Impact of diagnostic bronchoscopy in burned adults with suspected inhalation injury.

INTRODUCTION: Inhalation injury is a common complication of thermal trauma. Fiberoptic bronchoscopy (FOB) is regarded as current standard practice in diagnosing and grading inhalation injury. Nonetheless, its predictive value in terms of therapeutic decision-making and clinical outcome is controversial. METHODS: Adult burn patients with inhalation injury (InI) were selected from the National Burn Repository of the American Burn Association. Subjects were propensity score pair-matched based on injury severity and grouped based on whether or not FOB had been performed (FOB, CTR, respectively). Mortality, incidence of pneumonia, length of hospitalization, length of ICU stay and dependency on mechanical ventilation were compared between the two groups. RESULTS: 3014 patients were matched in two groups with a mean TBSA of 22.4%. There was no significant difference in carboxyhemoglobin fraction at admission. Patients, who underwent FOB on admission had a significantly increased incidence of pneumonia (p < 0.001), mortality (p < 0.05), length of hospitalization (p = 0.002), ICU stay (p < 0.001) and duration of mechanical ventilation (p = 0.006). In a subgroup analysis of patients with TBSA of at least 20%, incidence of pneumonia was significantly higher in the FOB group (p < 0.001) and longer mechanical ventilation was required (p = 0.036). DISCUSSION: Diagnosis and grading of InI through FOB is the current standard, although its predictive value regarding key outcome parameters and therapeutic decision-making, remains unclear. The potential procedural risk of FOB itself should be considered. This study demonstrates correlations of FOB with major clinical outcomes in both a general collective of burned adults as well as severely burned adults. Although these findings must be interpreted with caution, they may induce further research into potential harm of FOB and critical review of routine diagnostic FOB in suspected inhalation injury in thermally injured patients.

Expression profile of microRNAs in bronchoalveolar lavage fluid of rats as predictors for smoke inhalation injury.

Smoke inhalation injury (SII) is an independent risk factor for morbidity and mortality in patients with severe burns, however, the underlying mechanisms of SII are still not fully understood. In our study, we established an advanced rat model of SII based on the previous work, and explored the dynamic changes of pathophysiology and inflammatory factors during 28days post SII. We also measured the different expressions of miRNAs in bronchoalveolar lavage fluid (BALF) between SII and normal control rats by miRNA microarray. At 1day after smoke inhalation, the histopathological results exhibited inflammatory exudates in the lung tissue with significant edema. As time went on, the lung injuries gradually appeared at alveolar septum thickening and alveolar collapse, which suggested that it further induced damage to lung parenchyma by smoke inhalation. Particularly, the collagen deposition indicating pulmonary fibrosis happened at 28days post-injury. Plasma IL-6 and TNF-a were significantly increased after 1day of smoke inhalation. Plasma IL-10, BALF TNF-α and IL-10 were significantly increased after 2days of smoke inhalation. By extending the observation time, the levels of plasma IL-6, BALF TNF-a and IL-10 appeared a second peak again after 14days of injury. Compared with the normal control group, there were 23 upregulated miRNAs and 2 downregulated miRNAs in BALF of SII group at 1day post-injury. RT-qPCR validation assay confirmed that the changes of miR-34c-5p, miR-92b-3p, miR-205, miR-34b-3p, miR-92a-3p, let-7b-5p, let-7c-5p in BALF were consistent with the conclusion of the miRNA microarray. In summary, we showed the dynamic changes of pathologic changes and inflammatory factors in rats with SII, and a subset of seven miRNAs changed in BALF after SII which may be used for diagnosis and potential therapeutic targets.

Emergency department management of smoke inhalation injury in adults.

Smoke inhalation injury portends increased morbidity and mortality in fire-exposed patients. Upper airway thermal burns, inflammation from lower airway irritants, and systemic effects of carbon monoxide and cyanide can contribute to injury. A standardized diagnostic protocol for inhalation injury is lacking, and management remains mostly supportive. Clinicians should maintain a high index of suspicion for concomitant traumatic injuries. Diagnosis is mostly clinical, aided by bronchoscopy and other supplementary tests. Treatment includes airway and respiratory support, lung protective ventilation, 100% oxygen or hyperbaric oxygen therapy for carbon monoxide poisoning, and hydroxocobalamin for cyanide toxicity. Due to its progressive nature, many patients with smoke inhalation injury warrant close monitoring for development of airway compromise.

