Blood purification in the intensive care unit

The cornerstone of renal replacement therapy in critically ill patients with acute renal failure (ARF) in our hospital, was intermittent bicarbonate dialysis with synthetic membranes, prescribed daily for anuric patients. Filling of the extracorporeal circuit with 5% human albumin or saline solution before the start of dialysis, as well as hypernatraemic dialysis with profiling, lower dialysate temperature and higher ionized calcium concentration have been used to prevent harmful hypotensive episodes either at the start or during dialysis. Continuous renal replacement therapy (CRRT) in adults was used primarily for anuric, hypotensive patients who might not tolerate standard haemodialysis. All newborns and infants in whom peritoneal dialysis was not possible were treated by continuous procedures. Sustained low efficiency dialysis (SLED) or extended daily dialysis (EDD) were an acceptable compromise between intermitent haemodialysis and CRRT. However, in our opinion, the most promising approach to intensive care unit (ICU) patients with ARF would be the combination of CRRT in the anuric patient followed by intermittent daily dialysis thereafter. Although the mortality rate of ARF patients was as high as 88% in adults and 73% in small children due to the lack of reliable criteria for the selection of patients with poor or good prognosis, aggressive treatment for all patients who needed dialysis was recommended recently. Apheresis has dramatically improved the prognosis and outcome in patients with myasthenia gravis, Guillain-Barre syndrome, Goodpasture syndrome and thrombotic thrombocytopenic purpura. The mortality rate of patients with septic shock and fulminant hepatic failure was still very high, and the role of apheresis and dialysis, in spite of some encouraging results, remains controversial.