Inhalation of products of combustion

Scrambled eggs-Negative impacts of heat stress and chemical exposures on ovarian function in swine

Exposure to environmental toxicants and hyperthermia can hamper reproduction in female mammals including swine. Phenotypic manifestations include poor quality oocytes, endocrine disruption, infertility, lengthened time to conceive, pregnancy loss, and embryonic defects. The ovary has the capacity for toxicant biotransformation, regulated in part by the phosphatidylinositol-3 kinase signaling pathway. The impacts of exposure to mycotoxins and pesticides on swine reproduction and the potential for an emerging chemical class of concern, the per- and polyfluoroalkylated substances, to hamper porcine reproduction are reviewed. The negative impairments of heat stress (HS) on swine reproductive outcomes are also described and the cumulative effect of environmental exposures, such as HS, when present in conjunction with a toxicant is considered.

Systemic Lactate Elevation Induced by Tobacco Smoking during Rest and Exercise Is Not Associated with Nicotine

Lactate is a metabolite produced during anaerobic glycolysis for ATP resynthesis, which accumulates during hypoxia and muscle contraction. Tobacco smoking significantly increases blood lactate. Here we conducted a counter-balanced crossover study to examine whether this effect is associated with inhaling nicotine or burned carbon particles. Fifteen male smokers (aged 23 to 26 years) were randomized into 3 inhalation conditions: tobacco smoking, nicotine vaping, and nicotine-free vaping, conducted two days apart. An electronic thermal evaporator (e-cigarette) was used for vaping. We have observed an increased blood lactate (+62%, main effect: p < 0.01) and a decreased blood glucose (−12%, main effect: p < 0.05) during thermal air inhalations regardless of the content delivered. Exercise-induced lactate accumulation and shuttle run performance were similar for the 3 inhalation conditions. Tobacco smoking slightly increased the resting heart rate above the two vaping conditions (p < 0.05), implicating the role of burned carbon particles on sympathetic stimulation, independent of nicotine and thermal air. The exercise response in the heart rate was similar for the 3 conditions. The results of the study suggest that acute hypoxia was induced by breathing thermal air. This may explain the reciprocal increases in lactate and decreases in glucose. The impaired lung function in oxygen delivery of tobacco smoking is unrelated to nicotine.

Firefighter exposures to organic and inorganic gas emissions in emergency residential and industrial fires

The gas emissions generated from fires could cause mortalities and diseases in firefighters. Gas emissions from fire contain a mixture of a wide range of organic and inorganic gases, depending on several elements that are not currently known. In this study, firefighters were equipped with portable gas detectors to measure selected organic and inorganic gases in 26 emergency fire incidents. The fire incidents were categorized as industrial or residential based on their source. The exposure of firefighters to volatile organic compounds (VOCs) in residential fires was double that in industrial fires. This is probably due to the contents of the houses, as more VOCs are released from textiles and furniture. The concentration of toluene, which is widely used in cosmetics and paints in housing, was fifteen-fold higher in residential fires than industrial fires. The exposure of firefighters to inorganic gases was much higher in industrial fires than residential fires. The concentration of hydrogen chloride, which is generated from the combustion of chlorinated plastics, such as industrial pipes and cables, in industrial fires was 18-fold higher than that in residential fires. Additionally, in this study, we found that the concentration of VOCs that poses cancer and non-cancer health risk to firefighters increases in residential fire incidents to almost three times that in industrial fire incidents. Hydrogen sulfide and sulfur dioxide concentrations were higher in industrial fire incidents than in residential fire incidents. The level of hydrogen sulfide and sulfur dioxide were 19-fold and 8-fold higher, respectively, in industrial fire incidents than in residential fire incidents. This study reveals that gas emissions vary widely between industrial and residential fires.

Perceived Health Risks Among Firefighters; The New Jersey Firefighter Health Survey

OBJECTIVE

There is a growing literature on the risk of chronic disease among firefighters, including cardiovascular disease (CVD) and cancer. However there is little information on firefighter's perception thereof.

