title: Isotonic is better than hypotonic saline for intravenous rehydration of children with gastroenteritis: a prospective randomised study.
abstract: OBJECTIVE
  To determine whether the risk of hyponatraemia in children with gastroenteritis receiving intravenous (IV) fluids is decreased by the use of 0.9% saline.
  
  
  METHODS
  A prospective randomised study was carried out in a tertiary paediatric hospital. A total of 102 children with gastroenteritis were randomised to receive either 0.9% saline + 2.5% dextrose (NS) or 0.45% saline + 2.5% dextrose (N/2) at a rate determined by their treating physician according to hospital guidelines and clinical judgement. Plasma electrolytes, osmolality, and plasma glucose were measured before (T(0)) and 4 hours after (T(4)) starting IV fluids, and subsequently if clinically indicated. Electrolytes and osmolality were measured in urine samples. Results were analysed according to whether children were hyponatraemic (plasma sodium <135 mmol/l) or normonatraemic at T(0).
  
  
  RESULTS
  At T(0), mean (SD) plasma sodium was 135 (3.3) mmol/l (range 124-142), with 37/102 (36%) hyponatraemic. At T(4), mean plasma sodium in children receiving N/2 remained unchanged in those initially hyponatraemic (n = 16), but fell 2.3 (2.2) mmol/l in the normonatraemic group. In contrast, among children receiving NS, mean plasma sodium was 2.4 (2.0) mmol/l higher in those hyponatraemic at baseline (n = 21) and unchanged in the initially normonatraemic children. In 16 children who were still receiving IV fluids at 24 hours, 3/8 receiving N/2 were hyponatraemic compared with 0/8 receiving NS. No child became hypernatraemic.
  
  
  CONCLUSIONS
  In gastroenteritis treated with intravenous fluids, normal saline is preferable to hypotonic saline because it protects against hyponatraemia without causing hypernatraemia.
authors.affiliation: Department of Endocrinology, Sydney Children's Hospital, Sydney, Australia. kristen.neville@sesiahs.health.nsw.gov.au
authors.forename: K A
authors.initials: KA
authors.lastname: Neville
authors.forename: C F
authors.initials: CF
authors.lastname: Verge
authors.forename: A R
authors.initials: AR
authors.lastname: Rosenberg
authors.forename: M W
authors.initials: MW
authors.lastname: O'Meara
authors.forename: J L
authors.initials: JL
authors.lastname: Walker
mesh_terms: D000886:Anthropometry; D001786:Blood Glucose / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D005440:Fluid Therapy / Q000009:adverse effects / Q000379:methods*; D005759:Gastroenteritis / Q000628:therapy*; D006801:Humans; D007010:Hyponatremia / Q000517:prevention & control; D007038:Hypotonic Solutions / Q000627:therapeutic use; D007223:Infant; D007552:Isotonic Solutions / Q000627:therapeutic use; D008297:Male; D009994:Osmolar Concentration; D011446:Prospective Studies; D015532:Rehydration Solutions / Q000009:adverse effects / Q000627:therapeutic use*; D012964:Sodium / Q000097:blood / Q000652:urine
chemical_list: D001786:Blood Glucose; D007038:Hypotonic Solutions; D007552:Isotonic Solutions; D015532:Rehydration Solutions; D012964:Sodium