CARBOXYHEMOGLOBIN FORMATION DUE TO CARBON-MONOXIDE EXPOSURE IN RATS

The Coburn-Forster-Kane equation (CFKE) is a well-tested model for pre diction of carboxyhemoglobin (COHb) formation due to carbon monoxide ( CO) exposure in humans. There have been few and relatively poorly test ed attempts to implement a CFKE for rats. Such an implementation is of interest because many experiments on the effects of CO in rats were d one without measuring COHb. To extrapolate from rats to humans re quir es a rat version of the CFKE. Rats were exposed to 150, 250, 500, acid 1000 ppm CO for up to 240 min. Blood gases and COHb were measured. A CFKE was implemented for rats by using parameters found in the literat ure and estimating them from the data. It was deduced from the blood-g as data that rats hyperventilate slightly as COHb increases. The blood -gas data were used to estimate ventilation and alveolar capillary oxy gen partial pressure. The hyperventilation required an iterative solut ion to the CFKE. The iterative CFKE predictions were found to differ s tatistically from observations, but in explainable ways and/or in smal l amounts. (C) 1994 Academic Press, Inc.