METHODS

Firefighters attending a union convention in New Jersey completed a survey with four domains: firefighting experience; perceived additional risk for chronic diseases (six-point Likert scale); cancer screening history; demographics, and risk behaviors.

RESULTS

Among 167 enrolled firefighters, all were men and 86.6% active career. Median perceived risk ranged from high risk (colon, hematologic, breast, prostate, and testicular cancers) to very high risk (CVD, pulmonary diseases, all cancers, lung and oral cancer).

CONCLUSIONS

NJ Firefighters attributed considerable additional risk to acquiring chronic disease as a result of their firefighting activities. Understanding firefighter perceptions of their own morbidity and mortality will help develop future firefighter preparatory programs.

Bronchial wheezing predicts inflammation and respiratory failure in fire smoke victims

BACKGROUND

Acute fire smoke inhalation injury involves inflammatory mediators whose roles are poorly understood. We carried out a prospective observational study of fire smoke victims to identify clinical and biochemical markers that may predict pulmonary dysfunction and investigated possible correlations between dysfunction and cytokines in bronchoalveolar lavage (BAL) fluid and blood.

METHODS

Forty patients with respiratory and/or neurological symptoms following acute fire smoke inhalation had pulmonary function tests and blood gas analyses performed on admission, at discharge, and after 3 months. Cytokines were measured using BioPlex/XMap technology.

RESULTS

On admission, 30 (75%) patients had dyspnea. Patients presenting with bronchial wheezing (n = 14) had significantly lower PEF (201 l/min, 82-360) than non-wheezing patients (406 l/min, 100-683) (n = 16, P = 0.03). Bronchial wheezing predicted need for ICU treatment with OR = 93.3 at 95% CI (P < 0.001) and was associated with gas exchange impairment, with mean p_a O₂ /FiO₂ ratio 34.4 (11.8-49.8) kPa on admission and 21.3 (8.3-44.5) kPa 48 h later. Blood HbCO also predicted ICU treatment, with OR = 1.58 at 95% CI (P < 0.001). Serum CRP, IL-6, IL-8, and MCP-1 were significantly higher in wheezing patients after 12-24 h compared with non-wheezing patients and study controls. Cytokine levels were still elevated after 3 months. BAL fluid had significantly higher levels of IL-8, MCP-1, IL-1β, and G-CSF compared with healthy controls.

CONCLUSION

In victims of fire smoke inhalation, pulmonary wheezing predicts inflammation, pulmonary dysfunction, respiratory failure, and need for intensive care.

Bronchial damage and diffuse alveolar hemorrhage following chlorine gas inhalation: A case report

Chlorine is a toxic inhalant and sources of exposure for individuals include accidental releases of chlorine vapor due to industrial or chemical transportation accidents. Inhalation of a large quantity of gas may cause circulatory and respiratory disorders or even mortality; however, the effects of a small amount of chlorine gas may be asymptomatic. The present case study presents a successfully treated 55-year-old male patient exposed to chlorine gas, resulting in bronchial damage and diffuse alveolar hemorrhage. Endobronchial and alveolar injuries were evaluated by direct observation using fiberoptic bronchoscopy (FB) and analyzing bronchoalveolar lavage fluid obtained by FB. Taking a precise medical history from the patient is crucial to correctly diagnose toxic gas inhalation. In addition, a timely and proper evaluation with chest imaging as well as FB may provide useful clinical information. Therefore, clinicians should consider performing FB if the circumstances permit.

The Challenges of Dysphagia Management and Rehabilitation in Two Complex Cases Post Chemical Ingestion Injury

PURPOSE

Dysphagia is common sequelae of chemical ingestion injury, resulting from damage to critical swallowing structures. From a speech-language pathology perspective, this study outlines the physiological deficits in 2 individuals with severe injury (1 woman, acid; 1 man, alkali) and the pattern of dysphagia rehabilitation and recovery.

METHOD

A retrospective chart review of clinical and instrumental assessments was conducted to examine swallow characteristics and speech-language pathology management (compensatory and rehabilitation strategies) at multiple time points.

