Rapid fluid extraction with the Gambro Ultradiffuser

Four patients were given fourteen treatments with the Gambro Ultradiffuser. One hour of ultrafiltration without dialysate and with negative pressure on the dialysate side was followed by four hours of dialysis with negligible transmembrane pressure (TMP). Mean fluid removal was 2678 ml per ultrafiltration period and the mean ultrafiltration rate was 37 ml/min. During the dialysis period, TMP was about +30 mmHg giving an ultrafiltration rate of 4 ml/min. Pulse rate was unchanged. Hematocrit increased 3%, plasma protein increased 21% and plasma albumin increased 25%. Plasma values of potassium, sodium, urea, creatinine and osmolality were unchanged. One patient experienced a reversible hearing loss during two ultrafiltration periods and two patients had severe, yet reversible, cardiac arrhythmias. One patient had hypertension during the ultrafiltration period. Rapid extraction of fluid up to 49 ml/min was possible. The mean mean arterial pressure was unchanged thought it exhibited great variation and three patients developed side effects.