Carbon monoxide elimination

The elimination rates of carbon monoxide in anesthetized, spontaneously breathing dogs were determined following acute inhalation of varying amounts of this gas. Blood levels of carboxyhemoglobin (COHb) induced ranged between 5 and 43%. Following the administration of carbon monoxide, the decline in arterial blood %COHb was biphasic. The decline in the blood %COHb level could be described as an initial distribution curve which was exponential in nature, followed by an elimination curve which was linear for 90 min. Prediction equations for elimination of CO from blood according to the initial levels of COHb are presented. Animals having low (5-16%) and high (20-43%) COHb levels eliminated 50% of their total load in 190 plus or minus 6.4 and 134 plus or minus 5.3 min, respectively.