Intratracheal gas analysis for volatile substances by gas chromatography/mass spectrometry--application to forensic autopsies

Intratracheal gas analysis was carried out by gas chromatography/mass spectrometry (GC/MS) in 20 burned body cases (13 males and 7 females). Volatile aromatic and aliphatic hydrocarbons were detected by GC/MS using a GS-Q column with the intratracheal gas as well as the blood in 19 cases. The characteristic patterns of mass chromatograms for gasoline, kerosene (gas oil), and liquid petroleum gas could be differentiated from each other using the intratracheal gas. The burned body in one case showed no presence of volatile substances in the intratracheal gas, nor intratracheal soot, although high concentrations (1 microg/g and more) of volatile substances were detected on the clothes. The victim also had normal CO-Hb concentrations (0.1 to 0.2%) in the heart blood. The results of intratracheal gas analysis were consistent with signs of the vital reaction. In conclusion, intratracheal gas analysis provides a supportive method for diagnosing the cause of death in burned bodies, and yields for at least 48 hours valuable information on volatile hydrocarbons (being detected in deliberate or accidental fire cases) to which the body had been exposed just before death.     

Fire and suicide: a three-year study of self-immolation deaths.

Thirty-two self-immolation deaths by fire, representing about 1% of suicides, occurred in the province of Ontario (population 9 million), Canada, from 1986 through 1988. The victims, mostly male (male/female ratio, 26:6), were between 21 and 71 years old (mean age, 38 years). Although the scene of self-immolation was usually familiar to the deceased, some chose remote locations. Eleven were found dead in motor vehicles. An accelerant, usually gasoline, was used in most cases. Many of these individuals had, at some time, indicated their intent to commit suicide, a few by self-immolation, but only about half had a diagnosed psychiatric illness. Most of the victims had a reason to kill themselves, but the factors that motivated them to chose self-immolation by fire were uncertain. Fourteen individuals died in hospitals from severe burn complications. The remainder were found dead at the scene. The postmortem findings of soot in the airway and elevated carbon monoxide in the blood of most of these victims [the carboxyhemoglobin (COHb) concentration was in one case less than 10%, in ten cases greater than or equal to 10 to 50%, and in seven cases greater than 50%] were helpful in determining that the individuals were not only alive at the time of the fire but also that a significant number died from smoke inhalation and carbon monoxide poisoning. The highest levels of carbon monoxide were observed in victims discovered in motor vehicles.     

Problems associated with the diagnosis of vitality in burned bodies

The most important signs of vitality in burned bodies are soot deposits in the respiratory tract, the esophagus and the stomach as well as elevated CO-Hb values in the blood. But these findings show only that a person was exposed to fire fumes while alive; they are no indicator for vital heat exposure. As the external findings in burned bodies are often not very conclusive due to postmortem consumption by the fire, the internal findings are all the more important. Macroscopic signs that hot fumes were inhaled may be edematous swelling and vesicular detachment of the mucosa in the pharynx, the larynx and/or the upper section of the esophagus. As histological changes in the respiratory tract soot deposits, vesicular detachment of the epithelium, hyperemia and edema of the tracheal and bronchial mucosa as well as increased secretion of mucus have been described. These findings may partly be absent although the victim was alive during the fire, which can make diagnosis more difficult. Especially in peracute deaths vitality findings are usually sparse. The significance of the macroscopic and histological parameters of vitality was systematically investigated on the basis of our own autopsy material from the years 1996-2002 (88 cases) and compared with the statements found in the literature. In our study material, the vitality parameters were incomplete in 23% of the burned corpses. In 3% of the cases the question whether there was an antemortem heat exposure could not be answered.     

Stability of blood carbon monoxide and hemoglobins during heating

The effects of heating on hemoglobin (Hb) and carbon monoxide (CO) levels in human blood were investigated by in vitro experiments. Head-space gas chromatography (HS-GC) using a molecular sieve 5A stationary phase and thermal conductivity detection was adopted for the measurement of CO gas, and spectrophotometric methods were used for the measurement of various Hb forms, protein and heme contents. Deteriorated absorbance spectra were observed for heat-treated blood samples, and double wavelength spectrophotometry was proven to give wrong percent saturation of carboxyhemoglobin content (% CO-Hb). The blood sample taken from one fatal fire casualty gave significantly higher % CO-Hb measured spectrophotometrically, compared to that by HS-GC. Control blood or purified Hb solution, which was saturated with CO in designated extent, was heated in a sealed vial. Under the incubation below 54 degrees C, all Hb forms were stable, except for oxyhemoglobin (Hb-O(2)), which was partially oxidized to met-hemoglobin (Met-Hb). In contrast, under the incubation at 65 degrees C, Met-Hb was denatured completely to be insoluble, and Hb-O(2) was partially denatured via Met-Hb formation. CO-Hb was resistant against heating. The difference of heat susceptibility and precipitability among Hb forms resulted in artificial increase of % CO-Hb. During heating, spontaneous CO was produced from blood.     

