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.

[Advances on the application of physical airway clearance techniques in the treatment of inhalation injury].

Although the treatment of patients with burns combined with inhalation injury has achieved great success, from the perspective of epidemiology, inhalation injury is still the most common cause of death in mass burns. Such patients often suffered burns of large total body surface area, which is difficult to treat, with airway management as one of the core links. Physical airway clearance technique (ACT) acts on a patient's respiratory system by physical means, to discharge secretions and foreign bodies in the airway, achieve airway clearance, and improve gas exchange. In addition, the technique can prevent or alleviate many complications, thereby improving the clinical outcome of patients with inhalation injury. This article reviews the application of physical ACT in the field of inhalation injury, and to provide decision-making basis for clinical medical staff to choose physical ACT corresponding to the patient's condition.

Inhalation Injury: Which Providers Can Assess the Need for Intubation?

Previous studies have suggested that many burn patients undergo unnecessary intubation due to concern for inhalation injury. We hypothesized that burn surgeons would intubate burn patients at a lower rate than non-burn acute care surgeons (ACSs). We performed a retrospective cohort study of all patients admitted to an American Burn Association-verified burn center who presented emergently following burn injury from June 2015 to December 2021. Patients excluded include polytrauma patients, isolated friction burns, and patients intubated prior to hospital arrival. Our primary outcome was intubation rates between burn and non-burn ACSs. 388 patients met inclusion criteria. 240 (62%) patients were evaluated by a burn provider and 148 (38%) were evaluated by a non-burn provider; the groups were well-matched. In total, 73 (19%) of patients underwent intubation. There was no difference in the rate of emergent intubation, diagnosis of inhalation injury on bronchoscopy, time to extubation, or incidence of extubation within 48 hours between burn and non-burn ACSs. We found no difference between burn and non-burn ACSs in the airway evaluation and management of burn patients. Surgical providers with acute care surgery backgrounds and Advanced Trauma Life Support training are well-equipped for initial airway management in burn patients. Further studies should seek to compare other types of provider groups to identify opportunities for intervention and education in preventing unnecessary intubations.

Delayed Tracheoesophageal Fistula and Refractory Respiratory Failure Caused by Inhalation Burns and Emergency Venovenous ECMO to Facilitate Its Management: A Case Report.

Acquired tracheoesophageal fistulae are uncommon in burn patients but can occur as a complication of inhalation injury. We report a case of a 30-yr-old male patient presenting after suffering from inhalation and 25% total body surface area burns. On postburns day 14, he developed a massive tracheoesophageal fistula causing refractory acute respiratory failure. Veno-venous extracorporeal membrane (VV ECMO) oxygenation was initiated without systemic anticoagulation via bi-femoral cannulation under transthoracic echocardiography guidance. He underwent successful 5-hr apnoeic ventilation-assisted surgical repair of the fistula via a right posterolateral thoracotomy. ECMO was discontinued after 36 hr, and he was discharged to the ward after 33 d in the intensive care unit. Inhalation burn injury can cause a delayed life-threatening tracheoesophageal fistula. Surgical repair can be successfully performed for this condition. VV- ECMO can be used to facilitate prolonged apnoeic surgery and to manage refractory respiratory failure due to this condition.

Impact of inhalation injury on outcomes in critically ill burns patients: 12-year experience at a regional burns centre.

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Modified abbreviated burn severity index as a predictor of in-hospital mortality in patients with inhalation injury: development and validation using independent cohorts.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: We developed and validated the mABSI which accurately predicts in-hospital mortality.

Advances in airway management and mechanical ventilation in inhalation injury.

PURPOSE OF REVIEW: Airway management, mechanical ventilation, and treatment of systemic poisoning in burn patients with inhalation injury remains challenging. This review summarizes new concepts as well as open questions. RECENT FINDINGS: Several life-threatening complications, such as airway patency impairment and respiratory insufficiency, can arise in burn patients and require adequate and timely airway management. However, unnecessary endotracheal intubation should be avoided. Direct visual inspection via nasolaryngoscopy can guide appropriate airway management decisions. In cases of lower airway injury, bronchoscopy is recommended to remove casts and estimate the extent of the injury in intubated patients. Several mechanical ventilation strategies have been studied. An interesting modality might be high-frequency percussive ventilation. However, to date, there is no sound evidence that patients with inhalation injury should be ventilated with modes other than those applied to non-burn patients. In all burn patients exposed to enclosed fire, carbon monoxide as well as cyanide poisoning should be suspected. Carbon monoxide poisoning should be treated with an inspiratory oxygen fraction of 100%, whereas cyanide poisoning should be treated with hydroxocobalamin. SUMMARY: Burn patients need specialized care that requires specific knowledge about airway management, mechanical ventilation, and carbon monoxide and cyanide poisoning.

