Affiliation:
1. Mayo Clinic and Mayo Foundation: Section of Neurology and the Cerebrovascular Clinical Research Center, Rochester, Minnesota 55901
Abstract
The right middle cerebral artery (MCA) was occluded in cats; after subsequent craniectomy cortical blood flow (CBF) was measured bilaterally with
85
Kr, and photographs of the superficial microvasculature were made. Ventilation was controlled, and Pa
CO
CO2
was altered by changing the concentration of CO
2
in the inspired air. In nonischemic cortex CBF varied as an exponential function of Pa
CO
CO2
, and the caliber of superficial arterial vessels (50 to 200µ in diameter) increased with increasing Pa
CO
CO2
. In ischemic cortex, changes of Pa
CO
CO2
produced no change of CBF in six of ten animals studied within one day of occlusion; in four of these six, there was no change in the caliber of arterial vessels. In the four other animals of this group, there was a paradoxical response (an increase of Pa
CO
CO2
produced a decrease of CBF of ischemic cortex), and in two of these four animals, there also was a paradoxical response of the caliber of arterial vessels. In eight animals allowed to survive 5 to 12 days after MCA occlusion, the arterial vessels of ischemic cortex regained some reactivity: a normal response of CBF to changes of Pa
CO
CO2
was found in four, and appropriate changes of vessel caliber were found in all eight. The ischemia-induced impairment of the reactivity of cortical vessels to changes of Pa
CO
CO2
casts doubt on the usefulness of CO
2
inhalation for the treatment of strokes of humans.
Publisher
Ovid Technologies (Wolters Kluwer Health)
Subject
Advanced and Specialised Nursing,Cardiology and Cardiovascular Medicine,Clinical Neurology
Cited by
95 articles.
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