RESULTS

Chemical ingestion injury resulted in severe pharyngeal dysphagia for both participants, warranting speech-language pathology management. Dysphagia was characterized by poor base of tongue mobility and reduced laryngeal excursion. Decreased airway patency and protection, secondary to mucosal sloughing, widespread edema, and structural deficits necessitated tracheostomy. Recovery was complicated by physical alterations of pharyngeal and laryngeal structures (e.g., interarytenoid adhesions) and esophageal strictures. Participant 1 was discharged (Day 135) consuming a texture-modified diet; Participant 2 remained nil by mouth (Day 329).

CONCLUSIONS

Dysphagia recovery subsequent to chemical ingestion is protracted and complex. Clinical outcomes may be improved through individualized and intensive rehabilitation by speech-language pathologists.

Pulmonary function decline in firefighters and non-firefighters in South Korea

Objectives

The purpose of this study was to evaluate and compare changes to pulmonary function among firefighters and non-firefighters who were exposed to harmful substances in their work environments.

Methods

Firefighters (n = 322) and non-firefighters (n = 107) in Daegu who received a pulmonary function test in 2008 and 2011 as well as a regular health examination were included. Repeated measures ANOVA was performed to evaluate the pulmonary function of the two groups over the three-year period.

Results

After adjusting for age, height, body mass index, duration of exposure, physical activity, and smoking, which were statistically different between the two groups and known risk factors of pulmonary function, the forced expiratory volume in one s FEV₁, forced vital capacity FVC, and FEV₁/FVC% over the 3 year period were significantly lower among firefighters compared with non-firefighters.

Conclusions

Evaluating the working environment of firefighters is difficult; however, our study revealed that pulmonary function declined in firefighters. Thus, more effort should be made to prevent and manage respiratory diseases early by preforming strict and consistent pulmonary function tests in firefighters.

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.

Acrolein - a pulmonary hazard

Acrolein is a respiratory irritant that can be generated during cooking and is in environmental tobacco smoke. More plentiful in cigarette smoke than polycyclic aromatic hydrocarbons (PAH), acrolein can adduct tumor suppressor p53 (TP53) DNA and may contribute to TP53-mutations in lung cancer. Acrolein is also generated endogenously at sites of injury, and excessive breath levels (sufficient to activate metalloproteinases and increase mucin transcripts) have been detected in asthma and chronic obstructive pulmonary disease (COPD). Because of its reactivity with respiratory-lining fluid or cellular macromolecules, acrolein alters gene regulation, inflammation, mucociliary transport, and alveolar-capillary barrier integrity. In laboratory animals, acute exposures have lead to acute lung injury and pulmonary edema similar to that produced by smoke inhalation whereas lower concentrations have produced bronchial hyperreactivity, excessive mucus production, and alveolar enlargement. Susceptibility to acrolein exposure is associated with differential regulation of cell surface receptor, transcription factor, and ubiquitin-proteasome genes. Consequent to its pathophysiological impact, acrolein contributes to the morbidly and mortality associated with acute lung injury and COPD, and possibly asthma and lung cancer.

Pathophysiology, management and treatment of smoke inhalation injury

Smoke inhalation injury continues to increase morbidity and mortality in burn patients in both the third world and industrialized countries. The lack of uniform criteria for the diagnosis and definition of smoke inhalation injury contributes to the fact that, despite extensive research, mortality rates have changed little in recent decades. The formation of reactive oxygen and nitrogen species, as well as the procoagulant and antifibrinolytic imbalance of alveolar homeostasis, all play a central role in the pathogenesis of smoke inhalation injury. Further hallmarks include massive airway obstruction owing to cast formation, bronchospasm, the increase in bronchial circulation and transvascular fluid flux. Therefore, anticoagulants, antioxidants and bronchodilators, especially when administered as an aerosol, represent the most promising treatment strategies. The purpose of this review article is to provide an overview of the pathophysiological changes, management and treatment options of smoke inhalation injury based on the current literature.

