The impact of inhalation injury in patients with small and moderate burns

Epidemiology and timing of infectious complications from battlefield-related burn injuries

BACKGROUND

Infections are the most frequent complication and cause of mortality in burn patients. We describe the epidemiology and outcomes of infections among deployed U.S. military personnel with burns.

METHODS

Military personnel who sustained a burn injury in Iraq or Afghanistan (2009-2014) and were admitted to the Burn Center at U.S. Army Institute of Surgical Research at Brooke Army Medical Center were included in the analysis.

RESULTS

The study population included 144 patients who were primarily young (median 24 years) males (99 %) with combat-related burns (62 %) sustained via a blast (57 %), resulting in a median total body surface area burned (TBSA) of 6 % (IQR 3-14 %). Twenty-six (18 %) patients developed infections, with pneumonia being the predominant initial infection (= 16), followed by skin and soft-tissue infections (SSTI, = 6), bloodstream infections (BSI, = 3), and intra-abdominal infections (IAI, = 1). Initial infections were diagnosed at a median of 4 days (IQR 3-5) post-injury for pneumonia, 7 days (IQR 4-12) for SSTIs, 7 days (IQR 6-7) for BSI, and 17 days for IAI. Patients with infections were more severely injured with greater TBSA (median 31 % vs 5 %), more inhalation injury (38 % vs 12 %), and longer time to definitive surgical management (median of 34 days vs 9) compared to those who did not develop infections (p < 0.001). Among patients with inhalation injury, a higher proportion developed pneumonia (42 %) compared to those without inhalation injury (5 %; p < 0.001). Five patients developed an invasive fungal infection. Gram-negative bacilli were most frequently recovered, with 32 % of Gram-negative isolates being multidrug-resistant. Four patients died, of whom all had ≥ 4 infections.

CONCLUSIONS

Military personnel with burn injuries who developed infections were more severely injured with greater TBSA and inhalation injury. Improved understanding of risk factors for burn-related infections in combat casualties is critical for effective management.

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.

Multiplexed Human Gene Expression Analysis Reveals a Central Role of the TLR/mTOR/PPARγ and NFkB Axes in Burn and Inhalation Injury-Induced Changes in Systemic Immunometabolism and Long-Term Patient Outcomes

Burn patients are subject to significant acute immune and metabolic dysfunction. Concomitant inhalation injury increases mortality by 20%. In order to identify specific immune and metabolic signaling pathways in burn (B), inhalation (I), and combined burn-inhalation (BI) injury, unbiased nanoString multiplex technology was used to investigate gene expression within peripheral blood mononuclear cells (PBMCs) from burn patients, with and without inhalation injury. PBMCs were collected from 36 injured patients and 12 healthy, non-burned controls within 72 h of injury. mRNA was isolated and hybridized with probes for 1342 genes related to general immunology and cellular metabolism. From these specific gene patterns, specific cellular perturbations and signaling pathways were inferred using robust bioinformatic tools. In both B and BI injuries, elements of mTOR, PPARγ, TLR, and NF-kB signaling pathways were significantly altered within PBMC after injury compared to PBMC from the healthy control group. Using linear regression modeling, (1) DEPTOR, LAMTOR5, PPARγ, and RPTOR significantly correlated with patient BMI; (2) RPTOR significantly correlated with patient length of stay, and (3) MRC1 significantly correlated with the eventual risk of patient mortality. Identification of mediators of this immunometabolic response that can act as biomarkers and/or therapeutic targets could ultimately aid the management of burn patients.

Epidemiological retrospective analysis in major burn patients: single centre medical records from 2009 to 2019

Burns cause a loss of skin barrier function, rendering it prone to infection. The prevention of infection comprises a focus on the treatment of patients with burns. Therefore, we analysed the results of microbiological tests of patients with severe and extremely severe burns to provide a basis for the prevention and treatment of infection in patients with burns. The results of microbiological tests of patients with severe and extremely severe burns admitted to our burn centre between 2009 and 2019 were retrospectively reviewed. The overall positive rate of microbial detection was 40.67% and did not significantly decline over the 10-year study period. The most common positive sites were wounds, sputum, and urine. The most common bacterial species causing the infections were Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Furthermore, the predictors of a positive detection, overall and at various sites, mainly included the burn area and depth, inhalation injury, and length of the hospital stay. Positive detection was an important predictor of the prognosis. In particular, a positive blood culture and Klebsiella pneumoniae had better predictive strength for mortality than other sites and strains. This study analysed the microbiological testing results at a single burn centre over a period of 10 years. The results provide information regarding the predictors of a positive detection and the influence of a positive detection on prognosis, and can be used as a basis for the development of clinical infection prevention and treatment strategies, as well as the selection of treatment measures.

