title: Variations in mean cerebral blood flow under anesthesia at rest and during cortical activation.
abstract: More than one cerebral blood flow (CBF) measurement was performed on the same occasion in three groups of patients using the intracarotid 133Xenon technique. In the anesthetized group there was a highly significant reduction in CBF (mean = 24.3%) from the first to the second measurement. In those at rest under local anesthesia there was also a significant fall (mean 9.8%). The third group, who were stimulated during the second estimation, showed no change. A second CBF determination some time after beginning a study is recommended, especially in pharmacological studies, to provide a more reliable resting control, rather than the first value which represents flow in an "activated" brain which has not yet adapted fully to its new environment.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D000772:Anesthesia, Local; D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D006801:Humans; D008875:Middle Aged; D010812:Physical Stimulation