1. Shiraz Medical University
Faghihi Hospital
Dr-Ramin Radmehr
Dr R - Radmehr

2. Sustained Low Efficacy Daily Dialysis
SLEDD

3. TOPICS Introduction RRT in ICU (( SLED )) definition
Comparison and outcome
Conclusions
Questions
Dr R - Radmehr

4. Acute Kidney Injury in the ICU
AKI is common : 3-35%* of admissions
AKI is associated with increased mortality
“Minor” rises in Cr associated with worse outcome
AKI developing after ICU admission (late) is associated with worse outcome than AKI at admission.
AKI requiring RRT occurs in about 4-5% of ICU admissions and is associated with worst mortality risk **
* Brivet, FG et al. Crit Care Med 1996; 24:
** Metnitz, PG et al. Crit Care Med 2002; 30:
Dr R - Radmehr
Dr R-Radmehr

5. Mortality by AKI Severity
Dr R - Radmehr
Clermont, G et al. Kidney International 2002; 62:
Dr R-Radmehr

6. RRT for Acute Renal Failure
There is some evidence for a relationship between higher therapy dose and better outcome, at least up to a point
-This is true for IHD* and for CVVH**
There is no definitive evidence for superiority of one therapy over another, and wide practice variation exists***
Accepted indications for RRT vary
No definitive evidence on timing of RRT
Dr R - Radmehr
Dr R-Radmehr

7. AKI classification systems 1: RIFLE
Dr R - Radmehr
Dr R-Radmehr

8. Proposed Indications for RRT
Oliguria < 200ml/12 hours
Anuria < 50 ml/12 hours
Hyperkalaemia > 6.5 mmol/L
Severe acidaemia pH < 7.0
Uraemia > 30 mmol/L
Uraemic complications
Dysnatraemias > 155 or < 120 mmol/L
Drug overdose with dialysable drug
Dr R - Radmehr
Dr R-Radmehr

9. Major Renal Replacement Techniques
Intermittent
Hybrid
Continuous
CVVH
Continuous veno-venous haemofiltration
IHD
Intermittent haemodialysis
SLEDD
Sustained (or slow) low efficiency daily dialysis
IUF
Isolated Ultrafiltration
CVVHD
Continuous veno-venous haemodialysis
SLEDD-F
Sustained (or slow) low efficiency daily dialysis with filtration
CVVHDF
Continuous veno-venous haemodiafiltration
SCUF
Slow continuous ultrafiltration
Dr R - Radmehr
Dr R-Radmehr

10. Sustained Low Efficacy Dialysis
Hybrid technicque that is alternative to Intermittent Hemo Dialysis and CRRT
((SLED))
Dr R - Radmehr

11. Dr R - Radmehr

12. Intermittent hemodialysis (IHD)
Advantages
Disadvantages
- short duration
- less labour intensive
- less anticoagulation > less bleeding
- optional bicarbonate dialysate production
- better in high K+
- technically difficult
- requires hygienic removal of effluent
- requires a fresh water supply
- more electrolyte disequilibrium
- cardiovascular instability
- requires trained personnel
Cerebral edema
Hypotention
Dr R - Radmehr

13. Intradialytic Hypotension: Risk Factors
LVH with diastolic dysfunction or LV systolic dysfunction / CHF
Valvular heart disease
Pericardial disease
Poor nutritional status / hypoalbuminaemia
Uraemic neuropathy or autonomic dysfunction
Severe anaemia
High volume ultrafiltration requirements
Predialysis SBP of <100 mm Hg
Age 65 years +
Pressor requirement
Dr R - Radmehr

14. CRRT - haemodynamic stability - easy to operate
Advantages
Disadvantages
- haemodynamic stability
- easy to operate
- adequate nutritional support possible
- superior solute and volume control
- requires anticoagulation
- mobilization of patients difficult
- sterile haemofiltration fluid > cost ++
- no as good in hyperK+ as IHD
Dr R - Radmehr

