Indications of early intubation for patients with inhalation injury

Inhalational Injury Secondary to House Fire

Audience

This scenario was developed to educate emergency medicine residents on the diagnosis and management of patients with an inhalational airway injury secondary to a house fire.

Background

Burn injuries are a common occurrence encountered by the emergency physician. According to the National Hospital Ambulatory Medical Care Survey, around 371,000 patients were treated in emergency departments for fire or burn injuries across the United States in 2020. This represents around 1% of emergency department visits related to injury, poisoning, or adverse effects.1 One of the most dangerous and time critical aspects of managing severely burned patients is inhalation injury. Inhalation injury is a relatively vague term which may refer to pulmonary exposure to a wide range of chemicals in various forms. In the context of burn patients, this is most often smoke exposure. It is critical that the emergency medicine provider rapidly identifies the potential for an inhalational injury in order to determine the need for definitive airway management. It is also important that the provider has the necessary skills and systematic approach to manage what is likely to be a difficult airway. Furthermore, providers must then have the knowledge of how to best manage and resuscitate these severely burned patients post-intubation.

Educational Objectives

At the conclusion of the simulation session, learners will be able to: 1) recognize the indications for intubation in a thermal burn/inhalation injury patient; 2) develop a systematic approach to an inhalational injury airway; and 3) recognize indications for transfer to burn center.

Educational Methods

This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on the diagnosis, differential diagnosis, and management of inhalational airway injury secondary to a house fire. Debriefing methods may be left to the discretion of participants, but the authors have utilized advocacy-inquiry techniques. This scenario may also be run as an oral board case.

Research Methods

Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. The local institution's simulation center's electronic feedback form is based on the Center of Medical Simulation's Debriefing Assessment for Simulation in Healthcare (DASH) Student Version Short Form2 with the inclusion of required qualitative feedback if an element was scored less than a 6 or 7.

Results

Nine learners completed a feedback form. This session received all 6 & 7 scores (consistently effective/very good and extremely effective/outstanding, respectively) other than one isolated 5 score.

Discussion

This is a cost-effective method for reviewing inhalational airway injury diagnosis and management. The case may be modified for targeted audiences, expected resources, and learning objectives, such as removal of a bronchoscope availability in settings which are expected to be resource-limited. Some readers may choose to focus on other aspects of burn management instead of airway securement such as cyanide and/or carbon monoxide toxicity. We encourage readers to limit the number of learning objectives because airway algorithms and troubleshooting for this scenario was a rich, stand-alone debriefing. There was not enough time to review in detail all nuanced aspects of the burned patient, including: Lund-Browder versus rule of 9's, modified Brooke versus Parkland formulas, indications for and completion of escharotomies, and/or identification and treatment of cyanide and carbon monoxide toxicity.

Topics

Medical simulation, burns, airway emergencies, emergency medicine.

The NUTRIC Score as a Tool to Predict Mortality and Increased Resource Utilization in Intensive Care Patients with Sepsis

The Nutrition Risk in Critically Ill score (NUTRIC) is an important nutritional risk assessment instrument for patients in the intensive care unit (ICU). The purpose of this study was to evaluate the power of the score to predict mortality in patients treated for sepsis and to forecast increased resource utilization and nursing workload in the ICU. The NUTRIC score predicted mortality (AUC 0.833, p < 0.001) with the optimal cut-off value of 6 points. Among patients with a score ≥ 6 on ICU admission, the 28-day mortality was 61%, and 10% with a score < 6 (p < 0.001). In addition, a NUTRIC score of ≥6 was associated with a more intense use of ICU resources, as evidenced by a higher proportion of patients requiring vasopressor infusion (98 vs. 82%), mechanical ventilation (99 vs. 87%), renal replacement therapy (54 vs. 26%), steroids (68 vs. 31%), and blood products (60 vs. 43%); the nursing workload was also significantly higher in this group. In conclusion, the NUTRIC score obtained at admission to the ICU provided a good discriminative value for mortality and makes it possible to identify patients who will ultimately require intense use of ICU resources and an associated increase in the nursing workload during treatment.