Inhalation injury is associated with long-term employment outcomes in the burn population: Findings from a cross-sectional examination of the Burn Model System National Database.

INTRODUCTION: Inhalation injuries carry significant acute care burden including prolonged ventilator days and length of stay. However, few studies have examined post-acute outcomes of inhalation injury survivors. This study compares the long-term outcomes of burn survivors with and without inhalation injury. METHODS: Data collected by the Burn Model System National Database from 1993 to 2019 were analyzed. Demographic and clinical characteristics for adult burn survivors with and without inhalation injury were examined. Outcomes included employment status, Short Form-12/Veterans Rand-12 Physical Composite Score (SF-12/VR-12 PCS), Short Form-12/Veterans Rand-12 Mental Composite Score (SF-12/VR-12 MCS), and Satisfaction With Life Scale (SWLS) at 24 months post-injury. Regression models were used to assess the impacts of sociodemographic and clinical covariates on long-term outcome measures. All models controlled for demographic and clinical characteristics. RESULTS: Data from 1,871 individuals were analyzed (208 with inhalation injury; 1,663 without inhalation injury). The inhalation injury population had a median age of 40.1 years, 68.8% were male, and 69% were White, non-Hispanic. Individuals that sustained an inhalation injury had larger burn size, more operations, and longer lengths of hospital stay (p<0.001). Individuals with inhalation injury were less likely to be employed at 24 months post-injury compared to survivors without inhalation injury (OR = 0.63, p = 0.028). There were no significant differences in PCS, MCS, or SWLS scores between groups in adjusted regression analyses. CONCLUSIONS: Burn survivors with inhalation injury were significantly less likely to be employed at 24 months post-injury compared to survivors without inhalation injury. However, other health-related quality of life outcomes were similar between groups. This study suggests distinct long-term outcomes in adult burn survivors with inhalation injury which may inform future resource allocation and treatment paradigms.

A Multicenter Evaluation of Outcomes Following the Use of Nebulized Heparin for Inhalation Injury (HIHI2 Study).

Inhalation injury causes significant morbidity and mortality secondary to compromise of the respiratory system as well as systemic effects limiting perfusion and oxygenation. Nebulized heparin reduces fibrin cast formation and duration of mechanical ventilation in patients with inhalation injury. To date, no study has compared both dosing strategies of 5000 and 10,000 units to a matched control group. This multicenter, retrospective, case-control study included adult patients with bronchoscopy-confirmed inhalation injury. Each control patient, matched according to age and percent of total body surface area, was matched to a patient who received 5000 units and a patient who received 10,000 units of nebulized heparin. The primary endpoint of the study was duration of mechanical ventilation. Secondary endpoints included 28-day mortality, ventilator-free days in the first 28 days, difference in lung injury scores, length of hospitalization, incidence of ventilator-associated pneumonia, and rate of major bleeding. Thirty-five matched patient trios met inclusion criteria. Groups were well-matched for age (P = .975) and total body surface area (P = .855). Patients who received nebulized heparin, either 5000 or 10,000 units, had 8 to 11 less days on the ventilator compared to controls (P = .001). Mortality ranged from 3 to 14% overall and was not statistically significant between groups. No major bleeding events related to nebulized heparin were reported. Mechanical ventilation days were significantly decreased in patients who received 5000 or 10,000 units of nebulized heparin. Nebulized heparin, either 5000 units or 10,000 units, is a safe and effective treatment for inhalation injury.

The Predictive Applicability of Liberal vs Restrictive Intubation Criteria in Adult Patients With Suspected Inhalation Injury-A Retrospective Cohort Study.

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.

[Influence of inhalation injury on fluid resuscitation of massive burn patients during shock stage].