Fire fighters, combustion products, and urothelial cancer

Urothelial cancer may be induced by different workplace chemicals, including carcinogenic aromatic amines, coke oven fumes, and cigarette smoking. The general impact of combustion products on urothelial cancer risk of exposed persons is still controversial. This raises the question whether fire fighters may have an increased risk for urothelial cancer. The present review compiles the literature on combustion products, possibly relevant for fire fighters, and the available studies on urinary bladder cancer risk in fire fighters. Chemical analyses of smoke from experimental fires as well as from fires in cities, wildlands, and industry do not indicate a generally elevated risk of bladder cancer in fire fighters. This is supported by studies on bladder cancer in fire fighters. Based on mortality studies, studies on exposures, and cancer incidence, we conclude that an elevated risk of urothelial cancer in fire fighters, in general, is not confirmed. Only in professional fire fighters more severely exposed for decades, having started their career some decades before, occupational exposure might be discussed as causative for urothelial cancer.

Prehospital administration of hydroxocobalamin for smoke inhalation-associated cyanide poisoning: 8 years of experience in the Paris Fire Brigade

INTRODUCTION

This article reports the results of a retrospective study of 8 years of experience of the Paris Fire Brigade with the prehospital use of hydroxocobalamin.

METHODS

The head physician at the Paris Fire Brigade extracted and summarized data from standardized forms completed at the fire scene and, when available, hospital reports to assess survival status and clinical parameters associated with the use of hydroxocobalamin for each patient who received it for smoke inhalation-associated cyanide poisoning from 1995 to 2003.

RESULTS

Of the 101 patients administered hydroxocobalamin, 30 survived, 42 died (17 at the fire scene and 25 at the intensive-care unit), and survival status was not known in the remaining 29 patients. Among the 72 patients for whom survival status was known, survival rate was 41.7% after the administration of hydroxocobalamin. Of the 38 patients found in cardiac arrest, 21 had a return of spontaneous circulation during prehospital care. Of the 12 patients who were initially hemodynamically unstable (systolic blood pressure 0 to < or =90 mmHg), 9 recovered systolic blood pressure an average of 30.6 minutes after the start of hydroxocobalamin infusion. Among nonsedated patients in the sample as a whole (n = 52), mean (SD) Glasgow coma scale score improved from 7.9 (5.4) initially to 8.5 (5.7) after administration of hydroxocobalamin. Among nonsedated patients who were initially neurologically impaired (n = 18), Glasgow coma scale score improved in 9 patients, did not change in 8 patients, and worsened in 1 patient. Two adverse events--red or pink coloration of urine or skin (n = 5) and cutaneous rash (n = 1)--were assessed as being possibly related to hydroxocobalamin.

CONCLUSION

Hydroxocobalamin has a risk:benefit ratio rendering it suitable for prehospital use in the management of acute cyanide poisoning caused by smoke inhalation.

Carbon monoxide poisoning while using a small cooking stove in a tent

Carbon monoxide (CO) is formed wherever incomplete combustion of carbonaceous products occurs.(1) CO is the leading cause of poisoning in the United States, and common sources of CO poisoning include housefires, automobile exhaust, water heaters, kerosene space heaters, and furnaces.(2) Stoves used for cooking and heating during outdoor activities also produce significant amounts of CO. Mountain climbers have been reported to succumb to fumes generated by small cook stoves.(3) The aim of this study was to investigate if burning a cooking stove inside a tent is a potential health hazard. Seven healthy male volunteers used a cooking stove inside a small tent for 120 minutes. CO levels in the ambient tent air were measured in addition to hearth rate (HR) and pulse oximetry (SpO2). Venous blood samples were obtained every 15 minutes for measurement of carboxyhemoglobin (COHb). After 2 hours, all the subjects had significant CO levels in their blood (mean COHb = 21.5%). Mean SpO2, also fell from 98% to 95.3% (P <.05), whereas mean HR increased from 63 to 90 beats/min (P <.05). Kerosene camping stoves do produce CO when burned in a small tent. The concentration is high enough to cause significant COHb levels in venous blood after 120 minutes' stay in the tent.

