Inhalation injury is an independent predictor of mortality after burn injury. Although bronchoscopy remains the gold standard for diagnosing inhalation injury, there is a paucity of evidence to support repeat bronchoscopies for following inhalation injuries during a patient's clinical course. This study looks at the ability of serial bronchoscopies to prognosticate outcomes. This was a secondary analysis of a previously reported prospective observational study. Patients diagnosed with inhalation injury had repeat bronchoscopies with blinded investigators assigning severity scores. The study used multivariate regression analysis to investigate whether inhalation injury severity scores of the carinal images were predictive of mortality. Secondary outcomes included diagnosis of acute respiratory distress syndrome or pneumonia during hospitalization. The final analysis included 99 patients. After accounting for age, percent TBSA burn, and injury severity scores, there were no days that were significant for predicting outcomes. All days were poor predictors overall, with the area under the receiver operating curve being <0.8 in all instances. These results do not support the use of serial bronchoscopies for prognostication purposes. Until a larger, randomized clinical trial can evaluate this further, serial bronchoscopies performed for assessment of the progression of inhalation injury may provide more risk than benefit.

To evaluate variations in diagnostic criteria and management recommendations for smoke inhalation injury (SII) amongst the burn networks of England, Scotland, and Wales.

A descriptive cross-sectional study examining SII guidelines provided by adult burn units and centres in England, Scotland and Wales.

All 16 adult burn units and centres responded. Fourteen (87.5 %) had guidelines. Due to sharing of guidelines, ten unique guidelines were assessed. Diagnostic criteria showed variability with no universal criterion shared amongst guidelines. Bronchoscopy was recommended by 90 % of guidelines, but the timing varied. The use of bronchoscopic scoring systems was recommended by four guidelines. Bronchoalveolar lavage (BAL) was recommended by four, with considerable variation in frequency and choice of lavage fluid. All guidelines advised at least one nebulised agent: heparin (n = 8); N-acetyl cysteine (NAC) (n = 8); or salbutamol (n = 8). All guidelines included advice on carbon monoxide poisoning; however, carboxyhaemoglobin (COHb) cut-off levels for treatment varied (5 % [n-4], 10 % [n = 3], 15 % [n = 1]). All recommended high-flow oxygen. Seven (70 %) guidelines offered guidance on cyanide poisoning. Reduced/altered consciousness was the only consistent diagnostic criterion. Five (50 %) guidelines provided intubation guidance, emphasising the role of a 'senior clinician' as the intubator. Ventilatory guidance appeared in eight guidelines, focusing on lung protective ventilation (n = 8); oxygenation goals (n = 3); and permissive hypercapnia (n = 3). Within lung-protective ventilation, advice on tidal volume (6, or 6-8 ml/kg) and plateau pressures (>30 cmH2O) were presented most commonly (n = 7).

This study has outlined the substantial variations in guidance for the management of SII. The results underscore the need for a national guideline outlining a standardised approach to the diagnosis and management of SII, within the limitations of the current evidence.

The impact of inhalation injury on risk of nosocomial pneumonia (NP), an important complication in patients with burns, is not well established.

Is more severe inhalation injury associated with increased risk of NP?

We performed a retrospective cohort study of patients with suspected inhalation injury admitted to a regional burn center from 2011 to 2022 who underwent diagnostic bronchoscopy within 48 h of admission. We estimated the association of high-grade inhalation injury (Abbreviated Injury Scale grade 3 and 4) vs low-grade inhalation injury (Abbreviated Injury Scale grade 1 and 2) with NP adjusted for age, burn size, and comorbid obstructive lung disease. Death and hospital discharge were considered competing risks.

Of the 245 patients analyzed, 51 (21%) had high-grade injury, 180 (73%) had low-grade injury, and 14 (6%) had no inhalation injury. Among the 236 patients hospitalized for ≥ 48 h, NP occurred in 24 of 50 patients (48%) in the high-grade group, 54 of 172 patients (31%) in the low-grade group, and two of 14 patients (14%) in the no inhalation injury group. High-grade (vs low-grade) inhalation injury was associated with higher hazard of NP in both the proportional cause-specific hazard model (cause-specific hazard ratio, 2.04; 95% CI, 1.26-3.30; P = .004) and Fine-Gray subdistribution hazard model (subdistribution hazard ratio for NP, 2.24; 95% CI, 1.38-3.64; P = .001).

In this study, among patients with inhalation injury, more severe injury was associated with higher hazard of NP in competing risk analysis. Additional research is needed to investigate mechanisms that may explain the relationship between inhalation injury and NP and to identify more effective risk reduction strategies.

One in six people are projected to be 65 years or older by 2050. As the population ages, better treatments for injuries that disproportionately impact the aged population will be needed. Clinical studies show that people aged 65 and older experience higher rates of morbidity and mortality after burn injury, including a greater incidence of pulmonary complications when compared to younger burn injured adults, which we and others believe is mediated, in part, by inflammation originating in the intestines. Herein, we use our clinically relevant model of scald burn injury in young and aged mice to determine whether cohousing aged mice with young mice or giving aged mice oral gavage of fecal material from young mice is sufficient to alter the microbiome of the aged mice and protect them from inflammation in the ileum and the lungs. Aged burn injured mice have less DNA expression of Bacteroidetes in the feces and an unhealthy Firmicutes/Bacteroidetes ratio. Both Bacteroidetes and the ratio of these two phyla are restored in aged burn injured by prior cohousing for a month with younger mice but not fecal transfer from young mice. This shift in the microbiome coincides with heightened expression of danger-associated molecular patterns (DAMP), and pro-inflammatory cytokine interleukin-6 (il6) in the ileum and lung of aged, burn injured mice, and heightened antimicrobial peptide camp in the lung. Cohousing reverses DAMP expression in the ileum and lung, and cathelicidin-related antimicrobial peptide protein (camp) in the lung, while fecal transfer heightened DAMPs while reducing camp in the lung, and also increased IL-6 protein in the lungs. These results highlight the importance of the intestinal microbiome in mediating inflammation within the gut-lung axis, giving insights into potential future treatments in the clinic.