Objective: To explore the influence of inhalation injury on fluid resuscitation of massive burn patients during shock stage. Methods: A total of 74 massive burn patients (65 males and 9 females, aged 21 to 65 years) admitted to the Second Affiliated Hospital of Air Force Medical University (n=57) and Yan'an University Affiliated Hospital (n=17) from May 2009 to December 2019 were enrolled in this retrospective cohort study. Patients were divided into inhalation injury group (n=56) and non-inhalation injury group (n=18) based on clinical symptoms, vital signs, and results of bronchofibroscopy. Then 26 patients in inhalation injury group and 13 patients in non-inhalation injury group were 1∶2 matched by case-control matching based on the difference of total burn surface area. The total fluid replacement coefficient, crystalloid replacement coefficient, colloid replacement coefficient, glucose input volume, ratio of crystalloid to colloid, urine volume, and cumulative ratio of input to output volume during the first 24 h post injury, the second 24 h post injury, and the third 24 h post injury, heart rate, respiratory rate, mean arterial pressure (MAP), and hematocrit (HCT) at post injury hour (PIH) 24, 48, and 72 were recorded and compared between the two groups. Data were statistically analyzed with analysis of variance for repeated measurement and Bonferroni correction, t test, Fisher's exact probability test, and Mann-Whitney U test. Results: (1) After matching, during the first to third 24 h post injury, the total fluid replacement coefficient and glucose input volume of patients in inhalation injury group were significantly higher than those in non-inhalation injury group (F=4.202, 10.671, P<0.05 or P<0.01). During the first, second, and third 24 h post injury, the total fluid replacement coefficient, crystalloid replacement coefficient, colloid replacement coefficient, and ratio of crystalloid to colloid were similar between the patients in two groups(t=-1.336, -1.452, -1.998; -0.148, 0.141, 0.561; 0.916, -0.046, -0.509; -1.024, 0.208, 0.081, P>0.05). During the first, second, and third 24 h post injury, the glucose input volume of patients in inhalation injury group were respectively (2 996±1 176), (2 659±1 030), and (2 680±1 509) mL, which were significantly higher than (2 125±898), (1 790±828), and (1 632±932) mL in non-inhalation injury group (t=-2.334, -2.639, -2.297, P<0.05). (2) After matching, in overall comparison between groups, during the first to third 24 h post injury, the urinary output volumes and cumulative ratios of input to output volume of patients in inhalation injury group were significantly lower or higher than those in non-inhalation injury group, respectively (F=12.158, 9.111, P<0.01). At PIH 24, 48, and 72, heart rate of patients in inhalation injury group were significantly higher than those in non-inhalation injury group (F=4.675, P<0.05). There were no statistically significant differences in heart rate, respiratory rate, MAP, and HCT between patients in the two groups at PIH 24 and 48 (t=-0.039, -1.688, 1.399, 1.299, -1.741, 0.754, -0.677, 0.037, P>0.05). During the first and second 24 h post injury, the urine volume and cumulative ratio of input to output volume of patients in inhalation injury group were respectively significantly lower and higher than those in non-inhalation injury group (t(urine volume)=2.421, 2.876, t(cumulative ratio of input to output volume)=-2.687、-2.943, P<0.05 or P<0.01). At PIH 72, the heart rate and HCT of patients in inhalation injury group ( (114±13) times/min, 0.42±0.06) were significantly higher than those in non-inhalation injury group ( (98±18) times/min, 0.38±0.06, t=-3.182, -2.123, P<0.05 or P<0.01), there were no statistically significant differences in respiratory rate and MAP between the patients in two groups (t=0.359, 1.722, P>0.05). During the third 24 h post injury, there were no statistically significant differences in urine volume and cumulative ratio of input to output volume between the patients in two groups (t=1.664, -1.895, P>0.05). Conclusions: The presence of inhalation injury can lead to increased fluid requirement in massive burn patients during shock stage. An appropriate increase of fluid volume in the fluid resuscitation of burn patients combined with inhalation injury would be beneficial for maintaining ideal urine output.

"Awake" Extracorporeal Membrane Oxygenation Combined With Continuous Renal Replacement Therapy For the Treatment of Severe Chemical Gas Inhalation Lung Injury.

