Correlation coefficient between intracranial and arterial pressures: a gauge of cerebral vascular dilation

With the use of a laboratory model, arterial and intracranial pressure signals were obtained under conditions of varying depths of hypercapnia ranging from normocapnia to deep hypercapnia. Also, with the use of a closed cranial window, measures of cerebral arteriolar diameter and estimates of cerebral venous flow were obtained. The correlation of the intracranial and arterial pressure signals, arteriolar diameter, and estimates of venous flow exhibit a dose-dependent characteristic by increasing monotonically with increasing progressive states of increasing hypercapnia. These results indicate that the correlation between intracranial and arterial pressure signals provides an estimate of the gauge of the cerebral vasculature.