Adipose-derived stem cells (ASCs) are multipotent stem cells capable of differentiating into many cell lineages. They play an important role in wound healing by secreting cytokines. Prior studies have demonstrated the presence of proinflammatory cytokines in burn wounds. However, no studies have been performed evaluating the cytokines released by burn wounds with infections. We hypothesized that there is an alteration in the paracrine factors secreted by ASCs in burn wounds with concomitant infections.

Adipose tissue was collected from patients with burn injuries at their index operation. ASCs were extracted and grown under standard tissue culture techniques. The supernatant was extracted. Cytokine analyses were performed with multiplex assays. Infection was determined using a burn sepsis protocol. The cytokine profiles of the two groups were compared using a Mann-Whitney U test.

Sixteen patients were enrolled in the study, 50% with bacterial infection (n = 8). There was no significant difference in the baseline demographics of the two groups (P > 0.05). There were significantly lower concentrations of interleukin 13 and interferon gamma (P < 0.05) in burn patients with concomitant infections.

ASCs are critical to burn wound healing. This study demonstrated diminished production of interleukin 13, an immunoregulatory cytokine involved in the antiinflammatory pathway by downregulating macrophage activity. This study also demonstrated significantly lower levels of interferon gamma in patient with burns and concomitant infection. This cytokine is crucial for antimicrobial defenses.

Specific toxic compounds, such as polycyclic aromatic hydrocarbons (PAHs) and their metabolites, may affect the inhalation injury (INHI) grade, patients' status, and prognosis for recovery. This pilot prospective study aimed to: i) evaluate the suitability of bronchoalveolar lavage (BAL) for determination of PAHs in the LRT and of urine for determination of hydroxylated metabolites (OH-PAHs) in patients with INHI, ii) describe the dynamic changes in the levels of these toxic compounds, and iii) correlate these findings with clinical variables of the patients with INHI.

The BAL and urine samples from 10 patients with INHI were obtained on Days 1, 3, 5, 7, and 14 of hospitalization, if possible, and PAHs (BAL) and OH-PAHs (urine) were analyzed using chromatographic methods (GC-MS and HPLC).

Concentrations of analyzed PAHs were in most cases and time points below the limit of quantification in BAL samples. Nine OH-PAHs were detected in the urine samples; however, their concentrations sharply decreased within the first three days of the hospitalization. On Day 14, the total amount of OH-PAHs in urine was higher in surviving patients with High-grade INHI (≥3) than in those with Low-grade INHI (<3, p = 0.032). Finally, a significant correlation between certain OH-PAHs and clinical variables (AST/ALT, TBSA, ABSI) from Day 1 of the hospitalization was observed (p<0.05).

BAL samples are not suitable for the analysis of PAHs. However, the OH-PAHs levels in urine can be measured reliably and were correlated with several clinical variables. Moreover, High-grade INHI was associated with higher total concentrations of OH-PAHs in urine.

It remains unclear whether additional fluid supplementation is necessary during the acute resuscitation period for patients with combined inhalational injury (INHI) under the guidance of the Third Military Medical University (TMMU) protocol.

A 10-year multicenter, retrospective cohort study, involved patients with burns ≥ 50% total burn surface area (TBSA) was conducted. The effect of INHI, INHI severity, and tracheotomy on the fluid management in burn patients was assessed. Cumulative fluid administration, cumulative urine output, and cumulative fluid retention within 72 h were collected and systematically analyzed.

A total of 108 patients were included in the analysis, 85 with concomitant INHI and 23 with thermal burn alone. There was no significant difference in total fluid administration during the 72-h post-burn between the INHI and non-INHI groups. Although no difference in the urine output and fluid retention was shown in the first 24 h, the INHI group had a significantly lower cumulative urine output and a higher cumulative fluid retention in the 48-h and 72-h post-burn (all p < 0.05). In addition, patients with severe INHI exhibited a significantly elevated incidence of complications (Pneumonia, 47.0% vs. 11.8%, p = 0.012), (AKI, 23.5% vs. 2.9%, p = 0.037). For patients with combined INHI, neither the severity of INHI nor the presence of a tracheotomy had any significant influence on fluid management during the acute resuscitation period.

Additional fluid administration may be unnecessary in major burn patients with INHI under the guidance of the TMMU protocol.

Burn patients with inhalation injury are at higher risk of developing pneumonia, and yet there is no reliable tool for the assessment of the risk for such patients at admission. This study aims to establish a predictive model for pneumonia risk for burn patients with inhalation injury based on clinical findings and laboratory tests.

This retrospective study enrolled 546 burn patients with inhalation injury. They were grouped into a training cohort and a validation cohort. The least absolute shrinkage and selection operator (LASSO) regression analysis and binary logistic regression analysis were utilized to identify risk factors for pneumonia. Based on the factors, a nomogram for predicting pneumonia in burn patients with inhalation injury was constructed. Areas under the receiver operating characteristic curves (AUC), calibration plots, and decision curve analysis (DCA) were used to evaluate the efficiency of the nomogram in both the training and validation cohorts.

The training cohort included 432 patients, and the validation cohort included 114 patients, with a total of 225 (41.2%) patients experiencing pneumonia. Inhalation injury, tracheal intubation/tracheostomy, low serum albumin, and high blood glucose were independent risk factors for pneumonia in burn patients with inhalation injury and they were further used to build the nomogram. The AUC of the nomogram in the training and validation cohorts were 0.938 (95% CI: 0.917-0.960) and 0.966 (95% CI: 0.931-1), respectively. The calibration curve for probability of pneumonia showed optimal agreement between the prediction by nomogram and the actual observation, and the DCA indicated that the constructed nomogram conferred high clinical net benefit.

