title: The Effect of Hyponatremia and Sodium Variability on Outcomes in Adults with Aneurysmal Subarachnoid Hemorrhage.
abstract: BACKGROUND
  Hyponatremia is common in patients with subarachnoid hemorrhage, but its effect on outcomes remains contentious. Fluctuation in sodium has been reported to negatively affect perioperative outcomes in general surgical patients, but not specifically in patients with a subarachnoid hemorrhage. The primary aim was to describe the relationship between 1) hyponatremia and 2) sodium fluctuations during intensive care and neurologic outcome at hospital discharge.
  
  
  METHODS
  Adults with aneurysmal subarachnoid hemorrhage between January 2012 and September 2013 were retrospectively reviewed. Data were collected for admission to day 14 of intensive care or death. Severity of illness was assessed by Hunt and Hess grade and simplified acute physiology score. Hyponatremia was defined as any measurement <135 mEq/L. Sodium variability was categorized as a maximum change of <6, 6-12, or >12 mEq/L during intensive care. Neurologic outcomes at discharge were assessed by modified Rankin Scale. The relationship between sodium and outcome was assessed by ordinal logistic regression.
  
  
  RESULTS
  A total of 198 patients were included. After adjustment for Hunt and Hess grade, severity of systemic illness, patient age, surgical intervention, and whether or not the hyponatremia was treated with additional sodium, hyponatremia was not associated with worse neurologic outcomes. More patients with sodium variability of 6-12 and >12 mEq/L had cerebral infarction than those with variability <6 mEq/L and had modified Rankin Scale scores of 2-3 and 4-6, respectively (P = 0.001).
  
  
  CONCLUSIONS
  Sodium fluctuation, not hyponatremia, is associated with worse neurologic outcome in patients with aneurysmal subarachnoid hemorrhage. This is in contradistinction to current teaching and warrants further examination.
authors.affiliation: Department of Neurosurgery, University of Washington, Seattle, Washington, USA.
authors.forename: James
authors.initials: J
authors.lastname: Bales
authors.affiliation: Department of Pharmacy, and Oral Health Sciences, University of Washington, Seattle, Washington, USA.
authors.forename: Susan
authors.initials: S
authors.lastname: Cho
authors.affiliation: Department of Pharmacy, and Oral Health Sciences, University of Washington, Seattle, Washington, USA.
authors.forename: Thao Kim
authors.initials: TK
authors.lastname: Tran
authors.affiliation: Department of Pharmacy, and Oral Health Sciences, University of Washington, Seattle, Washington, USA.
authors.forename: Gina Alvis
authors.initials: GA
authors.lastname: Korab
authors.affiliation: Department of Anesthesiology and Pain Medicine, University of Washington and Harborview Medical Center, Seattle, Washington, USA.
authors.forename: Nita
authors.initials: N
authors.lastname: Khandelwal
authors.affiliation: Department of Oral Health Sciences, University of Washington, Seattle, Washington, USA.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Spiekerman
authors.affiliation: Department of Anesthesiology and Pain Medicine, University of Washington and Harborview Medical Center, Seattle, Washington, USA. Electronic address: joffea@uw.edu.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Joffe
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003422:Critical Care; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D012964:Sodium / Q000378:metabolism*; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000000981:diagnostic imaging / Q000378:metabolism / Q000628:therapy*; D013997:Time Factors; D015898:Tomography Scanners, X-Ray Computed
chemical_list: D012964:Sodium
keywords: Adults; Dysnatremia; Hyponatremia; Modified Rankin Scale; Outcome; Subarachnoid hemorrhage