Treatment of Severe Fluid Overload by Ultrafiltration

Abstract

A recently developed ultrafiltration cell was clinically evaluated and found to remove excess sodium and water efficiently, rapidly, and inexpensively from fluid-overloaded patients on chronic hemodialysis. The extracorporeal circuit is designed to run in series with the artificial kidney or as a separate unit. With constant blood flow, ultrafiltration flux rate increased as a linear function of transmembrane pressure up to 200 mm Hg. Ultrafiltration rates of 300 to 800 ml per hour were readily achievable, and the fluid removal rate was quantitated and adjusted as the clinical picture dictated. Complications of ultrafiltration were rare and included leg cramps and orthostatic hypertension. The solute concentrations in the ultrafiltrate were identical to plasma water, thereby avoiding electrolyte and acid-base disturbances. This therapy is simpler and safer than peritoneal dialysis or hemodialysis; we speculate that it could logically be extended to patients with refractory chronic edematous states or with pulmonary edema. (N Engl J Med 291:747–751, 1974