Noninvasive estimation of cerebral perfusion pressure and zero flow pressure in healthy volunteers: the effects of changes in end-tidal carbon dioxide.

Zero flow pressure (ZFP) in the cerebral circulation is defined as the arterial pressure at which flow ceases. Noninvasive methods of estimating cerebral perfusion pressure (CPP) and ZFP using transcranial Doppler ultrasonography have been described. There is a paucity of normal physiological data r