Continuous Renal Replacement Therapy

Jai Radhakrishnan, MD, MS

History of the CRRT program

1988Open heart programActive transplant programDeep dissatisfaction with peritoneal dialysis in hemodynamicallyunstable patients

Objectives

Physiologic principlesPatient Selection for CRRTModality SelectionPrescription VariablesFluid CompositionManagement of Fluid and Electrolyte problemsControversies

Basic Concepts

Pressure

Convection(Plasma water moves along pressure gradients)

•SCUF

•CVVH

•CVVHD

•CVVHDF

Continuous Renal Replacement Therapy

SCUF:Slow Continuous Ultra Filtration

Maximum Patient Fluid RemovalRate = 2000 ml/hr

Therapy Options

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CVVHContinuous Veno-Venous HemoFiltration

Maximum Patient Fluid Removal Rate = 1000 ml/hr

Therapy Options

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CVVHDContinuous Veno-Venous HemoDialysis

Maximum Patient Fluid Removal Rate = 1000 ml/hr

Therapy Options

Access

Return

Effluent

PRISMA

Dialysate

CVVHDFContinuous Veno-Venous HemoDiafiltration

Maximum Pt. fluidremoval rate = 1000 ml/hr

Therapy Options

Access

Return

Effluent

Replacement

PRISMA

Dialysate

A Case

35 year old female is s/p OHT, POD#1.Remains intubated, MAP 65 on Levo 20, Pit 3, Milrinone 0.25Urine output 10 ml.hour (Intake 150ml/h)PAD 20FiO2 0.60- ABG 7.45/35/102BMP 132/4.6/103/18/25/1.3 (Baseline 1.0)

Indications for Renal Replacement

Standard indications Volume overloadHyperkalemiaMetabolic AcidosisUremic Platelet DysfunctionUremic Encephalopathy

Modality Selection

SCUF

CVVHCVVHD

CVVHDF

CVVHDF

Volume only

Solutes +/- Volume

Hypercatabolic+/- Volume

Prescription Variables

Blood FlowUp to 180 ml/min

ReplacementUp to 4500 ml/hr

Dialysateup to 2500 ml/hr

Patient Fluid RemovalUp to 2000 ml/hr

Access

Return

Effluent

Replacement

PRISMA

Dialysate

Fluid Composition: Dialysate

Prismasate® 5000mLNa+ = 140 mEq/LK+ = 0 mEq/LCl- = 109.5 mEq/LCa2+ = 3.5 mEq/LMg2+ = 1 mEq/LLactate = 3 mEq/LHCO3 = 32 mEq/LGlucose = 0 mg/dL

Premixed Dialysate®

5000mL Na+ = 140 mEq/LK+ = 2.0 mEq/LCl- = 117 mEq/LCa2+ = 3.5 mEq/L Mg2+ = 1.5 mEq/LLactate = 30 mEq/LGlucose = 100 mg/dL

Peripheral Electrolyte Replacement

In the event of high volume Bicarbonate solutions, if Ca free:Peripheral CaCl2/MgSO4

In the event of high clearance:prn Na phosphate

Solutes: Azotemia

AzotemiaIncrease replacement fluid and/or dialysateflow rate

Solutes: Sodium

HyponatremiaAdd 3% NaCl to dialysate @70 cc/5L bag

HypernatremiaIncrease peripheral IV D5W (1L) or 1/2 NS

Solutes: K

HyperkalemiaZero K+, increase replacement and/or dialysate flow rate

1 L bag 5 L bag Serum Potassium

Add 0 mEq / Liter None None > 5.5 mEq / Liter

Add 3 mEq / Liter 7.5 mL 37.5 mL > 4.5 – 5.5 mEq / Liter

Add 4 mEq / Liter 10 mL 50 mL < 4.5 mEq / Liter

Solutes: pH

Metabolic AcidosisNaHCO3 (50%) 100 cc over 1 hour IVSS, prnChange replacement to D5W (1L) + 3 amps NaHCO3

Metabolic AlkalosisChange replacement solution to NS + sliding scale KCl

Solutes: Calcium

HypercalcemiaChange to HCO3 dialysate (Ca2+ free) Increase HCO3 dialysate or replacement flow rate

HypocalcemiaCaCl2 (10%) 10 cc/100 cc NS or D5W over one hour, prnPremixed calcium drip

