Stewart’s Approach for Acid-base Disorders: Does the Strong Ion Difference and Effects Have an Impact on Intensive Care Unit Mortality?

Abstract

Objective:The diagnosis and treatment of electrolyte and acid-base imbalances in intensive care unit (ICU) patients have critical importance. The value of Stewart’s approach in revealing acid-base disorders is known. There are parameters defined according to this approach. This study investigates the impact of the chloride effect (ClEffect), sodium effect (NaEffect), sodium-chloride effect (Na-ClEffect), strong ion difference (SIDnl) and Cl/Na ratio values calculated according to Stewart’s approach on ICU mortality.Materials and Methods:Two thousand patients whose Na, Cl, K, standard base excess (SBE), pH values were recorded and SIDnl, ClEffect, NaEffect, Na-ClEffect, Acute Physiology Assessment and Chronic Health Evaluation-II (APACHE-II) and Sequential Organ Failure Assessment (SOFA) scores calculated are included in this study. ClEffect, NaEffect, Na-ClEffect, SIDnl, Cl/Na ratio values were evaluated with a multivariable logistic regression model in terms of ICU mortality.Results:Abnormal ranges of SIDnl (SIDnl 7, and SIDnl <30 or SIDnl ≥43 (p<0.001, p<0.001, p=0.041, respectively).Conclusion:SIDnl is associated with ICU mortality, but pH, SBE, ClEffect, NaEffect, Na-ClEffect and Cl/Na ratio is not. SIDnl is one of the independent variables of Stewart’s approach and is a valuable parameter in blood gas evaluations.

Keywords

• acid-base
• strong ion difference
• sodium
• chloride
• base excess
• intensive care unit
• mortality