The toxicological examination of the victims of the British Air Tours Boeing 737 accident at Manchester in 1985

The results of toxicological analyses of the body fluids of the victims from the accident involving the British Air Tours Boeing 737 in August 1985 are presented for carboxyhemoglobin, cyanide, and volatiles. All the victims except one had raised concentrations of carbon monoxide. All the victims had raised concentrations of cyanide. All the victims showed the presence of volatile substances in the blood. Autopsies revealed that all the victims had carbon particles in the trachea and bronchi. Thus, all the victims must have inhaled fire products in the burning aircraft cabin. Six victims had concentrations of carbon monoxide or cyanide in the blood that were neither fatal nor incapacitating; therefore, it is reasonable to suggest that these six victims survived for a comparatively short time and that there may have been other causes, in addition to toxic fumes, for their deaths. The other 48 victims must have survived long enough in the fire to accumulate incapacitating or fatal concentrations of carbon monoxide or cyanide or both. The effects of these substances found in the blood of each of the 48 victims must have combined to produce an insurmountable impediment to escape from the aircraft.     

Experimental studies on death by fire in automobiles and exhaust gas poisoning

Studies were made on the acid-base balance, blood gases, and carbon monoxide (CO), cyanide, and sulfur dioxide concentrations in the blood of albino rabbits that died from automobile exhaust gas poisoning (group I) or fires in cars (complete combustion, group II; incomplete combustion, group III). In group I, the temperature and CO concentration increased gradually to 35 degrees C and 5.2% in 70 min. The animals died after 9 min, when the values were 20 degrees C and 5.2%, respectively. In group II the animals died after 9 min, when the values were 55 degrees C and 1.95%, respectively. In group III, the temperature was very high (870 degrees C), but the CO concentration was not (0.6-1.3%) after 4 min. The animals died after 5 min. In all experimental groups, marked acidosis and hypoxemia were seen, but the CO2 tension (PCO2) was high, in contrast to previous studies on pure CO poisoning. In group I, the level of carboxyhemoglobin (CO-Hb) was significantly higher (91.2 +/- 3.4% in arterial blood, 87.5 +/- 8.1% in venous blood; p less than 0.01) than in groups II and III. Although the O2 tensions of venous and arterial blood (PvO2, PaO2) were very low, that of arterial blood was higher, suggesting that O2 was still being utilized in the tissues at the time of death. In group II, CO-Hb was high (57.7 +/- 16.0% in arterial blood, 61.2 +/- 20.6% in venous blood) and the acid-base balance indicated marked acidosis. In group III, the CO-Hb, PCO2 and cyanide levels in the blood were very high.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atherosclerotic and Hypertensive Cardiovascular Disease are Associated with Death at Sublethal Carboxyhemoglobin Levels: A Postmortem Study

Residential fires are a significant cause for morbidity and mortality in the United States. Death is often the result of soot and smoke inhalation causing carbon monoxide (CO) toxicity. The approximate lethal level of carboxyhemoglobin (COHb) in healthy adults has been well described. However, a significant number of medical examiner cases involve infirmed decedents, often elderly, with complex cardiovascular disease burdens. It is well known that death in these cases will occur at sublethal levels of COHb; however, increased lethality has been largely documented via anecdotal experience and lacks quantification. Fifty-five cases were identified where death resulted from smoke and soot inhalation suffered in a residential fire. The control group, with no cardiovascular disease, had an age-adjusted mean COHb level of 61.6% at the time of death. Presence of hypertensive cardiovascular disease showed a 30% reduction in COHb (age-adjusted mean 43.2%), atherosclerotic disease showed a 33% reduction (age-adjusted mean 41.5%), and combined disease presentation accounted for 41% reduction (age-adjusted mean 36.3%). When controlling for age, atherosclerotic and hypertensive cardiovascular diseases were each associated with statistically significant decreases in COHb (p < 0.01). Increasing age was associated with decreased COHb levels at 2.8% per 10 years of life (p < 0.01), even when modeled with hypertensive and atherosclerotic disease. These findings carry important public health significance, as well as practical significance for the medical examiner when interpreting COHb levels in cases of suspected deaths due to smoke and soot inhalation.     

