Skip to content


Critical Care

Open Access

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

  • M Boniatti1,
  • RK Castilho1,
  • PR Cardoso1,
  • G Friedman1,
  • L Fialkow1,
  • SP Rubeiro1 and
  • SR Vieira1
Critical Care200913(Suppl 1):P451

Published: 13 March 2009


Hospital MortalityProspective Observational StudyDiagnostic EvaluationBase VariableGood Discrimination


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

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.

Authors’ Affiliations

Hospital de Clínicas de Porto Alegre, Brazil


  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.0000125517.28517.74PubMedView ArticleGoogle 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.PubMedView ArticleGoogle Scholar


© Boniatti et al; licensee BioMed Central Ltd. 2009

This article is published under license to BioMed Central Ltd.