Metabolic studies on the effects of ion exchange resins in edematous patients with cardiac and renal disease.

Abstract The effects of ion exchange resins on the metabolic balances of sodium, chloride, potassium, nitrogen and phosphorus were studied in eleven edematous patients with either cardiac or renal disease. Administration of 40 to 90 gm. daily of a carboxylic acid cation exchanger, two-thirds in the acid cycle and one-third in the potassium cycle, produced marked increases in fecal sodium excretion, significantly negative sodium balances, and effective loss of edema. These effects were observed even in patients in severe congestive failure on low sodium diets who exhibited evidence of actively functioning sodium-conserving mechanisms, such as negligible urinary sodium excretion and eosinopenia. As a result of removal of cation without anion, persistent hyperchloremic acidosis developed, despite the increased urinary chloride excretion and the negative chloride balance which promptly occurred in patients without organic renal disease. In patients with renal disease little chloruresis occurred and, consequently, the resulting acidosis was more severe. However, by intermittent administration of the resins and the concurrent use of mercurial diuretics, which produced loss of more chloride than sodium, mobilization of edema in the patients with renal disease was safely accomplished. In this series, addition of an anion exchanger to the resin mixture had no effect on either the acidosis or the fecal excretion of any electrolyte. The proportion of resins in the potassium cycle in carbo-resin provided sufficient additional potassium, as a rule, to prevent potassium depletion. Moreover, with gradual, resin-in-induced gastrointestinal losses, the kidney very efficiently conserved potassium by reducing the urinary excretion to less than 1 mEq./day. However, when patients on resin therapy developed anorexia and vomiting or diarrhea, the additional loss of potassium tended to produce depletion with or without hypokalemia. If signs of potassium deficit occur, oral supplementation of the patient's intake with organic potassium salt mixtures permits continued resin therapy. Hyponatremia is a rare consequence of resin therapy. Since there is generally greater diuresis and weight loss than can be explained on the basis of the increased sodium excreted, this cannot represent sodium depletion per se . Whether movement of sodium into some non-extracellular site may be involved in the transient, spontaneously reversible, mild hyponatremia observed in some cardiacs during the period of hyperchloremic acidosis of resin therapy remains to be established. It is concluded that, if periodic blood studies are made throughout therapy, the administration of resins constitutes a valuable and safe addition to the treatment of resistant edema in patients with cardiac and renal disease. The value of these agents in any individual patient must be determined empirically.