title: Hypotonic versus isotonic fluids in hospitalized children: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To determine whether the use of hypotonic vs isotonic maintenance fluids confers an increased risk of hyponatremia in hospitalized children.
  
  
  METHODS
  A search of MEDLINE (1946 to January 2013), the Cochrane Central Registry (1991 to December 2012), Cumulative Index for Nursing and Allied Health Literature (1990 to December 2012), and Pediatric Academic Societies (2000-2012) abstracts was conducted using the terms "hypotonic fluids/saline/solutions" and "isotonic fluids/saline/solutions," and citations were reviewed using a predefined protocol. Data on the primary and secondary outcomes were extracted from original articles by 2 authors independently. Meta-analyses of the primary and secondary outcomes were performed when possible.
  
  
  RESULTS
  A total of 1634 citations were screened. Ten studies (n = 893) identified as independent randomized controlled trials were included. Five studies examined subjects in the intensive care unit setting, including 4 on regular wards and 1 in a mixed setting. In hospitalized children receiving maintenance intravenous fluids, hyponatremia was seen more often in those receiving hypotonic fluids than in those receiving isotonic fluids, with an overall relative risk of 2.37 (95% CI, 1.72-3.26). Receipt of hypotonic fluids was associated with a relative risk of moderate hyponatremia (<130 mmol/L) of 6.1 (95% CI, 2.2-17.3). A subgroup analysis of hypotonic fluids with half-normal saline found a relative risk of hyponatremia of 2.42 (95% CI, 1.32-4.45).
  
  
  CONCLUSIONS
  In hospitalized children in intensive care and postoperative settings, the administration of hypotonic maintenance fluids increases the risk of hyponatremia when compared with administration of isotonic fluids. For patients on general wards, insufficient data are available based on the reviewed studies, and individual risk factors must be assessed.
authors.affiliation: Division of Inpatient Pediatrics, Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX. Electronic address: fosterba@uthscsa.edu.
authors.forename: Byron Alexander
authors.initials: BA
authors.lastname: Foster
authors.affiliation: Division of Inpatient Pediatrics, Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Dina
authors.initials: D
authors.lastname: Tom
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, San Antonio, TX.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Hill
mesh_terms: D002648:Child; D002673:Child, Hospitalized; D002675:Child, Preschool; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D007010:Hyponatremia / Q000209:etiology*; D007038:Hypotonic Solutions / Q000008:administration & dosage / Q000009:adverse effects*; D007223:Infant; D007262:Infusions, Intravenous; D007552:Isotonic Solutions / Q000008:administration & dosage / Q000009:adverse effects*; D012306:Risk; D018570:Risk Assessment
chemical_list: D007038:Hypotonic Solutions; D007552:Isotonic Solutions