Cerebral Blood Flow

Synonyms

Cerebral autoregulation; Cerebral perfusion pressure

Definition

Cerebral blood flow is the amount of blood that goes through the arterial tree in the brain in a given amount of time.

Current Knowledge

In adults, cerebral blood flow is typically 750 ml per minute, or about 50 ml per 100 g of brain tissue per minute. This amount is equivalent to about 15% of the total cardiac output. Cerebral blood flow is highly regulated, through “autoregulation,” in order to meet the metabolic demands of the functioning brain. If it is too high, it can cause elevated intracranial pressure, which will compress and damage brain tissue. If it is too low, it will fail to meet the demands of the brain, resulting in cerebral ischemia if blood flow is less than 20 ml per 100 g of brain tissue per minute and in cerebral infarction if blood flow is less than 10 ml per 100 g of brain tissue per minute. Cerebral blood flow is affected by blood viscosity, blood vessel size, intracranial pressure level,...