Blood carbon monoxide and hydrogen cyanide concentrations in the fatalities of fire and non-fire associated civil aviation accidents, 1991-1998

To evaluate pathophysiological significance of post-mortem urinary myoglobin levels in determining the cause of death, we investigated 210 forensic autopsy cases, partially in comparison with serum levels. Post-mortem serum myoglobin levels were extraordinary high in most cases possibly due to post-mortem change. Urinary myoglobin levels did not correlate with the serum levels, showing possible post-mortem elevation in cases of a prolonged post-mortem period over 48h. A high (>1000 ng/ml), moderate (100-1000 ng/ml), slight (50-100 ng/ml) and not significant (<50 ng/ml) elevation of urinary myoglobin were observed in 26, 43, 31 and 110 cases, respectively. Half the highly elevated cases were those with a survival time over 24h. In cases of minor muscle injury such as head trauma, elevation of urinary myoglobin level was closely related to longer survival. In acute/subacute deaths with a post-mortem interval within 48h, a significant difference was observed in relation to the blood carboxyhemoglobin (COHb) levels of fire victims: myoglobinuria over 100 ng/ml was more frequently and markedly observed in cases with COHb below 60% than over 60%, suggesting muscle damage in fatal burns. Similar elevation was observed in heat stroke victims, and also in some cases of acute and subacute death from polytrauma, asphyxiation, drowning, electricity and spontaneous cerebral bleeding, but not in myocardial infarction. Thus, it was suggested that high post-mortem urinary myoglobin levels in acute and subacute death cases may be a possible indicator of antemortem massive skeletal muscle damage as well as exertional muscle hyperactivity or convulsive disorders associated with hypoxia.     

Suicide by inhalation of carbon monoxide in a residential fire

Fire deaths are usually accidental, but atypical cases of homicide or suicide have been described. In suicide by fire, the only method reported by several authors consists of self-immolation. We present here the unusual case of an adult female who committed suicide by waiting in the living room after setting fire to her bedroom. The autopsy revealed smoke inhalation and the toxicological analysis revealed carboxyhemoglobin levels of 67%. Very few cases of suicide by fire not of the self-immolation type have been reported, and all have been anecdotal. A review of the literature is presented and a new term, "suicide by inhalation of carbon monoxide in a fire," is proposed for such cases.     

A study on house fire victims: age, carboxyhemoglobin, hydrogen cyanide and hemolysis.

Correlation among age, concentrations of carboxyhemoglobin and hydrogen cyanide, oxygen density and hemolysis were studied in 120 house fire victims. Victims aged over 60 years comprised approximately 50% of the pooled subjects. Blood samples were mainly collected from the left ventricle, but sometimes from both the right and left ventricles. The concentration of carboxyhemoglobin ranged from 1-95%, of which 71 persons (59.7%) died with carboxyhemoglobin concentrations below 60%. Carboxyhemoglobin concentrations below 10% were found in 9 persons (7.5%). Most of these cases involved the elderly persons. In this paper, we report on the death of elderly victims as a result of low carboxyhemoglobin concentrations. A significant correlation of blood carboxyhemoglobin concentrations existed between the right and left ventricles. The concentration of carboxyhemoglobin in the left ventricle was significantly higher than that in the right. Two out of 31 victims whose hydrogen cyanide concentrations were determined, succumbed to hydrogen cyanide poisoning, having a high concentration of hydrogen cyanide and a low concentration of carboxyhemoglobin. On analysis, oxygen density was found to be low in 13 persons. A negative correlation was shown between carboxyhemoglobin concentration and hemolysis. Inasmuch as hemolysis may indicate the extent of heat dissociation, hemolysis should provide an index of carbon monoxide dissociation from carboxyhemoglobin. In the present study of victims, possible causes of death i.e., carbon monoxide gas poisoning, hydrogen cyanide poisoning, oxygen deprivation, burning, shock due to burns and others were estimated. The survival time for elderly victims was considered to be short.     

