Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content ++ Continuous renal replacement therapy (CRRT) permits fluid and solute removal with greater hemodynamic stability than intermittent hemodialysisTwo principles underlie CRRT: Diffusion: net movement of solute across semipermeable membrane from high concentrated compartment to low concentrated compartment. Dialysis is a diffusive processConvection: movement of solute across semipermeable membrane due to transmembrane pressure gradient (also known as solvent drag). Hemofiltration is a convective process ++ Fluid overloadRefractory hyperkalemiaSevere acidosisUremic symptomsHeart failure ++ More effective for fluid removal in hemodynamically unstable patientCorrects abnormalities as they evolve, so better control of uremia, electrolyte, and acid–base balanceFacilitates administration of parental nutrition and obligatory intravenous medication as well as allowing continuous ultrafiltrationLess effect on intracranial pressure ++Table Graphic Jump Location|Download (.pdf)|PrintFour Main Types of CRRT 1Slow continuous ultrafiltration (SCUF)No dialysate and replacement fluid requiredLarge fluid removal via ultrafiltration2Continuous venovenous hemofiltration (CVVH)Solute removed by convectionDialysis solution is not used; instead a large volume of replacement fluid is infused either inflow or outflow of bloodline3Continuous venovenous hemodialysis (CVVHD)Solute removed by diffusionDialysis solution is passed through the dialysate compartment of filter in opposite direction of blood flow4Continuous venovenous hemodiafiltration (CVVHDF)Solute removed by diffusion and convectionUses dialysate and replacement solutionNB: Arterial access is no longer used because of high complication rate.(See Figure 208-1)++Figure 208-1. Diagrams of the Four Main Types of Renal Replacement TherapyGraphic Jump LocationView Full Size||Download Slide (.ppt)++Table Graphic Jump Location|Download (.pdf)|PrintTechnical ConsiderationsAccessRight internal jugular vein is preferred over any other central venous access as it is straight to superior vena cavaFemoral and subclavian accesses tend to kink and decrease flowReplacement fluidIt is added either prefilter or postfilter of CVVH or CVVHDF circuitPredilution (adding replacement fluid before filter) is better as it minimizes filter clotting and reduces downtime for CVVH machineEither lactate- or bicarbonate-buffered CVVH or CVVHDF found equivalent degrees of correction of acidosis at 24 h, but lactate buffer cannot be used in lactic acidosis, hepatic failure, or liver transplant patientMost commonly used fluids are Plasma-Lyte and 0.45% normal saline with 100 mEq/L of bicarbonateAnticoagulationFilter clotting is most frequent cause of therapy interruption in CRRTThere is no universally accepted anticoagulationUnfractionated heparin is the most common agent for anticoagulation as it is easy to manage, easy to reverse, and inexpensive. Avoid if HITLMWH; not superior to unfractionated heparinCitrate; avoid in hepatic failure, can cause hypocalcemia and, metabolic alkalosisProstacyclin; can cause systemic hypotensionNo anticoagulation, for example, in liver transplant patient with high INR++Table Graphic Jump Location|Download (.pdf)|PrintComplications of CRRTAccessThrombosisInfectionBleedingCircuit-related complicationAir embolismDisconnection/hemorrhageClottingKinkingMembrane hypersensitivity reactionTherapy-related complicationDecreased level ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.