Which of the following statement(s) is/are true concerning continuous arteriovenous hemofiltration (CAVH)?

a. The technique runs continuously

b. It is not associated with the hemodynamic instability

Continuous arteriovenous hemofiltration (CAVH) is an extracorporial filtration technique that removes extracellular fluid across a synthetic membrane via hydrostatic pressure gradient created between the indwelling arterial and venous catheters. Arteriovenous access is accomplished by percutaneous cannulation of femoral artery and vein with a low incidence of complications. Although full systemic anticoagulation is not necessary for CAVH, heparinization of the extracorporial circuit is required. CAVH is run continuously for as many days as renal replacement is required. Experience with CAVH has demonstrated very little or no hemodynamic instability with treatment of critically ill renal failure patients. The stable nature of this therapy is attributed to a slow and continuous fluid and solute removal and to the fact that the membrane does not induce compliment activation when in contact with blood. Fluid balance and serum electrolyte concentrations can be titrated to any level in a matter of hours by manipulating the composition and rate of replacement solution. Solute clearance with CAVH is limited by the ultrafiltration and replacement fluid exchange rate. In patients with high urea generation rates, solute removal with CAVH may be inadequate and variations of the technique may be used to enhance clearance.