title: Fluctuations in serum sodium level are associated with an increased risk of death in surgical ICU patients.
abstract: OBJECTIVE
  Dysnatremia may have an impact on outcomes in critically ill patients, but this has not been widely investigated in surgical ICU patients. We investigated the epidemiology of dysnatremia in a large cohort of surgical ICU patients and evaluated the possible influence of the time of acquisition of dysnatremia and fluctuations in serum sodium concentrations on hospital mortality in these patients.
  
  
  METHODS
  Retrospective analysis.
  
  
  METHODS
  Fifty-bed surgical ICU.
  
  
  METHODS
  All patients admitted to the ICU between January 2004 and January 2009.
  
  
  RESULTS
  Hyponatremia was defined as a serum sodium concentration <135 mmol/L and hypernatremia as a serum sodium concentration >145 mmol/L. Of the 10,923 surgical ICU patients included in the study, 1,215 (11.2%) had hyponatremia and 277 (2.5%) had hypernatremia at admission to the ICU. Among patients with normonatremia at admission to the ICU (n = 9431), the prevalence of ICU-acquired dysnatremia was 31.3%. Dysnatremia present at ICU admission (odds ratio 2.53; 95% confidence interval 2.06-3.12; p < .001) and ICU-acquired dysnatremia (odds ratio 2.06; 95% confidence interval 1.71-2.48; p < 0.001) were independently associated with an increased risk of in-hospital death compared to normonatremia. Dysnatremia at ICU admission (odds ratio 1.23; 95% confidence interval 1.01-1.50) was associated with a higher risk of in-hospital death, compared with ICU-acquired dysnatremia. Fluctuation in serum sodium concentration was also independently associated with an increased risk of in-hospital mortality, in patients who remained normonatremic (>6 mmol/L/ICU stay) and in those with dysnatremia (>12 mmol/L/24 hrs or >12 mmol/L/ICU stay).
  
  
  CONCLUSIONS
  Dysnatremia was common in surgical ICU patients and was independently associated with an increased risk of in-hospital death in these patients. Dysnatremia at ICU admission was associated with a higher risk of death compared with ICU-acquired dysnatremia. Fluctuations in serum sodium concentrations were independently associated with an increased risk of in-hospital death, even in patients who remained normonatremic during the ICU stay.
authors.affiliation: Departments of Anesthesiology and Intensive Care, Friedrich-Schiller-University Hospital, Jena, Germany. yasser.sakr@med.uni-jena.de
authors.forename: Yasser
authors.initials: Y
authors.lastname: Sakr
authors.forename: Steffen
authors.initials: S
authors.lastname: Rother
authors.forename: Alberto Mendonca Pires
authors.initials: AM
authors.lastname: Ferreira
authors.forename: Christian
authors.initials: C
authors.lastname: Ewald
authors.forename: Pedro
authors.initials: P
authors.lastname: Dünisch
authors.forename: Niels
authors.initials: N
authors.lastname: Riedemmann
authors.forename: Konrad
authors.initials: K
authors.lastname: Reinhart
mesh_terms: D015897:Comorbidity; D005260:Female; D005858:Germany / Q000453:epidemiology; D017052:Hospital Mortality; D006801:Humans; D006943:Hyperglycemia / Q000453:epidemiology; D006955:Hypernatremia / Q000453:epidemiology*; D007010:Hyponatremia / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011184:Postoperative Period; D057234:Preoperative Period; D015995:Prevalence; D012189:Retrospective Studies; D012964:Sodium / Q000097:blood*; D013514:Surgical Procedures, Operative / Q000401:mortality*
chemical_list: D012964:Sodium