1. Andrew Durward
St Thomas NHS Foundation Trust
Orlando 2017
CRRT IN AKI

2. Why use renal replacement in AKI?
AKI In critically ill is common >30%
Mortality with AKI increased (40-50%)
sepsis
Macedo Nephrol Dial Transplant 2010

3. Untreated AKI – is CCRT harmful
29 vs 43% sepsis
Schneider A G et al. Nephrol. Dial. Transplant. 2012;27:

4. CCRT in AKI – Benefit? Mortality benefit? With or with kidney injury ?
Mechanism benefit?
Dialysis mode benefit ?
GENETICS?

5. Treatment bundles – Outcomes in Sepsis
Over 1 million adult patients
(171 ICU’s Australia / NZ)
Absolute mortality in severe sepsis
35% to 18% in 2012
(1.3% reduction per year)
ARF
55%
ARF
35%
Giving antibiotics quicker
8% increase death / hour delay
CCM 2006;34:

6. Paediatric sepsis 2002 – 2012 (Australia / NZ)
97127 children
2.9% sepsis
2.1% septic shock
Mortality severe sepsis unchanged
19%
15%
Lancet Infect Dis 2015;15: 46–54

7. What are we trying to dialyse ?
Fluid overload
Electrolyte balance (Na/K/Ca/Phos)
3) Acid base balance
4) Waste products (Urea / Ammonia)
5) Cytokines (sepsis)
6) Mystical blood purification

8. Why are we using CCRT? Fluid overload
Electrolyte balance (Na/K/Ca/Phos)
3) Acid base balance
4) Waste products (Urea / Ammonia)
5) Cytokines (sepsis)
6) Mystical blood purification

9. Fluid overload and mortality risk
N=297 children
Multicentre
3% mortality per 1% increase fluid overload
Sepsis 25% % %

10. Which mode renal replacement in AKI
All modes work in AKI
Peritoneal
Continuous Renal Replacement
Intermittent Haemodialysis
Patient size
Vascular access
Expertise and skill
Use the mode you have experience with

11. Wide variation in practice
Not evidence based
No co-ordinated “plan of attack”

12. CVVHD vs CVVH CVVHD CVVH predilution Post dilution Dialysate filtrate

13. Blood flow rate vs solute clearance

14. Blood flow rate vs solute clearance

15. Bigger dialysis dose is better?

16. Mode dialysis in sepsis: CVVH vs CVVHD
Acute Kidney Injury (OMAKI) Canadian Trial group
CVVH vs CVVHD n=78 adults (80% sepsis)
Same dialysis dose of 35ml/kg/hr effluent rate
No difference mortality
CVVH / %
CVVHD 10/ %
Wald et al. Critical Care 2012, 16:R205

17. Dose dialysis in sepsis: No effect
RENAL study (n=1508) NEJM 2009
CVVHDF 25ml/kg vs 40ml/kg/hr
No difference mortality
Tolwani (n=200) J Am Soc Neph 2008
CVVHDF 20ml/kg vs 35ml/kg/hr
No difference mortality
NIH ATN (n=1124) NEJM 2008
CVVHDF 35ml/kg vs 20ml/kg/hr

18. Sieving coefficients

19. Nitrogen loss N=6 children BFR 4ml/kg/min
11-12% Amino acids lost of dialy intake
Maxfold CCM 28(4):1161-5

20. ECMO in AKI N=154 children CVVH On ECMO (44%) N=43 children ECMO
44% survived
26% Ongoing CCRT
96% recovered renal function at discharge
N=43 children ECMO
32% needed dialysis for ARF (double creatinine)
Survival only 19%
vs 92% if no renal injury
Weber Ann Thorac Surg. Nov; (5):720–3
Padden Pediatr Crit Care Med. 2011; 12(2): 153–158

21. CRRT Efficiency - Blood flow rate
400
200
100

22. Blood flow rate issues in children: Efficacy
Blood flow rate dependence:
Getting most of filter performance
2mm
4mm

23. CRRT Efficiency - Recirculation
long femoral 25cm
Short femoral 15cm
Internal Jugular
Subclavian

24. 15cm short femoral
Internal Jugular, Subclavian,
Long femoral 25cm

25. Could CRRT Be harmful?
n=76 adults sepsis CVVH (35ml/kg/hr) vs standard care
Worse organ failure scores with CVVH
Longer ventilation and inotrope need
Worsening SOFA Score
Time to death
Payen Crit Care Med 2009; 37:803–810

26. Conclusion CRRT is effective therapy for AKI
Use CCRT to achieve target goal
Modality less important (CVVH vs CVVHD)
Optimal Dose and Timing of CCRT unknown