Effects of hypercapnia on cerebral blood flow following prophylactic and delayed experimental superficial temporal artery-middle cerebral artery bypass.

Cerebral blood flow was studied in dogs to ascertain whether preexisting superficial temporal artery-middle cerebral artery bypass could preserve hypercapnic reactivity following acute ischemia and whether postischemic-delayed revascularization would restore hypercapnic reactivity. In six dogs flow was preserved and some degree of hypercapnic response remained following proximal occlusion with a patent bypass. During complete ischemia (bypass occluded) there was no hypercapnic reactivity in the ischemic zone.

Correlation of experimental rCBF determinations in goats with flow measurements from a Doppler-modified carotid artery shunt.

A carotid artery shunt system has been developed that continuously monitors blood flow rates by embedding a Doppler crystal in the shunt wall. The crystal ranges through a "liquid lens" that enables it to be placed without violation of the shunt lumen. Because the crystal is at a fixed angle (45 degrees) to the axis of blood flow and the diameter of the lumen remains constant, a linear relationship exists between flow rates and the Doppler velocity signal.

Cerebral autoregulation following prophylactic and delayed experimental STA-MCA bypass.

Cerebral autoregulation is impaired in ischaemic regions. We hypothesized that pre-existing STA-MCA bypass would be superior to delayed revascularization in maintaining ipsilateral rCBF and preserving cerebral autoregulation following experimental stroke. Two series of dogs were tested to evaluate this hypothesis, but which was disproved for the chosen experimental conditions.

Sequential measurement of somatosensory evoked potentials in a canine model of hemispheric ischaemia.

We have previously shown that occlusion of 6 canine intracranial vessels produces profound hemispheric ischaemia and abolishes the ipsilateral SSEP. In the present study, this work was extended to ascertain the differential contributions of 6 intracranial vessels to SSEP function. Five dogs underwent craniotomy, brain retractions, and ipsilateral arterial microdissection, and were prepared for SSEP recordings.