Renal Replacement Therapy

• • Intermittent Hemodialysis (IHD)
  • IHD is widely available, has only moderate technical difficulty, and is the most efficient way of removing a volume or solute from the vascular compartment quickly. Unfortunately, dialysis-associated hypotension may adversely affect remaining renal function, particularly in patients who are critically ill. This is one reason CVVH is widely recommended in this setting.
  • 2) Continuous Venovenous Hemofiltration (CVVH)
  • Continuous RRT techniques are more expensive and not universally available; however, in addition to avoiding hypotension, they are believed to achieve better control of uremia and clearance of solute from the extravascular compartment. Because it continues around the clock, CVVH is able to remove larger fluid volumes, which is a significant advantage with critical care patients on parenteral nutrition and multiple infusions. CVVH may also preserve cerebral perfusion pressure more effectively. A theoretical though contested advantage of CVVH is the clearance of mediators of the inflammatory cascade. Although several studies have sought to directly compare CVVH to IHD, no study has shown a convincing advantage for one therapy over the other; in spite of this, many authorities assert that the choice of IHD over CVVH in the setting of shock would be inappropriate and unethical.
  • 3) Peritoneal Dialysis (PD)
  • Peritoneal dialysis is inexpensive, widely available, and does not result in hypotension. However, it is not capable of removing large volumes of fluid or solute. Its use may be most common in children.