A Novel Application of Infrared Imaging for the Diagnosis of Death by Fire

This paper demonstrates a novel and simple technique for the diagnosis of death by fire using a digital infrared (IR) camera system. At autopsy, the inhalation of soot by a fire victim is a definite indicator proving a vital reaction during the fire. However, there can be difficulties in confirming the presence of soot because of the relative lack of soot or the similarity in color between soot and surrounding tissues. To evaluate the effectiveness of IR imaging at autopsy, we acquired internal images of the respiratory and gastrointestinal system by both an ordinary color and IR cameras. Using our method, the inhaled soot is visible as black particles or deposits, while the blood is transparent and the surrounding tissue is whitened. This technique enables the detection of normally undiscriminating soot in an ordinary color image. This is the first report suggesting the usefulness of IR imaging in forensic autopsy for the diagnosis of death by fire.     

The happy land homicides: 87 deaths due to smoke inhalation

We reviewed all 87 deaths from the Happy Land Social Club fire. All deaths were due to smoke inhalation. The carboxyhemoglobin (COHb) concentrations ranged from 37 to 93% with a mean of 76.5%. The vast majority (97%) of the decedents had a COHb concentration over 50%. Cyanide blood concentrations ranged from 0 to 5.5 mg/L with a mean of 2.2 mg/L. Nine decedents had no cyanide detected, and seven had cyanide concentrations of less than 1 mg/L. Fewer than one third of the decedents had thermal injuries, and most were partial thickness burns involving less than 20% body surface area. Ethanol was detected in 72% of decedents with a range of 0.01 to 0.29 g% and a mean blood concentration of 0.11 g%. Cocaine or cannabinoid use was identified in 9% of the decedents. All decedents were visually identified, and all had soot in the airway extending to the major bronchi. Carboxyhemoglobin concentrations corresponded well with deaths from smoke inhalation. Cyanide concentrations did not correspond with the extent of smoke inhalation, and the role of cyanide in contributing to these deaths is doubtful. Hydrogen chloride inhalation, as evidenced by comparison of the pH of tracheal mucosa to controls, was not a factor.     

The application of NIST's Fire Dynamics Simulator to the investigation of carbon monoxide exposure in the deaths of three Pittsburgh fire fighters

A case is reported in which computer fire modeling was used to reevaluate a fire that killed three fire fighters. NIST's Fire Dynamics Simulator (FDS) was employed to model the fire in order to estimate the concentration of carbon monoxide present in the dwelling, which was the immediate cause of death of two of the fire fighters, who appear to have removed their face pieces in order to share available air. This estimate, along with an assumed respiration volume and known blood carboxyhemoglobin, was plugged into a standard equation to estimate the time of exposure. The model indicated that 27 min into the fire, the carbon monoxide concentration had already reached approximately 3600 ppm. At this concentration, and a respiration of 70 L/min, an estimated 3 to 8 min of exposure would have been required to accumulate the concentrations of carboxyhemoglobin (49, 44, and 10%) measured on the fire fighters at autopsy.     

The role of hydrogen cyanide and carbon monoxide in fire casualties: a prospective study

Determinations of blood cyanide and carboxyhemoglobin concentrations were performed in 18 victims found dead in buildings after fires during a 2-year period. The results indicated that 50% of the victims had been exposed to toxic levels of hydrogen cyanide and 90% to toxic levels of carbon monoxide. Lethal concentrations of carbon monoxide were found in 83% of the victims. In one case a lethal blood cyanide but a non-toxic blood carboxyhemoglobin value was found. It is concluded that carbon monoxide appears to be more important than hydrogen cyanide as a toxic agent in the fire atmosphere, but cyanide poisoning without carbon monoxide poisoning may, under certain circumstances, be the cause of death in fire victims.     

Suicidal and accidental carbon monoxide poisonings due to charcoal fires in closed spaces

The number of fatal carbon monoxide poisonings has significantly decreased since the introduction of natural gas. Apart from their occurrence during house fires, accidental and suicidal carbon monoxide poisonings are only rarely seen nowadays. We report on 7 cases of unintentional and intentional fatal carbon monoxide poisoning (CO-Hb concentrations between 56.4% and 74%) due to improper handling of charcoal fires in closed spaces. Autopsy findings and results of the toxicological analysis are presented and discussed.     

