title: Hospital-acquired hyponatremia in postoperative pediatric patients: prospective observational study.
abstract: OBJECTIVE
  To establish the incidence and factors associated with hospital-acquired hyponatremia in pediatric surgical patients who received hypotonic saline (sodium 40 mmol/L plus potassium 20 mmol/L) at the rate suggested by the Holliday and Segar's formula for calculations of maintenance fluids.
  
  
  METHODS
  Prospective, observational, cohort study.
  
  
  METHODS
  Pediatric intensive care unit.
  
  
  METHODS
  : Eighty-one postoperative patients.
  
  
  METHODS
  None.
  
  
  RESULTS
  Incidence and factors associated with hyponatremia (sodium < or = 135 mmol/L). Univariate analysis was conducted post surgery at 12 hrs and at 24 hrs. Mean values were compared with independent t test samples. Receiver operating characteristics curve analysis was performed in variables with a p <.05, and relative risks were calculated. Eighty-one patients were included in the study. The incidence of hyponatremia at 12 hrs was 17 (21%) of 81 (95% confidence interval, 3.7-38.3); at 24 hrs, it was was 15 (31%) of 48 (95% confidence interval, 11.4-50.6). Univariate analysis at 12 hrs showed that hyponatremic patients had a higher sodium loss (0.62 mmol/kg/hr vs. 0.34 mmol/kg/hr, p = .0001), a more negative sodium balance (0.39 mmol/kg/hr vs. 0.13 mmol/kg/hr, p < .0001), and a higher diuresis (3.08 mL/kg/hr vs. 2.2 mL/kg/hr, p = .0026); relative risks were 11.55 (95% confidence interval, 2.99-44.63; p = .0004) for a sodium loss >0.5 mmol/kg/hr; 10 (95% confidence interval, 2.55-39.15; p = .0009) for a negative sodium balance >0.3 mmol/kg/hr; and 4.25 (95% confidence interval, 1.99-9.08; p = .0002) for a diuresis >3.4 mL/kg/hr. At 24 hrs, hyponatremic patients were in more positive fluid balance (0.65 mL/kg/hr vs. 0.10 mL/kg/hr, p = .0396); relative risk was 3.25 (95% confidence interval, 1.2-8.77; p = .0201), for a positive fluid balance >0.2 mL/kg/hr.
  
  
  CONCLUSIONS
  The incidence of hyponatremia in this population was high and progressive over time. Negative sodium balance in the first 12 postoperative hours and then a positive fluid balance could be associated with the development of postoperative hyponatremia.
authors.affiliation: Pediatric Intensive Care Unit, Hospital Italiano de Buenos Aires, Unidad de Cuidados Intensivos Pedatricos, Buenos Aires, Argentina. pablo.eulmesekian@hospitalitaliano.org.ar
authors.forename: Pablo G
authors.initials: PG
authors.lastname: Eulmesekian
authors.forename: Augusto
authors.initials: A
authors.lastname: Pérez
authors.forename: Pablo G
authors.initials: PG
authors.lastname: Minces
authors.forename: Desmond
authors.initials: D
authors.lastname: Bohn
mesh_terms: D002648:Child; D015331:Cohort Studies; D000075202:Contraindications; D003428:Cross Infection; D006801:Humans; D007010:Hyponatremia / Q000453:epidemiology* / Q000209:etiology*; D007038:Hypotonic Solutions / Q000008:administration & dosage; D007262:Infusions, Intravenous / Q000009:adverse effects; D015278:Intensive Care Units, Pediatric; D019370:Observation; D011182:Postoperative Care; D011188:Potassium / Q000008:administration & dosage; D011446:Prospective Studies
chemical_list: D007038:Hypotonic Solutions; D011188:Potassium