This nomogram can accurately predict the risk of developing pneumonia for burn patients with inhalation injury, and help professionals to identify high-risk patients at an early stage as well as to make informed clinical decisions.

The coronavirus disease pandemic has had a tangible impact on bronchoscopy for burn inpatients due to isolation and triage measures. We utilised the machine-learning approach to identify risk factors for predicting mild and severe inhalation injury and whether patients with burns experienced inhalation injury. We also examined the ability of two dichotomous models to predict clinical outcomes including mortality, pneumonia, and duration of hospitalisation.

A retrospective 14-year single-centre dataset of 341 intubated patients with burns with suspected inhalation injury was established. The medical data on day one of admission and bronchoscopy-diagnosed inhalation injury grade were compiled using a gradient boosting-based machine-learning algorithm to create two prediction models: model 1, mild vs. severe inhalation injury; and model 2, no inhalation injury vs. inhalation injury.

The area under the curve (AUC) for model 1 was 0·883, indicating excellent discrimination. The AUC for model 2 was 0·862, indicating acceptable discrimination. In model 1, the incidence of pneumonia (P < 0·001) and mortality rate (P < 0·001), but not duration of hospitalisation (P = 0·1052), were significantly higher in patients with severe inhalation injury. In model 2, the incidence of pneumonia (P < 0·001), mortality (P < 0·001), and duration of hospitalisation (P = 0·021) were significantly higher in patients with inhalation injury.

We developed the first machine-learning tool for differentiating between mild and severe inhalation injury, and the absence/presence of inhalation injury in patients with burns, which is helpful when bronchoscopy is not available immediately. The dichotomous classification predicted by both models was associated with the clinical outcomes.

Following the global COVID-19 pandemic, the incidence of tracheal epithelial injury is increasing. However, the repair of tracheal epithelial injury remains a challenge due to the slow renewal rate of tracheal epithelial cells (TECs). In traditional nebulized inhalation treatments, drugs are enriched in the lungs or absorbed into the blood, reducing drug concentration at the tracheal injury site. In this study, we prepared an epidermal growth factor (EGF)-loaded gamma-polyglutamic acid (γ-PGA)/epsilon-poly-L-lysine (ε-PLL) (PP) hydrogel (EGF@PP) to promote the repair of tracheal epithelial injury. Epidermal growth factor promotes the proliferation of TECs and enhances vascularization, thereby accelerating injury repair. The PP hydrogel exhibits outstanding wet adhesion, slow drug release, and antibacterial and anti-inflammatory properties, making it suitable for application in the airways and creating an environment conducive to epithelial repair. Here, we established a rabbit model of tracheal injury using a laser to destroy the tracheal epithelium and delivered EGF@PP powder to the injury site under fiberoptic bronchoscopy guidance. Our findings revealed that this was an effective therapeutic strategy for accelerating the repair of tracheal epithelial injury.

In patients with inhalation injury associated with major burns, the primary mechanism of tissue harm depends on the location within the respiratory tract. Proximal to the trachea, the upper respiratory tract epithelium is classically injured via direct thermal injury. Such injury occurs due to the inhalation of high-temperature air. These upper airway structures and the tracheobronchial tree's dense vasculature protect the lower airways and lung parenchyma from direct thermal damage. The lower respiratory tract epithelium and lung parenchyma typically become injured secondary to the cytotoxic effects of chemical irritants inhaled in smoke as well as delayed inflammatory host responses. This paper documents a rare case in which a patient demonstrated evidence of direct thermal injury to the lower respiratory tract epithelium. A 26-year-old Caucasian male presented to the emergency room with 66% total body surface area thermal burns and grade 4 inhalation injury after a kitchen fire. Instead of visualizing carbonaceous deposits in the bronchi, a finding common in inhalation injury, initial bronchoscopy revealed bronchial mucosa carpeted with hundreds of bullae. Despite the maximum grade of inhalation injury per the abbreviated injury score and a 100% chance of mortality predicted with the revised Baux score, as well as a clinical course complicated by pneumonia development, bacteremia, and polymicrobial external wound infection, this patient survived. This dissonance between his expected and observed clinical outcome suggests that the applicability of current inhalation injury classification systems depends on the precise mechanism of injury to the respiratory tract. The flaws of these grading scales and prognostic indicators may be rooted in their failure to account for other pathophysiologic processes involved in inhalation injury. It may be necessary to develop new grading and prognostic systems for inhalation injury that acknowledge and better account for unusual pathophysiologic mechanisms of tissue damage.

Tracheostomy has been proposed for patients with expected prolonged intubation. This study aims to determine the outcomes of tracheostomy on patients with burn inhalation injuries requiring mechanical ventilation.

This study is a retrospective review from 2011 to 2019. Inclusion criteria were recording of inhalation injury, ventilator support (at least 24 hours), and total body surface area of <15%. The patients were stratified into 2 groups: tracheostomy (group 1) versus no tracheostomy (group 2). The outcome measures were in-hospital mortality rate, hospital length of stay, intensive care unit length of stay, ventilator days, and ventilator- associated pneumonia (VAP).

A total of 33 burn patients met our inclusion criteria. Group 1 consisted of 10 patients and group 2 of 23 patients. There was no statistically significant difference in terms of percent total body surface area. There was a higher intensive care unit length of stay at 23.8 days in group 1 compared with 3.16 days in group 2, a higher hospital length of stay at 28.4 days in group 1 compared with 5.26 days in group 2, and higher ventilator days in group 1 with 20.8 days compared with 2.5 days in group 2. There was no statistically significant difference between the 2 groups in terms of mortality. The incidence of VAP was also significantly higher in group 1 than in group 2.

