Bilateral Cerebral Blood Flow

The nitrous oxide method for determination of the cerebral blood flow in humans¹is generally carried out with venous blood samples drawn from the superior bulb of only one internal jugular vein. It was originally assumed by Kety that blood from one internal jugular bulb was representation of "mixed cerebral venous blood." He was more concerned that the "mixed" applied to cortical and subcortical venous drainage, rather than to that between the hemispheres per se. He did report a series of 10 patients in whom cerebral blood flows and arteriovenous oxygen differences were determined simultaneously on blood from both jugular bulbs and showed the standard deviation of the cerebral oxygen consumption between the two sides was not significantly different from the standard deviation of sets of duplicate determinations done on the same side, seriatim. Munck and Lassen²showed that there were minor, but statistically significant, differences between values