Acute effects of carbon monoxide and cyanide on hepatic mitochondrial function

The effects of carbon monoxide and cyanide on the hepatic redox state and energy charge were investigated. Rats were used for the experiment under pentobarbital anesthesia. Immediately after laparotomy, a rat was placed in an animal chamber made of a transparent plastic box and exposed to a test gas for 3 min. Every test gas was produced in a gas chamber connected to the animal chamber with a flexible tube. HCN was produced from NaCN and H2SO4. In the CO inhalation experiment, various amounts of CO were introduced into the gas chamber. Immediately after an exposure, about 2 g liver was frozen in situ with a precooled clamp. Oozed blood from the wound surface was sampled. Concentrations of ATP, ADP, AMP, acetoacetate, and beta-hydroxybutyrate in hepatic mitochondria were determined, and the redox state and the energy charge were calculated. For cyanide as well as CO, significant negative correlations were found between the concentration in the blood and the redox state. The same held true for the energy charge. The redox state showed a slight increase at low concentrations of both gases; however, thereafter it began to decrease sharply with increases in concentrations. When concentrations of the toxicant in the blood reached certain levels, a kind of turning point, beyond which the redox state does not decrease any more, was observed. It was about 40% for HbCO and about 2.0 micrograms/ml for cyanide, and the points seemed to be related to the concentrations, beyond which cells are irreversibly damaged. On the other hand, the energy charge did not change at low concentrations. With an increase in toxicant concentrations, the energy charge decreased drastically. The rate of decrease in the energy charge became higher when blood concentrations exceeded certain levels. It was about 40% for HbCO and 2.0 micrograms/ml for cyanide. The presence of low levels of blood cyanide did not affect the relationship between the energy charge and the HbCO concentration.     

Interaction between carbon monoxide and ethanol in fire fatalities.

Impairment due to ethanol is clearly a risk factor in deaths due to fire. However, it is less clear whether there is a physiological interaction between ethanol and carbon monoxide (CO) that would alter the carboxyhemoglobin saturation level (COHb sat.) that accounts for death. In an attempt to explore this issue further, 196 fire fatalities investigated by the Office of the Chief Medical Examiner, State of Maryland over a 3-year period were examined. COHb sat. and blood ethanol concentrations (BAC) were tabulated. Twelve cases positive for therapeutic or abused drugs other than lidocaine or atropine were excluded; 184 cases were included. The data indicate that ethanol does not affect the COHb sat. that accounts for death, since the percentage of cases positive for ethanol at a given COHb range shows no trends. Therefore, we conclude that although ethanol remains a risk factor in fire fatalities, the risk appears to be related to the impairment that it produces as opposed to a direct interaction with CO.     

Hydrogen cyanide and carbon monoxide in blood of convicted dead in a polyurethane combustion: a proposition for the data analysis

Carbon monoxide is a well-known toxic component in fire atmospheres. However, the importance of hydrogen cyanide as a toxic agent in fire causalities is under discussion. A tragic polyurethane mattress fire provoked death of 35 convicts in a prison (Unit I, Olmos, Penitenciary Service of Buenos Aires Province, Argentina), in 1990. There is no report of any investigation carried out with such a large amount of victims in Argentina. Carboxihemoglobin (COHb) and hydrogen cyanide (HCN) were quantified in victims blood to elucidate the cause of the death. Saturation of COHb ranged between 4 and 18%, and HCN 2.0-7.2mg/l. These latter values were higher than the lethal levels reported in literature. Other toxic components routinely measured (ethanol, methanol, aldehydes and other volatile compounds) gave negative results on the 35 cases. Neither drugs of abuse nor psychotropics were detected. Statistical chi(2) analysis was applied to find differences between HCN and COHb concentrations. Saturation of COHb and HCN in blood were not independent variables (chi(2)=8.25). Moreover, the ratio COHb/HCN was constant (0.47+/-0.04). In order to evaluate the contribution of each toxic to the diagnosis, a lethal index was defined for each toxic (LI(CO) and LI(HCN)). The most probable cause of death could be inferred by a suitable plot of both indexes. The results indicated that death in the 35 fire victims was probably caused by HCN, generated during the extensive polyurethane decomposition provoked by a rapid increase of temperature.     

