Fig. 3
From: Traumatic brain injury: pathophysiology for neurocritical care
Changes in CBF related to PaCO2 level variation. In the case of respiratory acidosis, the effect of PaCO2 on the cerebral vasculature can augment cerebral blood flow (CBF). Conversely, CBF would be reduced by vasoconstriction after a drop in PaCO2. When PaCO2 values fall below 20Â mmHg from about 40Â mmHg, CBF also drops to half of the basic value (arrow)