Extracorporeal support for patients with hepatic failure

Extracorporeal support has been advocated for patients with acute and chronic liver failure. Patients with acute liver failure and those with decompensated cirrhosis can be broadly divided into two groups. The first group comprises those with acute liver failure and ongoing hepatic necrosis, and the second, those with long-standing chronic decompensation admitted with one or more complications of liver failure, such as encephalopathy without any evidence of a precipitating factor or accompanying acute deterioration of liver function. This second group includes patients with acute liver failure, where the insult causing hepatic necrosis has been resolved, and those patients with chronic decompensation who suffer another insult to the liver, such as acute infection or variceal hemorrhage that causes further liver injury in the setting of multiorgan failure. These two groups are likely to have different outcomes and may need to be managed differently. In the first group, liver transplantation is the only possible long-term therapeutic option, whereas in the second group, other possibilities such as extracorporeal liver support systems and/or medical therapy may allow these patients to return to their previous state before the acute insult. Over time extracorporeal support has expanded from simple peritoneal dialysis and hemodialysis, to the development of circuits designed primarily to remove both water and lipid-soluble toxins and, in addition, bioartificial devices to provide replacement synthetic hepatic function. Because many of the patients with an acute liver insult have ongoing chronic liver disease and develop hepatorenal syndrome, this group of patients has been targeted by several groups to study the role of liver support systems.