First-day computed tomography: does it has a role in the assessment of patients with inhalation lung injury?

Background

Inhalation lung injury occurs in almost one-third of all serious burns and is responsible for a considerable proportion of burn patient fatalities each year. History of closed space fire or unconsciousness at the accident site, occurrence of pharyngeal or facial burns, hoarseness, and wheezing, and laboratory tests that include blood gas abnormalities or Carboxyhemoglobin levels in blood ˃ 10% are used to diagnose inhalation lung injury. It is also characterized by radiological findings of alveolar or interstitial edema, atelectasis, and/or consolidations, as well as the presence of erythema with laryngeal or tracheal edema in the bronchoscope.

Objectives

To study the diagnostic and prognostic efficacy of radiologist score and bronchial wall thickening as radiological CT findings in inhalation lung injury.

Methods

This prospective case–control study included 48 patients with inhalation lung injury (ILI) as a case group and 10 patients without ILI were selected as the control group, all recruited from the burn and plastic department. Within the first 12 h of suspected ILI, a fiberoptic bronchoscope was done to confirm the diagnosis. An initial chest X-ray was done followed by computed tomography through which the radiologist score (RADS) together with bronchial wall thickening (BWT) was done.

Results

Duration of ventilation was higher in cases than in controls (8.50 ± 3.94 vs 3.25 ± 0.50). The hospital duration was higher in cases than in controls (13.6 ± 4.68 vs9.50 ± 4.52). The BWT was 2.12 ± 0.66 (mean ± SD) in the ILI group while the control group was 1.32 ± 0.48 (mean ± SD). Correlating between baseline PaO2 and RADS score and BWT, it was found that there was a highly significant negative correlation between PaO2 and RADS score and BWT among inhalation lung injury patients (P value 0.001). The sensitivity of BWT in the detection of the need for mechanical ventilation was 83% at a cut-off point of 1.65. Its specificity was 78% and accuracy 75%.

Conclusion

CT done within 24 h of burn patients has a good role in the diagnosis and management of ILI from the burn.

Analysis of risk factors of mortality for pediatric burned patients with inhalation injury and comparison of different treatment protocols

BACKGROUND

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

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Positive signs on physical examination are not always indications for endotracheal tube intubation in patients with facial burn

Background

After clinical evaluation in the emergency department (ED), facial burn patients are usually intubated to protect their airways. However, the possibility of unnecessary intubation or delayed intubation after admission exists. Objective criteria for the evaluation of inhalation injury and the need for airway protection in facial burn patients are needed.

Methods

Facial burn patients between January 2013 and May 2016 were reviewed. Patients who were and were not intubated in the ED were compared. All the intubated patients received routine bronchoscopy and laboratory tests to evaluate whether they had inhalation injuries. The patients with and without confirmed inhalation injuries were compared. Multivariate logistic regression analysis was used to identify the independent risk factors for inhalation injuries in the facial burn patients. The reasons for intubation in the patients without inhalation injuries were also investigated.

Results

During the study period, 121 patients were intubated in the ED among a total of 335 facial burn patients. Only 73 (60.3%) patients were later confirmed to have inhalation injuries on bronchoscopy. The comparison between the patients with and without inhalation injuries showed that shortness of breath (odds ratio = 3.376, p = 0.027) and high total body surface area (TBSA) (odds ratio = 1.038, p = 0.001) were independent risk factors for inhalation injury. Other physical signs (e.g., hoarseness, burned nostril hair, etc.), laboratory examinations and chest X-ray findings were not predictive of inhalation injury in facial burn patients. All the patients with a TBSA over 60% were intubated in the ED even if they did not have inhalation injuries.

Conclusions

In the management of facial burn patients, positive signs on conventional physical examinations may not always be predictive of inhalation injury and the need for endotracheal tube intubation in the ED. More attention should be given to facial burn patients with shortness of breath and a high TBSA. Airway protection is needed in facial burn patients without inhalation injuries because of their associated injuries and treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00594-9.