15. SLED - easy to perform - flexible timing for treatments
Advantages
Disadvantages
- easy to perform
- flexible timing for treatments
- 12 hour or overnight treatments
- increased patient mobility and access
- procedural simplicity
- clinical unfamiliarity
- hypophosphataemia
- unknown effects on clearance of drugs
- hypothermia
Dr R - Radmehr

16. SLED SLED - clinical unfamiliarity - hypophosphataemia
Advantages
Disadvantages
- cardiovascular stability comparable to CRRT
- small molecule clearance comparable to IHD and CRRT
- less anticoagulation required (air free tubing)
- composition of dialysate easily modified
- clinical unfamiliarity
- hypophosphataemia
- unknown effects on clearance of drugs
- hypothermia
Dr R - Radmehr

17. SLED SLED - clinical unfamiliarity - hypophosphataemia
Advantages
Advantages
Disadvantages
Disadvantages
- effective in hyperkalaemia
- no mortality difference when compared to CRRT
- able to use SLEDD-F = sustained low efficiency daily diafiltration -> removal of middle sized molecules in SIRS
- clinical unfamiliarity
- hypophosphataemia
- unknown effects on clearance of drugs
- hypothermia
Dr R - Radmehr

18. SLED
SLED
Advantages
Advantages
Disadvantages
Disadvantages
- in RRT for toxins it reduces rebound intoxication after ceasing of RRT
- no bag handling -> decreased infection risk
- cheaper than CRRT
- clinical unfamiliarity
- hypophosphataemia
- unknown effects on clearance of drugs
- hypothermia
Dr R - Radmehr

19. Kinetic Modelling of Solute Clearance
CVVH (predilution)
Daily IHD
SLED
Urea TAC (mg/ml)
40.3
64.6
43.4
Urea EKR (ml/min)
33.8
21.1
31.3
Inulin TAC (mg/L)
25.4
55.5
99.4
Inulin EKR (ml/min)
11.8
5.4
3.0
b2 microglobulin TAC (mg/L)
9.4
24.2
b2 microglobulin EKR (ml/min)
18.2
7.0
4.2
TAC = time-averaged concentration (from area under concentration-time curve)
EKR = equivalent renal clearance
Inulin represents middle molecule and b2 microglobulin large molecule.
CVVH has marked effects on middle and large molecule clearance not seen with IHD/SLED
SLED and CVVH have equivalent small molecule clearance
Daily IHD has acceptable small molecule clearance
Dr R - Radmehr
Dr R-Radmehr

20. 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: : metaanalysis of 9 randomized trials: No effect on mortality (OR 0.99) or recovery to RRT independence (OR 0.76).
suggestion that continuous RRT had fewer episodes of hemodynamic instability and better control of fluid balance
Continuous RRT is preferable in Unstable patients
Recent research shows more renal recovery in Continuous espiscially CRRT
Dr R - Radmehr
Vanholder et al. Pro/con debate: Continuous vs intermittent dialysis for acute kidney injury. Critical Care 2011, 15:204

21. Continuous RRT
Theoretical advantage of more hemodynamic stability allowing more adequate fluid removal
Metaanalysis of 15 RCTs (Rabindranath Cochrane Rev 2007, 3): no difference between CRRT and IRRT in haemodynamic instability or hypotension / escalation of pressors, or mortality or RRT independence.
Patients on CRRT had significantly higher MAP
However most trials excluded pts with major hemodynamic issues
Some RCTs (but not all) show more negative fluid balances with CRRT vs IRRT
Dr R - Radmehr
Dr R-Radmehr

22. Conclusions SLEDD is the most flexible and cheaper
AKI in the ICU is common and associated with high mortality
The best time to initiate and stop RRT is controversial
No good data that CRRT is better than IRRT in the ICU, except for a few specific situations :
Consider CRRT if severely unstable pts, severe volume overload, combined renal/hepatic failure
IRRT best if bleeding risk or acute hyperkalemia/poisoning ( Stable BP )
Renal recovery in CRRT is more probable due to better perfusion status
CVVH is the best in Sepsis due to its mechanism.
SLEDD is the most flexible and cheaper
Dr R - Radmehr

23. Best wishes
Dr R - Radmehr