Quantitative physical chemistry analysis of acid-base disorders in critically ill patients.
Compared with the Henderson-Hasselbalch approach, the Stewart approach may better describe the mechanisms of acid-base physiology and disorders. We prospectively examined the acid-base disorders of 100 routine blood samples from critically ill patients using Stewart's physical chemistry analysis. The median results were pH 7.45, PaCO2 5.5 kPa, bicarbonate 27.2 mmol.l-1 and base excess 3 mmol.l-1. The median reference strong ion difference was 46.0 meq.l-1 and the measured median was 45.5 meq.l-1. The median reference total weak-acid concentration was 11.1 mmol.l-1. The measured median total weak-acid concentration was 6.8 mmol.l-1. From Stewart's approach, the most likely explanation for the overall alkalosis was decreased total weak-acid concentration resulting from decreased plasma albumin concentration.
Story
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Department of Anaesthesia, and Director of Research, Department of Intensive Care, Austin and Repatriation Medical Centre, Studley Road, Heidelberg, Victoria 3084, Australia. davids@austin.unimelb.edu.au
Poustie
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Bellomo
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D000137:Acid-Base Imbalance / Q000097:blood*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003422:Critical Care / Q000379:methods; D016638:Critical Illness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011446:Prospective Studies; D012016:Reference Values; D012709:Serum Albumin / Q000032:analysis
D012709:Serum Albumin