2 The condition, current treatments and procedure
2.1 Acute liver failure is characterised by a rapid (typically in less than 4 weeks) decline in liver function. Causes include poisoning because of alcohol, pharmaceutical or recreational drugs, and viral infection. Less common causes are metabolic disease and acute fatty liver of pregnancy.
2.2 Untreated, acute liver failure can have a high mortality. Current treatment options include medication (to reverse poisoning and to prevent complications caused by acute liver failure), temporary liver support therapies (such as haemodialysis or filtration, plasma exchange, and bioartificial liver support), hepatocyte transplantation and liver transplantation.
2.3 In this procedure a veno-venous circuit is usually used to perfuse the patient's blood through an extracorporeal whole liver. The aim is to provide metabolic support and prolong survival, to allow time for the patient's liver function to recover or to find a suitable donor liver for transplantation.
2.4 Blood is pumped from a catheter inserted into the femoral vein through an oxygenator and the hepatic artery and portal vein of an extracorporeal whole liver. The liver may be a human liver not suitable for transplantation or a xenogeneic liver (typically a pig liver). Effluent blood from the extracorporeal liver, which is maintained at a normal temperature with a normal pH and electrolytes, is returned to the patient through a subclavian or jugular venous cannula. The literature describes modifications to the technique, such as isolating the patient's immune system from the extracorporeal liver and using different sites for venous access.
2.5 Extracorporeal perfusion is continued for up to 5 days until either the patient has a liver transplant or their liver function recovers.