Burn Injury Induces Proinflammatory Plasma Extracellular Vesicles That Associate with Length of Hospital Stay in Women: CRP and SAA1 as Potential Prognostic Indicators

Severe burn injury is a devastating form of trauma that results in persistent immune dysfunction with associated morbidity and mortality. The underlying drivers of this immune dysfunction remain elusive, and there are no prognostic markers to identify at-risk patients. Extracellular vesicles (EVs) are emerging as drivers of immune dysfunction as well as biomarkers. We investigated if EVs after burn injury promote macrophage activation and assessed if EV contents can predict length of hospital stay. EVs isolated early from mice that received a 20% total body surface area (TBSA) burn promoted proinflammatory responses in cultured splenic macrophages. Unbiased LC-MS/MS proteomic analysis of early EVs (<72 h post-injury) from mice and humans showed some similarities including enrichment of acute phase response proteins such as CRP and SAA1. Semi-unbiased assessment of early human burn patient EVs found alterations consistent with increased proinflammatory signaling and loss of inhibition of CRP expression. In a sample of 50 patients with large burn injury, EV SAA1 and CRP were correlated with TBSA injury in both sexes and were correlated with length of hospital stay in women. These findings suggest that EVs are drivers of immune responses after burn injury and their content may predict hospital course.

Plasma extracellular vesicles released after severe burn injury modulate macrophage phenotype and function

Extracellular vesicles (EVs) have emerged as key regulators of immune function across multiple diseases. Severe burn injury is a devastating trauma with significant immune dysfunction that results in an ∼12% mortality rate due to sepsis-induced organ failure, pneumonia, and other infections. Severe burn causes a biphasic immune response: an early (0-72 h) hyper-inflammatory state, with release of damage-associated molecular pattern molecules, such as high-mobility group protein 1 (HMGB1), and proinflammatory cytokines (e.g., IL-1β), followed by an immunosuppressive state (1-2+ wk post injury), associated with increased susceptibility to life-threatening infections. We have reported that early after severe burn injury HMGB1 and IL-1β are enriched in plasma EVs. Here we tested the impact of EVs isolated after burn injury on phenotypic and functional consequences in vivo and in vitro using adoptive transfers of EV. EVs isolated early from mice that underwent a 20% total body surface area burn injury (burn EVs) caused similar hallmark cytokine responses in naïve mice to those seen in burned mice. Burn EVs transferred to RAW264.7 macrophages caused similar functional (i.e., cytokine secretion) and immune gene expression changes seen with their associated phase of post-burn immune dysfunction. Burn EVs isolated early (24 h) induced MCP-1, IL-12p70, and IFNγ, whereas EVs isolated later blunted RAW proinflammatory responses to bacterial endotoxin (LPS). We also describe significantly increased HMGB1 cargo in burn EVs purified days 1 to 7 after injury. Thus, burn EVs cause immune outcomes in naïve mice and macrophages similar to findings after severe burn injury, suggesting EVs promote post-burn immune dysfunction.

Predictors of short-term outcomes of burn in a newly established burn centre in Iran

Aim

This study aimed to determine the predictors of hospital stay and mortality in patients with burns.

Design

This is a cross‐sectional, retrospective study.

Methods

This study was performed on 626 medical records in Velayat Subspecialty Burn and Plastic Surgery Center in Rasht, Iran, during 2008–2013.

