each group was 2.3% (3/128), 7.4% (6/81) and 30.7% (4/13) respectively. Median (interquartile range) duration of mechanical ventilation in each group was 26 (11-82) hours, 84 (32-232) hours and 94 (21-146) hours respectively. After adjusting for age, total body surface area burnt and severity of illness, only the severe inhalation injury group was independently associated with increased mortality (odds ratio 20.4 [95% confidence intervals {CI} 1.74 to 239.4], P=0.016). Moderate inhalation injury was independently associated with increased duration of ventilation (odds ratio 2.25 [95% CI 1.53 to 3.31], P <0.001), but not increased mortality. This study suggests that stratification of bronchoscopically-assessed inhalational injury into three categories can provide useful prognostic information about duration of ventilation and mortality. Larger multicentre prospective studies are required to validate these findings.

High-Frequency Ventilation Modalities as Salvage Therapy for Smoke Inhalation-Associated Acute Lung Injury: A Systematic Review.

BACKGROUND: Smoke inhalation-associated acute lung injury (SI-ALI) is a major cause of morbidity and mortality in victims of fire tragedies. To date, there are no evidence-based guidelines on ventilation strategies in acute respiratory distress syndrome (ARDS) after smoke inhalation. We reviewed the existing literature for clinical studies of salvage mechanical ventilation (MV) strategies in patients with SI-ALI, focusing on mortality and pneumonia as outcomes. METHODS: A systematic search was designed in accordance with preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Risk of bias assessment was performed using the Newcastle-Ottawa Quality Assessment Scale (NOS; 0 to 9 stars), with a score ≥7 being the threshold for inclusion in the meta-analysis. A systematic search strategy was used to search 10 databases. Clinical studies were included in which patients: (1) experienced smoke inhalation, (2) treated with MV, and (3) described a concurrent or historical control group. RESULTS: A total of 226 potentially relevant studies were identified, of which 7 studies on high-frequency percussive ventilation (HFPV) met inclusion criteria. No studies met inclusion for meta-analysis (NOS ≥ 7). In studies comparing HFPV to conventional mechanical ventilation (CMV), mortality and pneumonia incidence improved in 3 studies and remained unchanged in 3 others. No change in ventilator days or ICU length of stay was observed; however, oxygenation and work of breathing improved with HFPV. CONCLUSIONS: Mechanical ventilation in patients with SI-ALI has not been well studied. High-frequency percussive ventilation may decrease in-hospital mortality and pneumonia incidence when compared to CMV. The absence of "good" quality evidence precluded meta-analysis. Based upon low-quality evidence, there was a very weak recommendation that HFPV use may be associated with lower mortality and pneumonia rates in patients with SI-ALI. Given SI-ALI's unique underlying pathophysiology, and its potential implications on therapy, randomized controlled studies are required to ensure that patients receive the safest and most effective care. TRIAL REGISTRATION: The study was registered with PROSPERO International prospective register of systematic reviews (#47015).