The diagnosis and management of inhalation injury: An evidence based approach.

INTRODUCTION: Smoke inhalation injury (II) is an independent risk factor for mortality in burns and its management is inherently complex. We aim to make recommendations for best practice in managing II and its sequelae by reviewing all available current evidence in order to provide an evidence-based approach. METHODS: We conducted a systematic search of the Cochrane database and Embase using PRISMA guidelines with no patient population exclusion criteria. Published work was reviewed and evidence levels graded. RESULTS: We identified 521 abstracts for inclusion. Of the 84 articles identified for secondary review, 28 papers were excluded leaving 56 papers suitable for final inclusion. CONCLUSIONS: We are able to identify a number of strategies in both diagnosis and treatment of II that have support in the published literature, including the role of bronchoscopy, permissive hypercapnia, nebulized heparin and hydroxycobalamin. Other strategies have not been shown to be harmful, but their efficacy is also not firmly established, such as high frequency oscillatory ventilation and exogenous surfactant. Prophylactic antibiotics and corticosteroids are not recommended. In general, published evidence for II is mostly Level 3 or below, due to a noticeable lack of large-scale human studies. This represents a challenge for evidence-based burns practice as a whole.

Determining the role of nasolaryngoscopy in the initial evaluation for upper airway injury in patients with facial burns.

BACKGROUND: Upper airway injuries can be fatal in burn patients if not recognized, a scenario that causes a significant amount of anxiety for physicians providing initial assessment of burn patients. Early elective intubation is often performed; sometimes unnecessarily. However, some providers employ nasolaryngoscopy for patients presenting with facial burns or signs/symptoms of upper airway injury in order to assess the need for intubation, but this practice is not considered standard of care and may also be unnecessary. Evidence is currently lacking about the utility of nasolaryngoscopy as an adjuvant assessment during evaluation of potential upper airway burn injuries. The objective of this study was to determine if nasolaryngoscopy provides additional information to the history and physical in making the decision to electively intubate patients with facial burns. METHODS: This study was a retrospective analysis of all patients who underwent fiberoptic nasolaryngoscopy after facial burn injury to evaluate for upper airway injury associated with burns over a 2 year period at a regional burn center. During this time period, all patients who presented with facial burns, soot, or carbonaceous sputum underwent nasolaryngoscopy to look for upper airway injury regardless of mechanism of injury. Patients intubated prior to arrival were excluded from the study. Patients were considered to have signs/symptoms of airway injury (symptomatic) if they presented with dyspnea, tachypnea, hypoxia, or significant burns to buccal mucosa. Procedure notes were used to determine if supraglottic/glottic injury (erythema or edema) was present on nasolaryngoscopy. Presence of pathologic changes and whether they led to intubation were evaluated in the asymptomatic and the symptomatic groups of patients. Select individual records were inspected further to help determine if the nasolaryngoscopy findings altered management plans and if intubation was ultimately necessary based upon the presence or absence of a cuff leak and the duration of intubation. RESULTS: Twenty-two patients were symptomatic upon presentation, 14 of which had positive findings on laryngoscopy and 7 (50%) were intubated. One-hundred and eighty-eight patients were asymptomatic, 58 (31%) of which had either erythema or edema or carbonaceous debris on nasolaryngoscopy, and only 2 (1%) were intubated. These patients were both extubated within two days. None of the 130 asymptomatic patients with negative nasolaryngoscopy were intubated. CONCLUSIONS: This study showed disparity between signs and symptoms of airway injury and nasolaryngoscopy findings. Asymptomatic patients showed pathologic changes in 30% of scopes, but this finding only changed management 1% of the time. Furthermore, the two patients in this group were extubated quickly, suggesting they may have been suitable for observation without intubation. These results indicate that the presence of erythema or edema is of questionable clinical significance in asymptomatic patients and nasolaryngoscopy is of limited benefit in this group. Only 50% of the symptomatic patients with airway injury evident on nasolaryngoscopy were actually intubated, also bringing into question the significance of the pathologic changes in this group. However, negative nasolaryngoscopy may have had some benefit in preventing intubation in a few, select symptomatic patients. This study suggests that a thorough history and physical is the best tool to identify patients at higher risk of upper airway injury who need intubation, but this should be further studied in prospective trials to determine the definitive role of nasolaryngoscopy.

