【持续性肾脏替代治疗crrt英文精品课件】crrt in icu(45p)

Renal Replacement Therapies in Critical Care,Dr. Andrew Ferguson Consultant in Intensive Care Medicine & Anaesthesia Craigavon Area Hospital, United Kingdom,Where are we - too many questions?,What therapy should we use? When should we start it? What are we trying to achieve? How much therapy is enough? When do we stop/switch? Can we improve outcomes?,Does the literature help us?,Overview,Impact of Acute Kidney Injury in the ICU Dose-outcome relationships & IRRT v CRRT Mechanisms of solute clearance Therapies in brief IRRT, CRRT & Hybrid therapies e.g. SLEDD Solute clearance with IRRT v CRRT v SLEDD Extracorporeal blood purification in sepsis Putting it together making a rational choice,AKI classification systems 1: RIFLE,AKI classification systems 2: AKIN,Patients receiving RRT are Stage 3 regardless of creatinine or urine output,Acute Kidney Injury in the ICU,AKIis common: 3-35%* of admissions AKI is associated with increased mortality “Minor” rises in Cr associated with worse outcome AKI developing after ICU admission (late) is associated with worse outcome than AKI at admission (APACHE underestimates ROD) AKI requiring RRT occurs in about 4-5% of ICU admissions and is associated with worst mortality risk *,* Brivet, FG et al. Crit Care Med 1996; 24: 192-198 * Metnitz, PG et al. Crit Care Med 2002; 30: 2051-2058,Mortality by AKI Severity (1),Clermont, G et al. Kidney International 2002; 62: 986-996,Mortality by AKI Severity (2),Bagshaw, S et al. Am J Kidney Dis 2006; 48: 402-409,RRT for Acute Renal Failure,There is some evidence for a relationship between higher therapy dose and better outcome, at least up to a point This is true for IHD* and for CVVH* There is no definitive evidence for superiority of one therapy over another, and wide practice variation exists* Accepted indications for RTT vary No definitive evidence on timing of RRT,*Schiffl, H et al. NEJM 2002; 346: 305-310 * Ronco, C et al. Lancet 2000; 355: 26-30 * Uchino, S. Curr Opin Crit Care 2006; 12: 538-543,Therapy Dose in IRRT,p = 0.01,p = 0.001,Schiffl, H et al. NEJM 2002; 346: 305-310,Therapy Dose in CVVH,25 ml/kg/hr,35 ml/kg/hr,45 ml/kg/hr,Ronco, C et al. Lancet 2000; 355: 26-30,Outcome with IRRT vs CRRT (1),Trial quality low: many non-randomized Therapy dosing variable Illness severity variable or details missing Small numbers Uncontrolled technique, membrane Definitive trial would require 660 patients in each arm! Unvalidated instrument for sensitivity analysis,Kellum, J et al. Intensive Care Med 2002; 28: 29-37,“there is insufficient evidence to establish whether CRRT is associated with improved survival in critically ill patients with ARF when compared with IRRT”,Outcome with IRRT vs CRRT (2),Tonelli, M et al. Am J Kidney Dis 2002; 40: 875-885,No mortality difference between therapies No renal recovery difference between therapies Unselected patient populations Majority of studies were unpublished,Outcome with IRRT vs CRRT (3),Vinsonneau, S et al. Lancet 2006; 368: 379-385,Proposed Indications for RRT,Oliguria 6.5 mmol/L Severe acidaemia pH 30 mmol/L Uraemic complications Dysnatraemias 155 or 120 mmol/L Hyper/(hypo)thermia Drug overdose with dialysable drug,Lameire, N et al. Lancet 2005; 365: 417-430,Implications of the available data,The Ideal Renal Replacement Therapy,Allows control of intra/extravascular volume Corrects acid-base disturbances Corrects uraemia & effectively clears “toxins” Promotes renal recovery Improves survival Is free of complications Clears drugs effectively (?),Solute Clearance - Diffusion,Small ( 500d) molecules cleared efficiently Concentration gradient critical Gradient achieved by countercurrent flow Principal clearance mode of dialysis techniques,Solute Clearance Ultrafiltration & Convection (Haemofiltration),Water movement “drags” solute across membrane At high UF rates ( 1L/hour) enough solute is dragged to produce significant clearance Convective clearance dehydrates the blood passing through the filter If filtration fraction 30% there is high risk of filter clotting* Also clears larger molecular weight substances (e.g. B12, TNF, inulin),* In post-dilution haemofiltration,Major Renal Replacement Techniques,Intermittent,Continuous,Hybrid,IHD Intermittent haemodialysis,IUF Isolated Ultrafiltration,SLEDD Sustained (or slow) low efficiency daily dialysis,SLEDD-F Sustained (or slow) low efficiency daily dialysis with filtration,CVVH Continuous veno-venous haemofiltration,CVVHD Continuous veno-venous