Estimation of carboxyhemoglobin

Carbon monoxide can be lethal at concentrations of less than 0.1%. The kine tics and mechanism of its toxicology have been described elegantly by Cobur n et al. (J. Clin. Invest 1965, 44, 1899-1910): CO combines readily with bl ood hemoglobin to form carboxyhemoglobin (COHb). When a subject is exposed to potentially hazardous levels of CO, however, the achievement of the equi librium level of COHb in the bloodstream requires a number of hours. The Co burn equation is complex, using a number of input variables. What is desire d is a simple equation, requiring as input only two or three readily availa ble parameters, that will provide a good estimate of COHb concentration wit h time. Previous efforts to develop such an equation are reviewed. This wor k provides and tests a new empirical equation to generate COHb concentratio n-time curves. With this equation and for a given concentration of ambient CO, one can estimate how much of a subject's hemoglobin has been tied up as COHb after a given period of exposure. We believe this to be of value to f irefighters, police, and other emergency personnel.