Prognostic value of serum zinc levels in patients with acute HC/zinc chloride smoke inhalation.

Hexachloroethane (HC)/zinc chloride (ZnCl, smoke bomb) exposure in the military setting results in lung injury which is uncommon and has been rarely described in previous studies. The aim of this study is to investigate the correlation between the serum zinc in patients with HC/ZnCl smoke inhalation lung injury and disease severity. A total of 15 patients with HC/ZnCl-related conditions were recruited in this study. The serum zinc level and the pulmonary function tests and liver function tests including total lung capacity (TLC), forced vital capacity (FVC), forced expiratory pressure in 1 second (FEV1), alanine aminotransferase (ALT), and aspartate transaminase (AST) were analyzed. Eleven cases had mild clinical manifestations. Four cases rapidly developed features typical of severe adult respiratory distress syndrome. The level of serum zinc was increased, but FVC, FEV1, and TLC was decreased significantly in the moderate and severe cases. In addition, the serum zinc level correlated well with the TLC, FVC, and FEV1 (r = -0.587, -0.626, -0.617, respectively; P = .027, .017, .019, respectively). The 4 cases in moderate and severe group had delayed impairment of liver functions after the accident. This study suggested that the serum zinc level may be associated with the severity of lung and liver injuries after HC/ZnCl smoke inhalation.

Severity of Inhalation Injury is Predictive of Alterations in Gas Exchange and Worsened Clinical Outcomes.

Inhalation injury (INH) is present in one third of large burn injuries and increases oxygenation and fluid resuscitation requirements, incidences of pulmonary complications, risk for multiple organ dysfunction syndrome (MODS), and overall mortality. Previous studies have demonstrated inconsistent correlation between bronchoscopic evaluation and clinical outcomes. The authors reviewed 161 patients admitted with a diagnosis of INH or underwent diagnostic bronchoscopy for suspected INH over a period of 8.5 years. One hundred one patients had concomitant burn injury and 60 had isolated INH. Seventeen patients had abbreviated injury score (AIS) 0, 81 patients had low-grade injury (AIS 1 and 2), and 63 patients had high-grade injury (AIS 3 and 4). Patients with high-grade INH had worse pulmonary dysfunction, worse oxygenation indices (P = 0.01) and plasma carboxyhemoglobin (COHgb; P < 0.01) on admission, increased fluid requirements (P < 0.01 at 24 hours; P = 0.04 at 48 hours), MODS (P = 0.04), pneumonia (P < 0.01), acute respiratory distress syndrome (P = 0.01 at 48 hours), fewer 28-day ventilator-free days (P < 0.01), greater ventilator dependence (P = 0.03), and longer length of stay (P < 0.01). Multivariate analyses demonstrated increased risk of MODS (P = 0.03), acute respiratory distress syndrome at 48 hours (P < 0.01), pneumonia (P = 0.01), prolonged ventilator dependence (P = 0.03), and a trend toward mortality (P = 0.08) with higher AIS groups. More severe INH correlates with early oxygenation impairments and is associated with more complicated hospitalization, fluid resuscitation requirements, and ventilation demands. Severe INH is associated with and predictive of increased morbidity and mortality.

Orange-Pigmented Sputum as a Manifestation of Smoke Grenade Inhalation Injury.