Acetylcholine and tachykinin receptor antagonists attenuate wood smoke-induced bronchoconstriction in guinea pigs

To study the mechanisms of wood smoke-induced bronchoconstriction, we measured total lung resistance (RL) and dynamic lung compliance (Cdyn) in anesthetized and mechanically ventilated guinea pigs. Airway exposure to various doses of wood smoke (lauan wood; 5, 10, and 15 breaths) resulted in a dose-dependent increase in RL and decrease in Cdyn. The smoke-induced changes in RL and Cdyn were significantly attenuated by pretreatment with atropine, CP-96,345 [(2S,3S)-cis-2-(diphenylmethyl)-N-((2-methoxyphenyl)-methyl)-1-aza bicyclo(2.2.2.)-octan-3-amine; a tachykinin NK1 receptor antagonist], and SR-48,968 [(S)-N-methyl-N(4-(4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophen yl)-butyl)benzamide; a tachykinin NK2 receptor antagonist] in combination, atropine alone, and SR-48,968 alone, but were not significantly affected by pretreatment with the inactive enantiomers of CP-96,345 and SR-48,968, CP-96,345 alone, indomethacin (a cyclooxygenase inhibitor), and MK-571 [((3-(3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl((3-dimethyl amino-3-oxo-propyl)thio)methyl)propanoic acid; a leukotriene D4 receptor antagonist]. The activity of airway neutral endopeptidase, a major enzyme for tachykinin degradation, was not significantly influenced by wood smoke during the development of bronchoconstriction. We conclude that: (1) both cholinergic mechanisms and endogenous tachykinins, but not cyclooxygenase products or leukotriene D4, play an important role in the acute bronchoconstriction induced by wood smoke, and (2) the contribution of tachykinins to this airway response is primarily mediated via the activation of tachykinin NK2 receptors, but is not associated with inactivation of the airway neutral endopeptidase.

Comparison of community based smoke detector distribution methods in an urban community

OBJECTIVES

Various methods of soliciting participation for a large smoke detector giveaway program were tested to determine the most effective method of distributing smoke detectors to a high risk urban population.

SETTING

The target area was a 24 square mile (62 km2) section on the south side of Oklahoma City where 16% (73,301) of the city's population resided in 16% (34,845) of the dwellings (excluding apartments). Of the 66 persons in Oklahoma City who were injured in residential fires from September 1987 to April 1990, 45% (30) were in the target area. Of the target area injuries, 47% resulted from fires started by children playing with fire (fireplay).

METHODS

The number of homes without detectors was estimated by telephone survey. Four different methods of soliciting participants were used, including notifying residents by mail; placing flyers on the doors of every habitable residence; and displaying flyers at public places (grocery stores, convenience stores, restaurants, etc). Each of these methods alerted residents that free smoke detectors were available at specific fire stations. The fourth method was distributing detectors door-to-door (canvassing).

RESULTS

The canvassing method resulted in significantly more smoke detectors being distributed to homes without detectors (107%) than any of the three other methods (18%) (p < 0.00001). The canvassing method distributed detectors to 31% of the total target homes, compared with 5% with the other methods (p < 0.00001). Canvassing also resulted in the lowest estimated cost per detector distributed ($1.96) (all other methods, $3.95), and in the largest number distributed per volunteer hour (5.9 v 3.1 detectors per hour by other methods).

CONCLUSIONS

Distributing smoke detectors directly to homes (canvassing) was the most effective and cost efficient method to reach high risk urban residents.

Assessment of exposure to polycyclic aromatic hydrocarbons during firefighting by measurement of urinary 1-hydroxypyrene

Firefighters may be exposed to carcinogenic agents in the smoke from fires, and there has been some concern regarding firefighters' risk of developing occupational-related cancer. Polycyclic aromatic hydrocarbons (PAHs) are present in most fires, posing a cancer risk. The objective of this study was to evaluate the PAH exposure among firefighters. Students (n = 9) and teachers (n = 4) at a firefighter training school delivered urine samples before and 6 to 7 hours after extinguishing burning diesel fuel. The urine samples were analyzed by high-performance liquid chromatography for 1-hydroxypyrene. A small but significant increase in 1-hydroxypyrene levels in the urine was found after the firefighting. This means that firefighting may cause exposure to PAHs. Although the exposure levels were low in this study, they may be different during other types of fires.