Analysis of hydrogen cyanide in air in a case of attempted cyanide poisoning

A 32-year-old man attempted to poison his ex-girlfriend with hydrogen cyanide by hiding the pesticide Uragan D2 in her car. During the police investigation, chemical analysis of the air inside the car was performed. Hydrogen cyanide was detected through on-site air analysis using a portable Fourier transform infrared (FTIR) spectroscopy gas analyzer and colorimetric gas detection tubes. Furthermore, impinger air-sampling was performed for off-site sample preparation and analysis by gas chromatography-mass spectrometry (GC-MS). All three independent techniques demonstrated the presence of hydrogen cyanide, at concentrations of 14-20ppm. Owing to the high volatility of hydrogen cyanide, the temperature and the time since exposure have a substantial effect on the likelihood of detecting hydrogen cyanide at a crime scene. The prevailing conditions (closed space, low temperature) must have supported the preservation of HCN in the car thus enabling the identification even though the analysis was performed several days after the hydrogen cyanide source was removed. This paper demonstrates the applicability of combining on-site FTIR measurements and off-site GC-MS analysis of a crime scene in order to ensure fast detection as well as unambiguous identification for forensic purposes of hydrogen cyanide in air.     

Experimental study on postmortem formation of carbon monoxide

Rats were drowned and kept immersed for 1 month in either boiled city water, or boiled or unboiled fresh water collected from a river. A small amount of carbon monoxide (CO) formed after death and a low carboxyhemoglobin (HbCO) saturation was found in blood and thoracic cavity fluid of the animals immersed in boiled city water and in boiled fresh water. A considerable amount of CO and a high HbCO saturation was observed in blood and thoracic cavity fluid in two out of three rats immersed in unboiled fresh water at 4-6 degrees C, and in one out of three at 6-16 degrees C. It is suggested that microorganisms in the water, in which the rats were drowned and kept immersed, and low temperatures of around 5 degrees C during storage, played an important role in the postmortem formation of carbon monoxide.     

血液保存中碳氧血红蛋白稳定性研究进展

通过分析近年来有关血液样品中碳氧血红蛋白稳定性方面的研究资料,发现血液中碳氧血红蛋白的稳定性受到盛放容器、保存温度、容器顶部空气体积、初始HbCO饱和度及防腐剂的添加与否的影响,其中保存温度、容器顶部空气体积及初始HbCO饱和度则是其主要影响因素。     

Production of carbon monoxide in cadavers

Carbon monoxide (CO), total hemoglobin (Hb) and carboxyhemoglobin (HbCO) in the blood and reddish discolored body cavity fluids of cadavers which had not been exposed to fire and CO were analyzed. In 13 cadavers found on land, the maximum saturation of HbCO in the blood was 3.6%, and was 10.1% in the body cavity fluids. There was only one case in which the HbCO saturations in the body cavity fluids were more than 10%. In seven drowned bodies found in fresh water, the highest HbCO saturation in the blood was 6.1%, and was 44.1% in the body cavity fluids. There were three cases in which the HbCO saturations in the body cavity fluids were more than 10%. In 12 drowned bodies found in sea water, the HbCO saturations in the blood were not more than 6.2%, and the maximum saturation of HbCO in the body cavity fluids was 83.7%. There were eight cases in which the HbCO saturations in the body cavity fluids were more than 10%. The results seem to indicate that the interpretation of HbCO saturation in the blood would not be affected significantly by the postmortem formation of CO, and that body cavity fluids should not be used for CO determination.     

