Analysis of CO ₂ Vasomotor Reactivity and Vessel Diameter Changes by Simultaneous Venous and Arterial Doppler Recordings

Abstract

We have demonstrated a different reaction pattern between intracranial venous and arterial vessels related to end-tidal CO2. Relating the flow velocities to the square of the vessel diameter and assuming a global rise of CBF and not extensible sinus walls, our results indicate that the MCA undergoes a vasodilation of 9.5+/-7% in maximal hypercapnia.