Smoke inhalation injury

Smoke inhalation injury in children still represents a significant cause of pulmonary disease and mortality. Carbon monoxide and other toxic products of combustion are major determinants of severity. Early hypoxemia is a contributor to over 50% of deaths. There are several clinical entities: upper airway obstruction, bronchospasm, consolidation, pulmonary edema, ARDS, and late pneumonia. Intensive care has improved outcome from burns, but pulmonary injury is still an important cause of mortality. New therapies such as high frequency ventilation may improve the outcome. Primary prevention is the most important way to reduce the poor outcome from significant exposure.

Hospital treatment of victims exposed to combustion products

Combustion toxicology is complex so, although victims exposed to combustion products are mainly treated symptomatically, it is important to identify those situations when specific therapeutic measures might be of importance. Victims presenting respiratory symptoms including severe cough, bronchoconstriction, hypoxia and respiratory distress should be given oxygen and ventilatory assistance or support. Furthermore, bronchoconstriction should be treated with bronchodilators (beta-2-adrenoreceptor agonists, theophylline). Corticosteroids should be considered both for inhalation and systemically due to the risk of developing toxic pulmonary oedema that may appear after a symptom-free interval that might last up to 48-72 h. Victims with impaired consciousness should be regarded as being exposed to carbon monoxide and cyanides. Apart from oxygen and optimal symptomatic treatment hyperbaric oxygen therapy should be considered in carbon monoxide poisoning. Certain cyanide antidotes, namely those with low intrinsic toxicity (as sodium thiosulphate, hydroxocobalamin) should be given liberally in these situations. Other specific therapeutic measures that might be considered when appropriate are administration of organophosphate antidotes (atropine, oximes), heavy metal chelators (e.g. dimercaptopropane sulfonate, dimercaptosuccinic acid) and methemoglobinemia antidotes (methylthionine, toluidine blue). Inhalation of hot fumes may cause upper respiratory tract oedema (e.g. laryngeal oedema) necessitating orotracheal intubation and ventilatory support.

Effects of ibuprofen on pulmonary oedema in an animal smoke inhalation model

The ability of ibuprofen to lower extravascular lung water significantly was examined in an animal smoke inhalation model. Adult New Zealand White rabbits weighing 3-5 kg were anaesthetized and intubated. They were then allowed to breathe cooled cotton smoke until the carboxyhaemoglobin (COHb) reached a level of 60 per cent or higher. Each ibuprofen-treated animal received a dose of 50 mg/kg either intraperitoneally or intravenously. Ibuprofen was administered to animals that received smoke inhalation alone and those that received smoke inhalation combined with a 10 per cent BSA partial skin thickness thermal injury. Control groups were established for both of the above-mentioned groups. Peak carboxyhaemoglobin levels as well as CO half-lives were not significantly different between ibuprofen-treated groups and the controls. Ibuprofen treatment resulted in significantly (P less than 0.05) decreased lung water in both smoke, and smoke plus thermal injury groups as compared to controls. These results suggest that ibuprofen promotes the reduction of early-onset lung water resulting from smoke inhalation injury alone or from smoke inhalation injury plus a thermal injury.

