An induction dose of propofol does not alter cerebral blood flow determined by single-photon-emission computed tomography.

Abstract

To examine the effect of propofol per se on cerebral blood flow (CBF), we measured CBF by single-photon-emission computed tomography (SPECT) using a technetium-99m ethyl cysteinate dimer before and after propofol administration. Ten healthy adult male volunteers were studied. Ten minutes after isotope injection, CBF was measured using a SPECT system. After this first SPECT scan, 1.5 mg.kg(-1) of 1% propofol was administered over 30 s and the same dose of isotope was injected 2 min thereafter. Ten minutes later, a second SPECT scan was carried out. A subtraction SPECT image was obtained by reducing the first SPECT image from the second SPECT image. Based on these SPECT images, various regions of interest (ROI) were traced. Changes in regional CBF to each ROI were analyzed by a comparison of the total gamma-ray counts in each ROI between the first and subtraction SPECT images. The total gamma-ray counts in each ROI did not change significantly after propofol administration. At this time, end-tidal carbon dioxide concentration and heart rate did not change, but blood pressure and oxygen saturation decreased slightly. The present result suggests that the induction dose of propofol does not alter CBF.