Effect of heating on COHb% of the blood

Abstract

The blood from burned cadavers heat-coagulates badly and COHb% at autopsy is expected to be lower than that at death. To study such an effect of heating on COHb% in the blood, we have carried out experiments on heating of dead bodies of CO intoxicated guinea pigs as well as that of blood containing COHb in vitro. Three high temperatures (300 degrees C, 500 degrees C, 700 degrees C) and five exposure times (5 min, 10 min, 15 min, 20 min, 30 min) were used to stimulate conditions of real fire. Supposing that the effect of heat can be expressed in terms of a product of heating temperature with exposure time, a relation between the product and CO liberation rate was examined. The release of CO is at most 20% of the CO initially present when the product is under 5,000 and the blood retains still fluid, whereas the release of CO is about 50% when the product is over 10,000 and the blood is clotted. It is difficult to adapt CO release from COHb observed in experiments on heating in vitro and in the dead body to the judgment of the causes of death of burnt corpses, but if taking into consideration the degree of burns of charred bodies and the degree of the heat coagulation of the blood, it is suggested that one is able to anticipate COHb% at death from the gas chromatographic measurement of COHb% at autopsy in medico-legal practice.