Results

Men comprised 78.4% of the study population. Overall, 50.2% of the participants lived in rural areas, and 72.5% were married. The majority of burns occurred at home (49.5%), and thermal factor (87.4%) was the major cause of burn injuries. Also, 6.9% of the patients died after burns. The mean length of hospital stay was 12.62 ± 13 days. Age (OR = 1.07), total body surface area (TBSA%) (OR = 1.12) and length of ICU stay (OR = 1.06) were the strongest predictors of mortality. Gender (IRR = 0.85), TBSA% (IRR = 1.01), location of burn (IRR = 1.1), skin graft (IRR = 2.12), length of ICU stay (IRR = 1.04), re‐hospitalization (IRR = 1.77) and burn degree (IRR = 1.09) were the predictors of the length of hospital stay.

Conclusion

BSA is still an important predictor of mortality and length of hospital stay, as the most important short‐term outcomes of burns.

Respiratory Characteristics in Patients With Major Burn Injury and Smoke Inhalation

This study aimed to evaluate pulmonary function measurements and respiratory muscle parameters in patients with major burn injury and smoke inhalation. The inclusion criteria included patients who were diagnosed with a smoke inhalation burn or a major burn of more than 20% of total body surface area (TBSA). All subjects underwent a pulmonary function test, respiratory muscle strength test, peak cough flow and fluoroscopic diaphragmatic movement measurement, and 6-minute walk test before starting pulmonary rehabilitation. Evaluations were conducted on the 88th day after the injury, the average time of admission to the Department of the Rehabilitation Medicine for burn rehabilitation after the completion of the acute treatment. The average degree of burns of the total 67 patients was 34.6% TBSA. All parameters in the patient group were significantly lower than the healthy controls, and a mild restrictive pattern of impairment with a reduction in diffusing capacity and more reduced expiratory muscle, than inspiratory muscle strength were observed. Peak cough flow, respiratory muscle strength, and forced vital capacity in the patient group with inhalation burn were significantly lower than in those without inhalation burn. The conditions of the majority of patients with major burn and inhalation injury were consistent with restrictive impairment and significant reduction in diffusion capacity. The patients had expiratory muscle weakness, decreased diaphragmatic movement, and exercise capacity impairment.

Ventilation practices in burn patients—an international prospective observational cohort study

Background

It is unknown whether lung-protective ventilation is applied in burn patients and whether they benefit from it. This study aimed to determine ventilation practices in burn intensive care units (ICUs) and investigate the association between lung-protective ventilation and the number of ventilator-free days and alive at day 28 (VFD-28).

Methods

This is an international prospective observational cohort study including adult burn patients requiring mechanical ventilation. Low tidal volume (VT) was defined as VT ≤ 8 mL/kg predicted body weight (PBW). Levels of positive end-expiratory pressure (PEEP) and maximum airway pressures were collected. The association between VT and VFD-28 was analyzed using a competing risk model. Ventilation settings were presented for all patients, focusing on the first day of ventilation. We also compared ventilation settings between patients with and without inhalation trauma.

Results

A total of 160 patients from 28 ICUs in 16 countries were included. Low VT was used in 74% of patients, median VT size was 7.3 [interquartile range (IQR) 6.2–8.3] mL/kg PBW and did not differ between patients with and without inhalation trauma (p = 0.58). Median VFD-28 was 17 (IQR 0–26), without a difference between ventilation with low or high VT (p = 0.98). All patients were ventilated with PEEP levels ≥5 cmH2O; 80% of patients had maximum airway pressures &lt;30 cmH2O.

Conclusion

In this international cohort study we found that lung-protective ventilation is used in the majority of burn patients, irrespective of the presence of inhalation trauma. Use of low VT was not associated with a reduction in VFD-28.

Trial registration

Clinicaltrials.gov NCT02312869. Date of registration: 9 December 2014.

Variation in documented inhalation injury rates following burn injury in Australia and New Zealand

INTRODUCTION

The negative impact of inhalation injuries on in-hospital outcomes for burn patients is well known, but the burns community is yet to form a consensus on diagnostic criteria and clinical definitions. The diagnosis of inhalation injuries is consequently highly subjective. This study aimed to assess the variation in the rate of documented inhalation injury for adult patients in Australian and New Zealand burn units.

