title: Association between maintenance fluid tonicity and hospital-acquired hyponatremia.
abstract: OBJECTIVE
  To evaluate whether the administration of hypotonic fluids compared with isotonic fluids is associated with a greater risk for hyponatremia in hospitalized children.
  
  
  METHODS
  Informatics-enabled cohort study of all hospitalizations at Lucile Packard Children's Hospital between April 2009 and March 2011. Extraction and analysis of electronic medical record data identified normonatremic hospitalized children who received either hypotonic or isotonic intravenous maintenance fluids upon admission. The primary exposure was the administration of hypotonic maintenance fluids, and the primary outcome was the development of hyponatremia (serum sodium <135 mEq/L).
  
  
  RESULTS
  A total of 1048 normonatremic children received either hypotonic (n = 674) or isotonic (n = 374) maintenance fluids upon admission. Hyponatremia developed in 260 (38.6%) children who received hypotonic fluids and 104 (27.8%) of those who received isotonic fluids (unadjusted OR 1.63; 95% CI 1.24-2.15, P < .001). After we controlled for intergroup differences and potential confounders, patients receiving hypotonic fluids remained more likely to develop hyponatremia (aOR 1.37, 95% CI 1.03-1.84). Multivariable analysis identified additional factors associated with the development of hyponatremia, including surgical admission (aOR 1.44, 95% CI 1.09-1.91), cardiac admitting diagnosis (aOR 2.08, 95% CI 1.34-3.20), and hematology/oncology admitting diagnosis (aOR 2.37, 95% CI 1.74-3.25).
  
  
  CONCLUSIONS
  Hyponatremia was common regardless of maintenance fluid tonicity; however, the administration of hypotonic maintenance fluids compared with isotonic fluids was associated with a greater risk of developing hospital-acquired hyponatremia. Additional clinical characteristics modified the hyponatremic effect of hypotonic fluid, and it is possible that optimal maintenance fluid therapy now requires a more individualized approach.
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Lucile Packard Children's Hospital, Stanford, CA; Air Force Institute of Technology, Wright-Patterson Air Force Base, Dayton, OH.
authors.forename: Francis
authors.initials: F
authors.lastname: Carandang
authors.forename: Andrew
authors.initials: A
authors.lastname: Anglemyer
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Longhurst
authors.forename: Gomathi
authors.initials: G
authors.lastname: Krishnan
authors.forename: Steven R
authors.initials: SR
authors.lastname: Alexander
authors.forename: Madelyn
authors.initials: M
authors.lastname: Kahana
authors.forename: Scott M
authors.initials: SM
authors.lastname: Sutherland
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005440:Fluid Therapy / Q000009:adverse effects*; D006760:Hospitalization; D006801:Humans; D007010:Hyponatremia / Q000453:epidemiology* / Q000209:etiology*; D007038:Hypotonic Solutions / Q000009:adverse effects*; D007223:Infant; D007552:Isotonic Solutions / Q000009:adverse effects*; D008297:Male; D012189:Retrospective Studies
chemical_list: D007038:Hypotonic Solutions; D007552:Isotonic Solutions
keywords: 5% Dextrose in water; ADH; Antidiuretic hormone; D5W; EFW; EMR; Electrolyte-free water; Electronic medical record; IV; Intravenous; NS; Normal saline