Complex Acid-Base Disorders
Review methods of analyzing acid-base disturbances.
Differentiate anion gap and normal anion gap metabolic acidoses.
Understand the clinical manifestations of acid-base disorders.
Review appropriate treatment for common causes of acidosis and alkalosis.
Three methods of analysis have been used to describe the acid-base status of patients: the traditional approach, base excess (BE) approach, and the physicochemical approach. All methods describe the respiratory component of acid-base changes based on change in Paco2 but differ in analysis of the metabolic component. The traditional method relies on changes in bicarbonate concentration and the anion gap to assess the metabolic component. The BE approach is based on nomograms and algorithms based on the amount of acid or base needed to restore a normal pH. The physicochemical approach uses three independent variables: Paco2, strong ion difference, and total nonvolatile weak acids.