Continuous Renal Replacement Therapy in Acute Kidney Injury: Pros and Cons

1. Continuous Renal Replacement Therapy in
Acute Kidney Injury:
Pros and Cons
MD, PhD. Head of Extracorporeal Hemocorrection Unit,
National Scientific Medical Research Center, Astana, Kazakhstan
Продленная заместительная почечная терапия
при острой почечной недостаточности:
за и против
Dr Abduzhappar Gaipov

2. Acute Kidney Injury (AKI): definition
AKI is defined as any of the following:
• Increase in SCr by ≥0.3 mg/dl (≥ 26.5 µmol/l)
within 48 hours; or
• Increase in SCr to ≥1.5 times baseline, which is
known or presumed to have occurred within
the prior 7 days; or
• Urine volume <0.5 ml/kg/h for 6 hours.
2012 KDIGO

3. AKI classification systems: RIFLE

4. Staging of AKI (KDIGO 2012)
Kidney International Supplements (2012) 2, 19–36

5. Conceptual model for AKI
Kidney International Supplements (2012) 2, 19–36

6. Evalution of current AKI
Increased frequency of adverse
prognostic forms of AKI:
• Inhospital mortality increased ≥2
times, associated with sepsis,
cardiopulmonary distress and
multiple organ dysfunctions
• Increased group of “AKI on CKD“
• Increased frequency of non-
oligouric AKI (50 - 70% of the AKI)
• Increased number of “catabolic”
form of AKI
High mortality in the
ICU
• Depending on
definition of AKI, up
to 50-60% of patients
in the ICU
• Up to 70% of these
will require RRT
• Independent risk
factor for mortality,
50 - 60% mortality in
critically ill
Curr Opin Nephrol Hypertens. 2007 Mar;16(2):64-70
Current Anaesthesia and Critical Care 2005; 16:321-329

7. AKI after cardiac surgery (n=813)
• According to the RIFLE criteria, 19.3% of
patients had renal impairment after cardiac
surgery.
• a 90-day mortality rate according to RIFLE:
Risk – 8,0%;
Injury – 21,4%;
Failure – 32,5%.
Kuitunen A et al. Ann Thorac Surg 2006; 81:542-546

8. AKI - treatment
• Treatment of AKI is principally supportive -- renal
replacement therapy (RRT) indicated in patients with severe
AKI.
• Goal: optimization of fluid & electrolyte balance
• Paranteral nutrition during the oligouria
• Multiple modalities of RRT:
– Intermittent hemodialysis (IHD),
– continuous renal replacement therapies (CRRTs)
– hybrid therapies, ie sustained low-efficiency dialysis (SLED)

9. Molecuar mechanisms of RRT
Water soluble molecules
“small”
“middle”
“large”
High Flux
Low Flux
Kuf <10 mL/h/mmHg
Kuf >20 mL/h/mmHg
30000-50000 Daltons
< 500 - 600 Daltons
Convection
Water soluble molecules Dialysers Mechanisms
Diffusion

12. ConvectionDiffusion
Diffusion
Convection
Hemodialysis Hemofiltration Hemodiafiltration

13. Modalities of RRT
 SCUF – Slow Continuous Ultrafiltration
 Медленная продолжительная ультрафильтрация
 CVVH – Continuous Venovenous Hemofiltration
 Продолжительная вено-венозная гемофильтрация
 CVVHDF – Continuous Venovenous Hemodiafiltration
 Продолжительная вено-венозная гемодиафильтрация
 SLED – Slow low efficiency dialysis
 Медленный низкой эффективности диализ
 EDD – Extended daily dialysis
 Длительный ежедневный диализ
 IHD – Intermittent hemodialysis
 Интермиттируюший гемодиализ
 IUF – Isolated ultrafiltration
 Изолированная ультрафильтрация
Intermittent
Continuous
Hybrid

14. Sürekli Venovenöz hemofiltrasyon (CVVH)
CVVH clearance (K)
KHF = Qf x S
Qf = Ultrafiltration rate
S = Sieving coefficient
S = Cef/Cb
Cef = Concentration in Effluent
Cb = Concentration in blood

15. Sürekli venovenöz Hemodiyafiltrasyon (CVVHDF)
CVVHDF clearance (K)
KHDF = (Qf x S) + (Qd x Sd)
Qf = Ultrafiltration rate
S = Sieving coefficient
S = Cef/Cb
Cef = Concentration in Effluent
Cb = Concentration in blood
Qd = Dialysate rate
Sd = Dialysate saturation

16. Pre-dilüsyon ve Post dilüsyon
Replasman sıvısı, filtreye girmeden verilir ise
predilüsyon, filtreden sonra verilir ise
postdilüsyon denilir

17. Devices for renal replacement therapy
CRRT machines
Pump #
HD, UF
HD, UF,
HDF-Online,
SLED, EDD
CVVH: pre or
post dilution
CVVH: pre , post
and mixt dilution
CVVHDF: pre or
post dilution
CVVH: pre , post
and mix dilution
CVVHDF: pre, post
and mixt dilution,
Citrate protocole
iHD machines
Pump # Possible modalities

18. Absolute and relative indications to initiate RRT in AKI
Gibney et al, Clin J Am Soc Nephrol 2008

19. CLINICAL PRACTICE GUIDELINES – AKI
Initiation of RRT
UK Renal Association, 5th Edition, 2011
2012 KDIGO

20. CLINICAL PRACTICE GUIDELINES – AKI
Which modality of RRT?
UK Renal Association, 5th Edition, 2011
2012 KDIGO

21. The choice of modalities of RRT
Optimal modality of renal replacement therapy in acute renal failure according to the clinical
status of the patient. IIUF: intermittent isolated ultrafiltration; CEPD: continuous equilibrium
peritoneal dialysis; TPE: therapeutic plasma exchange.