The ideal timing and implementation of tracheostomy with inhalation injury has yet to be determined. In this study, tracheostomy was associated with much longer lengths of stay and pneumonia. The impact of the underlying lung injury versus the tracheostomy itself on these observations is unclear. The challenge of characterizing the severity of an inhalation injury based on early visual inspection remains.

Respiratory failure occurs with some frequency in seriously burned patients, driven by a combination of inflammatory and infection factors. Inhalation injury contributes to respiratory failure in some burn patients via direct mucosal injury and indirect inflammation. In burn patients, respiratory failure leading to acute respiratory distress syndrome, with or without inhalation injury, is effectively managed using principles evolved for non-burn critically ill patients.

Facial burns frequently occur in occupational or household accidents. While dysphagia and dysphonia are known sequelae, little is known about impaired smell and taste after facial burns.

In a prospective observational controlled study, we evaluated hyposmia via the Sniffin' Stick Test (SnS), hypogeusia via a taste strip test, and dysphonia and dysphagia via validated questionnaires acutely and one-year after burn, respectively. A matched control group consisting of a convenience sample of healthy volunteers underwent the same assessments.

Fifty-five facial burn patients (FB) and 55 healthy controls (CTR) were enrolled. Mean burn size was 11 (IQR: 29) % total body surface area (TBSA); CTR and FB were comparable regarding age, sex and smoking status. Acutely, hyposmia was present in 29% of the FB group (CTR: 9%, p = 0.014) and burn patients scored worse on the SnS than CTR (FB: 10; CTR: 11; IQR: 2; p = 0.013). Hyposmia per SnS correlated with subjective self-assessment. Hyposmia and SnS scores improved over time (FB acute: 10.5 IQR: 2; FB one year: 11; IQR: 2; p = 0.042) and returned to normal at one-year post burn in most patients who completed the study (lost to follow-up: 21 patients). Taste strip scores were comparable between FB and CTR, as was the acute prevalence of dysphagia and dysphonia.

Hyposmia acutely after facial thermal trauma appeared frequently in this study, especially when complicated by inhalation trauma or large TBSA involvement. Of all complete assessments, a fraction of burn patients retained hyposmia after one year while most improved over time to normal. Prevalence of dysphonia, dysphagia and hypogeusia was comparable to healthy controls in this study, perhaps due to overall minor burn severity.

The frequency of bushfires in Australia is increasing and it is expected bushfire smoke will become a more prevalent phenomenon impacting air quality. The objective of this position statement is to provide guidance to the sport sector regarding exercise in air affected by bushfire smoke.

This is position statement from the Australian Institute of Sport, based on a narrative review of the literature regarding bushfire smoke and its effects on health and exercise performance.

A narrative review of scientific publications regarding the effects of bushfire smoke on health and exercise performance.

Bushfire smoke has negative impacts on health and performance. Athletes exercising at high intensity over a prolonged duration will increase their exposure to air pollutants. Athletes with a history of elevated airway responsiveness are likely to be at increased risk of an adverse response to bushfire smoke exposure.

Athletes, coaches, support staff and sport organisations should monitor air quality (PM2.5 concentration) and make appropriate adjustments to training duration and intensity.

The abbreviated injury score (AIS) is commonly used as a grading system for inhalation injuries. While inhalation injury grades have inconsistently been shown to correlate positively with the time mechanical ventilation is needed, grading is subjective and relies heavily on the clinicians' experience and expertise. Additionally, no correlation has been shown between these patients' inhalation injury grades and outcomes. In this paper, we propose a novel inhalation injury grading method which uses deep learning algorithms in bronchoscopy images to determine the injury grade from the carbonaceous deposits, blistering, and fibrin casts in the bronchoscopy images. The proposed method adopts transfer learning and data augmentation concepts to enhance the accuracy performance to avoid overfitting. We tested our proposed model on the bronchoscopy images acquired from eighteen patients who had suffered inhalation injuries, with the degree of severity 1, 2, 3, 4, 5, or 6. As performance metrics, we consider accuracy, sensitivity, specificity, F-1 score, and precision. Experimental results show that our proposed method, with both transfer learning and data augmentation components, provides an overall 86.11% accuracy. Moreover, the experimental results also show that the performance of the proposed method outperforms the method without transfer learning or data augmentation.

Fire smoke enters the human lungs through the respiratory tract. The damage to the respiratory tract and lung tissue is known as smoke inhalation injury (SII). Fire smoke can irritate airway epithelium cells, weaken endothelial cell adhesion and lyse alveolar type II epithelia cells, leading to emphysema, decreased lung function, pneumonia and risk of acute lung injury/acute respiratory distress syndrome (ARDS). The purpose of the present study was to analyze the clinical characteristics of patients with SII and the risk factors affecting their prognosis. A total of 103 patients with SII admitted between January 2016 to December 2021 to the Burns Unit of the Characteristic Medical Center of Chinese People's Armed Police Force and 983 Hospital of the Joint Logistics Support Force of the Chinese People's Liberation Army were selected for the present study. The demographics and clinical features between different severities of SII were analyzed. Univariate/multivariate logistic regression was used to analyze the potential predictors for severity, ARDS and mortality of patients with SII. Receiver operating characteristic (ROC) curves were used to screen independent risk factors and identify their prediction accuracy. It was concluded that total body surface area (TBSA), III burn area (of total %TBSA), cases of respiratory infections, ARDS morbidity, mortality, acute physiology and chronic health evaluation II, lung injury prediction score, lactic acid, white blood cells (WBC), alanine transaminase, blood urea nitrogen, serum creatinine and uric acid were indicators that were raised with increasing severity of SII. However red blood cells, hemoglobin, platelet count, total protein, albumin, and albumin/globulin were decreased with the increasing severity of SII (P<0.05). WBC >20.91 (10⁹/l) was a reliable indicator for severe SII. Lactic acid >9.60 (mmol/l) demonstrated a high degree of accuracy in predicting ARDS development in patients with SII. Hemoglobin <83.00 (g/l) showed a high degree of accuracy in predicting mortality. In summary, the highlighted assessment parameters could be used to contribute to devising improved treatment plans to preempt worsening conditions (such as shock, ARDS, multiple organ dysfunction syndrome and death).

