Cerebral Blood flow and Its Responsiveness to CO2 after Traumatic and Ischemic Brain Injuries
The dynamics of regional cerebral blood flow (rCBF) after brain trauma and in ischemia were studied in adult rabbits. Brain trauma was produced by aseptic destruction of an area 4 mm2, 5 mm deep, in the parietal cortex (n= 13). The cerebral hemispheres were made ischemic bilaterally by permanent occlusion of the carotid arteries (n= 14). rCBF was measured in cortical grey and subcortical white matter by the H2 clearance method (Pt electrodes of 100 µm diameter), and also by rheoencephalography (REG), using the same electrodes. REG is based on measuring the vascular pulse-related fluctuation of tissue electric impedance (cf refs 1,2). Measurements by REG roughly matched those by H2 clearance. Measurements were made while the animal was breathing room air and also during 7% CO2 inhalation, which raised PaCO2 by 6–8 mmHg Responsiveness to CO2 was quantified as the ratio of rCBF with and without elevated PaCO2.
- 2.Moskalenko, Y.E., Weinstein, G.B., Demchenko, I.T., Kislyakov, Y.Y., Krivchenko, A.I., 1980, “Biophysical aspects of cerebral circulation.” Pergamon Press, Oxford.Google Scholar