title: Low-dose remifentanil increases regional cerebral blood flow and regional cerebral blood volume, but decreases regional mean transit time and regional cerebrovascular resistance in volunteers.
abstract: We have used contrast media-enhanced perfusion magnetic resonance imaging MRI to measure regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), regional mean transit time (rMTT) and regional cerebrovascular resistance (rCVR) in volunteers at baseline and during infusion of remifentanil (0.1 microgram kg-1 min-1). Remifentanil increased rCBF and rCBV in white and grey matter (striatal, thalamic, occipital, parietal, frontal) regions, with a parallel decrease in rMTT in those regions with the exception of occipital grey matter. rCVR was decreased in all regions studied. The relative increase in rCBF was greater than that in rCBV. Cerebral haemodynamics were increased significantly in areas less rich in mu-opioid receptors with a tendency towards more pronounced increases in rCBF and rCBV in pain-processing areas. Furthermore, interhemispheric differences in rCBF, rCBV and rMTT found prior to drug administration were almost eliminated during infusion of remifentanil. We conclude that, apart from direct and indirect cerebrovascular effects of remifentanil, these findings are consistent with cerebral excitement and/or disinhibition.
authors.affiliation: Department of Anesthesia and Intensive Care Medicine, University of Innsbruck, Austria.
authors.forename: I H
authors.initials: IH
authors.lastname: Lorenz
authors.forename: C
authors.initials: C
authors.lastname: Kolbitsch
authors.forename: M
authors.initials: M
authors.lastname: Schocke
authors.forename: C
authors.initials: C
authors.lastname: Kremser
authors.forename: F
authors.initials: F
authors.lastname: Zschiegner
authors.forename: M
authors.initials: M
authors.lastname: Hinteregger
authors.forename: S
authors.initials: S
authors.lastname: Felber
authors.forename: C
authors.initials: C
authors.lastname: Hörmann
authors.forename: A
authors.initials: A
authors.lastname: Benzer
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects; D001810:Blood Volume / Q000187:drug effects*; D001921:Brain / Q000098:blood supply / Q000187:drug effects*; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003287:Contrast Media; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D008279:Magnetic Resonance Imaging; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects; D010880:Piperidines / Q000008:administration & dosage / Q000494:pharmacology*; D000077208:Remifentanil; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects*
chemical_list: D000701:Analgesics, Opioid; D003287:Contrast Media; D006993:Hypnotics and Sedatives; D010880:Piperidines; D000077208:Remifentanil