COHb formation and acute carbon monoxide intoxication in adult male rats and guinea-pigs.

Respiratory exchange recordings and percentage survivals to lethal concentrations show that rats are more sensitive than guinea-pigs to an acute carbon monoxide intoxication. To avoid circadian respiratory an comportmental differences between rats and guinea-pigs experiments were performed on urethane anesthetized and artificially ventilated animals. This procedure demonstrates that, for an inhaled concentration of 0.05% CO, the rates of formation of COHb do not statistically differ in rats and in guinea-pigs, but that a higher (0.01 less than p less than 0.05) COHb saturation is reached in rats (35%) than in guinea-pigs (25%). For a 2.84% CO inhalation, no statistically significant difference is observed in the rate of COHb formation, but cardiac arrest is sooner (p less than 0.001) observed in rats than in guinea-pigs.