Continuous renal replacement therapy in critically ill patients

Acute renal failure is an evolving syndrome in which new pathogenetic mecha nisms have recently been elucidated. The evolution of the field of haemodia lysis has led to a parallel development in the therapeutic approach to pati ents suffering from this syndrome. In particular, acute renal failure is mo re frequently seen as part of a more complex syndrome, defined as multiple organ failure. In this clinical setting, patients are almost inevitably con fined to intensive care units and sepsis is a frequent underlying mechanism of organ failure. The use of new devices and new machines, together with a better understanding of the underlying mechanisms of solute and water remo val, have allowed us to achieve higher levels of efficiency and clinical to lerance during artificial renal replacement therapy. The first objective ha s been reached by increasing the automation of the extracorporeal circuits and the operational levels of the different techniques; the second has been achieved by means of a new generation of monitoring techniques and new mac hines equipped with specific interfaces and alarms. This progress has made continuous forms of renal replacement (CRRT) possible and easy to perform w ithout major problems or complications. The most promising and effective op tions for treating acute renal failure in critically ill patients are today offered by continuous renal replacement therapies. Classic indications, bu t also alternative non-renal indications, have been proposed for these tech niques. The most advanced indication is the multiple organ dysfunction occu rring in septic patients. The possible removal of proinflammatory mediators may permit a blockade of the systemic inflammation, a modulation of the al tered immune response in these patients, and it may lead to a partial or to tal restoration of the lost homeostasis.