Regional cerebral blood flow of the rat in acute carbon monoxide intoxication.

The effect of carbon monoxide (CO) on the regional cerebral blood flow was studied by exposing lightly anesthetized rats for 30 min to 0.5, 1.0, 1.5, and 2.0% CO gas mixtures. Cortical cerebral blood flow (CBF) increases of near 200%, 300%, and 400% control were observed at 0.5, 1.0, and 1.5% CO, respectively; whereas at 2.0% CO a reversal of the CBF increase was observed with values declining to near 300% control. The CBF response of subcortical, cerebellar, and brain stem areas was quantitatively similar to that of cortex, indicating that the CBF changes in CO intoxication are general. The decrease in CBF at 2.0% CO was related to significant decreases in arterial CO2 tension. Comparison of the CBF data to previous metabolic results in CO poisoning suggests that the CBF increases are a principal factor in the maintenance of an intact energy state in CO poisoning.