Tissue pO₂ and pCO₂ of the Cerebral Cortex, Related to Blood Gas Tensions

Abstract

GLEICHMANN, U., D. H. INGVAR, D. W. LUBBERS, B. K. SIESJO and G. THEWS. Tissue PO, andpCO, of the cerebral cortex, releated to blood gas tensions. Acta physiol. scand. 1962. 55. 127-138. -Quantitative measurements of the PO, and the pC0, on the intact surface of the cerebral cortex were made in anesthetized dogs. Simultaneous measurements of the cortical metabolic rate of oxygen and carbon dioxide, as well as of the arterial and cortical venous PO, and pC0, (GLEICH-MANN et al. 1962), allowed calculation of the average tissue PO, and pC0, according to THEWS (1960 a and b). The results indicate that the PO, and the pC0, electrodes measure tensions which are close to the calculated average tissue PO, and pC0, respectively. I t has long been recognized that direct measurements of the tissue oxygen and carbon dioxide tensions could yield useful information on important events in the central nervous system. A step forward was the development of polarographic electrodes for measurement of the oxygen tension in tissue (DAVIES and BRINK 1942). Since that time a number of qualitative studies of the oxygen tension of the cerebral cortex have been performed (DAVIS, MCCULLOCH and ROSEMAN 1944, DAVIES and REMOND 1947, MOCHIZUCK~ 1951, MEYER and DENNY-BROWN 1955 SIESJO 1960, 1962, MEYER and GOTOH 196 1 ) . Although quantitative measurements have been possible with the "recessed" type of platinum cathode (DAVIES and BRINK 1942, DAVIES and BRONK 1957 ; $. CATER 1960) such measurements have not been performed systematically to any larger extent (See discussion). On leave of absence from the Institute of Physiology, Cologne. Present adress: Department of Applied Physiology, Marburg. On leave of absence from the Institute of Physiology, Kiel.

Direct Measurements of the Partial Oxygen Tension in Different Cortical and Subcortical Structures of the Brain and in Gliomas during Stereotactic Operation

“…The mean value with our grouping lies at 42.619.6 mm Hg and is thus within the realm of values found by others [1,7,9,10,14,23].…”

Hydrogen ion buffering during complete brain ischemia

“…In the interstitial space, excess H + also combines with HCO 3 − to form CO 2 and water. Excess CO 2 which diffuses readily through cell compartments 12,16,28 quickly enters blood. CO 2 also diffuses into astroglial cells to be rapidly hydrated to carbonic acid by carbonic anhydrase 11,17,23,44,45 .…”

Oxidative metabolism in cerebral ischemia. Part 1. Measurement of oxygen extraction slopes of grey and white matter in vivo.

“…Reported differences in ATP and phosphocreatine concentration" may reflect autolytic changes resulting from a freezing delay in deeper structures of the brain. Within the cerebral cortex of the dog Gleichmann, et al 12 found a wide variation in metabolic rates for oxygen from 2.3-13.4 ml/100 g/min with a mean CMRo 2 of 7.0 ml/100 g/min. Homberger et al 13 found a value of 5.9 ml/100 g/min in light anesthesia with a range of 4.2-7.6 ml/100 g/min.…”