The short-term effects of smoke exposure on the pulmonary function of firefighters

The short-term effects of smoke inhalation have been little studied. This study evaluated whether firefighters experience a significant change in spirometric values following exposure to smoke from a fire. Sixty firefighters from the city of Pittsburgh completed a questionnaire (Medical Research Council) and underwent spirometric testing following exposure to house fires. The group contained 25 current smokers, 14 ever smokers, and 21 never smokers. Firefighters reporting cough, phlegm, breathlessness, and chest illnesses were more likely to be current or ever smokers than never smokers. Mean spirometric data obtained before exposure, after a minimum of four off-duty days, showed the following: FVC, 4.50 +/- 0.60L (90 percent of predicted); FEV1, 3.65 +/- 0.56L (96 percent of predicted); FEV1/FVC, 81 +/- 8 percent (106 percent of predicted); FEF25-75%, 3.71 +/- 1.13L/s (96 percent of predicted); and PEF, 7.95 +/- 1.70L/s (87 percent of predicted). After exposure, spirometry was performed on 22 firefighters. All spirometric values decreased after exposure; however, a significant decline was only seen in two indices, the FEV1 and FEF25-75%. This decline was small (3 to 11 percent). Two firefighters experienced an exaggerated decline in spirometric values after exposure, compared to the group as a whole. Neither age, smoking history, location of firefighting, intensity of smoke exposure, or use of a self-contained breathing apparatus explained the reasons for the greater decline in these two individuals. Thus, while firefighters do experience a small decrease in pulmonary function after exposure to house fires, there appears to be a small subgroup of firefighters who develop more substantial and potentially clinically important decreases in pulmonary function after smoke exposure.

Trial of normobaric and hyperbaric oxygen for acute carbon monoxide intoxication

The value of hyperbaric oxygen in the treatment of acute carbon monoxide intoxication was assessed in 629 adults who had been poisoned at home in the 12 h before admission to hospital. In patients without initial impairment of consciousness (group A) the effect of 6 h of normobaric oxygen (NBO) (group A0, n = 170) was compared with that of 2 h of hyperbaric oxygen (HBO) at 2 atmospheres absolute (ATA) plus 4 h NBO (group A1, n = 173). At the 1 month follow-up 66% of A0 and 68% of A1 patients had recovered. In patients with initial impairment of consciousness the effect of one session of HBO (group B1, n = 145) was compared with that of two sessions (group B2, n = 141); all group B patients also received 4 h of NBO. At 1 month of follow-up 54% group B1 and 52% group B2 patients had recovered. The 7 patients left with neuropsychiatric sequelae (3 B1, 4 B2) and the 4 who died (2 B1, 2 B2) had all presented with coma. HBO was not useful in patients who did not lose consciousness during carbon monoxide intoxication, irrespective of their carboxyhaemoglobin level, nor were two sessions of HBO in patients who sustained only a brief loss of consciousness. The prognosis is poorest for those presenting with coma; the trial needs to be pursued in this group of patients until the power of the study is sufficient to demonstrate the value or otherwise of HBO.

Self-reported short- and long-term respiratory effects among PVC-exposed firefighters

Firefighters exposed to burning polyvinyl chloride (PVC) were studied to assess respiratory effects at 5-6 wk post-incident and again 22 mo following the fire. Exposed subjects reported significantly more frequent and severe respiratory symptoms at both time points than did firefighter controls. In longitudinal analyses, a number of symptoms persisted over time, and acute symptom scores were significantly correlated with chronic scores. At Time 2, approximately 18% of exposed firefighters, compared with none of the controls, reported that since the time of the PVC exposure, a physician had told them that they had either asthma and/or bronchitis.

Inhalation injuries

Inhalation injuries occur in approximately one-third of all major burns and account for a significant number of deaths in those burn patients each year. Victims die as a result of carbon monoxide poisoning, hypoxia, and smoke inhalation. These deaths can occur without thermal wounds as well as with burn injuries. There are three distinct problems with inhalation injuries: thermal burns of the upper airway, carbon monoxide poisoning, and smoke inhalation. Each has different symptoms and signs, different treatment, and different prognosis. Thermal burns occurring in the upper airway are usually manifested within 48 hours of injury. Diagnosis is made by direct visualization of the upper airway, looking for signs of thermal injury. Admission for observation with humidified oxygen, attentive pulmonary toilet, bronchodilators as needed, and prophylactic endotracheal intubation as indicated are the mainstays of treatment. Resolution of the injury usually occurs within days. Carbon monoxide poisoning, the most common cause of death in inhalation injury, is a result of combustion. Symptoms and signs correlate with blood levels, but arterial blood gases are used to determine the degree of carbon monoxide intoxication. Treatment is based on the principle that carbon monoxide dissociation occurs much faster if the patient is placed on 100% oxygen. Occasionally the patient's symptoms may persist or get worse despite adequate treatment. Smoke inhalation significantly damages normal respiratory physiology, resulting in injury progressing from acute pulmonary insufficiency to pulmonary edema to bronchopneumonia, depending on the severity of exposure. Diagnosis is based on history, but clinical findings, arterial blood gases, and fiberoptic bronchoscopy are helpful. Treatment is supportive with careful attention paid to fluid resuscitation in the patient with burns.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhalation injury in burned patients: effects and treatment

