Exchangeable body potassium and sodium in patients in congestive heart failure

Abstract

Total exchangeable mass of potassium was measured in 43 patients with longstanding heart disease; 30 were in congestive heart failure, 22 recovered, 8 died. Exchangeable mass of sodium was measured simultaneously in 29 patients. In 11 subjects, measurements were made on several occasions. These data, and some previously published, are evaluated, visually, using relationships calculated to obtain in controls between the logarithm of exchangeable mass of potassium (or sodium) and the logarithm of body weight and the logarithm of body height. Where values are available for Na e, “oedema-free” body weight was calculated: assumptions and approximations are discussed. Some subjects were weighed when free from oedema. Evaluation of exchangeable potassium is facilitated by the use of “oedema-free” weight. Excess of sodium in congestive failure can be extensive; subnormal serum levels of sodium commonly coexist; excess can be present in the absence of oedema or failure. It is submitted that excess of sodium reflects cellular gain as well as accumulation of oedema. Dearth of potassium was common in our subjects; serum potassium levels may be high. In addition to cachexia, cellular depletion contributes towards potassium dearth. The extent of cachexia was calculated from comparison of standard weight and observed, or calculated, “oedema-free” weight. The extents of sodium excess, potassium dearth, and cachexia did not differ in patients dying during the episode of congestive failure, from those subsequently recovering.