METHODS

Data for sequential admissions collected from eight adult burn centres across Australia and New Zealand between July 2009 and June 2016 were extracted from the Burns Registry of Australia and New Zealand (BRANZ). Inhalation injury was classified in two ways: (i) a field in the BRANZ data dictionary, and (ii) through a series of International Classification of Disease 10th Revision Australian Modification (ICD-10-AM) codes. Variation in inhalation injury prevalence was assessed using descriptive statistics, funnel plots, logistic regression, and predicted probabilities.

RESULTS

There were 11,206 admissions to BRANZ sites over the study period. Inhalation injury prevalence was the highest at Site D (13.1% for the BRANZ field and 11.8% for the ICD-10-AM codes), but there was significant variation between the contributing sites and the inhalation injury classification methods.

CONCLUSION

There is significant variation in the prevalence of documented inhalation injury among Australian and New Zealand burns units. The variation in the prevalence of documented inhalation injury across Australian and New Zealand sites reinforces the need for a consensus definition in the diagnosis of these injuries. Further work is required to improve data quality and reconcile the differences between clinical and ICD-10-AM coding prevalence before changes in clinical practice can be recommended from these data.

Quantifying the impact of inhalational burns: a prospective study

BACKGROUND

Inhalational injury is a major cause of morbidity and mortality in burns patients. This study aims to analyse the clinical outcomes, complications and bacteriology of inhalational burn patients.

METHODS

A prospective study was done on consecutive admissions to Burn Department, Singapore General Hospital over 15 months from January 2015 to March 2016. Presence of inhalational injury, demographics, complications and outcomes was recorded. Diagnosis of inhalational injury was based on history, symptoms and nasoendoscopy. Diagnosis of acute respiratory distress syndrome (ARDS), acute kidney injury (AKI) and infective complications were according to the Berlin criteria, acute kidney injury network (AKIN) classification stage 2 and above and the American Burns Association guidelines.

RESULTS

Thirty-five patients (17.3%) had inhalational burns out of 202 patients (63.4% male, 57.4% Chinese population). The average age was 43 ± 16.7 years (range 16-86), and percentage of total body surface area (%TBSA) was 12.1 ± 18.0 (range 0-88). In patients with inhalational injury, age was 38.9 ± 17.2 years and %TBSA was 30.3 ± 32.3. In patients without inhalational injury, age was 44.1 ± 12.8  years and %TBSA was 8.3 ± 9.59. Compared to patients with cutaneous injury alone, patients with inhalational burns had more surgeries (3 ± 7.07 vs 1 ± 1.54, p = 0.003), increased length of stay (21 days vs 8 days, p = 0.004) and higher in-hospital mortality rate (17.1% vs 0.6%, p < 0.001). Incidence of ARDS and AKI was 48.6% and 37.1%, respectively, compared to 0.6% and 1.2% in the patients without inhalational injury (p < 0.001). Patients with inhalational injury had increased incidence of bacteraemia (31.4% vs 2.4%, p < 0.001), pneumonia (37.1% vs 1.2%, p < 0.001) and burn wound infection (51.4% vs 25.1%, p = 0.004). Inhalational injury predicted AKI with an adjusted odds ratio (OR) of 17.43 (95% confidence interval (CI) 3.07-98.87, p < 0.001); ARDS, OR = 106.71 (95% CI 12.73-894.53, p < 0.001) and pneumonia, OR = 13.87 (95% CI 2.32-82.94, p = 0.004). Acinetobacter baumannii was the most frequently cultured bacteria in sputum, blood and tissue cultures with inhalational injury. Gram-negative bacteria were predominantly cultured from tissue in patients with inhalational injury, whereas gram-positive bacteria were predominantly cultured from tissue in patients without inhalational injury.

CONCLUSIONS

Inhalational injury accompanying burns significantly increases the length of stay, mortality and complications including AKI, ARDS, infection and sepsis.

Risk of pneumonia in patients with burn injury: a population-based cohort study

Background

Burns are the main cause of accidental injury, and pneumonia is a common respiratory disease in humans.

Aim

The purpose of this study was to investigate the relationship between burn injury and pneumonia.

