The document discusses continuous renal replacement therapy (CRRT) in critical care units. It begins with definitions and history of renal replacement therapy. It then covers principles, techniques, applications, results and complications of CRRT. The techniques discussed include continuous venovenous hemofiltration (CVVH), hemodialysis (CVVHD) and hemodiafiltration (CVVHDF). Advantages include hemodynamic stability, precise volume control and removal of toxins and cytokines. Complications can include bleeding, infection and electrolyte imbalances. CRRT remains the preferred technique for critically ill patients with acute kidney injury in many intensive care settings.

1. ‫خرد‬ ‫و‬ ‫جان‬ ‫خداوند‬ ‫نام‬ ‫به‬‫کزین‬‫برنگذرد‬ ‫اندیشه‬ ‫برتر‬
‫رهنمای‬ ‫ده‬ ‫روزی‬ ‫خداوند‬ ‫جای‬ ‫خداوند‬ ‫و‬ ‫نام‬ ‫خداوند‬

2. Renal Replacement
Therapy in critical care unit
Mansoor Masjedi ; MD & FCCM
Ass. professor of anesthesia & critical care
Nemazee hosp. ,General & Central ICU , Azar -93

3. Learning Objectives
 Definition and nomenclature of RRT
 Principle of CRRT
 Technique of CRRT
 Applications of CRRT
 Results of CRRT
 Complications of CRRT
 Summary

4. History of Renal Replacement Therapy
 The use of artificial kidneys began during the Korean War,
when it was called “dialysis”, derived from Greek and
meaning “to pass across”.
 Since 50 yrs ago named ,
“Renal Replacement Therapies (RRT)” to describe :
 Hemodialysis
 Peritoneal dialysis
 Continuous hemofiltration
 Continuous hemodialfiltration

5. •Initial description of
continuous arteriovenous
hemofiltration (CAVH) in 1977
by Peter Kramer and
colleagues
•In 1984, Dr. Claudio Ronco,
treated this child with CAVH in
Vicenza, Italy ( the first
patient treated with CAVH in
the world. The patient
survived ).
History of Renal Replacement Therapy

6. Intensivist Nephrologist
Maintain tissue O2 delivery Fluid management
Increased cardiac output
Enhance ventilation Solute control
Maintain blood pressure
Prevent hypermetabolism
Provide adequate nutrition Acid-base balance
Treat primary process Electrolyte balance
* Acute Renal Failure in ICU
Goals for treatment

7. Indications to Start and Stop
Renal Replacement Therapies
i. Indications for the initiation of RRT
ii. Biochemical or clinical marker that is
achieved by the therapy
iii. Techniques and timing of weaning
patients from RRT

8. Indications for Renal Replacement Therapy
• Anuria-oliguria (diuresis ≤ 200 mL in 12 hr)
• Severe metabolic acidosis (pH < 7.10)
• Hyperazotemia (BUN ≥ 80 mg/dL) or creatinine > 4 mg/dL
• Hyperkalemia (K+≥ 6.5 mEq/L)
• Clinical signs of uremic toxicity
• Severe dysnatremia (Na+≤ 115 or ≥ 160 mEq/L)
• Hyperthermia (temperature > 40°C without response to medical therapy)
• Anasarca or severe fluid overload
• Multiple organ failure with renal dysfunction and/or systemic inflammatory
response syndrome, sepsis, or septic shock with renal dysfunction
* The presence of one indication suggests, two indications strongly suggest, and three
indications mandate initiation of renal replacement therapy.

9. Techniques and Modalities
So, I’ve decided to dialyse the pt,
what modes are available to me?

10. Mechanisms of Action: Convection
 Convective flux of solutes
 membrane permeability coefficient
 blood hydrostatic pressure
 hydrostatic pressure on ultrafiltrate side
 blood oncotic pressure
 Efficient at removal of larger molecules compared with diffusion
Pressure
Na
H2O H2O + Na

11. Mechanisms of Action: Diffusion
 Solutes flux is a function of
 concentration gradient between the two sides of the semipermeable
membrane
 temperature
 diffusivity coefficient
 membrane thickness
 surface area
Osmolarity
H2O H2O
Osmolarity
Urea Urea
Uremia

12. Modalities of RRT for AKI in ICU
 Intermittent therapies: Intermittent hemodialysis (IHD),
extended daily dialysis (EDD), slow low-efficiency dialysis (SLED)
 Peritoneal Dialysis (PD)
 Continuous Renal Replacement Therapy (CRRT): SCUF, CAVH,
CAVHD, CAVHDF, CVVH, CVVHD, CVVHDF

13. Continuous v/s Intermittent RRT
 Hemodynamic stability
 Superior management of volume
overload and nutritional
requirements
 Clearance of inflammatory
mediators (septic patients,
particularly convective modes of
continuous therapy )
 In acute brain injury or fulminant
hepatic failure, continuous
therapy may be associated with
better preservation of cerebral
perfusion
 Removes much more water and
solute per hour
 Does not require continuous
anticoagulation
 Does not require complete
patient immobilization

14. Definition of CRRT
 CRRT represents a family of modalities
that provide continuous support for
severely ill patients with AKI.
 These include continuous hemofiltration,
hemodialysis, and hemodiafiltration,
which involve both convective and
diffusive therapies.

