Acid-base relationships in the different body compartments: the basis for a simplified diagnostic approach.

Special characteristics of cellular buffering must be taken into account in order to describe accurately acid-base relationships in the whole body. In particular, tissues other than blood are able to neutralize mineral acid independent of changes in Pco(2) and hence independent of large changes in extra- and intracellular pH. Although mechanistic details remain to be clarified, relationships that describe this tissue buffering in quantitative terms are well established. In this report, emphasis is placed on quantitative relationships that stress the need for diagnostic interpretation derived from acid-base changes within the whole body rather than simply within the blood compartment. Theoreticalproblems with respect ot buffering mechanisms in various body compartments are reviewed and analyzed.