Patients and methods

A nationwide population-based cohort study was conducted using data from the National Health Insurance Research Database in Taiwan. We identified and enrolled 2,893 subjects with burn injury, who were individually matched to 2,893 subjects in the comparison group by using the propensity score. Furthermore, we used a self-controlled case-series design to estimate the temporal association between burn injury and pneumonia.

Results

Exposure to burn injury revealed a higher risk of pneumonia than that to non-burn injury within 1 year. The Cox proportional hazards model revealed that, compared with the non-burn injury, burn injury yielded a 2.39-fold (95% CI=1.44-3.96) increase in risk of pneumonia. The exposure period of burn injury within 30 days showed 2.76-fold increase in risk of pneumonia (95% CI=1.44-3.96) compared with that in the baseline period.

Conclusion

Burn injury was associated with a significant increased risk of pneumonia, especially occurring within 30 days.

Acute clinical manifestations in toxic smoke inhalation victims: systematic review of observational studies

Abstract Introduction: Lung injuries from toxic smoke inhalation are the main causes of death in fire victims; however, information regarding the acute effects on the respiratory system after smoke inhalation and its constituents in closed environments are still scarce in literature. Objective: To investigate the acute clinical manifestations observed in victims of smoke inhalation during enclosed-space fires by means of systematic review. Methods: A systematic search was conducted in the following databases: MEDLINE (via PubMed), Lilacs, Scopus and Web of Science. There were no appliedrestrictions in terms of thepublication date. In addition, a manual search was performed on the references of published studies. Observational studies assessing the prevalence of acute clinical manifestations in victims of toxic smoke inhalation in closed environments were included. Results: Of the 4,603 articles identified, eight were included, comprising a total of 233 patients. The signs and symptoms were identified and ranked according to frequency. Dyspnea (58.80%, six studies), carbonaceous sputum (54.51%, four studies), hoarseness (39.91%, three studies), wheezing (34.33%, five studies) and sore throat (33.90%, two studies) were the most frequent acute clinical manifestations of smoke inhalation. Besides these, chest pain and pulmonary edema were observed, respectively in 13.30%, 5.15% of the studies. Conclusion: The results suggest that dyspnea, carbonaceous sputum, hoarseness, wheezing and sore throat were the most frequent acute clinical manifestations in victims of smoke inhalation. Further studies of a higher level of evidence and greater methodological rigor are required.

Inhalation Injury: State of the Science 2016

This article summarizes research conducted over the last decade in the field of inhalation injury in thermally injured patients. This includes brief summaries of the findings of the 2006 State of the Science meeting with regard to inhalation injury, and of the subsequent 2007 Inhalation Injury Consensus Conference. The reviewed studies are categorized in to five general areas: diagnosis and grading; mechanical ventilation; systemic and inhalation therapy; mechanistic alterations; and outcomes.

Smoke inhalation increases intensive care requirements and morbidity in paediatric burns

Burn survival has improved with advancements in fluid resuscitation, surgical wound management, wound dressings, access to antibiotics and nutritional support for burn patients. Despite these advancements, the presence of smoke inhalation injury in addition to a cutaneous burn still significantly increases morbidity and mortality. The pathophysiology of smoke inhalation has been well studied in animal models. Translation of this knowledge into effectiveness of clinical management and correlation with patient outcomes including the paediatric population, is still limited. We retrospectively reviewed our experience of 13 years of paediatric burns admitted to a regional burn's intensive care unit. We compared critical care requirements and patient outcomes between those with cutaneous burns only and those with concurrent smoke inhalation injury. Smoke inhalation increases critical care requirements and mortality in the paediatric burn population. Therefore, early critical care input in the management of these patients is advised.

Evidence for multidimensional resilience in adult patients with transfusion-dependent thalassemias: Is it more common than we think?

BACKGROUND

Life expectancy of patients with transfusion-dependent thalassemias has increased with the development of improved treatment over the last few decades. However, β-thalassemia disorder still has considerable lifetime treatment demands and heightened risk of frequent complications due to transfusion-transmitted infections and iron overload, which may affect thalassemic patients' functioning in different domains.

OBJECTIVES

The vast majority of published studies on thalassemic patients have focused on children and adolescent functioning, and little research has examined adults. Hence, the current study was planned to examine the functioning and resilience of adult thalassemic patients in a comprehensive way.