Prehospital management of a non-intubated inhalation injury patient using transcutaneous monitoring of carbon dioxide

A 46-year-old man experienced facial burns due to a fire in his house. In the prehospital setting, suspecting inhalation injury and carbon monoxide poisoning, an emergency physician decided to bring him to the hospital for carbon dioxide (CO₂) monitoring without endotracheal intubation for approximately 20 min because of less severe respiratory distress. On the way to the hospital, the patient's end-tidal CO₂ monitoring ranged from 19 to 30 mm Hg, and transcutaneous carbon dioxide (TcPCO₂) remained between 50 and 55 mm Hg. On arrival at the hospital, PaCO₂ showed 51.6 mm Hg. Endotracheal intubation using a bronchoscope was performed in the emergency room, and inhalation injury was observed. He was extubated on day 5 and discharged on day 10. In the prehospital setting, TcPCO₂ monitoring is useful for initial management of non-intubated inhalation injury patients even with high concentration oxygen.

Management of facial burns: an update

PURPOSE OF REVIEW

This article reviews literature on the recent progress made on management of facial burns. The discussion focuses on those aspects of the management in which recent studies brought new ideas, and reviews some that failed to change practices in the management of facial burns.

RECENT FINDINGS

Recent innovations and models have been proposed in an attempt to reduce the incidence of unnecessary intubations in patients with burns to the face and with suspected inhalational injury. However, the decision to secure the airway is still a challenging one. A new escharotomy method based on facial subunits principles has been described, while the practice of early tangential excision is still debated in the literature. Tarsorrhaphy without occluding the eyes has also been described in the management of peri-oral burns. Self-retaining and expandable stents for the nose have also been demonstrated to be effective in preventing nasal stenosis. 3D printed face masks have been more recently developed to improve the current wound-care methods used in facial scar management.

SUMMARY

This article highlights recent developments in the management of facial burns in areas such as acute facial burn care, subsequent wound care and facial scar management. It highlights areas wherein progress has been made, as well as the need for further studies in certain areas.

Acute respiratory failure and burn patient outcomes

PURPOSE OF REVIEW

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.

RECENT FINDINGS

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.

SUMMARY

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.

The utility of arterial blood gas parameters and chest radiography in predicting appropriate intubations in burn patients with suspected inhalation injury-A retrospective cohort study

BACKGROUND

This study evaluates the utility of arterial blood gas (ABG) parameters and chest radiography in predicting intubation need in patients with burn injuries with suspected inhalation injury.

METHODS

Patients with suspected inhalation injury admitted to a single centre, Burn Intensive Care Unit, between April 4th 2016 and July 5th 2019, were included. Admission ABG parameters and chest radiograph opacification were compared with whether the patient received an appropriate intubation: defined as intubation for a duration of over 48 h. Area under the receiver operator characteristic curve was calculated (AUROC).

RESULTS

Eighty-nine patients were included. The majority (84%; n = 75) were intubated, of which 81% (n = 61) received appropriate intubations. pH had an AUROC of 0.88 and a pH of <7.30 had an 80% sensitivity and specificity for detecting appropriate intubation. P/F ratio had an AUROC of 0.81 and a P/F ratio of <40 had a 70% sensitivity and specificity for appropriate intubation. Chest radiograph opacification had poor utility in this regard (AUROC = 0.69). Adding pH and P/F ratio to the ABA criteria improved their sensitivity in detecting appropriate intubations (sensitivity: ABA + pH + P/F = 0.97 vs ABA = 0.86; p = 0.013), without altering their specificity.

CONCLUSIONS

In patients suspected inhalation injury, pH and P/F ratio were good predictors for appropriate intubations. Incorporating the parameters into the ABA criteria improved their clinical utility.

