title: The comparative effects of sevoflurane versus isoflurane on cerebrovascular carbon dioxide reactivity in patients with previous stroke.
abstract: OBJECTIVE
  The use of volatile anesthetics is reportedly related to altered cerebrovascular carbon dioxide (CO2) reactivity. We examined the comparative effects of sevoflurane versus isoflurane on cerebrovascular CO2 reactivity in patients with previous stroke.
  
  
  METHODS
  Twenty-four patients with previous stroke and 20 patients without previous stroke (serving as controls) were studied. Anesthesia was maintained with either end-tidal 1.0 minimum alveolar concentration (MAC) sevoflurane or 1.0 MAC isoflurane in 33% oxygen and 67% nitrous oxide. A 2.5-MHz pulsed transcranial Doppler (TCD) probe was attached to the patient's head at the right or left temporal window for continuous measurement of mean blood flow velocity in the middle cerebral artery (Vmca). After establishing baseline values of Vmca and cardiovascular hemodynamics, we increased end-tidal CO2 by decreasing the ventilatory frequency by 2-5 breaths x min(-1).
  
  
  RESULTS
  We found that values for absolute and relative CO2 reactivity in the sevoflurane groups were lower than those in the isoflurane groups (absolute CO2 reactivity in the sevoflurane groups: control, 3.3 +/- 0.4*; previous stroke, 3.4 +/- 0.4*; absolute CO2 reactivity in the isoflurane groups: control, 4.2 +/- 0.3; previous stroke, 4.5 +/- 0.4, cm x s(-1) x mmHg(-1); *P < 0.05 compared with isoflurane group). There were no significant differences in the values for absolute and relative CO2 reactivity between the controls and the previous-stroke patients within each of the sevoflurane and isoflurane groups.
  
  
  CONCLUSIONS
  Our findings suggest that, in patients with previous stroke, cerebrovascular CO2 reactivity under sevoflurane anesthesia was lower than that under isoflurane anesthesia.
authors.affiliation: Department of Anesthesiology, Gunma University Hospital, Maebashi, Gunma, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kadoi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Saito
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Takahashi
mesh_terms: D000768:Anesthesia, General; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006801:Humans; D007530:Isoflurane / Q000494:pharmacology*; D008738:Methyl Ethers / Q000494:pharmacology*; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009609:Nitrous Oxide / Q000494:pharmacology; D011446:Prospective Studies; D000077149:Sevoflurane; D020521:Stroke / Q000503:physiopathology* / Q000601:surgery; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane; D007530:Isoflurane; D009609:Nitrous Oxide