INTERRELATIONS OF PLASMA POTASSIUM CONCENTRATION, PLASMA SODIUM CONCENTRATION, ARTERIAL pH AND TOTAL EXCHANGEABLE POTASSIUM*

Abstract

The relationships between plasma K concentration (Kp), plasma Na concentration (Nap), extracellular fluid pH, and body K content, expressed as exchangeable K/kg of dry body weight (Ke/DBW), were explored by simultaneous measurements in a heterogeneous group of chronically ill patients with a variety of acid-base disturbances. Kp concentration correlates poorly or slightly with Nap, partial pressure of CO2 in ml of Hg in arterial plasma, and Ke/DBW. A modest correlation exists between Kp and arterial blood H+ concentration (Ha) which is enhanced significantly when Kp is plotted against [image]. string differences in correlation appear between [image] subgroups of patients with metabolic and respiratory acid-base disturbances. In the group of patients with metabolic disturbances a close correlation was found between Kp and [image] which is not apparent in the group with respiratory [image] acid-base disturbances. The physiological implications of these findings are discussed, and possible differential mechanisms in these 2 types of acid-base disturbance are presented.