Extracorporeal treatment of acute renal failure in the intensive care unit: a critical view.

Acute renal failure in critically ill patients is seldom an isolated problem but is more usually associated with multiple organ failure. When choosing an extracorporeal kidney replacement therapy, these other failing organs must be taken into account. Therefore the choice of an artificial kidney in patients requiring intensive care depends on both the efficacy of the technique and its possible adverse effects on cerebral, pulmonary and cardiovascular function. The most important pathogenic factors in the development of dysequilibrium syndromes, arterial hypoxemia and hypotension are treatment timing, diffusive solute transfer, bio-incompatible membranes and some specific dialysate components (buffer, electrolyte concentrations). It is important to understand the mechanisms by which these factors exert their adverse effects. Application of these pathophysiological mechanisms to the cardiopulmonary and neurologic status of the individual patient permits the prediction of their clinical outcome. This approach will lead to individualised treatment selection, thereby avoiding deleterious side-effects without loss of efficacy.

Left ventricular assist with an axial flow pump (Hemopump): clinical application.

Eighteen patients suffering from acute left heart failure were selected as candidates for Hemopump support. In 6 patients, peripheral atheromatosis prevented insertion of the device. Of the remaining 12 patients, 9 had postcardiotomy shock, 2 had acute rejection after orthotopic heart transplantation, and 1 had acute myocardial infarction complicated by a large postinfarction ventricular septal defect. During Hemopump support, hemodynamics recovered in all patients. Major complications were related to mechanical pump failure, such as fracture of the drive cable and expulsion of the cannula out of the ventricle, or to hemolysis of variable degree. Seven patients (58%) survived and were discharged from the hospital: the 2 patients bridged to heart transplantation and 5 of the 9 postcardiotomy patients, including 1 who could not be weaned but later underwent successful transplantation. The patient with the postinfarction ventricular septal defect died after removal of the device because of hemolysis. These results indicate that the Hemopump is a relatively noninvasive and efficacious left ventricular system of moderate power.