Liver dialysis

From ArticleWorld

Liver dialysis is also called “artificial extracorporeal liver support” and like kidney dialysis, it provides temporary support in cases of liver dysfunction. There are several different types of liver dialysis methods available.

Functions

Liver dialysis must provide the same functions as a normal liver would. In someone with liver failure, the liver cannot detoxify the toxins absorbed by the intestinal tract or created as part of normal body metabolism. Bilirubin from red blood cell destruction is not able to be gotten rid of, bile acids build up and byproducts from the metabolism of certain amino acids (protein precursors) cannot be eliminated properly. Other metabolites cannot be processed by the liver. Generally, these metabolites are albumin-bound (or protein-bound), making the use of kidney dialysis ineffective. Kidney dialysis only removes water-soluble molecules.

The ailing liver doesn’t synthesis some of the things the body needs. Coagulation factors are made in the liver and without them, bleeding complications can occur. Glycogen is stored in the liver and is made by putting molecules of glucose together for the purposes of storage.

Methods

There are currently three available types of liver dialysis currently under evaluation. The first is the Molecular Adsorbents Recirculation System (MARS). It was designed in Germany in the mid 1990’s. It has an albumin-membrane circuit that puts the patient’s blood in contact with human albumin that binds the toxic metabolites and external toxins and removes them from the blood. The second circuit cleans or filters the albumin-bound molecules, separating the toxins away from the albumin and sending the albumin back to the first circuit.

The Single Pass Albumin Dialysis (SPAD) system uses a standard kidney dialysis machine but adds a special pump system that pushes blood through a fibrous hemodiafilter, not unlike the MARS system. Albumin in solution is pushed through in the opposite direction, picks up toxic metabolites and is then discarded along with the waste. The downside to this system is that new albumin must be used all the time and is not recycled. Studies show that both techniques remove albumin-bound metabolites like bilirubin with the same effectiveness.

The Prometheus System is a German device that combines albumin absorption of toxins and metabolites along with a high-flow hemodialysis circuit that takes out water-soluble toxins like that of kidney dialysis machines. This system, like the others, is not in general use yet.