Push-pull sorbent-based pheresis and hemodiabsorption in the treatment of hepatic failure: preliminary results of a clinical trial with the BioLogic-DTPF System.

The BioLogic-DTPF System combines hemodiabsorption (the BioLogic-DT System with dialysis against powdered sorbent) with push-pull sorbent-based pheresis (the BioLogic-PF System with powdered sorbent surrounding plasma filters). At blood flow rates of 200 ml/min, the system clears creatinine and aromatic amino acids at 120-160 ml/min, unconjugated bilirubin at 20-40 ml/min, and cytokines at 15-25 ml/min. This article outlines a study of the DTPF System in treatment of patients with hepatic failure with Grade 3 or 4 encephalopathy and respiratory and kidney insufficiency. Treatment appeared to be safe, and there are no significant hematologic changes. Physiologic changes include improved blood pressure and encephalopathy and stable urine output. Chemical changes include decrease in plasma levels of bilirubin, aromatic amino acids, ammonium, creatinine, and interleukin-3 (IL-1beta). The BioLogic-DT System is now marketed for treatment of acute hepatic failure with encephalopathy. The BioLogic-DTPF System adds the capability of removing bilirubin and other strongly protein-bound toxins from treated patients and may be of clinical benefit in management of patients with the most severe hepatic failure and encephalopathy.

Push-pull sorbent based pheresis for treatment of acute hepatic failure: the BioLogic-detoxifier/plasma filter System.

The BioLogic-DT (detoxifier) System is an extracorporeal blood treatment device that uses the membranes of a cellulosic plate dialyzer to propel blood in and out through a single lumen access (on a 12 sec cycle) and circulates a suspension of powdered charcoal and cation exchanger through the dialysate spaces to absorb many soluble toxins in the treatment of hepatic failure. The BioLogic-DTPF (detoxifier/plasma filter) System adds two Gambro plasma filters downstream from the plate dialyzer, which allows most of the blood plasma to pass out of the blood, contact powdered charcoal in a suspension, and then return to the blood during each 12 sec cycle (creating push-pull sorbent based pheresis). A roller pump exchanges charcoal suspension between the plasma filter case and a 700 ml bag of powdered charcoal suspension. At a blood flow rate of 150-200 ml/min, 100 ml/min of plasma moves bidirectionally through the plasma filter membranes. Direct contact of plasma with charcoal outside the plasma filter membranes removes creatinine with a clearance rate equal to plasma flow (100 ml/min); clearance of strongly protein bound toxins, such as unconjugated bilirubin, is lower (10-40 ml/min). In this article, the authors explain the mechanisms of operation of this system and present in vitro tests that define its chemical efficiency. Also described are potential problems, tests that indicate the severity of these problems, and monitors and algorithms to detect or avoid these problems in clinical use of the system. The results of the treatment of two patients with acute hepatic failure and coma using the BioLogic-DTPF System are reviewed.