Renal Replacement TherapyRenal Replacement Therapy

Trauma ConferenceTrauma Conference

11-27-200611-27-2006

Amanda Wheeler, MDAmanda Wheeler, MD

PrinciplesPrinciples

4 Main Modalities in ICU4 Main Modalities in ICU

HDHD PDPD CVVHCVVH CVVHDCVVHD

Definition of TermsDefinition of Terms

SCUF- Slow Continuous UltrafiltrationSCUF- Slow Continuous Ultrafiltration CAVH- Continuous Arteriovenous CAVH- Continuous Arteriovenous

HemofiltrationHemofiltration CAVH-D- Continuous Arteriovenous CAVH-D- Continuous Arteriovenous

Hemofiltration with DialysisHemofiltration with Dialysis CVVH- Continuous Venovenous CVVH- Continuous Venovenous

HemofiltrationHemofiltration CVVH-D- Continuous Venovenous CVVH-D- Continuous Venovenous

Hemofiltration with DialysisHemofiltration with Dialysis

Indications for Continuous Renal Indications for Continuous Renal Replacement TherapyReplacement Therapy

Volume OverloadVolume Overload Electrolyte ImbalanceElectrolyte Imbalance UremiaUremia Acid-Base DisturbancesAcid-Base Disturbances DrugsDrugs

Hemodialysis vs Hemofiltration Hemodialysis vs Hemofiltration MembraneMembrane

The The hemofiltrationhemofiltration membrane membrane consists of relatively consists of relatively straight channels of ever-straight channels of ever-increasing diameter that increasing diameter that offer little resistance to offer little resistance to fluid flow.fluid flow.

Hemodialysis membranes contain long, tortuous inter-connecting channels that result in high resistance to fluid flow.

Hemodialysis allows the removal of water and solutes by diffusion across a concentration gradient.

HemodialysisHemodialysis

maximum solute maximum solute clearanceclearance

best tx for severe best tx for severe hyper-K+hyper-K+

ready availabilityready availability limited anti-coagulation limited anti-coagulation

timetime bedside vascular bedside vascular

accessaccess

hemodynamic hemodynamic instabilityinstability

hypoxemiahypoxemia rapid fluid + solute rapid fluid + solute

shiftsshifts complex equipmentcomplex equipment specialized specialized

personnelpersonnel

advantages disadvantages

Peritoneal DialysisPeritoneal Dialysis

simple to set up + simple to set up + performperform

easy to useeasy to use hemodynamic stabilityhemodynamic stability no anti-coagulationno anti-coagulation bedside peritoneal bedside peritoneal

accessaccess

unreliable ultrafiltrationunreliable ultrafiltration slow fluid + solute slow fluid + solute

removalremoval drainage failure, drainage failure,

leakageleakage catheter obstructioncatheter obstruction respiratory compromiserespiratory compromise hyperglycemiahyperglycemia peritonitisperitonitis

advantages disadvantages

CVVHD vs CVVHCVVHD vs CVVH

CVVHCVVH

1. near-complete control of the rate of 1. near-complete control of the rate of fluid removal (i.e. the ultrafiltration rate)fluid removal (i.e. the ultrafiltration rate)

2. precision and stability2. precision and stability

3. electrolytes or any formed element 3. electrolytes or any formed element of the circulation, including platelets or of the circulation, including platelets or red or white blood cells, can be red or white blood cells, can be removed or added independent of removed or added independent of changes in the volume of total body changes in the volume of total body waterwater

CVVHCVVH

easy to use in ICUeasy to use in ICU rapid electrolyte correctionrapid electrolyte correction excellent solute clearancesexcellent solute clearances rapid acid/base correction rapid acid/base correction controllable fluid balancecontrollable fluid balance tolerated by unstable tolerated by unstable

patientspatients early use of TPNearly use of TPN bedside vascular access bedside vascular access

routineroutine

systemic systemic anticoagulation *anticoagulation *

citrate anticoagulation citrate anticoagulation newnew

frequent filter clottingfrequent filter clotting hypotensionhypotension

advantages disadvantages