Solute: Mg and Phospate

HypomagnesemiaMgSO4 (50%) 2 ml in 100 cc NS or D5W over one hour, prnPremixed magnesium drip

HypermagnesemiaSame as Rx for hypercalcemia

HypophosphatemiaNa Phosphate (3 mmol/ml) 5cc in 100cc NS IVSS over 2 hours, prn (repeat x 1 if PO4 <1.0 mg/dl)

HyperphosphatemiaSame as Rx for hypercalcemia

Anticoagulation

Heparin250 - 500 U/hr

HIT: Argatroban0.5 - 1 mg/hr

Bleeding risk:CitrateNo anticoagulation

Argatroban CRRT Anticoagulation Protocol

1. Call Hematology for approval.2. In a 20 cc syringe (1000 mcg/mL): 30 microgram/kg/hr (0.5 microgram/kg/min)

Rate: _____ microgram/hr = ____ mL / hr (Range 0.5 – 5 mL/hr)Use lower dose with liver failure. (15 mcg/kg/hr)

Disconnect: Flush lumen with _____ mL of 1000 microgram/mL argatroban in each port (use internal volume as stated on catheter).

Reconnection: Aspirate 5 mL from each port before re-connecting.3. Write argatroban order separately.4. Check PTT q 12 hours

Citrate Regional Anticoagulation

Cointault O.. Nephrol Dial Transplant. 2004 Jan;19(1):171-8.

CRRT in LVAD circuit

LVAD

CRRT

CRRT- Controversial Issues

HCO3- vs lactate solutions

High vs standard delivered doseConvection vs diffusionCost of CRRT vs HD.Does CRRT improve outcome (vs HD)?CRRT to prevent contrast nephropathy

Lactate vs HCO3 Replacement

N=117Open-label trial randomized to Replacement Fluid:

HCO3

Lactate

Kidney International 58 (4), 1751-1757

Effects of different doses of CVVH on outcomes of ARF

425 patients with ARF.Patients were randomly assigned ultrafiltration at

• 20 mL/kg/h (Gr 1, n=146)• 35 mL/kg/h (Gr 2, n=139)

• 45 mL/kg/h (Gr 3, n=140).

Primary endpoint: survival at 15 days after stopping haemofiltration.

Lancet. 2000 Jul 1;356(9223):26-30

Intensity of Renal Support in Critically Ill Patients with Acute Kidney Injury

N Engl J Med. 2008 Jul 3;359(1):7-20

Diffusion vs. Convection

100

40

80

120

160

Molecular Weight

Cle

aran

ce (m

l/min

)

102 103 104 105 106 Urea, 60 DCreatinine, 113 DVit. B12, 1355 DInulin, 5200 DAlbumin, 55-60 kD

Diffusive transportConvective transport

Cost of acute renal failure requiring dialysis in the intensive care unit: clinical and resource implications of renal recovery.

DesignRetrospective cohort study Patients with ARF needing dialysis April 1, 1996, - March 31, 1999.

Setting: Two tertiary care intensive care units in Calgary, Canada.Patients: 261 critically ill patients.Outcomes:

in-hospital and subsequent survival and renal recoveryThe immediate and potential long-term costs

Manns: Crit Care Med, 31(2). 2003.449-455

Impact of dialytic modality on mortality (HD vs CRRT)

Am J Kidney Dis. 2002 Nov;40(5):875-85

Impact of dialytic modality on renal recovery.

Efficacy and cardiovascular tolerability of extended dialysis incritically ill patients: A randomized controlled study

Kielstein JT..Am J Kidney Dis. 2004 Feb;43(2):342-9.

Genius single-pass dialysis machine

Clearances

Hemodynamic Parameters

MAP HR

CO SVR

The Prevention of Radiocontrast-Agent–Induced Nephropathy by Hemofiltration

N Engl J Med 2003; 349:1333-1340,

•CVVH 1000 ml/h,

•4-8 hours pre and 18-24 hours after angiogram.

Outcome: Renal Function

Outcomes

OUTCOME CONTROLS CVVH

25% increase in Serum Creatinine

50% 5%

Renal replacement: (Oliganuriafor >48 h despite 1 g IV furosemide)

25% 3%

MortalityIn hospital One-year

14%30%

2%10%

Complications