Severe burn injury leads to a cascade of local and systemic immune responses that trigger an extreme state of immune dysfunction, leaving the patient highly susceptible to acute and chronic infection. When combined with inhalation injury, burn patients have higher mortality and a greater chance of developing secondary respiratory complications including infection. No animal model of combined burn and inhalation injury (B+I) exists that accurately mirrors the human clinical picture, nor are there any effective immunotherapies or predictive models of the risk of immune dysfunction. Our earlier work showed that the mechanistic/mammalian target of rapamycin (mTOR) pathway is activated early after burn injury, and its chemical blockade at injury reduced subsequent chronic bacterial susceptibility. It is unclear if mTOR plays a role in the exacerbated immune dysfunction seen after B+I injury. We aimed to: (1) characterize a novel murine model of B+I injury, and (2) investigate the role of mTOR in the immune response after B+I injury. Pulmonary and systemic immune responses to B+I were characterized in the absence or presence of mTOR inhibition at the time of injury. Data describe a murine model of B+I with inhalation-specific immune phenotypes and implicate mTOR in the acute immune dysfunction observed.

Lung injury from smoke inhalation manifests as airway and parenchymal damage, at times leading to the acute respiratory distress syndrome. From the beginning of this millennium, the approach to mechanical ventilation in the patient with ARDS was based on reduction of tidal volume to 6 milliliters/kilogram of ideal body weight, maintaining a ceiling of plateau pressure, and titration of driving pressure (plateau pressure minus PEEP). Beyond these broad constraints, there is little specification for the mechanics of ventilator settings, consideration of the metabolic impact of the disease process on the patient, or interaction of patient disease and ventilator settings. Various studies suggest that inhomogeneity of lung injury, which increases the risk of regional lung trauma from mechanical ventilation, may be found in the patient with smoke inhalation. We now appreciate that energy transfer principles may affect optimal ventilator management and come into play in damaged heterogenous lungs. Mechanical ventilation in the patient with inhalation injury should consider various factors. Self-injurious respiratory demand by the patient can be reduced using analgesia and sedation. Dynamic factors beginning with rate management can reduce the incidence of potentially damaging ventilation. Moreover, preclinical study is underway to examine the flow of gas based on the ventilator mode selected, which may also be a factor triggering regional lung injury.

We present our approach of pediatric burned patients with the suspicion of inhalation injury.

This retrospective study was conducted on children with the suspicion of inhalation injury admitted to our burn center from December 2009 to December 2019. We collected data on patient demographics, total burn surface area (TBSA), presence of inhalation injury, level of carboxyhemoglobin, grade of inhalation injury, duration of mechanical ventilation, reintubation rate, total length of hospital stay, and the mortality rate. We also reviewed the required treatment of patients with inhalation injury.

A total of sixty pediatric burn patients were suspected inhalation injury were included in this retrospective study. 40 pa-tients included in the study were male. Age average of the patients was 87.7 months. Total burned surface area average was 32%. 46 of these patients had inhalation injury. Patients with larger cutaneous burn and needed early intubation have a higher risk of inhalation injury. There was no significant relation between inhalation injury grades and mortality and treatment protocols. Higher levels of car-boxyhemoglobin and larger TBSA are the risk factors for mortality at univariate analysis. Pediatric patient with inhalation injury whose TBSA is higher than 47.5% has a 5 times higher risk of mortality at multivariate analysis.

This study demonstrated that TBSA is the risk factor that independently affects the mortality in pediatric patients with inhalation injury. Among the patients with higher than 47.5% burn surface area, the mortality rate rises 5 times.

Clinical studies have demonstrated that age 50 years or older is an independent risk factor associated with poor prognosis after burn injury, the second leading cause of traumatic injuries in the aged population. While mechanisms driving age-dependent postburn mortality are perplexing, changes in the intestinal microbiome, may contribute to the heightened, dysregulated systemic response seen in aging burn patients. The fecal microbiome from 22 patients admitted to a verified burn center from July 2018 to February 2019 was stratified based on the age of 50 years and total burn surface area (TBSA) size of ≥10%. Significant differences (P = .014) in overall microbiota community composition (ie, beta diversity) were measured across the four patient groups: young <10% TBSA, young ≥10% TBSA, older <10% TBSA, and older ≥10% TBSA. Differences in beta diversity were driven by %TBSA (P = .013) and trended with age (P = .087). Alpha diversity components, richness, evenness, and Shannon diversity were measured. We observed significant differences in bacterial species evenness (P = .0023) and Shannon diversity (P = .0033) between the groups. There were significant correlations between individual bacterial species and levels of short-chain fatty acids. Specifically, levels of fecal butyrate correlated with the presence of Enterobacteriaceae, an opportunistic gut pathogen, when elevated in burn patients lead to worsen outcomes. Overall, our findings reveal that age-specific changes in the fecal microbiome following burn injuries may contribute to immune system dysregulation in patients with varying TBSA burns and potentially lead to worsened clinical outcomes with heightened morbidity and mortality.

Burns inhalation injury increases the attributable mortality of burns related trauma. However, diagnostic uncertainties around bronchoscopically graded severity, and its effect on outcomes, remain. This study evaluated the impact of different bronchoscopic burns inhalation injury grades on outcomes.

