Effects on Cerebral Blood Flow of Infusion of Hyperosmolar Saline During Cerebral Vasodilation in the Dog

In six anaesthetized dogs, cerebrovascular reaction to experimental hyperosmolality (plasma osmolality in the range of 350–400 mosm kg water^-1) induced by intravenous infusion of 0.6 M saline was studied. In order to provoke and reinforce any effects from saline passage over the blood-brain barrier, pre-experimental submaximal vasodilation was induced by means of hypercapnia and in some cases haemodilution. Cerebral blood flow (CBF) was measured by the radioactive gas elimination method. CBF was unaffected by progressive hyperosmolality during a 2-h observation period.