continous versus intermittent RRT in the ICU

1. Continuous vs. intermittent RRT in the ICU
Salwa Ibrahim, MD FRCPE
Professor of Nephrology

2. Agenda
• Introduction
• Modalities of CRRT
• Clinical and laboratory effects of
CRRT
• Outcome and cost analysis
• SLED therapy
• Take home message

3. Introduction
• Before the introduction of hemodialysis, the mortality rates of ARF
were 90% -100%
• After that, the mortality of ARF improved to around 50% to 70%
• Those figures have not changed much during the last 3 decades
• IHD frequently induces hemodynamic instability and some patients
could not safely complete dialysis therapy

4. Kramer 1977 first described CRRT for critically ill
patients

5. Is an extracorporeal blood purification therapy intended to
substitute impaired renal function over an extended period of
time and applied for 24 hours a day
– Bellomo R., Ronco C., Mehta R, Nomenclature for Continuous Renal
Replacement Therapies, AJKD, Vol 28, No. 5, Suppl 3, November 1996
Continuous Renal Replacement Therapy (CRRT)

6. CRRT Modalities

8. 20-25 ml/kg/hour

12. Potential advantages of CRRT
• CRRT by its lower rate of fluid removal can be used in
hemodynamically unstable, critically ill patients with
associated comorbid conditions eg. M.I, ARDS , sepsis
• CRRT can help in administration of parenteral nutrition and
inotropes through continuous ultrafiltration

13. Potential advantages of CRRT
• Hemofiltration modality may be effective in lowering
intracranial Pressure v/s IHD which sometimes raises ICP
• Proinflammtory mediators of inflammation were shown to
have been removed by this modality eg.IL-1, IL-6, IL-8, TNF-a

14. Effect on Hemodynamics

15. Hemodynamic parameters (systemic arterial pressure [SAP],
cardiac index [CI]) significantly increased during treatment and
norepinephrine doses decreased significantly

16. Intracranial pressure

17. ICP increases with IHD

18. ICP remained stable during CVVH

19. CYTOKINE REMOVAL

20. The plasma concentrations of the inflammatory cytokines
decreased significantly in the first hour but No decreases were observed at other
time points

21. Outcome analysis

22. How to make unbiased clinical decisions
• Decisions in health care are being
made on the basis of research based
evidence rather expert opinion or
clinical experience alone
• Randomized clinical trials involving
large numbers of patients can provide
strong evidence to support or decline a
modality of therapy
• Structured systematic reviews (meta-
analyses) can provide the highest
standard of evidence

23. Evidence from randomized controlled trials

24. A total of 360 critically ill casesA total of 360 critically ill cases
Were randomly assigned toWere randomly assigned to
Either CRRT or IHDEither CRRT or IHD
60 days survival was 32% in60 days survival was 32% in
IHD and 33% in CRRT groupsIHD and 33% in CRRT groups

25. Evidence from observational studies

26. • This metanylsis showed that no
significant differences in mortality
between those treated with CRRT vs.
IHD
• Earlier studies favor CRRT as IHD was
delivered using cellulose membrane and
acetate based dialysate
• Late studies favor IHD as more
A. Biocompatible membranes were used
B. Volumetric controlled machines
C. Lower dialysate temperature and flow
rates and
D. Bicarbonate dialysis

27. Evidence from systematic Review

29. No differences in mortality rates between the two groups

30. No differences in recovery rates of renal Function

31. No differences in hemodynamic stability

32. Higher incidence of clotting problems in CRRT group

33. Complications of CRRT

34. Potential risks of CRRT
• Bleeding risk
• Clotting of lines and filters
• Increased blood loss and anemia
• Expensive
• Needs special training of staff

35. Slow low Efficiency Dialysis

36. SLEDD
• Slow low efficiency daily dialysis was introduced as a hybrid therapy
that mix the benefits of CRRT with the economics of IHD
• Daily sessions for 6-12 hours
• BFR 150 -250 ml/m
• DFR 100-350 ml/min
• Traditional dialysis machine
• Heparin anticoagulation /Saline flushes

37. CRRT vs. SLED

38. Hemodynamic stability

40. SLED therapies were more frequently associated with >20 % decline
in MAP but Pressor dose escalation was observed more with CRRT

41. Survival analysis

43. Treatment assignment
• Patients allocated to SLED were assigned to receive 12-h of
dialysis with a blood flow rate of 100 to 120 ml/min with high-flux
polysulfone filters
• Patients assigned to the CVVH-group were treated with 35 ml/kg
per hour replacement fluid. Treatment was scheduled for 24-h and
blood flow was maintained between 100 and 120 ml/min with high-
flux polysulfone filters
Schwenger et al. Critical Care 2012

44. No significant difference in survival among SLED and CRRT groups
Schwenger et al. Critical Care 2012

45. C-SLED

48. A COST ANALYSIS OF CRRT VS. SLEDA COST ANALYSIS OF CRRT VS. SLED

49. ItemItem
SLEDSLED CRRTCRRT
Machine
$22,000.00$22,000.00 $42,000.00$42,000.00
R/O Consumables $300.00
Endotoxin Filter $155.00
Dialysis Filter $55.00 $265.00
Blood Lines $32.00
Concentrate $34.00 N/A
Hemofiltration Fluids N/A $38.50
Daily CostsDaily Costs $140.00$140.00 $642.00$642.00

50. • There is no evidence that CRRT results in better survival compared
to IHD and SLED
• The only potential advantage of CRRT (higher MAP) can be offered
By SLEDD as well
• SLEDD is less expensive technique as the same infrastructure is
used
Key Message