Prevalence of hydrogen cyanide and carboxyhaemoglobin in victims of smoke inhalation during enclosed-space fires: a combined toxicological risk.

BACKGROUND: Hydrogen cyanide (HCN) is one of the most toxic components of fire smoke, but insufficient attention is paid to its potential role as a cause of injury or death in victims (alive or dead) of enclosed-space fires. OBJECTIVE: To analyse the prevalence of toxic HCN exposure in fire victims and factors that may influence its toxicity, particularly the co-presence of carbon monoxide (CO) and ethanol. MATERIALS AND METHODS: Blood samples from fire victims and persons rescued from fires were analysed. RESULTS: A positive result for HCN (mean concentration 16.83 mg/l) was detected in blood samples from 169 of 285 fire-related deaths (59%). Ethanol was present in 91 (65%) of 139 samples with coincident presence of HCN and carboxyhaemoglobin (COHb). HCN (mean 4.0 mg/l) was also detected in 20 of 40 (50%) fire survivors. DISCUSSION: The high prevalence of coincident CO and HCN in enclosed-space, fire-related deaths should alert clinicians to suspect toxic HCN exposure in all persons rescued from fire with signs and symptoms of respiratory distress. CONCLUSIONS: Medical procedures in persons rescued from enclosed-space fires, especially in the pre-hospital setting, should be augmented to cover the possibility of toxic HCN exposure, particularly in individuals who do not respond to standard supportive therapy. Likewise, post-mortem investigations should routinely include assays for HCN when determining probable cause of death.

[Methods of carbon monoxide determination in postmortem blood--advantages and disadvantages]. / Metody oznaczania tlenku wegla we krwi sekcyjnej--zalety i ograniczenia.

With respect to epidemiology of carbon monoxide poisonings, the diagnostic management of poisonings caused by this xenobiotic is among the fundamental objectives of forensic toxicology. In forensic practice, to determine carbon monoxide, colorimetric and spectrophotometric methods, as well as gas chromatography are used. Based on literature data and their own experience, the authors discuss analytical methods universally applied in determinations of carbon monoxide in postmortem blood. The advantages and disadvantages, as well as the cause of errors resulting from the specificity of the examined material (postmortem blood) are indicated.

[Assessment of exposure to hydrogen cyanide in fire fatalities in the aspects of endogenous hydrogen cyanide production as a result of putrefaction processes in the deceased]. / Ocena ekspozycji na cyjanowodór u smiertelnych ofiar pozarów w aspekcie powstawania w zwlokach endogennego cyjanowodoru w procesach gnilno-rozkladowych.

On account of endogenous hydrogen cyanide (HCN) production in the deceased, it is not easy to assess exposure to HCN in people who died in fire involving closed rooms (flats, garages, cellars, etc). In the paper, the authors present the results of blood determinations of hydrogen cyanide in fatalities of explosions and fires occurring in coal-mines, as well as fires in closed rooms. It has been demonstrated that the time of exposure to a high temperature and the temperature itself hamper autolysis processes that lead to production of endogenous HCN in fire fatalities.

[The effect of high temperature on the levels of selected endogenous compounds]. / Wplyw wysokiej temperatury na poziom wybranych zwiazków endogennych.

The authors present their research on the levels of carboxyhemoglobin, hydrogen cyanide and ethyl alcohol in the blood of 23 fatalities found in the extreme conditions (methane explosion, fire, high temperature) associated with a mining disaster. Determinations of the presence of carboxyhemoglobin, hydrogen cyanide, and ethyl alcohol were performed as soon as the blood samples were collected from the deceased. The concentration of ethyl alcohol ranged from 0.2 per thousand to 1.3 per thousand in 18 cases. Blood HbCO levels tested within the range of 11% to 83% in 17 cases. In six cases, HbCO tested negative, and the injuries found at autopsy indicated these individuals to have been killed at the moment of the explosion. Blood cyanide content tested negative in all the examined cases. The extreme conditions of the mining disaster, especially high temperature, to which the bodies were exposed, did not have any effect either on endogenous cyanide or carboxyhemoglobin, causing, however, a significant increase in the level of ethyl alcohol in the blood.

[Opinionating on the cause of poisoning and death in fire victims]. / Opiniowanie o przyczynie zatrucia i smierci w przypadku badania zwlok wydobytych z pozaru.

In the years 1995-2005, 273 cases of fatalities resulting from a fire were investigated in the Chair of Forensic Medicine, Medical University of Silesia, Katowice. To explain the circumstances and determine the cause of death, in each case, autopsies, as well as toxicological determinations of toxic gases, such as carbon monoxide or hydrogen cyanide, were carried out. Alcohol intoxication status of the victims was also determined. Based on the obtained results, comprehensive toxicological and medico-legal opinions on the cause of death of all the examined fire-associated fatalities were done.

[The role of ethanol in complex poisonings with carbon monoxide and hydrogen cyanide in fire victims]. / Rola etanolu w kompleksowych zatruciach tlenkiem wegla i cyjanowodorem u ofiar pozarów.

A total of 230 cases of deaths in burning spaces dating from the years 1995-2003 were investigated in Forensic Medicine Department, Silesian University of Medicine, Katowice. HbCO and HCN found in 177 blood samples ranged from 4-95 % (mean, 31,5 %) and 0,5-40,3 microg/ml (mean, 9,98 microg/ml), respectively. Moreover, ethanol was found in 122 blood samples. Its concentration ranged from 0,89-5,0 per thousand (mean, 1,45 per thousand). A comparative analysis of HbCO and HCN levels in the groups with and without ethanol showed that the range and the mean concentration of both these xenobiotics were higher in the group with no alcohol. It was also shown that the increased ethanol caused a drop in HbCO and HCN levels. To evaluate HbCO and HCN levels, the regression and correlation analysis was used.

[Attempt to estimate risks of fatal poisoning on the basis of HCN and HbCO concentrations in blood of fire victims]. / Próba oceny ryzyka smiertelnego zatrucia na podstawie ksztaltowania sie stezenia cyjanowodoru i karboksyhemoglobiny we krwi ofiar pozarów.

Using the results of HCN and HbCO concentrations in the blood of 174 deceased found in different burning spaces and 35 people with symptoms of poisoning evacuated from the scene of a fire and then admitted to hospital. The correlation between blood concentration of both these xenobiotics and death or chance of survival in a fire was estimated by statistical analysis. An attempt was made to define a value of so-called "cut-off" points for HbCO and HCN by independence test chi 2 with Yates's correction. Point and interval estimations (95% Comfield's confidence interval) were used for the odds ratio (OR). The research showed that there was a strict statistical correlation between the chance of survival and death risks dependent on blood concentrations of HCN and HbCO in all the groups examined.