Stroke, Vol 15, 108-114, Copyright © 1984 by American Heart Association
R von Kummer
Thirty six small hydrogen sensitive electrodes were inserted into the
brains of 6 cats to evaluate the local vascular response to change in
PaCO2, of cortex, subcortical white matter, and caudate nucleus. Repeated
measurements (617) of local cerebral blood flow (ICBF) were performed over
a period of 12 weeks. Within a PaCO2 range from 19 to 96 mmHg the local
response of CBF was linear in most of the regions measured. The absolute
local CO2 reactivity (CO2-R) showed a positive correlation to ICBF at PaCO2
= 40 mmHg (ICBF40) with the regression line: absolute CO2-R = 0.02 ICBF40 +
0.22, r = 0.71 (p less than 0.01). Therefore relative ICBF change was
calculated in relation to ICBF40 to make comparisons between the CO2
response of different measuring days and of different regions examined. No
significant change in relative CO2-R was observed during the 12 weeks
interval. Differences of relative CO2-R between investigated regions were
insignificant. The uniformity of relative CO2 response might support the
hypothesis of a direct effect of PaCO2 or pH on the vessel wall. For
comparison of CBF, the individual determination of CBF40 and relative CO2-R
would be necessary.
ARTICLES
Local vascular response to change in carbon dioxide tension. Long term observation in the cat's brain by means of the hydrogen clearance technique
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