Cerebral blood flow during propofol induced sedation.

Purpose: This work determined if 2, 6-diisopropylphenol (propofol) selectively affects cerebral blood flow in regions associated with wakefulness.
Procedures: Cerebral blood flow (CBF) was measured with positron emission tomography (PET) using the 15O-water bolus technique in 10 subjects while awake and during light and deep sedation. Arterial blood was sampled for CBF estimation, blood gases and propofol plasma concentrations.
Results: Global CBF decreased under deep sedation. A regression analysis of CBF vs. propofol concentration showed significant decreases in CBF in the thalamus and posterior cingulate and increases in the hippocampus and cerebellum. An ANCOVA analysis on condition (controlling for pCO(2) levels) showed mean CBF decreased in the thalamus and posterior cingulate cortex and increased in the primary motor and hippocampal areas during the light and deep sedation compared to awake conditions.
Conclusions: These data support the hypothesis that propofol preferentially alters CBF in specific brain regions necessary to maintain wakefulness.