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Critical Care

Open Access online decision support in complex acid–base disorders using the Stewart approach

  • P Elbers1 and
  • R Gatz2
Critical Care200913(Suppl 1):P449

Published: 13 March 2009


Decision SupportSupport ToolClinical PatientDecision Support ToolOnline Tool


The Stewart approach to acid–base management has evolved to be the method of choice [1]. While the quantitative approach and the traditional Henderson–Hasselbalch method do not mathematically exclude one another, the Stewart approach may provide better mechanistic insight in complex acid–base disturbances. However, the approach is perceived as complex, requiring many calculations. This is why we developed an online tool that may facilitate its use.


We programmed several scripts interacting with a MySQL database. Users may reach the application online [2] and must enter acid–base and chemistry data. Cases can be saved anonymously for later review. A tool is provided to run hypothetical scenarios by changing different physiological parameters. The application was tested using historical data from the author's hospital and limited public use.


The application has been online since January 2008 (Figure 1). Initial testing led to various improvements. Without advertising, over 500 doctors worldwide have used the software generating a total of 15,000 page-views as of December 2008. Feedback by users is voluntary and indicates multiple changes in diagnostic and/or therapeutic strategies.
Figure 1

Summary interpretation.


We have shown it is feasible to build an online software application that aids in the interpretation of complex acid–base disorders using the Stewart approach. In addition this tool enables the clinician to judge the impact of possible intervention using simulation. We will next set out to investigate the impact of exposure to this decision support tool on clinical patient management.

Authors’ Affiliations

St Antonius Hospital, Nieuwegein, the Netherlands
Skaraborg Central Hospital, Skovde, the Netherlands


  1. Stewart's Textbook of Acid–Base2009. []
  2. []


© Elbers and Gatz; licensee BioMed Central Ltd. 2009

This article is published under license to BioMed Central Ltd.