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.