title: Desflurane increases brain tissue oxygenation and pH.
abstract: BACKGROUND
  Desflurane anesthesia can produce cerebral metabolic depression and increase cerebral blood flow. We evaluated the effect of desflurane on brain tissue oxygen pressure (PO2), carbon dioxide pressure (PCO2) and pH during neurosurgery.
  
  
  METHODS
  Following a craniotomy, the dura was opened and a Paratrend 7 sensor, which measures PO2, PCO2, pH and temperature, was inserted into brain tissue. In 6 control patients in group 1, anesthesia was maintained constant with 3% end-tidal desflurane over 60 min, including a 30-min stabilization period. In group 2, 9 patients were ventilated with 3% desflurane under baseline conditions. After a 30-min stabilization period, baseline tissue gases and pH were measured and end-tidal desflurane was increased to 6% and then 9% for 15-min intervals. Mean arterial pressure (MAP) was maintained with intravenous phenylephrine.
  
  
  RESULTS
  Under baseline conditions, cardiovascular and brain tissue measures were similar between the 2 groups. Increasing end-tidal desflurane from 3% to 9% produced burst-suppression EEG in all patients and significantly increased tissue PO2 and pH and decreased PCO2. No parameters changed significantly in the control group during steady-state anesthesia.
  
  
  CONCLUSIONS
  These results show that 9% desflurane can improve brain tissue metabolic status before temporary brain artery occlusion if cerebral perfusion pressure is maintained. This may be particularly important in patients with symptoms of ischemia before surgery.
authors.affiliation: Department of Anaesthesiology, University of Illinois Hospital, Chicago, USA.
authors.forename: W E
authors.initials: WE
authors.lastname: Hoffman
authors.forename: F T
authors.initials: FT
authors.lastname: Charbel
authors.forename: G
authors.initials: G
authors.lastname: Edelman
mesh_terms: D000328:Adult; D000368:Aged; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000601:surgery; D002245:Carbon Dioxide / Q000378:metabolism; D000077335:Desflurane; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*
chemical_list: D018685:Anesthetics, Inhalation; D002245:Carbon Dioxide; D000077335:Desflurane; D007530:Isoflurane; D010100:Oxygen