A single-centre cohort study of all patients admitted to the London Burns centre intensive care unit (BICU) over 12 years. Demographic data, burn and burns inhalation injury characteristics, and ICU-related parameters were collected retrospectively. The primary outcome was mortality. Secondary outcomes were hospital and ICU lengths of stay. The impact of pneumonia was determined. Univariate and multivariable Cox's proportional hazards regression analyses informed factors predicting mortality.

Burns inhalation injury was diagnosed in 84 of 231 (36%) critically ill burns patients; 20 mild (grade 1), 41 severe (grades 2/3) and 23 unclassified bronchoscopically. Median (IQR) total body surface area burned (TBSA) was 20% (10-40). Mortality was significantly higher in patients with burns inhalation injury vs those without burns inhalation injury (38/84 [45%] vs 35/147 [24%], p < 0.001). Patients with pneumonia had a higher mortality than those without (34/125 [27%] vs 8/71 [11%], p = 0.009). In multivariable analysis, severe burns inhalation injury significantly increased mortality (adjusted HR=2.14, 95%CI: 1.12-4.09, p = 0.022), compared with mild injury (adjusted HR=0.58, 95% CI: 0.18-1.86, p = 0.363). Facial burns (adjusted HR=3.13, 95%CI: 1.69-5.79, p < 0.001), higher TBSA (adjusted HR=1.05, 95%CI: 1.04-1.06, p < 0.001) and older age (adjusted HR=1.04, 95%CI: 1.02-1.07, p < 0.001) also independently predicted mortality, though pneumonia did not.

Severe burns inhalation injury is a significant risk factor for mortality in critically ill burns patients. However, pneumonia did not increase mortality from burns inhalation injury. This work confirms prior implications of bronchoscopically graded burns inhalation injury. Further study is suggested, through registries, into the diagnostic accuracy and reliability of bronchoscopy in burns related lung injury.

Although it has been widely proposed that inhalation injuries worsen burn outcomes, large-scale studies have yet to demonstrate the exact relationship. This study proposes inhalation injuries as an independent risk factor that worsens burn outcomes.

A retrospective review of the American Burn Association Registry from 2002 to 2011 was conducted. Inclusion criteria included burn patients with a total body surface area (TBSA) of less than 15% and adequate data recording of the inhalation injury within the registry. Patients were stratified into 2 groups: inhalation injuries (group 1) vs non-inhalation injuries (group 2). Outcome measures included in-hospital mortality rate, hospital length of stay (LOS), intensive care unit (ICU) LOS, and days on a ventilator.

A total of 93781 burn patients met the inclusion criteria. There were 4204 patients in group 1 and 89577 patients in group 2. There was no statistically significant difference between the 2 groups in terms of TBSA, with 3.50% in group 1 and 3.58% in group 2. There was a significantly higher ICU LOS at 8.55 days in group 1 compared to 6.27 days in group 2. There was a significantly higher hospital LOS at 11.48 days in group 1 compared to 6.27 days in group 2. The in-hospital mortality was significantly higher in group 1 at 8.54% vs group 2 at 1.42%.

The presence of inhalation injury may be a predictor of increased mortality and poor outcome in burn patients, even in those with small sized burns.

Burn injury is associated with endothelial dysfunction and coagulopathy and concomitant inhalation injury increases morbidity and mortality. The aim of this work is to identify associations between inhalation injury (IHI), coagulation homeostasis, vascular endothelium, and clinical outcomes in burn patients. One-hundred and twelve patients presenting to a regional burn center were included in this retrospective cohort study. Whole blood was collected at set intervals from admission through 24 hours and underwent viscoelastic assay with rapid TEG (rTEG). Syndecan-1 (SDC-1) on admission was quantified by ELISA. Patients were grouped by the presence (n=28) or absence (n=84) of concomitant IHI and rTEG parameters, fibrinolytic phenotypes, SDC-1, and clinical outcomes were compared. Of the 112 thermally injured patients, 28 (25%) had IHI. Most patients were male (68.8%) with a median age of 40 (IQR, 29-57) years. Patients with IHI had higher overall mortality (42.68% vs. 8.3%; p<0.0001). rTEG LY30 was lower in patients with IHI at hours 4 and 12 (p<0.05). There was a pattern of increased abnormal fibrinolytic phenotypes among IHI patients. There was a greater proportion of IHI patients with endotheliopathy (SDC-1 > 34 ng/mL) (64.7% vs. 26.4%; p=0.008). There was a pattern of increased mortality among patients with inhalation injury and endotheliopathy (0% vs. 72.7%; p=0.004). Significant differences between patients with and without IHI were found in measures assessing fibrinolytic potential and endotheliopathy. Mortality was associated with abnormal fibrinolysis, endotheliopathy, and inhalation injury. However, the extent to which IHI associated dysfunction is independent of TBSA burn size remains to be elucidated.

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.

To explore the protective effects and related mechanism of aerosol inhalation of edaravone on inflammation, oxidative stress and pulmonary function (PF) in rats with smoke inhalation injury.

Twenty-four rats were stochastically and equally divided into four groups: group A (edaravone-preventing group), group B (model group), group C (low-dose group) and group D (high-dose group). The serum of rats was collected to determine the expression of miR-320, inflammatory mediators (TNF-α, IL-6, IL-10), oxidative stress indexes (MDA, SOD, MPO) and oxygenation index (OI). Pulmonary tissues of rats were collected to determine the total lung water (TLW), wet-to-dry ratio (W/D) and other parameters. HE staining was adopted for pathological evaluation.

