CEREBRAL BLOOD-FLOW DURING ACUTE ACIDOSIS IN PERINATAL GOATS

Changes in cerebral blood flow in response to 3 states of acute acidosis, posthypoxic, lactic acid and respiratory, were estimated by the radionuclide microsphere technique. In all 3 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 [CO2 arterial partial pressure] and to H+. The flow rate increases with hypercapnia, but the increase associated with an increase in H+ concentration while the PaCO2 was maintained at control levels was not apparently seen in mature animals. 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.