Clinical indices to predict simple and mixed acid-base disturbances

We propose that in any acid-base disturbance there is a predictable mathematical relationship between the changes in the individual serum anionic concentrations of chloride, bicarbonate and the unmeasured anion gap. Two indices were developed, from the ratios of the changes in these anionic concentrations, that are useful in predicting the presence of an acid-base disturbance. Based on recent experimental evidence we determined the mathematical values of these 2 indices, alpha and beta, in 17 acid-base disturbances. By utilizing the paired values of these indices, the 17 disturbances including simple, metabolic plus respiratory and triple disorders were subcategorized into 7 groups. It is suggested that the use of these indices will facilitate the diagnosis of complicated mixed acid-base disorders.