15. CRRT: AV v.s VV
* Arteriovenous therapies (AV)
- Technique simplicity
- Required large-bore arterial catheter
- Blood flow dependent on MAP
* Venovenous therapies (VV)
- No arterial line
- Pump-assisted
- Blood flow independent of blood pressure

16. Vascular access
 Circuit failure is more often due to inadequacy of the vascular
access than to insufficient anticoagulation
 Cannulation of the right internal jugular vein, with the tip of
the catheter reaching the right atrium, is associated with
circuit blood flow rates of up to 300 mL/min

18. Blood In
Blood Out
to waste (from patient)
(to patient)
HIGH PRESS.LOW PRESS.
Repl.
Solution
CA/VVH
Continuous Veno-Venous Hemofiltration
(Convection)
Post-dilution
Pre-dilution

19. CA/VVHD
• Mid/high flux membranes
• Extended period up to weeks
• Diffusive solute clearance
• Countercurrent dialysate
• UF for volume control
• Blood flow 100-250 ml/min
• UF rate 1-8 ml/min
• Dialysate flow 15-60 ml/min

20. Repl.
Solution
Dialysate
Solution
Blood In
Blood Out
to waste
(from patient)
(to patient)
HIGH PRESSLOW PRESS
HIGH CONC.LOW CONC.
CVVHDF
Continuous Veno-Venous Hemodiafiltration
(Diffusion)
(Convection)

21. Anticoagulation
 Circuit Set-up Optimization
 Unfractioned Heparin
 Low-Molecular-Weight Heparins
 Prostacyclin (PGI2)
 Citrate

22. Anticoagulation
Drug Pro Con
No anticoagulation
High risk of bleeding
patients
Relative shorter circuit
lifespan
Unfractionated heparin Routine HIT
Low-molecular-weight
heparin
Routine (alternative to
UH)
HIT
Prostacyclin Very short circuit lifespan Hypotension
Citrate
Routine/very short circuit
lifespan
Hypocalcemia
Danaparoid HIT Insufficient data available
Argatroban HIT Insufficient data available
Irudine HIT Insufficient data available
Nafamostat mesylate HIT Insufficient data available
Heparin-coated circuits Routine Insufficient data available
UH, unfractionated heparin; HIT, heparin-induced thrombocytopenia.

23. Advantages of using CRRT
 Hemodynamic stability
 Precise volume control
(immediately adaptable to changing circumstances)
 Very effective control of uremia, ↓phosphatemia & ↑K
 Good Control of metabolic acidosis
 Improved nutritional support (full protein diet)
 Available 24 hours a day with minimal training
 Safer in brain injuries and cardiovascular disorders
(particularly diuretic resistant CHF)
 Sepsis ?
 Renal recovery ?

24. Disadvantages of using CRRT
 Expense
 Anticoagulation
 Complications of line insertion and CREBSI
 Risk of line disconnection
 Hypothermia
 Severe depletion of electrolytes –
particularly K+ and PO4, where care is not
taken

25. RRTs in Different Clinical Conditions
 Sepsis and Multiple Organ Dysfunction Syndrome
 Ultrafiltration During Cardiopulmonary Bypass
 Congestive Heart Failure

27. Implications of the available data

28. Management of AKI in ICU
Critical care nephrology is necessary in an intensivist's curriculum
 Fluid balance
 Electrolyte dist.
 Hemodynamic status
(Vasopressor dosage)
 Mechanical ventilation
support
 Arterial blood gas
exchange including
PaO2/FIO2 ratio
 Nutrition
 Inflammation & Infection
(SIRS , Sepsis)
 Coagulopathy( DIC, HIT,
TTP, HUS )
 Trauma , CVA
 GI bleeding
 Recent op.
 Type of RRT
 Time to start & stop RRT
 Dialysis dose
 Ultrafiltration (UF)
requirement
 Anticoagulation strategy
need to be
linked to

29. Convection vs. Diffusion

30. Major Renal Replacement Techniques
Intermittent ContinuousHybrid
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

31. Continuous vs intermittent dialysis
 Ongoing debate
 Theoretical benefits to both
 At least 7 RCTs and 3 meta-analyses have not demonstrated
difference in outcome
 Eg Bagshaw Crit Care Med 2008, 36:610-617:
metaanalysis of 9 randomized trials: No effect on
mortality or recovery to RRT independence
 suggestion that continuous RRT had fewer episodes
of hemodynamic instability and better control of
fluid balance
 May be preferable in specific subpopulations
Vanholder et al. Pro/con debate: Continuous vs intermittent dialysis for acute kidney injury.
Critical Care 2011, 15:204

32. Potential Complications with CRRT
 Technical Clinical
 Vascular access Bleeding
 malfunction Hematomas
 Circuit clotting Thrombosis
 Circuit explosion Infection and sepsis
 Catheter and circuit kinking Allergic reactions
 Insufficient blood flow Hypothermia
 Line-catheter disconnection Nutrient losses
 Fluid balance errors Insufficient blood
purification
 Loss of efficiency Hypotension, arrhythmia

33. What is going on?
 CRRT remains the preferred technique for
most intensivists in Europe INTENSIVE CARE MEDICINE ; jan 2013
 I.D.E.A.L.-I.C.U. (Initiation of Dialysis EArly
Versus Late in Intensive Care Unit) in progress

34. Any ?

35. THANKS FOR YOUR ATTENTION & HAVE A NICE TIME