title: Effects of xenon anesthesia on cerebral blood flow in humans: a positron emission tomography study.
abstract: BACKGROUND
  Animal studies have demonstrated a strong neuroprotective property of xenon. Its usefulness in patients with cerebral pathology could be compromised by deleterious effects on regional cerebral blood flow (rCBF).
  
  
  METHODS
  15O-labeled water was used to determine rCBF in nine healthy male subjects at baseline and during 1 minimum alveolar concentration (MAC) of xenon (63%). Anesthesia was based solely on xenon. Absolute changes in rCBF were quantified using region-of-interest analysis and voxel-based analysis.
  
  
  RESULTS
  Mean arterial blood pressure and arterial partial pressure for carbon dioxide remained unchanged. The mean (+/-SD) xenon concentration during anesthesia was 65.2+/-2.3%. Xenon anesthesia decreased absolute rCBF by 34.7+/-9.8% in the cerebellum (P<0.001), by 22.8+/-10.4% in the thalamus (P=0.001), and by 16.2+/-6.2% in the parietal cortex (P<0.001). On average, xenon anesthesia decreased absolute rCBF by 11.2+/-8.6% in the gray matter (P=0.008). A 22.1+/-13.6% increase in rCBF was detected in the white matter (P=0.001). Whole-brain voxel-based analysis revealed widespread cortical reductions and increases in rCBF in the precentral and postcentral gyri.
  
  
  CONCLUSIONS
  One MAC of xenon decreased rCBF in several areas studied. The greatest decreases were detected in the cerebellum, the thalamus and the cortical areas. Increases in rCBF were observed in the white matter and in the pre- and postcentral gyri. These results are in clear contradiction with ketamine, another N-methyl-D-aspartate antagonist and neuroprotectant, which induces a general increase in cerebral blood flow at anesthetic concentrations.
authors.affiliation: Turku PET Centre, Department of Anesthesiology and Intensive Care, Turku University Hospital, Finland. ruut.laitio@tyks.fi
authors.forename: Ruut M
authors.initials: RM
authors.lastname: Laitio
authors.forename: Kaike K
authors.initials: KK
authors.lastname: Kaisti
authors.forename: Jaakko W
authors.initials: JW
authors.lastname: Låangsjö
authors.forename: Sargo
authors.initials: S
authors.lastname: Aalto
authors.forename: Elina
authors.initials: E
authors.lastname: Salmi
authors.forename: Anu
authors.initials: A
authors.lastname: Maksimow
authors.forename: Riku
authors.initials: R
authors.lastname: Aantaa
authors.forename: Vesa
authors.initials: V
authors.lastname: Oikonen
authors.forename: Hannu
authors.initials: H
authors.lastname: Sipilä
authors.forename: Riitta
authors.initials: R
authors.lastname: Parkkola
authors.forename: Harry
authors.initials: H
authors.lastname: Scheinin
mesh_terms: D000328:Adult; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography; D012039:Regional Blood Flow / Q000187:drug effects; D014978:Xenon / Q000494:pharmacology*
chemical_list: D018685:Anesthetics, Inhalation; D014978:Xenon