The elusive goal of liver support--quest for the Holy Grail.

The history of liver support devices is traced from early attempts with dialysis based on the known dialysability of ammonia--the major identified toxin in liver failure--and exchange transfusion with removal of protein-bound toxins, to the later techniques based on whole organ perfusion in extracorporeal circuits. Perfusion through charcoal as an adsorbent represented a major advance and remains a component of more recently introduced devices based on bioreactors of cultured hepatocytes and in the albumin dialysis techniques of molecular adsorbent recirculating system and the Prometheus device. The latter are the most highly efficient to date in toxin removal but whether survival is improved and the need for liver transplantation remain to be proven.