Compared with group B, the levels of miR-320, TNF-α, IL-6, MDA, MPO, TLW and W/D in group A were significantly down-regulated, while IL-10, SOD and OI levels were significantly up-regulated, and the trend of this change was more obvious than that in group C and group D, with notably better improvement degree in group D than group C. In HE staining, the pulmonary tissue structure was basically normal in group A, and was better than that of the other three groups. In group B, the pulmonary tissue was seriously damaged, accompanied by a large number of inflammatory cells infiltration and alveolar wall thickening. The pathological condition of group C was notably ameliorated, the extent of this improvement was more pronounced in group D, and the degree of pathological improvement in group D was superior to that in group C.

Aerosol inhalation of edaravone in advance can reduce the levels of inflammatory factors and oxidative stress indexes in serum of smoke inhalation injury rats, thus protecting PF, which may be related to the down-regulation of miR-320 by edaravone.

Advances in the care of inhalational injuries have not kept pace with advances that have been seen in the treatment of cutaneous burns. There is not yet a standard of care for best outcomes for airway management of patients with known or suspected inhalational injuries. Clinicians must decide if to intubate the patient, and if so, whether to intubate early or late in their presentation. Unnecessary intubation affects morbidity and mortality. This review will summarize literature that highlights present practices in the treatment of patients with inhalation injuries.

There have been promising investigations into biomarkers that can be used to quantify a patient's risk and better target therapies. Grading systems serve to better stratify the burn victim's prognosis and then direct their care. Special ventilator modes can assist in ventilating burn patients with inhalation injuries that experience difficulties in oxygenating.

Inhalational injuries are a significant source of morbidity and mortality in thermally injured patients. Treatment modalities, such as modified ventilator settings, alteration in fluid resuscitation, and a standardized grading system may improve morbidity and mortality.

Pulmonary and systemic insults from inhalation injury can complicate the care of burn patients and contribute to significant morbidity and mortality. However, recent progress in diagnosis and treatment of inhalation injury has not kept pace with the care of cutaneous thermal injury. There are many challenges unique to inhalation injury that have slowed advancement, including deficiencies in our understanding of its pathophysiology, the relative difficulty and subjectivity of bronchoscopic diagnosis, the lack of diagnostic biomarkers, the necessarily urgent manner in which decisions are made about intubation, and the lack of universal recommendations for the application of mucolytics, anticoagulants, bronchodilators, modified ventilator strategies, and other measures. This review represents a summary of critical shortcomings in our understanding and management of inhalation injury identified by the American Burn Association's working group on Cutaneous Thermal Injury and Inhalation Injury in 2018. It addresses our current understanding of the diagnosis, pathophysiology, and treatment of inhalation injury and highlights topics in need of additional research, including 1) airway repair mechanisms; 2) the airway microbiome in health and after injury; and 3) candidate biomarkers of inhalation injury.

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.

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.

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).

Plasma sST2 in the first 24 h of admission predicts the occurrence of pneumonia in patients with inhalation injury.

To characterize serious inhalation injuries seen during recent military operations, and assess whether bronchoscopic severity findings were associated with clinical presentation and outcomes.

Service members who suffered inhalation injuries while deployed to Iraq, Afghanistan, or Syria from 2001-2018 were identified using ICD-9 and 10 codes from the Expeditionary Medical Encounter Database (EMED), which is abstracted from patient records in forward-deployed medical facilities. Further information including demographics, mechanism of injury, mortality, total burn surface area (TBSA), degree of facial burn, total Injury Severity Score (ISS), and first post-injury bronchoscopy notes were collected. Patients were excluded with ISS less than 16 or without sufficient details regarding bronchoscopy. Injuries were grouped based on bronchoscopic Abbreviated Injury Scores (AIS) into low-grade (AIS of 1), moderate-grade (AIS of 2), or high-grade (AIS of 3 or 4).

91 patients met inclusion criteria, with no significant differences in age, gender, paygrade, or service branch between degrees of injury. There were no statistical correlations between grade of injury and battle versus non-battle injury, blast versus non-blast mechanism, TBSA, or degree of facial burn. High-grade injuries had significantly higher ISS than low or moderate-grade injuries. After adjusting for ISS, the odds ratio of death was 10.4 (95% CI 1.47 to 74.53) for those with high-grade and 3.7 (95% CI 0.45 to 32.30) for those with moderate-grade compared to low-grade injuries.

In this cohort of deployed military members with inhalation injuries, initial bronchoscopic severity findings are strongly associated with mortality even after adjusting for ISS. The AIS may be an important prognostic tool in all of those with serious inhalation injuries.

The ability to accurately evaluate the severity of inhalation injury can help to optimize patient care. However, there is no accepted severity grading system, especially for inhalation injury.

We screened a multicenter burn registry and included adult patients who required oxygen treatment or mechanical ventilation. After the patient data were divided into development and validation cohorts, missing values were replaced with multiple imputation. Twelve potential predictors were analyzed using multivariate logistic regression to identify prognostic variables for in-hospital mortality and scores were assigned to each predictor based on odds ratios to develop the Modified Abbreviated Burn Severity Index, mABSI. The mABSI was validated using c-statistics and calibration curves.

We randomly assigned 1377 and 919 patients to the development and validation cohorts, respectively. Age, self-inflicted injury, cutaneous burn area, and mechanical ventilation requirement were identified as independent predictors, and the mABSI (1-17 scale) was, thus, developed. The mABSI has a high discriminatory power (c-statistic = 0.94; 95% CI 0.92-0.97), and both estimated and observed in-hospital mortalities increased from 1% at score ≤ 5 to almost 100% at score ≥ 14 with linear calibration plots.

We developed and validated the mABSI which accurately predicts in-hospital mortality.

