Decision making in acute dialysis

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1 Decision making in acute dialysis Geoffrey Bihl MB.BCh M.MED FCP(SA) Nephrologist and Director Winelands Kidney and Dialysis Centre Somerset West South Africa

2 Important questions in AKI What is the cause? Pre-renal Primary renal Obstructive Combination/Acute on chronic SONAR EVERY PATIENT WITH ARF URINALYSIS IN EVERY PATIENT P:CR ratio; Microscopy

3 Important questions in AKI Can I manage the AKI without dialysis? Fluids Remove or treat primary cause Avoid further nephrotoxins in ICU Anti-biotics/analgesics/Contrast Blood pressure management Sodium bicarbonate in acidosis

4 Differences Between Renal Support in AKI and ESRD Time-frame Days to weeks versus years Burden of concomitant illness Hemodynamic instability Recoverability of kidney function

5 Renal Replacement Therapy in Acute Kidney Injury When should renal replacement therapy be initiated in AKI? Which modality is most appropriate? What is the appropriate dose of therapy?

6 Renal Replacement Therapy in Acute Kidney Injury When should renal replacement therapy be initiated in AKI? Which modality is most appropriate? What is the appropriate dose of therapy?

7 Timing of RRT While there is increasing recognition of the value of earlier dialysis, the published consensus, and the practice in many centers at present, is still to apply dialysis to relatively ill rather than to relatively healthy patients Teschan PE, et al: Ann Intern Med 1960; 53:

8 KDIGO Acute Kidney Injury Clinical Practice Guidelines 5.1.1: Initiate RRT emergently when lifethreatening changes in fluid, electrolyte, and acid-base balance exist (Not Graded) 5.1.2: Consider the broad clinical context, the presence of conditions that can be modified with RRT, and trends of laboratory tests rather than single U&E thresholds alone when making the decision to start RRT (Not Graded)

9 Classic indications for Acute renal support Volume overload unresponsive to medical therapy Metabolic acidosis unresponsive to medical therapy Hyperkalemia unresponsive to medical therapy Uremic state Encephalopathy Pericarditis Azotemia without uremic manifestations Oliguria unresponsive to medical therapy

10 Dialysis Prescription in acutely ill patient requires assessment of the: Fluid Balance Status Acid-Base Status Respiratory Status / Ventilation parameters Cardiac Status Coagulation Status Central Nervous System Status Haemodynamic Status Inflammation Status

11 Dialysis Prescription in acutely ill patient requires assessment of the: Fluid Balance Status Acid-Base Status Respiratory Status / Ventilation parameters Cardiac Status Coagulation Status Central Nervous System Status Haemodynamic Status Inflammation Status

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14 PICARD Study: Impact of Fluid Overload at Initiation of RRT Bouchard J, et al. Kidney Int 2009; 76:

15 Dialysis Prescription in acutely ill patient Choice of Dialysis Mode Duration of procedure Dialyser (Filter) Parameters Dialysate (Fluid) Parameters including i. Sodium concentration / modeling ii. Potassium concentration iii. Calcium concentration iv. Bicarbonate / Acetate concentration v. Temperature vi. Pumps speed vii. Anticoagulation regimen viii. Ultrafiltration volume / modeling ix. Management of Haemodynamic instability x. Transfusion instructions xi. Intradialytic Parenteral Nutrition (if required)

16 Renal Replacement Therapy in Acute Kidney Injury When should renal replacement therapy be initiated in AKI? Which modality is most appropriate? What is the appropriate dose of therapy?

17 Modalities of treatment Intermittent hemodialysis Continuous therapies Continuous hemofiltration Continuous hemodialysis Continuous hemodiafiltration Prolonged intermittent RRT Peritoneal dialysis

18 Continuous vs. Intermittent Therapy in Acute Kidney Injury CRRT IHD p N Apache II NS Apache III ICU Mortality 59.5% Hospital mortality ICU stay NS Renal recovery 34% 33% NS Mehta R, et al: Kidney Int 2001; 60:

19 Continuous vs. Intermittent Therapy in Acute Kidney Injury CRRT IHD p N CCF score NS Mortality NS ICU Mortality 59.5% 41.5% NS Mean LOS Survivors NS Non-survivors NS Renal recovery 12.5% 10% NS Augustine JJ, et al. Am J Kidney Dis 2004; 44:

20 Continuous vs. Intermittent Therapy in Acute Kidney Injury CRRT IHD p N ICU Mortality 34% 38% NS Hospital Mortality 47% 51% NS Uehlinger DE, et al. Nephrol Dial Transplant :

21 CRRT vs. IHD in Acute Kidney Injury: Hemodiafe Study Vinsonneau C,, et al: Lancet 2006; 368:

22 CRRT vs. IHD in Acute Kidney Injury: SHARF Study Lins RL, et al. Nephrol Dial Transplant 2009; 24:

23 Meta-analysis of Studies Comparing IHD to CRRT Bagshaw SM, et al. Crit Care Med 2008; 36:

24 Issues in Specific Clinical Settings CRRT may better To protect cerebral perfusion in patients with: Fulmanent hepatic failure Acute brain injury Cerebral edema

25 Prolonged Intermittent Renal Replacement Therapies Extended Daily Dialysis (EDD) Sustained low-efficiency dialysis (SLED)

26 SLEDD Apparent less effect on haemodynamic profile Affords judicious fluid removal Excellent for ph correction Good solute removal Can be performed overnight Requires prolonged anti-coagulation

27 SLEDD versus CVVHDF

28 Renal Replacement Therapy in Acute Kidney Injury When should renal replacement therapy be initiated in AKI? Which modality is most appropriate? What is the appropriate dose of therapy?

29 Dose of CVVHDF in ARF % 57% 58% % Survival ml/kg/h ml/kg/h ml/kg/h Ronco C, et al: Lancet 2000; 356:26-30

30 Renal Replacement Therapy in AKI: Dose of CRRT 24±6 ml/kg/h 25±5 ml/kg/h p = Saudan P, et al. Kidney Int 2006; 70:

31 ANZICS RENAL Study: 90-Day Survival 40ml/kg/h 25ml/kg/h Bellomo R, et al. N Engl J Med 2009; 361:

32 RRT Dose and Survival Dose Survival Dependent Dose Independent RRT dose

33 So what do we do?

34 ? There are insufficient data to determine the optimal timing of RRT in AKI Clinical trials to evaluate timing need to include patients who meet criteria for early initiation but recover or die without receiving RRT. Although severity of fluid overload is strongly associated with adverse outcomes, there are insufficient data to conclude that initiation of therapy based on severity of fluid overload decreases mortality

35 So... Studies comparing modalities of RRT in AKI have not demonstrated superiority of any individual modality Selection of modality should be guided by expertise and resources available at the individual institution

36 KDIGO Acute Kidney Injury Clinical Practice Guidelines 5.6.1: Use continuous and intermittent RRT as complementary therapies in AKI patients. (Not Graded) 5.6.2: We suggest using CRRT, rather than standard intermittent RRT, for hemodynamically unstable patients. (2B) 5.6.3: We suggest using CRRT, rather than intermittent RRT, for AKI patients with acute brain injury or other causes of increased intracranial pressure or generalized brain edema. (2B)

37 Therefore... Consider NOT dialysing Individualise patients Assess haemodynamic stability and fluid status Manage precipitating cause Consider de-escalating frequency and changing modality when stabilised

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