Figure 2.

Capillary flow heterogeneity during reduced cerebral perfusion pressure (CPP): Increased intracranial pressure (ICP) versus reduced mean arterial pressure (MAP). Bragin et al,⁵⁴ recorded cortical capillary erythrocyte velocities in rats at three CPP levels. In the top row, CPP reductions were the result of increased ICP, in the bottom row of reduced MAP. Note that intracranial hypertension lead to increased flow heterogeneity, with some capillaries displaying extremely high-flow velocities. During systemic hypotension , similar CPP values lead to homogenization and reductions of capillary flows, which is predicted to provide efficient oxygen extraction. Reproduced from ref. 54 with permission from the publisher.