一氧化碳（CO）中毒检测方法

作者查阅近20年国内外相关文献的基础上,对一氧化碳(CO)中毒的检验方法进行了全面的阐述,同时对每种方法的优缺点和适用条件作了比较,并对适用于我国国情的顶空气质联用法进行了改良.     

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.     

一氧化碳中毒血分光光度定量分析法比较

目的比较7种一氧化碳中毒血样分光光度含量测定方法的特点及适用性。方法用空白血添加一氧化碳配制不同浓度的样品,采用双波长法、还原法（3种）、切线法和导数光谱法（2种）进行检测,对各种方法线性范围、重现性和操作中注意事项等内容进行考察,并用实际案件检材验证和比较。结果还原法一在30%~70%、还原法三在20%~100%,其他方法在20%~70%范围内,线性关系良好;样本浓度超过或低于50%,采用切线法有一定误差;导数法及还原法三因需要制备CO饱和样本,操作略微繁琐,但导数光谱法计算结果准确性好。结论几种方法均可用于一氧化碳中毒血的检测,实验结果可为方法的实际应用提供借鉴和帮助。     

Apoptotic and necrotic brain lesions in a fatal case of carbon monoxide poisoning

A 41-year-old man was accidentally exposed to carbon monoxide (CO) gas and found in a state of cardiopulmonary arrest while he took bath. After admission, he was resuscitated and underwent artificial ventilation in a comatose state and died about 19h later. Computed tomography (CT) examination disclosed bilateral low density area in the basal ganglia and the thalamus, a well-known finding in the CO intoxication. Necropsy, histological examination, DNA ladder assay gave the first line of evidence for the presence of apoptosis as well as necrosis in the human case of CO intoxication. TdT-mediated dUTP-biotin nick-end labeling (TUNEL) positive apoptotic cells were more predominant in the CA2 area than in CA1 area. There is general co-relation between the ratio of TUNEL-positive cells and the DNA laddering on the agarose gel. Basal ganglia and thalamus, which showed bilateral low density area in CT, were revealed to be severe edema. The two types of cell death occurred in the cortex, basal ganglia, hippocampus, thalamus, and cerebellum. Hypoxia caused by CO-hemoglobin formation alone cannot explain the phenomena.     

甲醛对一氧化碳中毒血检验干扰的研究

目的探讨甲醛对一氧化碳中毒血的检测是否产生干扰,提高一氧化碳中毒鉴定的可靠性。方法采用常用的血中一氧化碳或碳氧血红蛋白饱和度的检测方法对未加甲醛和加甲醛的血样分别进行实验研究。结果甲醛对加热法、氢氧化钠法、氯化钯法、分光光度法等检测方法均可产生不同程度的干扰。结论经福尔马林灌注或固定的检材不宜用于一氧化碳中毒血检测,否则可能导致错误的鉴定结论。     

A comparative study of analytical methods to determine postmortem changes in carbon monoxide concentration

Twenty-one autopsy blood samples were analyzed using spectrophotometric and gas chromatographic procedures after storage for 30 and 150 days.When carboxyhemoglobin was measured spectrophotometrically at the absorbance ratio of $\text{540}\text{nm}\text{555}\text{nm}$, the observed average percent losses were 8 ± 9% and 35 ± 27% after 30 and 150 days of storage, respectively. When measured at the absorbance ratio of $\text{540}\text{nm}\text{579}\text{nm}$, the average percent losses of carboxyhemoglobin were 7 ± 8% and 34 ± 25% after 30 and 150 days, respectively. Wavelength shifts and distorted spectral scans were observed at 150 days.When carbon monoxide was determined by gas chromatographic methods based on combining capacity, the average percent loss was 15 ± 24% and 37 ± 36% after 30 days and 150 days, respectively. The average percent loss of calculated CO based on hemoglobin concentration after 30 days was 31 ± 14% and at 150 days, 40 ± 24%. The average percent loss of calculated CO based on iron content was 23 ± 13% and 37 ± 23% after 30 and 150 days, respectively.