Extracorporeal blood detoxification by sorbent
therapy long has been applied in treatment of
hepatic failure and
encephalopathy, starting with
hemoperfusion columns and more recently with the currently marketed Liver Dialysis Unit. Liver Dialysis employs hemodiabsorption (dialysis of blood against powdered sorbents including
charcoal and
cation exchanger) to remove selectively numerous small-molecular-weight toxins of
hepatic failure. Liver Dialysis is used in treatment of acute
hepatic encephalopathy (AHE) because of decompensation of chronic
liver disease (A-on-C) or
fulminant hepatic failure (FHF). Controlled, prospective and randomized studies of daily 6-hour Liver Dialysis have shown physiologic and neurologic improvement of patients with AHE, regardless of etiology. Liver dialysis significantly improved the incidence of positive outcomes (recovery of hepatic function or improvement for transplant) of A-on-C patients versus controls (71.5% treated, and 35.7% control, P =.036), but had an insignificant improvement in outcome of patients with FHF as compared with the control group. Other extracorporeal sorbent devices are now in clinical testing phase. The molecular adsorbent regenerating system (MARS) device employs a
polysulfone high-permeability dialyzer with
albumin on the
dialysate side to aid transfer of
protein-bound toxins such as
bilirubin and
bile acids across the membranes. Sorbent columns of
charcoal and an
anion exchanger remove hepatic toxins from the
albumin dialysate, and a second dialyzer removes water-soluble toxins, such as
ammonium. Clinical results of daily MARS treatments of patients with
hepatic failure are similar to that of Liver Dialysis, with neurologic and physical improvement occurs in most patients with AHE, and improved outcome for patients with A-on-C. The system extends the life of patients with
hepatorenal syndrome. PF-Liver Dialysis is an experimental device combining hemodiabsorption with push-pull sorbent-based
pheresis with powdered sorbent surrounding plasmafilters. PF-Liver Dialysis (Hemocleanse, Inc, W. Lafayette, IN) has been tested in a few patients with
hepatic failure, grade 3-4
encephalopathy, and respiratory and
kidney insufficiency. Treatments appeared to be safe and resulted in marked decreases in plasma levels of
bilirubin,
aromatic amino acids,
ammonium,
creatinine, and
interleukin-1beta (IL-1beta). The PF add-on module adds the capability to Liver Dialysis to remove
bilirubin,
bile acids, 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, including patients with FHF or concomitant
sepsis.