These are the most commonly used forms of CRRT: (indicate what conditions
use what)
- CUF (continuous ultrafiltration), removes only water. Used in
patients with fluid overload or severe electrolyte abnormalities. - CVVH (continuous veno-venous hemofiltration). Uses convection
and requires a replacement solution. It helps remove medium to large
molecules. Replacement solutions are electrolyte and bicarbonate-
based solutions. Indicated in patients with severe kidney injury, uremia
or severe pH/electrolyte imbalance with or without fluid overload that
require removal of solutes (large molecules) maintaining a near normal
volume. Some hypothezise that it helps remove mediators in
inflammatory states (i.e cytokines, lipopolysaccharide) and succesfully
used in conditions such as SIRS, ARDS, septic shock or criticall ill burn
patients. - CVVHD (continuous veno-venous hemodialysis). Uses diffusion and
requires a dialysate solution to create a concentration gradient across
the filter (semipermeable membrane). It helps remove small molecules.
No replacement solution is required. The dialysate solution uses
buffering agents, electrolytes and glucose at normal plasma values
with concentrations that can be changed according to the indications
for RRT. Used in critically ill patients with hemodinamyc unstability or
in children with inborn errors of metabolism.[53] - CVVHDF (continuous veno-venous hemodiafiltration) – uses both
convection and diffusion providing clearance of a wide range of solutes
at very low flow rates. Requires both dialysate and replacement
solution. Commonly used in critically ill patients with multiple organ
dysfunction syndrome.