Initially suspected killing with a political background identified as accidental carbon monoxide poisoning

During a parish fair the police was called to a conflict between two rival right-wing youth groups in the early morning hours. Shortly afterwards a burning car was discovered near the marquee with a charred male body on the driver's seat. It was assumed that there was a connection between the two events. At autopsy no injuries were found that were not attributable to postmortem consumption by the fire. The BAC value was 1.76 per thousand, the CO-Hb concentration 78%. The body could be identified by comparing pre- and postmortem X-rays of the molars and premolars of the right upper jaw. Reconstruction of the course of events and classification as an accident was possible only after calling in technical experts: The victim had gone back to his car to take a nap and kept the engine running because of the cold temperature. The car had been fitted improperly with a sport exhaust pipe, which caused both the carbon monoxide poisoning and the fire.     

Carbon monoxide concentrations in the 2009 Victorian Bushfire disaster victims

Blood was available for the estimation of carboxyhemoglobin saturation (COHb) in 30 of the 173 persons who died in the Victorian bushfires in February 2009. The ages of these 30 deaths ranged from 3 to 80 years and there were 8 females. 13 cases (43%) were considered negative (less than 5% COHb), 12 (40%) were between 5 and 40% COHb, 2 (6.7%) between 40 and 50% and 3 (10%) were greater than 50% COHb. There were 6 persons either found within a building or a car and the COHb in these cases ranged up to 69% (mean 50%). There were 5 cases where the location was unable to be determined as either indoor or outdoor due to the extensive nature of the fire. The remaining 19 deceased persons were all located outside in the open and the concentration of COHb in these cases ranged up to 30% (mean 19%). Hydrogen cyanide was only detected in two deceased persons at concentrations of 0.5 and 2.7 mg/L, respectively. 13 deceased were found to have soot in the airways following necropsy but this did not correlate with the COHb levels.     

Combustion and Toxic Gas Production from Disposable Barbecues in Enclosures

The production of carbon monoxide from disposable barbecues in an enclosed room has been investigated. Hazard calculations have shown that lethal concentrations of CO and CO₂ can be produced easily. Burning rates and the relative formation of CO and CO₂ depend on the ambient oxygen concentration. Smoke does not correlate with CO concentration as it is mostly produced by the combustion of volatile hydrocarbons added to facilitate ignition. In a typical room, this results in smoke clearing before the maximum CO concentration is reached. Smoke obscuration is therefore a poor indicator of the danger posed by CO. This is an important observation for those discovering or attempting to resuscitate or rescue comatose victims. Dilution caused by ventilation is described numerically and has allowed total volumes of CO and CO₂ produced to be estimated.     

Cyanide, carboxyhemoglobin and blood acid-base state in animals exposed to combustion products of various combinations of acrylic fiber and gauze

In order to examine the usefulness of blood cyanide concentrations as an indicator of whether or not a victim was alive at the start of a fire, blood cyanide concentrations were measured in the bodies that we autopsied in our institute between January 1986 and March, 1987. In the present study, bodies with advanced decomposition were excluded. Thirty-six bodies were included: cyanide as well as carboxyhemoglobin (COHb) were detected in four charred bodies found at the scene of a fire. On the other hand, cyanide was not detected in any of the remaining 30 bodies except in two cases suspected of having ingested a cyanide compound. Rats and rabbits were made to inhale the combustion products of various combinations of acrylic fiber (hydrogen cyanide generating material when heated) and gauze (carbon monoxide generating material when heated). The exposure to the combustion products was continued until death in the rat and until apnea in the rabbit. The concentration of hydrogen cyanide in the exposure chamber and that of blood cyanide, at the time the animal died, correlated with the amount of acrylic fiber heated. In addition to differences in blood COHb and cyanide concentrations, there were also differences in blood gas concentrations between the acrylic fiber and the gauze groups. When the rabbits were switched to room air after the occurrence of apnea, the blood gas value began to normalize.     