A 34-year-old man presented with scanty hemoptysis, orange-colored expectoration, and mild dyspnea. He was in an enclosed building taking part in a military training exercise inhaling an orange-colored smoke from a smoke grenade ignition. His symptoms developed immediately after the initial exposure but he sought medical assistance 20 hours later because of their persistence. Fiberoptic bronchoscopy was performed revealing diffuse inflammatory tracheobronchial tree with streaky orange-pigmented secretions in the trachea and both main-stem bronchi. Acute tracheobronchitis was diagnosed and the patient was treated with nebulized bronchodilators and intravenous corticosteroids showing complete recovery. To our knowledge, this is the first well-documented report of inhalation injury induced by a smoke bomb explosion including potassium chlorate oxidizer and Sudan I and presenting with orange-pigmented sputum production. Smoke inhalation injury is associated with significant morbidity and mortality. The heterogeneity of the smoke and the large variety of the resulting symptoms may be the reason why a definition, specific diagnostic criteria, and therapeutic guidelines are still lacking.

Does Bronchoscopic Evaluation of Inhalation Injury Severity Predict Outcome?

Although fiber-optic bronchoscopy is essential in the diagnosis of smoke inhalation injury (INH), controversy still exists over whether or not the visualized severity of the mucosal injury predicts clinically meaningful outcomes. The purpose of this study was to assess whether the grade of mucosal INH severity was associated with various outcomes among adult burn patients. We conducted a retrospective review of all patients requiring greater than or equal to 48 hours of mechanical ventilation who were admitted between January 1, 2007 and June 1, 2014 to an adult regional American Burn Association-verified burn center. Bronchoscopy was performed on all subjects at burn center admission and grading of severity was documented using the grades 0 to 4 abbreviated injury score (AIS). Subjects with grade 1 or 2 injury formed the low-grade INH group, whereas those with grade 3 or 4 injury formed the high-grade INH group. Values are shown as the median (first to third quartiles). A P value less than .05 was considered significant. The study population consisted of 160 subjects (age, 48 [35-60] years; %TBSA burn, 28 [19-39.9]; % full thickness burn, 12.8 [0-30]; and 61% with INH). There were no significant differences in age, %TBSA burn, or % full thickness burn between subjects with different individual INH severity grades. Oxygenation on the day of injury worsened significantly as the severity of INH increased, but otherwise there were no significant differences in 24 and 48-hour fluid requirements, duration of ventilation, ventilator free days, incidence of acute respiratory distress syndrome, or mortality between subjects with different individual grades of INH severity. Subjects with high-grade INH showed statistically insignificant trends toward larger 48-hour fluid volumes (P = .07), poorer oxygenation over the first 3 post burn days (P = .055), longer duration of ventilation (P = .08), and fewer ventilator free days (P = .047) than low-grade INH. High-grade and low-grade INH subjects did not differ significantly in the incidence of acute respiratory distress syndrome or mortality. The individual grades of the 0 to 4 AIS INH severity grading scale were not particularly robust in the prediction of various outcomes among a population of adult burn patients. However, clinically relevant trends toward worsened oxygenation over postburn days 0 to 3, longer duration of mechanical ventilation, and reduced ventilator-free days in association with more severe INH were identified when subjects were broadly stratified into low-grade (grades 1and 2) INH and high-grade (grades 3 and 4) INH. This suggests that there may clinically meaningful differences between patients with less and more severe INH, and that further refinement of the grades 0 to 4 AIS INH severity should be subjected to additional investigation.

Diagnosis and management of inhalation injury: an updated review.

In this article we review recent advances made in the pathophysiology, diagnosis, and treatment of inhalation injury. Historically, the diagnosis of inhalation injury has relied on nonspecific clinical exam findings and bronchoscopic evidence. The development of a grading system and the use of modalities such as chest computed tomography may allow for a more nuanced evaluation of inhalation injury and enhanced ability to prognosticate. Supportive respiratory care remains essential in managing inhalation injury. Adjuncts still lacking definitive evidence of efficacy include bronchodilators, mucolytic agents, inhaled anticoagulants, nonconventional ventilator modes, prone positioning, and extracorporeal membrane oxygenation. Recent research focusing on molecular mechanisms involved in inhalation injury has increased the number of potential therapies.

