title: Efficacy of oral versus intravenous hypertonic saline in runners with hyponatremia.
abstract: OBJECTIVE
  To determine more conclusively whether intravenous (IV) administration of 3% saline is more efficacious than oral administration in reversing below normal blood sodium concentrations in runners with biochemical hyponatremia.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  26 hyponatremic race finishers participating in the 161-km Western States Endurance Run were randomized to receive either an oral (n=11) or IV (n=15) 100mL bolus of 3% saline. Blood sodium concentration (Na(+)), plasma protein (to assess %plasma volume change), arginine vasopressin (AVP), blood urea nitrogen (BUN) and urine (Na(+)) were measured before and 60 min following the 3% saline intervention.
  
  
  RESULTS
  No significant differences were noted with respect to pre- to post-intervention blood [Na(+)] change between intervention groups, although blood [Na(+)] increased over time in both intervention groups (+2 mmol/L; p<0.0001). Subjects receiving the IV bolus had a greater mean (± SD) plasma volume increase (+8.6 ± 4.5% versus 1.4% ± 5.7%; p<0.01) without significant change in [AVP] (-0.2 ± 2.6 versus 0.0 ± 0.5 pg/mL; p=0.49). 69% of subjects completing the intervention trial were able to produce urine at race finish with a mean (± SD) pre-intervention urine [Na(+)] of 15.2 ± 8.5 mmol/L (range 0-35; NS between groups). [BUN] of the entire cohort pre-intervention was 30.7 ± 10.5mg/dL (range 13-50).
  
  
  CONCLUSIONS
  No group difference was noted in the primary outcome measure of change in blood [Na(+)] over 60 min of observation following a 100mL bolus of either oral or IV 3% saline. Administration of an oral hypertonic saline solution can be efficacious in reversing low blood sodium levels in runners with mild EAH.
authors.affiliation: Sir Charles Gairdner Hospital, Australia.
authors.forename: Bethan E
authors.initials: BE
authors.lastname: Owen
authors.affiliation: St John of God Murdoch Hospital and University of Notre Dame, Australia.
authors.forename: Ian R
authors.initials: IR
authors.lastname: Rogers
authors.affiliation: VA Northern California Health Care System, United States; University of California Davis Medical Center, United States.
authors.forename: Martin D
authors.initials: MD
authors.lastname: Hoffman
authors.affiliation: Gettysburg College, United States.
authors.forename: Kristin J
authors.initials: KJ
authors.lastname: Stuempfle
authors.affiliation: Via Christi family MEDICAL residency, United States.
authors.forename: Douglas
authors.initials: D
authors.lastname: Lewis
authors.affiliation: VA Northern California Health Care System, United States.
authors.forename: Kevin
authors.initials: K
authors.lastname: Fogard
authors.affiliation: Georgetown University Medical Center, United States.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Verbalis
authors.affiliation: Oakland University, United States. Electronic address: hew@oakland.edu.
authors.forename: Tamara
authors.initials: T
authors.lastname: Hew-Butler
mesh_terms: D000284:Administration, Oral; D000328:Adult; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000188:drug therapy*; D007262:Infusions, Intravenous; D008297:Male; D010807:Physical Endurance / Q000502:physiology; D012420:Running; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D012462:Saline Solution, Hypertonic
keywords: EAH; Fluid balance; Ultra-endurance running