Detection of carbon monoxide poisoning that occurred before a house fire in three cases

Analyses of physical factors that contribute to the blood carboxyhemoglobin saturation in autopsy cases of house fire fatalities

The authors analyzed data from forensic autopsies of 75 patients who died as a result of house fires to clarify the physical factors that affect blood carboxyhemoglobin (COHb) saturation. Blood COHb saturation levels were significantly lower in patients who survived in the hospital. No significant differences were found in the blood COHb saturation levels between patients who died immediately at the scene and those who were pronounced dead at the receiving hospital without heartbeat being restored. The COHb saturation levels were significantly different among the groups of patients classified by the amount of soot. Although age, coronary artery stenosis, and blood alcohol concentration did not significantly affect blood COHb saturation, on comparing patients who died in the same fire, lower COHb saturation was observed in two patients, one with severe coronary artery stenosis and other with severe alcohol intoxication. To accurately interpret blood COHb saturation during forensic autopsy, the heartbeat status (present or absent) at the time of the rescue and the amount of soot in the trachea must be determined. Low levels of COHb saturation may be observed in fatalities with severe coronary atherosclerosis or severe alcohol intoxication.

A case of carbon monoxide poisoning before a vehicle fire: Availability of volatile hydrocarbons analysis

Benzene is one of volatile hydrocarbons contained in fire smoke, and the concentrations in the blood are known to be positively correlated with that of carbon monoxide-hemoglobin (CO-Hb) in fire-related deaths. In this report, we present a vehicle fire case in which CO and benzene concentration is atypically un-correlated. The car driven by the vehicle dweller ran into an oncoming lane at high speed, hitting a traffic signal pole. A vehicle fire started when the rescuer opened the car door. A burned body and briquette stove were found when the fire was extinguished. An autopsy revealed a small amount of soot deposit in the airways. The CO-Hb concentration in the heart blood was 63%. Volatile hydrocarbon analysis of the blood was performed; compared with the CO-Hb concentration, the benzene concentration was significantly lower than expected. High CO-Hb concentration without a hydrocarbon component indicated that the deceased inhaled CO that was not related to fire smoke. Thus, we concluded that the cause of death was CO poisoning caused by the briquette stove before the vehicle fire started. Comparing volatile hydrocarbon concentrations with CO-Hb concentrations could provide more information about the circumstances surrounding a vehicle fire-related death.

Volatile Hydrocarbon Analysis in Blood by Headspace Solid-Phase Microextraction: The Interpretation of VHC Patterns in Fire-Related Incidents

A headspace solid-phase microextraction (HS-SPME) technique was used to quantitate the concentration of volatile hydrocarbons from the blood of cadavers by cryogenic gas chromatography-mass spectroscopy. A total of 24 compounds including aromatic and aliphatic volatile hydrocarbons were analyzed by this method. The analytes in the headspace of 0.1 g of blood mixed with 1.0 mL of distilled water plus 1 µL of an internal standard solution were adsorbed onto a 100-µm polydimethylsiloxane fiber at 0°C for 15 min, and measured using a GC-MS full scan method. The limit of quantitation for the analytes ranged from 6.8 to 10 ng per 1 g of blood. This method was applied to actual autopsy cases to quantitate the level of volatile hydrocarbons (VHCs) in the blood of cadavers who died in fire-related incidents. The patterns of the VHCs revealed the presence or absence of accelerants. Petroleum-based fuels such as gasoline and kerosene were differentiated. The detection of C8-C13 aliphatic hydrocarbons indicated the presence of kerosene; the detection of C3 alkylbenzenes in the absence of C8-C13 aliphatic hydrocarbons was indicative of gasoline; and elevated levels of styrene or benzene in the absence of C3/C4 alkylbenzenes and aliphatic hydrocarbons indicated a normal construction fire. This sensitive HS-SPME method could help aid the investigation of fire-related deaths by providing a simple pattern to use for the interpretation of VHCs in human blood.