Estimation of the Major Cause for Toxic Gases Inhalation-Induced Death in Fire Accident, with the Use of the Classification of Gas Toxicity in Rabbits

Abstract

It has been well known that the majority of fire-related deaths are due to the inhalation of toxic combustion products and carbon monoxide (CO) plays a main lethal role in fire accidents. Furthermore, hypoxia and carbon dioxide (CO2) in the hypoxic condition have recently been shown to potentiate CO-induced death. This study was aimed at examining whether the relation between pO2 and COHb concentration clarify the major cause for death of fire victims.   Blood gases and COHb concentration in the blood of fire victims (n=10) and the rabbits inhaled with the toxic gases (CO2-toxic gas : O2 5.0% ; CO2 16.0% ; CO 1.8% ; N2 77.2%, room air + CO gas : O2 21.0% ; CO 1.8% ; N2 77.2%, hypoxic condition : O2 2.0% ; N2 98.0%) were measured. From the relation between pO2 level and COHb concentration of the victims and the rabbits, the major causes for death classified into 4 groups : 1) pure CO intoxication, 2) hypoxia + (CO intoxication), 3) potentiation of CO2 in the hypoxic condition and/or potentiation of hypoxia for CO intoxication, 4) others.