decision making in acute dialysis - physician in acute dialysis - dr bihl.pdf · azotemia without...
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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
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
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
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
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?
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?
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; 53:992-1016
KDIGO Acute Kidney Injury Clinical
Practice Guidelines
5.1.1: Initiate RRT emergently when life-
threatening 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)
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
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
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
PICARD Study: Impact of Fluid Overload at
Initiation of RRT
Bouchard J, et al. Kidney Int 2009; 76: 422-427
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)
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?
Modalities of treatment
Intermittent hemodialysis
Continuous therapies
Continuous hemofiltration
Continuous hemodialysis
Continuous hemodiafiltration
Prolonged intermittent RRT
Peritoneal dialysis
Continuous vs. Intermittent Therapy in
Acute Kidney Injury
CRRT IHD p
N 84 82
Apache II 23.7 25.5 NS
Apache III 96.4 87.5 0.045
ICU Mortality 59.5% 41.5 0.02
Hospital mortality 65.5 47.5 0.02
ICU stay 15.1 16.7 NS
Renal recovery 34% 33% NS
Mehta R, et al: Kidney Int 2001; 60:1154-1163
Continuous vs. Intermittent Therapy in
Acute Kidney Injury
CRRT IHD p
N 40 40
CCF score 11.6 12.0 NS
Mortality 67.5 70.0 NS
ICU Mortality 59.5% 41.5% NS
Mean LOS
Survivors 35.8 41.9 NS
Non-survivors 14.3 10.4 NS
Renal recovery 12.5% 10% NS
Augustine JJ, et al. Am J Kidney Dis 2004; 44:1000-1007
Continuous vs. Intermittent Therapy in
Acute Kidney Injury
CRRT IHD p
N 70 55
ICU Mortality 34% 38% NS
Hospital Mortality 47% 51% NS
Uehlinger DE, et al. Nephrol Dial Transplant 2005 20: 1630-1637
CRRT vs. IHD in Acute Kidney Injury:
Hemodiafe Study
Vinsonneau C,, et al: Lancet 2006; 368:379-385
CRRT vs. IHD in Acute Kidney Injury: SHARF Study
Lins RL, et al. Nephrol Dial Transplant 2009; 24:512-518
Meta-analysis of Studies Comparing IHD to CRRT
Bagshaw SM, et al. Crit Care Med 2008; 36: 610-617
Issues in Specific Clinical Settings
CRRT may better
– To protect cerebral perfusion in patients
with:
– Fulmanent hepatic failure
– Acute brain injury
– Cerebral edema
Prolonged Intermittent Renal
Replacement Therapies
Extended Daily Dialysis (EDD)
Sustained low-efficiency dialysis (SLED)
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
SLEDD versus CVVHDF
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?
Dose of CVVHDF in ARF
0
10
20
30
40
50
60
20 35 40
% Survival
Ronco C, et al: Lancet 2000; 356:26-30
41% 57% 58%
ml/kg/h ml/kg/h ml/kg/h
Renal Replacement Therapy in
AKI: Dose of CRRT
24±6 ml/kg/h
25±5 ml/kg/h
Saudan P, et al. Kidney Int 2006; 70:1312-1317
p = 0.005
ANZICS RENAL Study: 90-Day
Survival
Bellomo R, et al. N Engl J Med 2009; 361: 1627-1638
40ml/kg/h
25ml/kg/h
RRT Dose and Survival
Survival
RRT dose
Dose
Dependent
Dose
Independent
So what do we do?
?
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
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
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)
Therefore...
Consider NOT dialysing
Individualise patients
Assess haemodynamic stability and fluid
status
Manage precipitating cause
Consider de-escalating frequency and
changing modality when stabilised