INCREASING DOSES OF INTRACAROTID AIR AND CEREBRAL BLOOD-FLOW IN RABBITS

We studied the natural history of brain air embolism by observing bubbles in the piai vessels of rabbits and the effect of different doses of intracarotid air on brain function and blood flow. We identified and then studied two doses of air; 25 γrl in five rabbits caused rapid bubble transit, recovery, and then deterioration in brain function and blood flow and 400 γl in five rabbits caused temporary bubble trapping and sustained deterioration in brain function. These dose responses correlate well with the natural history of divers with air embolism of the brain. All doses of air caused both arteriolar dilatation and reduced blood flow, which were independent of dose, whereas the detrimental effect of air embolism on brain function was dose dependent. Our results suggest that this is a good model of brain air embolism. (Stroke 1990;21:1340-1345). © 1990 American Heart Association, Inc.