Is there a role for continuous renal replacement therapies in patients with liver and renal failure?

Continuous renal replacement therapy (CRRT) has now been in use for more than a decade in the management of patients with combined renal and hepatic failure. CRRT remains the treatment of choice in this group of critically ill patients because of improved cardiovascular and intracranial stability when compared with conventional intermittent hemofiltration and/or dialysis and effective solute clearances when compared with forms of peritoneal dialysis. Over the last decade, the technique has evolved with the introduction of pumped CRRT circuits, using machines that can accurately regulate fluid balance, and the commercial introduction of bicarbonate-based or "lactate-free" substitution fluids and/or dialysates. Whether continuous dialysis or hemofiltration is the mode of treatment choice remains unanswered, with greater amino acid and ammonia losses during dialysis, whereas hemofiltration leads to increased middle molecule and cytokine removal when compared with dialysis, the latter mainly caused by membrane adsorption. Whether the improved cardiovascular stability observed during these techniques is due to the removal of inflammatory mediators or is related to cooling as a consequence of the technique remains to be determined.