Changes in cerebral blood flow in response to three states of acute acidosis, posthypoxic, lactic acid, and respiratory, were estimated by the microsphere technique. In all three states, the fraction of the systemic blood flow reaching the brain and the rate (ml/min) of blood flow to it increased. The increase in flow was linearly related both to the PaCO2 and to H+. Others have shown the flow rate to increase with hypercapnia, but the increase associated with an increase in hydrogen ion concentration while the PaCO2 was maintained at control levels does not appear to have been observed in mature animals.Speculation
The significant increase in cerebral blood flow seen in perinatal goats during acute acidosis seems to be a result of a decrease in cerebral vascular resistance in an attempt by the cerebral vascular bed to preserve flow to the brain during stress.