METHODS

We examined multidimensional resilience and functioning across different domains (psychological adjustment, treatment adherence, social functioning and occupational functioning). We also examined demographic and medical variables that may relate to resilience and functioning. Participants were adult patients [n = 38; age M = 31·63, standard deviation (SD) = 7·72; 72% female] with transfusion-dependent thalassemia in treatment in a hospital in the northeastern United States.

RESULTS

The results suggest that most adult thalassemic patients tend to be resilient, demonstrating good functioning in four main domains: psychological adjustment, treatment adherence, social functioning and occupational functioning.

CONCLUSION

Despite the considerable demands of their illness, adult thalassemic patients appeared to be adapting well, demonstrating evidence of multidimensional resilience.

Prehospital Care of Burn Patients and Trajectories on Survival

We sought to identify factors associated with the prognosis and survival of burn patients by analyzing data related to the prehospital treatment of burn patients transferred directly to the burn unit from the accident site. We also aimed to assess the role of prehospital physicians and paramedics providing care to major burn patients. This study included adult burn patients with severe burns treated between 2006 and 2010. Prehospital patient records and clinical data collected during treatment were analyzed, and the Injury Severity Scale (ISS) was calculated. Patients were grouped into two cohorts based on the presence or absence of a physician during the prehospital phase. Data were analyzed with reference to survival by multivariable regression model. Specific inclusion criteria resulted in a sample of 67 patients. The groups were comparable with regard to age, gender, and injury etiology. Patients treated by prehospital physicians (group 1, n = 49) were more severely injured than patients treated by paramedics (group 2, n = 18) in terms of total burn surface area (%TBSA) (32% vs. 17%, p = 0.033), ISS (25 vs. 8, p < 0.000), and inhalation injuries (51% vs. 16%, p = 0.013), and presented with a higher pulse rate, lower systolic blood pressure, and lower median pH. Age, gender, %TBSA, and ISS were significantly associated with survival in both groups. Survival at 30 days was associated with age, gender, the amount of intravenous fluids (in liters) received during the first 24 hours, and the final %TBSA. Variables found to be independently associated by multivariable regression model with 30 day mortality were age, female gender, and final TBSA. We identified prehospital prognostic factors affecting patient outcomes. Based on the results from this study, our current EMS system is capable of identifying seriously injured burn patients who may benefit from physician attendance at the injury scene.

Validation of the prognostic burn index: a nationwide retrospective study

BACKGROUND

The burn index (BI=full thickness total burn surface area [TBSA]+1/2 partial thickness TBSA) and prognostic burn index (PBI=BI+age) are clinically used particularly in Japan. However, few studies evaluated the validation of PBI with large sample size. We retrospectively investigated the relationships between PBI and mortality among burn patients using data from a nationwide database.

METHODS

Data of all burn patients with burn index ≥1 were extracted from the Japanese Diagnosis Procedure Combination (DPC) inpatient database from 1 July 2010 to 31 March 2013 (17,185 patients in 1044 hospitals). The primary endpoint was all-cause in-hospital mortality.

RESULTS

Overall in-hospital mortality was 5.9% (1011/17,185). Mortality increased significantly as the PBI increased (Mantel-Haenszel trend test, P<0.001). The area under the receiver operating characteristic curve for PBI was 0.90 (95%CI, 0.90-0.91), and a PBI above a threshold of 85 showed the highest association with in-hospital mortality. Logistic regression analysis showed that PBI≥85 (odds ratio (OR), 14.6; 95%CI, 12.1-17.6), inhalation injury with mechanical ventilation (OR, 13.0; 95%CI, 10.8-15.7), Charlson Comorbidity Index≥2 (OR, 1.8; 95%CI, 1.5-2.3), and male gender (OR, 1.5; 95%CI, 1.3-1.8) were significant independent risk factors for death.

CONCLUSIONS

Our study suggested that a PBI above a threshold of 85 was significantly associated with mortality. The PBI and mechanical ventilation were the most significant factors predicting in-hospital mortality, after adjustment for inhalation injury, comorbidity, and gender.