Cerebral vascular resistance following platelet and leukocyte removal from perfusate.

The rapid increases in cerebral vascular resistance (CVR) frequently observed during extracorporeal perfusion of isolated organs with whole or diluted blood have been investigated using the isolated canine brain preparation. Our data strongly suggest that these increases are caused by a vasoconstrictor that is present in the buffy coat. Plasma serotonin levels were measured and found to be insignificant after conditioning and storage. Conditioning the blood reduced the platelets and the potential for thromboxane A2 production to approximately 40% of normal. However, there was no correlation between thromboxane B2 levels and increases in CVR. Removal of the buffy coat effectively removed all of the leukocytes. Thus, one of the leukotrienes may have been responsible for the buffy coat-induced vasoconstriction.