title: Early Moderate Hyperoxemia Does Not Predict Outcome After Aneurysmal Subarachnoid Hemorrhage.
abstract: BACKGROUND
  Targeting hyperoxemia is common practice in neurocritical care settings, but the safety of hyperoxemia has been questioned.
  
  
  OBJECTIVE
  To investigate the independent effect of hyperoxemia on outcome in patients with aneurysmal subarachnoid hemorrhage (SAH).
  
  
  METHODS
  We included 432 patients with aneurysmal SAH on mechanical ventilation for at least 24 hours after intensive care unit (ICU) admission. Arterial blood gas levels were calculated as time-weighted averages (TWAs) of all blood gas measurements during the first 24 hours in the ICU. Patients were categorized into 3 TWA-PaO2 bands (low, <97.5 mm Hg; intermediate, 97.5-150 mm Hg; high, ≥150 mm Hg). Outcome measures were unfavorable outcome at 3 months (Glasgow Outcome Scale score 1-3) and mortality. Multivariate logistic regression analysis was used to assess the independent effect of oxygen on outcome.
  
  
  RESULTS
  Overall, 28% of patients died, and a total of 53% had an unfavorable outcome at 3 months. Patients with an unfavorable outcome had significantly higher TWA-PaO2 levels compared with patients with a favorable outcome (137 mm Hg vs 118 mm Hg, P < .001). Multivariate analysis demonstrated no significant association between TWA-PaO2 bands and unfavorable outcome (with intermediate PaO2 as a reference, odds ratio [OR] for low PaO2 1.05, 95% confidence interval [CI]: 0.52-2.12, P = .89; OR for high PaO2: 1.09, 95% CI: 0.61-1.97, P = .77) or mortality (with intermediate PaO2 as reference, the OR for low PaO2 was 0.67 (95% CI: 0.30-1.46, P = .31), and the OR for high PaO2 was 0.73 (95% CI: 0.38-1.40, P = .34).
  
  
  CONCLUSIONS
  Early moderate hyperoxemia may not increase or decrease the risk of a poor outcome in mechanically ventilated aneurysmal SAH patients.
authors.affiliation: *Department of Intensive Care Medicine, Kuopio University Hospital, Kuopio, Finland; ‡Department of Neurosurgery, University of Helsinki, Helsinki University Central Hospital, Helsinki, Finland; §Division of Intensive Care, University of Helsinki and Helsinki University Central Hospital, Helsinki, Finland; ¶Department of Neurosurgery, Kuopio University Hospital, Kuopio, Finland; ‖Department of Intensive Care Medicine, North Karelia Central Hospital, Joensuu, Finland.
authors.forename: Maarit
authors.initials: M
authors.lastname: Lång
authors.forename: Rahul
authors.initials: R
authors.lastname: Raj
authors.forename: Markus Benedikt
authors.initials: MB
authors.lastname: Skrifvars
authors.forename: Timo
authors.initials: T
authors.lastname: Koivisto
authors.forename: Hanna
authors.initials: H
authors.lastname: Lehto
authors.forename: Riku
authors.initials: R
authors.lastname: Kivisaari
authors.forename: Mikael
authors.initials: M
authors.lastname: von Und Zu Fraunberg
authors.forename: Matti
authors.initials: M
authors.lastname: Reinikainen
authors.forename: Stepani
authors.initials: S
authors.lastname: Bendel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D003422:Critical Care; D016208:Databases, Factual; D005260:Female; D023261:Glasgow Outcome Scale; D006801:Humans; D018496:Hyperoxia / Q000097:blood* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011237:Predictive Value of Tests; D012121:Respiration, Artificial; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000097:blood* / Q000401:mortality / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010100:Oxygen