haemodialysis,CVVHDF Continuous veno-venous haemodiafiltration,SCUF Slow continuous ultrafiltration,Intermittent Therapies - PRO,Intermittent Therapies - CON,Intradialytic Hypotension: Risk Factors,LVH with diastolic dysfunction or LV systolic dysfunction / CHF Valvular heart disease Pericardial disease Poor nutritional status / hypoalbuminaemia Uraemic neuropathy or autonomic dysfunction Severe anaemia High volume ultrafiltration requirements Predialysis SBP of 100 mm Hg Age 65 years + Pressor requirement,Managing Intra-dialytic Hypotension,Dialysate temperature modelling Low temperature dialysate Dialysate sodium profiling Hypertonic Na at start decreasing to 135 by end Prevents plasma volume decrease Midodrine if not on pressors UF profiling Colloid/crystalloid boluses Sertraline (longer term HD),2005 National Kidney Foundation K/DOQI GUIDELINES,Continuous Therapies - PRO,Continuous Therapies - CON,SCUF,High flux membranes Up to 24 hrs per day Objective VOLUME control Not suitable for solute clearance Blood flow 50-200 ml/min UF rate 2-8 ml/min,CA/VVH,Extended duration up to weeks High flux membranes Mainly convective clearance UF volume control amount Excess UF replaced Replacement pre- or post-filter Blood flow 50-200 ml/min UF rate 10-60 ml/min,CA/VVHD,Mid/high flux membranes Extended period up to weeks Diffusive solute clearance Countercurrent dialysate UF for volume control Blood flow 50-200 ml/min UF rate 1-8 ml/min Dialysate flow 15-60 ml/min,CVVHDF,High flux membranes Extended period up to weeks Diffusive & convective solute clearance Countercurrent dialysate UF exceeds volume control Replacement fluid as required Blood flow 50-200 ml/min UF rate 10-60 ml/min Dialysate flow 15-30 ml/min Replacement 10-30 ml/min,SLED(D) & SLED(D)-F : Hybrid therapy,Conventional dialysis equipment Online dialysis fluid preparation Excellent small molecule detoxification Cardiovascular stability as good as CRRT Reduced anticoagulation requirement 11 hrs SLED comparable to 23 hrs CVVH Decreased costs compared to CRRT Phosphate supplementation required,Fliser, T 2: 32-39,Berbece, AN 70: 963-968,Kinetic Modelling of Solute Clearance,TAC = time-averaged concentration (from area under concentration-time curve) EKR = equivalent renal clearance Inulin represents middle molecule and b2 microglobulin large molecule. CVVH has marked effects on middle and large molecule clearance not seen with IHD/SLED SLED and CVVH have equivalent small molecule clearance Daily IHD has acceptable small molecule clearance,Liao, Z et al. Artificial Organs 2003; 27: 802-807,Uraemia Control,Liao, Z et al. Artificial Organs 2003; 27: 802-807,Large molecule clearance,Liao, Z et al. Artificial Organs 2003; 27: 802-807,Comparison of IHD and CVVH,John, S 19: 455-464,Beyond renal replacement RRT as blood purification therapy,Extracorporeal Blood Purification Therapy (EBT),Intermittent,Continuous,TPE Therapeutic plasma exchange,HVHF High volume haemofiltration,UHVHF Ultra-high volume haemofiltration,PHVHF Pulsed high volume haemofiltration,CPFA Coupled plasma filtration and adsorption,Peak Concentration Hypothesis,Removes cytokines from blood compartment during pro-inflammatory phase of sepsis Assumes blood cytokine level needs to fall Assumes reduced “free” cytokine levels leads to decreased tissue effects and organ failure Favours therapy such as HVHF, UHVHF, CPFA But tissue/interstitial cytokine levels unknown,Ronco, C 27: 792-801,Threshold Immunomodulation Hypothesis,More dynamic view of cytokine system Mediators and pro-mediators removed from blood to alter tissue cytokine levels but blood level does not need to fall ? pro-inflammatory processes halted when cytokines fall to “threshold” level We dont know when such a point is reached,Honore, PM 32: 896-897,Mediator Delivery Hypothesis,HVHF with high incoming fluid volumes (3-6 L/hour) increases lymph flow 20-40 times “Drag” of mediators and cytokines with lymph Pulls cytokines from tissues to blood for removal and tissue levels fall High fluid exchange is key,Di Carlo, JV 28: 777-786,High Volume Hemofiltration,May reduce unbound fraction of cytokines Removes endothelin-I (causes early pulm hypertension in sepsis) endogenous cannabinoids (vasoplegic in sepsis) myodepressant factor PAI-I so may eventually reduce DIC Reduces post-sepsis immunoparalysis (CARS) Reduces inflammatory cell apoptosis Human trials probably using too low a dose (40 ml/kg/hour vs 100+ ml/kg/hour in animals),CRRT, Haemodynamics & Outcome,114 unstable (pre