22. The choice of modalities of RRT in Septic patients
Comprehensive Clinical Nephrology: Fourth Edition

23. iHD vs CVVH:
Kinetics of BUN in RRTs

24. Ronco C et al
Nephrol Dial Transplant 13[Suppl 6]:76-85
iHD vs CVVH:
Kinetics of HCO3 in RRTs

25. Ronco C et al
Nephrol Dial Transplant 13[Suppl 6]:76-85
iHD vsCVVH :
Effect on the hydration of brain tissue
Данные компьютерной томографии головного мозга

26. CRRT vs IHD
Prowle, J. R. & Bellomo, R. Nat. Rev. Nephrol. 6, 521–529 (2010)

27. Intermittent versus continuous renal replacement
therapy for acute renal failure in adults
Copyright © 2008 The Cochrane Collaboration. Published by JohnWiley & Sons, Ltd.
15 RCTs with 1550 patients comparing CRRT with IRRT.
MEDLINE,
EMBASE,
Cochrane Central Register of Controlled Trials (CENTRAL)
У гемодинамически стабильных пациентов, вид
заместительной почечной терапии не влиял на важные
исходы лечения пациентов, и поэтому преимущество CRRT
над IRRT у таких больных не обосновано по имеющимся
данным. Пациенты, получившие лечения CRRT имели лучшие
гемодинамикие параметры как СрАД.

28. PROS AND CONS OF DIFFERENT MODALITIES

29. COMPARE AND CONTRAST DIFFERENT MODALITIES
IHD SLEDD CRRT
Name Intermittent hemodialysis
Slow (or sustained) low efficiency
daily dialysis
Continuous renal replacement therapy
Mechanism and
molecules removed
Dialysis – mostly low MWt
Small + middle molecules
with SLEDD/F
Small + middle molecules with
CVVHDF
Use
Ambulatory ESRD
Hyperkalemia
Critically ill
Hyperkalemia
Critically ill
Non-ambulatory
Blood flow 300-400 mL/min 200-300 mL/min 100-200 mL/min
Dialysate flow 500-800 mL/min 1-2L/h 2-3 L/h
Efficiency High Moderate Low
Hemodynamic
stability
Poor
(hypotension common)
Good Good
Duration 3-4 h 3x/week 6-12 h daily Continuous (24h/filter)
Access
Fistula or vascath
(must be good!)
Fistula or vascath
(must be good!)
Vascath only
Anticoagulation Not needed
Usually not needed
(if filter clots lose 150 mL blood)
Important
(if filter clots lose 150 mL blood)
Dialysis
Dysequilibrium
Syndrome (DDS)
Insufficient time for equilibration between
compartments can cause cerebral edema
N/A N/A
Drugs and
toxicology
Risk of rebound if high VD
Better for low VD (e.g. toxic alcohols)
Unclear effects on drug
pharmacokinetics
Slower removal
Logistics
Need tap water supply,
need hygienic effluent
removal, Technically difficult
High start up costs, low familiarity,
low running costs,
Hypophosphatemia
High workload, clearance limited by
interruptions, costly sterile dialysate
bags, immobility

30. Rev colomb anestesiol. 2013;41(2):88–96

31. Kidney International (2006) 70, 963–968.

32. Kitchlu et al. BMC Nephrology (2015) 16:127

34. Quality indicator of CRRT and measures
Indicators Measures
Dose prescription High vs. low dose
Dose delivery Percentage of prescribed dose delivered
Anticoagulation selection Heparin vs. citrate vs. none
Anticoagulation monitoring PTT monitoring, citrate monitoring
Anticoagulation complications Bleeding, hypocalcaemia, incidence of HIT
Treatment interruption
Number of interruptions and duration of
interruptions; time to establish new circuit
Catheter-related issues Infections, bleeding, obstruction/thrombosis
Circuit-related issues Filter clotting, pressure alarming
Rewa et al. Systematic Reviews (2015) 4:102

35. CRRT: What is new in 2015 ?

36. Stucker et al. Critical Care (2015) 19:91

37. J Crit Care. 2015 Jun 26.

40. Conclusion: A well-trained CRRT team could be beneficial for mortality
improvement of AKI patients requiring CRRT.

41. CLINICAL PRACTICE GUIDELINES - AKI
Treatment facilities & referral to renal services
• Guideline 5.1- Renal services should work together with other
specialties to develop guidelines for the management of AKI.
These should include clear guidelines with respect to when to
request a renal referral. (1A)
• Guideline 5.2 – Specialist renal advice should be given with
consultant renal physician input. (1B)
• Guideline 5.5 – Renal physicians and intensivists should work
together to provide care for patients with AKI on the intensive
care unit (ICU). Nephrology trainees should be trained to care for
acutely ill patients with AKI. (2C)
UK Renal Association, 5th Edition, 2011

42. Thank you for attention