Skip to main content

Acid–base disorders evaluation in critically ill patients: hyperchloremia is associated with mortality


Acid–base disorders are common in critically ill patients, and they are generally associated with greater morbidity and mortality. The objectives of this study are to find out whether the diagnostic evaluation of acid–base disorders in a population of critically ill patients can be improved using Stewart's method compared with the traditional model, and whether acid–base variables are associated with hospital mortality.


This prospective observational study took place in a university-affiliated hospital in Porto Alegre, Brazil, during the period of February to May 2007. We recorded clinical data and acid–base variables from 175 patients at ICU admission.


The evaluation according to Stewart's method would allow an additional diagnosis of metabolic disorder in 59 (33.7%) patients. Individually, none of the variables appear to be good predictors of hospital mortality. However, using the multivariate stepwise logistic regression, we had a model with good discrimination containing the SOFA score, age, chloride and albumin (area under receiver operating characteristic curve = 0.80; 95% CI = 0.73 to 0.87). See Figure 1.

Figure 1
figure 1

ROC curves for the models including SOFA, age, albumin and chloride.


The Stewart approach, compared with the traditional evaluation, allows identifying more patients with major acid–base disturbances. Hypoalbuminemia and hyperchloremia were associated with mortality.


  1. Kaplan LJ, et al.: Initial pH, base deficit, lactate, anion gap, strong ion difference, and strong ion gap predict outcome from major vascular injury. Crit Care Med 2004, 32: 1120. 10.1097/01.CCM.0000125517.28517.74

    Article  PubMed  CAS  Google Scholar 

  2. Fencl V, et al.: Diagnosis of metabolic acid–base disturbances in critically ill patients. Am J Resp Crit Care Med 2000, 162: 2246.

    Article  PubMed  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Reprints and Permissions

About this article

Cite this article

Boniatti, M., Castilho, R., Cardoso, P. et al. Acid–base disorders evaluation in critically ill patients: hyperchloremia is associated with mortality. Crit Care 13 (Suppl 1), P451 (2009).

Download citation

  • Published:

  • DOI:


  • Hospital Mortality
  • Prospective Observational Study
  • Diagnostic Evaluation
  • Base Variable
  • Good Discrimination