Comparison of virtual bronchoscopy to fiber-optic bronchoscopy for assessment of inhalation injury severity.

PURPOSE: Compare virtual bronchoscopy (VB) to fiberoptic bronchoscopy (FOB) for scoring smoke inhalation injury (SII). METHODS: Swine underwent computerized tomography (CT) with VB and FOB before (0) and 24 and 48 h after SII. VB and FOB images were scored by 5 providers off line. RESULTS: FOB and VB scores increased over time (p<0.001) with FOB scoring higher than VB at 0 (0.30±0.79 vs. 0.03±0.17), 24 h (4.21±1.68 vs. 2.47±1.50), and 48h (4.55±1.83 vs. 1.94±1.29). FOB and VB showed association with PaO2-to-FiO2 ratios (PFR) with areas under receiver operating characteristic curves (ROC): for PFR≤300, VB 0.830, FOB 0.863; for PFR≤200, VB 0.794, FOB 0.825; for PFR≤100, VB 0.747, FOB 0.777 (all p<0.001). FOB showed 80.3% specificity, 77% sensitivity, 88.8% negative-predictive value (NPV), and 62.3% positive-predictive value (PPV) for PFR≤300 and VB showed 67.2% specificity, 85.5% sensitivity, 91.3% NPV, and 53.4% PPV. CONCLUSIONS: VB provided similar injury severity scores to FOB, correlated with PFR, and reliably detected airway narrowing. VB performed during admission CT may be a useful screening tool specifically to demonstrate airway narrowing induced by SII.

In vivo detection of inhalation injury in large airway using three-dimensional long-range swept-source optical coherence tomography.

We report on the feasibility of using long-range swept-source optical coherence tomography (OCT) to detect airway changes following smoke inhalation in a sheep model. The long-range OCT system (with axial imaging range of 25 mm) and probe are capable of rapidly obtaining a series of high-resolution full cross-sectional images and three-dimensional reconstructions covering 20-cm length of tracheal and bronchial airways with airway diameter up to 25 mm, regardless of the position of the probe within the airway lumen. Measurements of airway thickness were performed at baseline and postinjury to show mucosal thickness changes following smoke inhalation.

Report on a study of fires with smoke gas development : determination of blood cyanide levels, clinical signs and laboratory values in victims.

BACKGROUND: This is a report on an international non-interventional study of patients exposed to fires with smoke development in closed rooms. The objective of the study was to document clinical symptoms, relevant laboratory values and blood cyanide concentrations from fire victims in order to confirm or rule out presumptive correlations between the individual parameters. MATERIALS AND METHODS: The study was conducted in five European countries with patients being included if they presented with the characteristic clinical signs, such as soot deposits and altered neurological status. Venous blood samples were taken from victims prior to administration of an antidote in all cases and determination of cyanide concentration was performed in a central laboratory using high performance liquid chromatography. RESULTS: Data from 102 patients (62 % male, average age 49 years) were included in the evaluation with no blood samples being available for analysis from 2 patients. In 25 patients the blood cyanide concentration was below the limit of detection of 1.2 µmol/l. Cyanide levels between 1.2 and 10 µmol/l were measured in 54 patients, 7 patients had values between 10 and 20 µmol/l, 4 patients between 20 and 40 µmol/l while levels above 40 µmol/l were determined in 10 patients. The results of the study could not demonstrate that the cyanide level was influenced either by the interval between smoke exposure and blood sampling or the duration presence at the fire scene. The following clinical signs or laboratory values were recorded as relevant for increased and possibly toxic cyanide levels: respiratory arrest, dyspnea, resuscitation requirement, tracheal intubation, respiratory support measures, low Glasgow coma scale (GCS) score and respiratory frequency. A correlation between cyanide concentration and the total amount of soot deposits on the face and neck, in the oral cavity and in expectoration was confirmed. A correlation between cyanide and carboxyhemoglobin (COHb) levels in the blood of fire victims was also confirmed. CONCLUSIONS: As long as it is not possible to immediately determine the blood cyanide concentration in patients exposed to fire with smoke development, a decreased GCS score, soot deposits particularly in expectoration, dyspnea and convulsions are to be regarded as risk markers for intoxication. In their presence immediate administration of hydroxocobalamin as an antidote is recommended.

