title: Association Between Hyponatremia and Higher Bronchiolitis Severity Among Children in the ICU With Bronchiolitis.
abstract: OBJECTIVE
  It remains unclear whether hyponatremia independently predicts a higher severity of bronchiolitis in children. The objective of this study was to investigate the association between hyponatremia and bronchiolitis severity in children hospitalized in the ICU for bronchiolitis.
  
  
  METHODS
  We conducted a 16-center, prospective cohort study of hospitalized children aged <2 years with bronchiolitis during the winters of 2007 through 2010. Patients were classified into 2 groups (normonatremic [135-145 mEq/L] and hyponatremic [<135 mEq/L]) based on the first-measured serum sodium concentration on the day of hospitalization. Outcomes were use of mechanical ventilation and ICU length of stay (LOS). To examine the association of sodium status with outcomes, we fit logistic and linear regression models with propensity score adjustment.
  
  
  RESULTS
  Of 231 children hospitalized in the ICU for bronchiolitis, 193 (84%) were categorized into the normonatremic group and 38 (16%) into the hyponatremic group. Compared with children with normonatremia, those with hyponatremia had higher risks of mechanical ventilation use (40% vs 58%; P = .04) and longer ICU LOS (median, 3 vs 6 days; P = .007). Likewise, in the adjusted analyses, children with hyponatremia had significantly higher risks of mechanical ventilation use (odds ratio, 2.14 [95% confidence interval, 1.03-4.48; P = .04) and longer ICU LOS (β-coefficient, 2.21 days [95% confidence interval, 0.68-3.73; P = .005]).
  
  
  CONCLUSIONS
  In this prospective, multicenter study of children hospitalized for bronchiolitis, hyponatremia on the day of hospitalization was associated with a higher severity of disease. Our data support hyponatremia as a prognostic factor that might improve the ability of clinicians to predict the disease course of children with severe bronchiolitis.
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; khasegawa1@partners.org.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hasegawa
authors.affiliation: Department of Pediatrics, University of Louisville, Louisville, Kentucky;
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Stevenson
authors.affiliation: Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts;
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Mansbach
authors.affiliation: Department of Pediatrics, Santa Clara Valley Medical Center, San Jose, California; and.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Schroeder
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts;
authors.forename: Ashley F
authors.initials: AF
authors.lastname: Sullivan
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts;
authors.forename: Janice A
authors.initials: JA
authors.lastname: Espinola
authors.affiliation: Departments of Molecular Virology and Microbiology, and Pediatrics, Baylor College of Medicine, Houston, Texas.
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Piedra
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts;
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Camargo
mesh_terms: D001988:Bronchiolitis / Q000150:complications* / Q000628:therapy; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000150:complications*; D007223:Infant; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012720:Severity of Illness Index