Pulmonary pathology in major thermal injury is found in 30-80 per cent of burn fatalities. The incidence and mortality from inhalation injury increases both with age and increasing burn size. Toxic smoke inhalation injury, characterized by increased lung microvascular permeability, is attenuated by increasing cardiac output to normal levels, indicating that fluid restriction after inhalation injury may lead to excessive lung fluid formation and hypoxia. Fluid administration of approximately 2 ml/kg/% area burned above the calculated resuscitation volume is required following an inhalation injury to provide adequate support for the systemic circulation and maintain cardiac output at normal levels. This additional volume does not contribute to the development of pulmonary oedema, but may decrease its formation by increasing shear forces thus reducing polymorphonuclear leucocyte deposition in the pulmonary microcirculation. Nasotracheal intubation is preferred when airway integrity is compromised by inhalation injury. The advantages are non-operative placement, ease of discontinuation, minimal bacterial contamination and leaving neck burns undisturbed. The administration of the appropriate antibiotics for documented infection is recommended, while steroids have been shown to be of no benefit.

Toxic smoke inhalation: cyanide poisoning in fire victims

The most common cause of death in fires is the inhalation of noxious gases rather than thermal injury. Hydrogen cyanide gas, the most toxic product of combustion, seldom is recognized as a significant hazard in smoke inhalation. During the first four months of 1986, toxic amounts of cyanide were found in four of the six fatalities from house fires in Akron, Ohio. These cases illustrate the increasing frequency of cyanide poisoning in household fires. Sources of cyanide toxicity include the increased use of synthetic polymers in building materials and furnishings. Prompt recognition of and therapy for cyanide intoxication may reduce the morbidity and number of delayed deaths in fire victims. The key point in the diagnosis of cyanide poisoning is a high index of suspicion. The clinical presentation of cyanide intoxication, its diagnosis, and subsequent treatment are discussed. Finally, a prehospital protocol for treating smoke-inhalation victims who may have been exposed to cyanide gas is suggested.

Pulmonary injury in burned patients

Inhalation injury has emerged as the number one cause of fatality in the burn patient. Fiberoptic bronchoscopy and 133Xe scanning complement traditional clinical signs of inhalation injury and have led to discovery of a higher incidence of these injuries among patients with burns. Patients with inhalation injury typically demonstrate three stages: acute pulmonary insufficiency, pulmonary edema, and bronchopneumonia, all of which carry at least 50 per cent mortality rates. The major early pathophysiologic changes in the lungs of burned patients are related to upper-airway obstruction and lower-airway permeability edema. Treatment consists of intubation for signs of respiratory distress, pulmonary toilet, humidification of inspired air, and antibiotics for documented infection.

Carboxyhemoglobinemia caused by inhalation of methylene chloride

Spray-paint inhalation, once a common and inexpensive source of drug abuse, is now rare. Newer organic solvents, such as methylene chloride, were thought to decrease the toxicity of aerosol solvents, but they carry unique toxicities of their own. Methylene chloride toxicity is difficult to diagnose, as early symptoms are similar to those associated with many intoxicants; however, a rising carboxyhemoglobin level, despite removal of the patient from the source of exposure, is pathognomonic. In dealing with industrial exposures or organic aerosol abuse, a carboxyhemoglobin level should be part of the initial diagnostic workup, and treatment with oxygen is mandatory until toxicity resolves.