Tissue pO2 of human brain cortex--method, basic results and effects of pentoxifylline.

A polarographic multiwire surface electrode was used for measurement of local oxygen partial pressure (pO2) on human brain cortex during neurosurgical operations. The two major problems encountered in this application of the electrode involved sterility of the equipment and mounting of the electrode. The described method of sterilization does not alter the electrical properties of the electrode. A special mount was designed to allow free three-dimensional placement of the electrode without exerting pressure on the cortex. Basic results of this technique demonstrated that it is possible to distinguish different pO2 distribution patterns displayed in pO2 histograms for various types of brain tumors and edematous brain tissue. In patients with arteriovenous malformations (AVMs) of the brain, an increase of tissue pO2 in cortical areas adjacent to the AVM was the result of extirpation of the lesion. The effect of intravenously administered pentoxifylline was studied during extraintracranial bypass operations in patients with cerebrovascular disease. In 7 patients a consistent shift of the pO2 histograms to the right, i.e., to higher pO2 values, could be demonstrated. Mean pO2 values increased statistically significantly by 16 +/- 7 mmHg as early as ten minutes after infusion of pentoxifylline. The rapid improvement of tissue oxygenation of human brain cortex is thought to be the result of an improvement of microcirculation, for other parameters influencing tissue pO2 showed no significant alterations if any.