Effects of xenon anesthesia on cerebral blood flow in humans: a positron emission tomography study.
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.
Laitio
Ruut M
RM
Turku PET Centre, Department of Anesthesiology and Intensive Care, Turku University Hospital, Finland. ruut.laitio@tyks.fi
Kaisti
Kaike K
KK
Låangsjö
Jaakko W
JW
Aalto
Sargo
S
Salmi
Elina
E
Maksimow
Anu
A
Aantaa
Riku
R
Oikonen
Vesa
V
Sipilä
Hannu
H
Parkkola
Riitta
R
Scheinin
Harry
H
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*
D018685:Anesthetics, Inhalation; D014978:Xenon