"The black bronchoscopy": a case of airway soot deposition.

The term "black bronchoscopy" is used to describe the black pigmentation of the airways. It is a rare condition with multiple etiologies. We describe a case of a "black bronchoscopy" due to severe soot deposition as a result of smoke inhalation during a household fire in a 71-year-old woman. Early flexible bronchoscopy allowed for a precise diagnosis of severe inhalation injury, and bronchial lavage was carried out to remove soot casts to reduce complications. Any patient suspected of having smoke inhalation injury should undergo early bronchoscopy to allow for a precise diagnosis, staging, and more aggressive treatment measures as the mortality among patients exposed to smoke with inhalation airway injury is high.

Inhalation injury: epidemiology, pathology, treatment strategies.

Lung injury resulting from inhalation of smoke or chemical products of combustion continues to be associated with significant morbidity and mortality. Combined with cutaneous burns, inhalation injury increases fluid resuscitation requirements, incidence of pulmonary complications and overall mortality of thermal injury. While many products and techniques have been developed to manage cutaneous thermal trauma, relatively few diagnosis-specific therapeutic options have been identified for patients with inhalation injury. Several factors explain slower progress for improvement in management of patients with inhalation injury. Inhalation injury is a more complex clinical problem. Burned cutaneous tissue may be excised and replaced with skin grafts. Injured pulmonary tissue must be protected from secondary injury due to resuscitation, mechanical ventilation and infection while host repair mechanisms receive appropriate support. Many of the consequences of smoke inhalation result from an inflammatory response involving mediators whose number and role remain incompletely understood despite improved tools for processing of clinical material. Improvements in mortality from inhalation injury are mostly due to widespread improvements in critical care rather than focused interventions for smoke inhalation.Morbidity associated with inhalation injury is produced by heat exposure and inhaled toxins. Management of toxin exposure in smoke inhalation remains controversial, particularly as related to carbon monoxide and cyanide. Hyperbaric oxygen treatment has been evaluated in multiple trials to manage neurologic sequelae of carbon monoxide exposure. Unfortunately, data to date do not support application of hyperbaric oxygen in this population outside the context of clinical trials. Cyanide is another toxin produced by combustion of natural or synthetic materials. A number of antidote strategies have been evaluated to address tissue hypoxia associated with cyanide exposure. Data from European centers supports application of specific antidotes for cyanide toxicity. Consistent international support for this therapy is lacking. Even diagnostic criteria are not consistently applied though bronchoscopy is one diagnostic and therapeutic tool. Medical strategies under investigation for specific treatment of smoke inhalation include beta-agonists, pulmonary blood flow modifiers, anticoagulants and antiinflammatory strategies. Until the value of these and other approaches is confirmed, however, the clinical approach to inhalation injury is supportive.

"Smoking wet": respiratory failure related to smoking tainted marijuana cigarettes.

Reports have suggested that the use of a dangerously tainted form of marijuana, referred to in the vernacular as "wet" or "fry," has increased. Marijuana cigarettes are dipped into or laced with other substances, typically formaldehyde, phencyclidine, or both. Inhaling smoke from these cigarettes can cause lung injuries. We report the cases of 2 young adults who presented at our hospital with respiratory failure soon after they had smoked "wet" marijuana cigarettes. In both patients, progressive hypoxemic respiratory failure necessitated rescue therapy with extracorporeal membrane oxygenation. After lengthy hospitalizations, both patients recovered with only mild pulmonary function abnormalities. To our knowledge, this is the first 2-patient report of severe respiratory failure and rescue therapy with extracorporeal oxygenation after the smoking of marijuana cigarettes thus tainted. We believe that, in young adults with an unexplained presentation of severe respiratory failure, the possibility of exposure to tainted marijuana cigarettes should be considered.