This study compares the ability of liberal vs restrictive intubation criteria to detect prolonged intubation and inhalation injury in burn patients with suspected inhalation injury. Emerging evidence suggests that using liberal criteria may lead to unnecessary intubation in some patients. A single-center retrospective cohort study was conducted in adult patients with suspected inhalation injury admitted to intensive care at Queen Elizabeth Hospital, Birmingham between April 2016 and July 2019. Liberal intubation criteria, as reflected in local guidelines, were compared to restrictive intubation criteria, as outlined in the American Burn Association guidelines. The number of patients displaying positive characteristics from either guideline was compared to the number of patients who had prolonged intubation (more than 48 hours) and inhalation injury. In detecting a need for prolonged intubation (n = 85), the liberal criteria had greater sensitivity (liberal = 0.98 [0.94-1.00] vs restrictive = 0.84 [0.75-0.93]; P = .013). However, the restrictive criteria had greater specificity (restrictive = 0.96 [0.89-1.00] vs liberal = 0.48 [0.29-0.67]; P < .001). In detecting inhalation injury (n = 72), the restrictive criteria were equally sensitive (restrictive = 0.94 [0.87-1.00] vs liberal = 0.98 [0.84-1.00]; P = .48) and had greater specificity (restrictive = 0.86 [0.72-1.00] vs liberal = 0.04 [0.00-0.13]; P < .001). In patients who met liberal but not restrictive criteria, 65% were extubated within 48 hours and 90% did not have inhalation injury. Liberal intubation criteria were more sensitive at detecting a need for prolonged intubation, while restrictive criteria were more specific. Most patients intubated based on liberal criteria alone were extubated within 48 hours. Restrictive criteria were highly sensitive and specific at detecting inhalation injury.

Inhalation injury is an independent risk factor in burn mortality, imparting a 20% increased risk of death. Yet there is little information on the natural history, functional outcome, or pathophysiology of thermal injury to the laryngotracheal complex, limiting treatment progress. This paper demonstrates a case series (n = 3) of significant thermal airway injuries. In all cases, the initial injury was far exceeded by the subsequent immune response and aggressive fibroinflammatory healing. Serial examination demonstrated progressive epithelial injury, mucosal inflammation, airway remodeling, and luminal compromise. Histologic findings in the first case demonstrate an early IL-17A response in the human airway following thermal injury. This is the first report implicating IL-17A in the airway mucosal immune response to thermal injury. Their second and third patients received Azithromycin targeting IL-17A and showed clinical responses. The third patient also presented with exposed tracheal cartilage and underwent mucosal reconstitution via split-thickness skin graft over an endoluminal stent in conjunction with tracheostomy. This was associated with rapid abatement of mucosal inflammation, resolution of granulation tissue, and return of laryngeal function. Patients who present with thermal inhalation injury should receive a thorough multidisciplinary airway evaluation, including early otolaryngologic evaluation. New early endoscopic approaches (scar lysis and mucosal reconstitution with autologous grafting over an endoluminal stent), when combined with targeted medical therapy aimed at components of mucosal airway inflammation (local corticosteroids and systemic Azithromycin targeting IL-17A), may have potential to limit chronic cicatricial complications.

Inhalation of thermal and chemical products of combustion evokes an immune response measurable at a systemic level. Inhalation injury related kinetics of currently available inflammatory biomarkers and novel Pancreatic Stone Protein (PSP) as well as their interference with septic events has not been addressed to literature yet.

Analysis of the influence of inhalation injury and ARDS on biomarker kinetics (PSP, procalcitonin (PCT), C-reactive Protein (CRP), white blood cells (WBC)) in 90 patients admitted to Zurich Burn Center between May 2015 and October 2018 with burns ≥15% total body surface area (TBSA) over 14 days.

Twenty-five (27%) of 90 included patients presented with inhalation injury (median age 52 years [IQR 27], median TBSA 31.5% [IQR 21], mean ABSI-Score 7±3). At admission, only WBC demonstrated significantly higher values in the inhalation injury group (p=0.011). Acute respiratory distress syndrome (ARDS) was present in 32% without association to the severity of inhalation injury (p=0.11). WBC, CRP and PCT failed to delineate inhalation injury related inflammation from septic progression at most time points. PSP was the strongest marker to identify septic patients both by its higher values and steeper increase over time (p<0.001).

Inhalation injury leads to an inflammatory response at a systemic level with alterations of biomarkers. While routine inflammatory markers demonstrated strong interferences between inhalation injury with its associated ARDS and evolving sepsis, PSP reliably identified septic patients in a setting of inflammatory turbulences secondary to inhalation injury.

On August 27 and 28, 2018, the American Burn Association, in conjunction with Underwriters Laboratories, convened a group of experts on burn and inhalation injury in Washington, DC. The goal of the meeting was to identify and discuss the existing knowledge, data, and modeling gaps related to understanding cutaneous thermal injury and inhalation injury due to exposure from a fire environment, and in addition, address two more areas proposed by the American Burn Association Research Committee that are critical to burn care but may have current translational research gaps (inflammatory response and hypermetabolic response). Representatives from the Underwriters Laboratories Firefighter Safety Research Institute and the Bureau of Alcohol, Tobacco, Firearms and Explosives Fire Research Laboratory presented the state of the science in their fields, highlighting areas that required further investigation and guidance from the burn community. Four areas were discussed by the full 24 participant group and in smaller groups: Basic and Translational Understanding of Inhalation Injury, Thermal Contact and Resulting Injury, Systemic Inflammatory Response and Resuscitation, and Hypermetabolic Response and Healing. A primary finding was the need for validating historic models to develop a set of reliable data on contact time and temperature and resulting injury. The working groups identified common areas of focus across each subtopic, including gaining an understanding of individual response to injury that would allow for precision medicine approaches. Predisposed phenotype in response to insult, the effects of age and sex, and the role of microbiomes could all be studied by employing multi-omic (systems biology) approaches.