Complex suicide by ethanol intoxication and inhalation of fire fumes in an old lady: interdisciplinary elucidation including post-mortem analysis of congener alcohols

An 88-year-old woman committed suicide by drinking a toxic amount of highly concentrated alcohol and setting two rooms of her flat on fire. As there was not enough oxygen, the fire went out, however. At autopsy, no thermal lesions were found on the body, but soot depositions in the airways and a COHb value of 14% pointed to the inhalation of fire fumes. The ethanol concentration in femoral blood was 6.62 per mille. The gastric mucosa was fixed by the ingested alcohol and showed hardly any autolytic changes despite a post-mortem interval of five days. Congener analysis of the gastric contents and the femoral blood indicated the uptake of a fruit distillate or its foreshot.     

Correlation between 'on admission' blood toluene concentrations and the presence or absence of signs and symptoms in solvent abusers

For 1 year, from June 1987 to June 1988, toluene concentrations in blood samples of patients admitted to a psychiatric hospital after inhaling solvent vapor, collected on admission and 4 h later, were analyzed by gas chromatograph. Toluene levels in the first urine samples collected after admission were also analyzed and case histories were kept listing age, sex and physical and psychiatric effects. In all, 51 cases were studied--34 males and 17 females. (1) The average age of the males was 21.4 years and of the female 16.2 years. (2) The toluene concentrations in the blood collected on admission ranged from 0.3 to 22.8 micrograms/g. (3) Physical signs were observed in 9 patients with an "on admission" blood toluene concentrations of more than 3.0 micrograms/g; twice as many subjects (18), however, with blood toluene concentration greater than 3.0 micrograms/g were without physical signs. (4) The blood toluene concentrations of three cases in the condition known as twilight state were more than 10.0 micrograms/g. (5) In 24 cases with blood toluene concentrations below 3.0 micrograms/g, there were no physical signs. (6) Five subjects with blood toluene concentrations in the 0.8-5.2 micrograms/g range showed neuropsychiatric effects; however, 23 subjects in the same blood toluene concentration range did not exhibit psychiatric effects, and none of the subjects with blood toluene concentrations greater than 5.2 micrograms/g, 15 in all, had such effects.     

Simple determination of carboxyhemoglobin by double wavelength spectrophotometry of absorbance difference and the comparison with gas chromatographic method

This paper describes the spectrophotometric determination of carboxyhemoglobin (CO-Hb) in blood on the basis of double wavelength spectrophotometry of absorbance difference. Absorbance measurements are made in the 500–600 nm region at a blood dilution of 100–200-fold. Blood is diluted with a solution containing Na₂S₂O₄ to provide two components of CO-Hb and deoxyhemoglobin (deoxy-Hb). Absorbance difference at the two wavelengths at which deoxy-Hb has the same absorbance reflects only the CO-Hb component because the opposite component is nulled out of the mixture. After measurement of the absorbance difference, the measuring solution is saturated with CO gas to make all Hb derivative CO-Hb and remeasured at the same wavelengths. The percent of CO-Hb is considered the absorbance difference ratio. Results obtained by the present method was in satisfactory agreement with gas chromatographic data in blood not containing methemoglobin (Met-Hb). Comparative experiments using the gas chromatographic method and the present method were performed with samples containing Met-Hb. However, while there is a deficiency in the gas chromatographic method when the samples contain Met-Hb, the results of the present method were in close agreement with theoretical values when samples are mixed with CO-Hb, O₂-Hb and Met-Hb. Advantages of this method are that it is simple and accurate, standard curve or equation for calculation and accurate dilution are not necessary.     

Cannabinoids in blood and urine after passive inhalation of Cannabis smoke

To test the possibility that cannabinoids are detectable following passive inhalation of Cannabis smoke the following study was performed. Five healthy volunteers who had previously never used Cannabis, passively inhaled Cannabis smoke for 30 min. Cannabis smoke was provided by other subjects smoking either marijuana or hashish cigarettes in a small closed car, containing approximately 1650 L of air. delta 9-Tetrahydrocannabinol (THC) could be detected in the blood of all passive smokers immediately after exposure in concentrations ranging from 1.3 to 6.3 ng/mL. At the same time total blood cannabinoid levels (assayed by radioimmunoassay [RIA] ) were higher than 13 ng/mL in four of the volunteers. Both THC and cannabinoid blood concentrations fell close to the cutoff limits of the respective assays during the following 2 h. Passive inhalation also resulted in the detection of cannabinoids in the urine by RIA and enzyme multiple immunoassay technique (EMIT) assays (above 13 and 20 ng/mL, respectively). It is concluded that the demonstration of cannabinoids in blood or urine is no unequivocal proof of active Cannabis smoking.