Transcript Document
PCRRT Tûr'mə-nŏl'ə-jē Helen Currier BSN, RN, CNN Assistant Director, Renal/Pheresis Texas Children’s Hospital Houston, Texas History of Continuous Renal Replacement Therapy (CRRT) 1960 1974 1975 1979-82 SCUF and CAVH used by Paganini (MD) and Whitman (RN) at Cleveland Clinic Continuous arteriovenous approach first described for treatment of renal failure Ultrafiltration isolated from hemodialysis circuit and the addition of a hemofilter Hemofiltration technique proposed History of Continuous Renal Replacement Therapy (CRRT) 1980s 1987 1990 1993 CRRT used in pediatrics Pump-assisted CRRT introduced CRRT considered state of the art therapy for treatment of acute renal failure Standards of Clinical Practice for CRRT published by the American Nephrology Nurses’ Association (ANNA) and endorsed by the American Association of Critical Care Nurses (AACN) History of Continuous Renal Replacement Therapy (CRRT) 1998 SLEDD introduced as an alternative to CRRT 2000 2002 2004 Continued development of integrated blood pump and fluid balance equipment for CRRT 2nd International pCRRT meeting in Orlando, FL 3rd International pCRRT meeting in Orlando, FL History of Continuous Renal Replacement Therapy (CRRT) 2006 2008 2010 4th International pCRRT meeting in Zurich, Switzerland 5th International pCRRT meeting in Orlando, FL 6th International pCRRT meeting in Rome, Italy The Founding Five Bunchman Brophy Goldstein Symons Somers Indications for CRRT in the Critical Care Setting Fluid removal Solute removal Basic Concepts of CRRT: Concepts Related to Fluid Removal or Ultrafiltration Blood flow – Arteriovenous – Venovenous Hydrostatic pressure – Arteriovenous – Venovenous Other factors – Hematocrit – Plasma proteins – Transmembrane pressure Basic Concepts of CRRT: Concepts Related to Solute Removal or Clearance Convection – solute drag; hemofiltration Diffusion – concentration gradient; hemodiafiltration Convection High pressure to low pressure across a membrane Pressure gradient Solute dissolved in solvent = solvent drag Bulk-flow of solute across a semipermeable membrane together with a solvent in a manner that is dependent on transmembrane pressure and membrane characteristics. Basic Concepts of CRRT: Concepts Related to Solute Removal or Clearance Convection – solute drag; hemofiltration Diffusion – concentration gradient; hemodiafiltration Diffusion Describes solute transport across a semi-permeable membrane generated by a concentration gradient. Hemodiafiltration (HDF) http://www.usa-gambro.com/upload/Site_us/Patient%Resources/IC/cvvhdf.gif A technique associated with high ultrafiltration rates and diffusion across a highly permeable membrane. Blood and dialysate are circulated as in hemodialysis, but in addition, ultrafiltration, in excess of the scheduled weight loss, is provided. Replacement fluid is used to achieve fluid balance. Solute Mass Transfer in CRRT Post-Dilution CVVH Qr Qb CVVHD Qb Qef Qef f Qd f Qr Qr Qb Qb Qef Qef f Pre-Dilution CVVH f CVVHDF Qd Solute Molecular Weight and Clearance Solute (MW) Sieving Coefficient Diffusion Coefficient Urea (60) 1.01 ± 0.05 1.01 ± 0.07 Creatinine (113) 1.00 ± 0.09 1.01 ± 0.06 Uric Acid (168) 1.01 ± 0.04 0.97 ± 0.04* Vancomycin (1448) 0.84 ± 0.10 0.74 ± 0.04** *P<0.05 vs sieving coefficient **P<0.01 vs sieving coefficient Definition of Acronyms and Terms SCUF CAVH CAVHD CVVH CVVHD CVVHDF slow continuous ultrafiltration continuous arteriovenous hemofiltration continuous arteriovenous hemodialysis continuous venovenous hemofiltration continuous venovenous hemodialysis continuous venovenous hemodiafiltration Definition of Acronyms and Terms SLEDD slow low efficient daily dialysis or sustained lowefficiency daily dialysis Intermittent therapies Are those usually prescribed for a period of 12 hours or less. Extended Daily Dialysis (EDD) Slow Low Efficiency Dialysis (SLED) EDD+SLED=SLEDD Continuous Renal Replacement Therapy Advantages – – – – Slower blood flows Slower UF rates Adjust UF rates with hourly patient intake Increased cytokine (bad humors) removal? Disadvantages – Prolonged anticoagulation – Increased cytokine (good humors) removal? Dialysate http://www.shodor.org/master/biomed/physio/dialysis/hemodialysis/sixa.htm#hollowfiber A solution of variable composition designed to facilitate diffusion of solutes into the ultrafiltratedialysate compartment of the hemofilter or hemodialyzer. Peritoneal Dialysis An intracorporeal therapy where solute and water are transported across the peritoneal membrane based on osmotic and concentration gradients. Hemodialysis An extracorporeal, primarily diffusive therapy, where solute and water are transported across a semi-permeable membrane into dialysate. High flux A dialysis membrane designed to provide high water permeability, thereby increasing solute clearance especially large solute such as beta-2 microglobulin. Transmembrane Pressure The hydrostatic pressure gradient across the membrane. This is the driving force that causes ultrafiltration. The Pediatric Ideal: CRRT Circuit Minimum priming volume with low resistance Exchangeable components Biocompatible membrane The Pediatric Ideal: CRRT Equipment Separate and accurate pumps and scales for each component of CRRT Range of blood flows with a minimum of 20ml/min Thermoregulation Maximum safety features The Pediatric Ideal: CRRT Equipment Comes with a expert nurse!