title: Hyperoxia may be related to delayed cerebral ischemia and poor outcome after subarachnoid haemorrhage.
abstract: OBJECTIVE
  To determine the association between exposure to hyperoxia and the risk of delayed cerebral ischaemia (DCI) after subarachnoid haemorrhage (SAH).
  
  
  METHODS
  We analysed data from a single centre, prospective, observational cohort database. Patient inclusion criteria were age ≥18 years, aneurysmal SAH, endotracheal intubation with mechanical ventilation, and arterial partial pressure of oxygen (PaO2) measurements. Hyperoxia was defined as the highest quartile of an area under the curve of PaO2, until the development of DCI (PaO2≥173 mm Hg). Poor outcome was defined as modified Rankin Scale 4-6 at 3 months after SAH.
  
  
  RESULTS
  Of 252 patients, there were no differences in baseline characteristics between the hyperoxia and control group. Ninety-seven (38.5%) patients developed DCI. The hyperoxia group had a higher incidence of DCI (p<0.001) and poor outcome (p=0.087). After adjusting for modified Fisher scale, rebleeding, global cerebral oedema, intracranial pressure crisis, pneumonia and sepsis, hyperoxia was independently associated with DCI (OR, 3.16; 95% CI 1.69 to 5.92; p<0.001). After adjusting for age, Hunt-Hess grade, aneurysm size, Acute Physiology and Chronic Health Evaluation II score, rebleeding, pneumonia and sepsis, hyperoxia was independently associated with poor outcome (OR, 2.30; 95% CI 1.03 to 5.12; p=0.042).
  
  
  CONCLUSIONS
  In SAH patients, exposure to hyperoxia was associated with DCI. Our findings suggest that exposure to excess oxygen after SAH may represent a modifiable factor for morbidity and mortality in this population.
authors.affiliation: Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea Departments of Neurology and Neurosurgery, The University of Texas Medical School at Houston, Houston, Texas, USA Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Sang-Beom
authors.initials: SB
authors.lastname: Jeon
authors.affiliation: Departments of Neurology and Neurosurgery, The University of Texas Medical School at Houston, Houston, Texas, USA Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: H Alex
authors.initials: HA
authors.lastname: Choi
authors.affiliation: Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Badjatia
authors.affiliation: Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Schmidt
authors.affiliation: Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Hector
authors.initials: H
authors.lastname: Lantigua
authors.affiliation: Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Claassen
authors.affiliation: Departments of Neurosurgery, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: E Sander
authors.initials: ES
authors.lastname: Connolly
authors.affiliation: Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Mayer
authors.affiliation: Departments of Neurology and Neurosurgery, The University of Texas Medical School at Houston, Houston, Texas, USA Department of Neurology, Columbia University College of Physicians and Surgeons, New York, New York, USA.
authors.forename: Kiwon
authors.initials: K
authors.lastname: Lee
mesh_terms: D002545:Brain Ischemia / Q000209:etiology*; D005260:Female; D006801:Humans; D018496:Hyperoxia / Q000150:complications*; D008297:Male; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects; D011446:Prospective Studies; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000628:therapy*; D016896:Treatment Outcome
keywords: SUBARACHNOID HAEMORRHAGE