Lung injury caused by chemical gas inhalation is a common clinically severe disease that very easily progresses to acute respiratory distress syndrome (ARDS). Traditional respiratory support consists mainly of mechanical ventilation, but the prognosis of this condition is still poor. "Awake" extracorporeal membrane oxygenation (ECMO) maintains oxygenation, improves ventilation, adequately allows the injured lungs to rest, and avoids complications associated with sedation, intubation, and mechanical ventilation. Continuous renal replacement therapy (CRRT) can provide better fluid management and reduce pulmonary edema. Herein, we describe the case of a patient with severe chemical gas inhalation lung injury who failed to respond to traditional mechanical ventilation and was subsequently treated with awake ECMO combined with CRRT.

Role of systemic antibiotic prophylaxis in acute burns: A retrospective analysis from a tertiary care center.

INTRODUCTION: Burns are a worldwide problem with majority of them occurring in low and middle-income countries. The hurdles in treatment of burns in the resource restricted setting are unique and challenging. The role of intravenous antibiotics in reducing mortality and morbidity related to infection and sepsis has not been studied extensively in the Indian sub-continent. MATERIALS AND METHODS: This was a retrospective study conducted at a tertiary burn care center in India over a period of six months with follow up of one month from the day of burn injury. RESULTS: Data from a total of 157 patients were collected and analysed. In Prophylaxis group (n = 77), sepsis was detected in 33 patients and 38 patients expired. In No Prophylaxis group (n = 80), sepsis was detected in 37 patients and 40 patients expired. In Inhalational burns subgroup, patients belonging to Prophylaxis group (n = 30) had 20 patients diagnosed with pneumonia while 22 patients did not survive till 30th post burn day. Patients in No Prophylaxis group who had inhalational burns were 38 in number. Pneumonia was diagnosed in 29 of them while 27 did not survive till 30th post burn day. In Pneumonia subgroup, patients belonging to Prophylaxis group had lower mortality rate as compared to No Prophylaxis group. CONCLUSION: Our study does not support the routine usage of antibiotic prophylaxis in patients with burn injuries, but their administration can be considered in certain specific subgroups like patients with inhalational burns and patients developing pneumonia. Pneumonia is an independent risk factor for mortality when no antibiotic prophylaxis is used in burn patients.

Standards in Biologic Lesions: Cutaneous Thermal Injury and Inhalation Injury Working Group 2018 Meeting Proceedings.

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.

Ventilación mecánica en el paciente quemado crítico con inhalación: ¿podemos evitarla? / Mechanical ventilation in critically ill burn patient with inhalation injury: Can we avoid it?

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Recovery from Total Acute Lung Failure After 20 Months of Extracorporeal Life Support.

Since the first successful case report in 1972, extracorporeal life support or extracorporeal membrane oxygenation (ECMO) has become a standard approach for severe respiratory failure unresponsive to other therapy. In the past, if there was no recovery by approximately 30 days or if right ventricular heart failure occurred, ECMO was discontinued and the patient died. More recently patients with severe lung disease have been maintained for months, as opposed to days, with eventual decannulation and recovery. We report the case of a child, 7 years old, with severe inhalational burn injury and rapid progression to multisystem organ failure. She was supported by ECMO with no lung function for almost 2 years. Central nervous system function remained normal and lung function recovered. This is the longest successful case of ECMO to date and prompts further discussion regarding "irreversible" lung injury.

Airway management in inhalation injury: a case series.

Inhalation injury is a serious consequence of a fire or an explosion, with potential airway compromise and respiratory complications. We present a case series of five patients with inhalational burns who presented to Singapore General Hospital and discuss our approach to their early management, including early evaluation and planning for the upper and lower airway, coexisting cutaneous burns, and monitoring their ICU (intensive care unit) severity of illness, sepsis and acute respiratory distress syndrome. All five patients suffered various grades of inhalation injury. The patients were initially assessed by nasolaryngoscopy, and three patients were prophylactically intubated before being sent to the emergency operating theatre for definitive airway and burns management with fibreoptic bronchoscopy. All patients were successfully extubated and discharged stable. Various complications can arise as a result of an inhalation injury. Based on our cases and literature review, we propose a standardised workflow for patients with inhalation injury.