title: A pilot study of normobaric oxygen therapy in acute ischemic stroke.
abstract: OBJECTIVE
  Therapies that transiently prevent ischemic neuronal death can potentially extend therapeutic time windows for stroke thrombolysis. We conducted a pilot study to investigate the effects of high-flow oxygen in acute ischemic stroke.
  
  
  METHODS
  We randomized patients with acute stroke (<12 hours) and perfusion-diffusion "mismatch" on magnetic resonance imaging (MRI) to high-flow oxygen therapy via facemask for 8 hours (n=9) or room air (controls, n=7). Stroke scale scores and MRI scans were obtained at baseline, 4 hours, 24 hours, 1 week, and 3 months. Clinical deficits and MR abnormalities were compared between groups.
  
  
  RESULTS
  Stroke scale scores were similar at baseline, tended to improve at 4 hours (during therapy) and 1 week, and significantly improved at 24 hours in hyperoxia-treated patients. There was no significant difference at 3 months. Mean (+/-SD) relative diffusion MRI lesion volumes were significantly reduced in hyperoxia-treated patients at 4 hours (87.8+/-22% versus 149.1+/-41%; P=0.004) but not subsequent time points. The percentage of MRI voxels improving from baseline "ischemic" to 4-hour "non-ischemic" values tended to be higher in hyperoxia-treated patients. Cerebral blood volume and blood flow within ischemic regions improved with hyperoxia. These "during-therapy" benefits occurred without arterial recanalization. By 24 hours, MRI showed reperfusion and asymptomatic petechial hemorrhages in 50% of hyperoxia-treated patients versus 17% of controls (P=0.6).
  
  
  CONCLUSIONS
  High-flow oxygen therapy is associated with a transient improvement of clinical deficits and MRI abnormalities in select patients with acute ischemic stroke. Further studies are warranted to investigate the safety and efficacy of hyperoxia as a stroke therapy.
authors.affiliation: Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass 02114, USA. asinghal@partners.org
authors.forename: Aneesh B
authors.initials: AB
authors.lastname: Singhal
authors.forename: Thomas
authors.initials: T
authors.lastname: Benner
authors.forename: Luca
authors.initials: L
authors.lastname: Roccatagliata
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Koroshetz
authors.forename: Pamela W
authors.initials: PW
authors.lastname: Schaefer
authors.forename: Eng H
authors.initials: EH
authors.lastname: Lo
authors.forename: Ferdinando S
authors.initials: FS
authors.lastname: Buonanno
authors.forename: R Gilberto
authors.initials: RG
authors.lastname: Gonzalez
authors.forename: A Gregory
authors.initials: AG
authors.lastname: Sorensen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000628:therapy*; D005260:Female; D006801:Humans; D018496:Hyperoxia; D007511:Ischemia; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D010865:Pilot Projects; D012039:Regional Blood Flow; D020521:Stroke / Q000628:therapy*
chemical_list: D010100:Oxygen