Laryngeal inhalational injuries: A systematic review

Laryngeal inhalation injury carries a significant increase in mortality rate and often indicates immediate airway evaluation. This may be difficult in the setting of clinical deterioration necessitating immediate intubation, which itself can synergistically cause mucosal damage. Prior studies do not encompass predictive factors or long-term outcomes for the laryngotracheal complex. This systemic review of PubMed, Embase, and Cochrane identified studies investigating inhalational injuries of the upper airway. Demographic data as well as presentation, physical findings, and delayed sequelae were documented. Laryngotracheal burn patients were divided into two cohorts based on timing of laryngeal injury diagnosis (before- versus after-airway intervention). 1051 papers met initial search criteria and 43 studies were ultimately included. Airway stenosis was more common in patients that were intubated immediately (50.0%, n = 18 versus 5.2%, n = 13; p = 0.57). Posterior glottic involvement was only identified in patients intubated prior to airway evaluation (71.4%, n = 15). All studies reported a closed space setting for those patients in whom airway intervention preceded laryngeal evaluation. Laryngeal inhalational injuries are a distinct subset that can have a variety of minor to severe laryngotracheal delayed sequelae, particularly for thermal injuries occurring within enclosed spaces. Given these findings, early otolaryngology referral may mitigate or treat these effects.

Predicting the need for intubation in the first 24 h after critical care admission using machine learning approaches

Early and accurate prediction of the need for intubation may provide more time for preparation and increase safety margins by avoiding high risk late intubation. This study evaluates whether machine learning can predict the need for intubation within 24 h using commonly available bedside and laboratory parameters taken at critical care admission. We extracted data from 2 large critical care databases (MIMIC-III and eICU-CRD). Missing variables were imputed using autoencoder. Machine learning classifiers using logistic regression and random forest were trained using 60% of the data and tested using the remaining 40% of the data. We compared the performance of logistic regression and random forest models to predict intubation in critically ill patients. After excluding patients with limitations of therapy and missing data, we included 17,616 critically ill patients in this retrospective cohort. Within 24 h of admission, 2,292 patients required intubation, whilst 15,324 patients were not intubated. Blood gas parameters (P_aO₂, P_aCO₂, HCO₃⁻), Glasgow Coma Score, respiratory variables (respiratory rate, S_pO₂), temperature, age, and oxygen therapy were used to predict intubation. Random forest had AUC 0.86 (95% CI 0.85–0.87) and logistic regression had AUC 0.77 (95% CI 0.76–0.78) for intubation prediction performance. Random forest model had sensitivity of 0.88 (95% CI 0.86–0.90) and specificity of 0.66 (95% CI 0.63–0.69), with good calibration throughout the range of intubation risks. The results showed that machine learning could predict the need for intubation in critically ill patients using commonly collected bedside clinical parameters and laboratory results. It may be used in real-time to help clinicians predict the need for intubation within 24 h of intensive care unit admission.

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.

Serious Inhalation Injuries From Military Operations in Afghanistan, Iraq, and Syria

OBJECTIVE

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

METHODS

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).

RESULTS

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.

CONCLUSION

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 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.

A novel scale for predicting delayed intubation in patients with inhalation injury

BACKGROUND

Strategies to predict delayed airway obstruction in patients with inhalation injury have not been extensively studied. This study aimed to develop a novel scale, predicting the need for Delayed Intubation after inhalation injury (PDI) score.

METHODS

We retrospectively identified patients with inhalation injury at four tertiary care centers in Japan between 2012 and 2018. We included patients aged 15 or older and excluded those intubated within 30 min after hospital arrival. Predictors for delayed intubation were identified with univariate analyses and scored on the basis of odds ratios. The PDI score was evaluated with the area under the receiver operating characteristic (AUROC) curve and compared with other scaling systems for burn injuries.

RESULTS

Data from 158 patients were analyzed; of these patients, 18 (11.4%) were intubated during the delayed phase. Signs of respiratory distress, facial burn, and pharyngolaryngeal swelling observed on laryngoscopy, were identified as predictors for delayed intubation. The discriminatory power of the PDI (AUROC curve = 0.90; 95% confidence interval, 0.83 to 0.97; p < 0.01) was higher than that of the other scaling systems.

CONCLUSIONS

We developed a novel scale for predicting delayed intubation in inhalation injury. The score should be further validated with other population.

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.