Regional Cerebral Cortical Metabolic Rate of Oxygen and Carbon Dioxide, Related to the EEG in the Anesthetized Dog

The regional oxygen consumption and carbon dioxide production of a small area of the cerebral cortex (somato‐sensory cortex) in anesthetized dogs at steady state were determined quantitatively by means of a new method for measuring the regional cerebral blood flow (Lassen and Ingvar 1961, 1962) and by determination of the cortical arteriovenous difference of oxygen and carbon dioxide. Samples of cortical venous blood were obtained from the anterior part of the superior sagittal sinus after elimination of the diploic anastomoses. There were 26 complete sets of determinations. The a. v. differences (rAVDo1, and rAVDco2,) were found to be fairly stable (averages 11.3 and 11.7 vol. per cent). Large variations were found in the regional cortical blood flow (rCBF; 0.19 –1.06 ml per g per minute, average 0. 65 ± S.D. 0.23). The regional cortical oxygen consumption (rCMRo2 = rCBF × rAVDo2) hence varied between 2.3 and 13.4, average 7.0 (± S. D. 2.8), ml per 100 g tissue per minute. Studies of the EEG patterns prevailing at the time of the determinations showed that an EEG pattern dominated by faster frequencies (5–12 cycles per second) had an average rCMRo2, of 8.6 ml per 100 g per minute. A pattern dominated by high voltage slow waves (0.5 to 4 cycles per second) showed an average of 5.0, and a mixed EEG pattern of fast and slow waves an average rCMRo2 of 6.8 ml per 100 g per minute.