Crrt indications and modalities [autosaved]

Prof Yasser M. Abdelhamid MD
Professor of Nephrology
Cairo University
Prof. Yasse Abdelhamid

• 80% of patients with AKI in the ICU are
currently treated with continuous therapies,
• 17% with intermittent Therapies
• 3% with peritoneal dialysis or slow continuous
ultrafiltration
(Uchino et al, Intensive Care Med, 2007)

• Hemodynamic stability of the critically ill
patient is the main determinant of the choice
of dialysis modality
(Palevsky et al, N Engl J Med, 2008)

Advantages of CRRT
 Hemodynamic Stability
 Recovery of Renal Function
 Correction of Metabolic Acidosis
 Biocompatibility
 Correction of Malnutrition
 Removal of Cytokines
 Solute Removal

• Gradual
• Gradual removal of solutes and metabolic
waste helps to clear inflammatory mediators
and ensure adequate nutrition for patients

IHD or CRRT
Deepa and Muralidhar, J Anaesthiology clin Pharmcol,2012,386-396Prof. Yasse Abdelhamid

Why
• Maintenance of intravascular compartment volume
• Prolonged treatments permit lower fluid removal rates
– IHD: 3 L in 3 hours = 1 L/h UF rate
– CRRT: 3 L in 24 hrs = 0.125 ml/h UF rate
• Urea diffusion is faster with IHD than CRRT
– IHD: Urea clearance ~160 ml/min
– CRRT: Urea clearance ~15-30 ml/min
• Convective sodium removal rate
[hemofiltration/hemodiafiltration] is less than diffusive
removal rate [hemodialysis]
• Decreased core temperature.
• Convective removal of inflammatory mediators could
contribute to hemodynamic stability.

Renal Recovery
• Forty-nine studies were included
• Conclusion: Findings of the conducted
assessment show that initial CRRT is
associated with higher rates of renal recovery.
Potential long term effects on clinical
outcomes for more than three months could
not be analyzed and should be investigated in
further studies Prof. Yasse Abdelhamid

AGENDA
 Principles
 Indications
 Modalities

• CRRT Principles

• All available RRT rely on two basic principles,
-Diffusion and Convection.
• Dialysis depends primarily on diffusion, while
hemofiltration uses convection.
• The two modalities may be combined (CVVHDF)
Principles

• Convection is used for higher than 1000 kDa
up to several thousand kDa
Principles

• Adsorption:
Principles

Intermittent Hemodialysis
 Diffusion.
 High clearance for
 small molecules
 Dialysate
 High dialysate flow.
 May be no anticoagulationProf. Yasse Abdelhamid

CRRT (SLOW, Continuous)
 Convection + Diffusion.
 Small and middle
molecules
 Use of substitution fluid.
 Continuous
anticoagulation.

CRRT Circuit
Dose

• Limitations to use Kt/V in critically ill:
• High catabolic rate.
• Variable fluid volumes,
• Post-dialysis “rebound "of urea from hypo
perfused organs.
Dose of Dialysis (IHD)

• A significant survival benefit was seen in
patients who received middle (35 mL/kg/h)
and high ultrafiltration rates (45 mL/kg/h)
versus the low filtration (20 mL/kg/h rate)
group.
• No difference between the middle and high
filtration rate groups.
Ronco C, Bellomo R, Hommel P, et al. Effects of different doses in continuous veno-venous
hemofiltration on outcomes in acute renalfailure: A prospective, randomized trial.
Lancet2000;355:26-30.
Dose of Dialysis (CRRT)

Dose of Dialysis (CRRT)
In critically ill patients with acute kidney injury,
treatment with higher-intensity continuous renal-
replacement therapy did not reduce mortality at
90 days.

Dose of Dialysis (IHD)
• Intensive renal support
involving IHD, SLEDD 6
times / wk or CVVHDF
at 35 ml/kg/h in
critically ill patients with
AKI.
• As compared with less-
intensive therapy
involving a defined dose
of IHD 3 times per week
or CRRT at 20 ml/kg/h.
Did not decrease mortality, improve recovery of kidney
function, or reduce the rate of non-renal organ failure.

CRRT Membrane
• High-flux: high
permeability for water
• Low- and middle-
molecular weight
solutes (in the range of
1000–12,000Daltons)
• High ‘‘biocompatibility.’’

Replacement Methods
• Hemoconcentration
• Filter life
• Anticoagulation
• Convection
• Solute Clearance
• UF amount

Anticoagulation
Drug Pro Cons
No anticoagulation No risk of bleeding Clotting
Short time circiut
Unfractionated heparin Routine Risk of bleeding
HIT
LMWH Could be used Risk of bleeding
HIT
Citrate Regional Hypocalcemia
Prostacyclin Short circuit life span Hypotension
New anticoagulants Insufficient data

• INDICATIONS

Absolute Indications
– Hyperkalemia >6 mEq/l with ECG
abnormalities
– pH <7.15
– Uremic complications (encephalopathy /
pericarditis)
– Fluid overload (diuretic resistant)
– Lactic acidosis related to metformin use
– Hypermagnesemia with anuria and absent
deep tendon reflexes
INDICATIONS

Relative indications:
–Fluid overload (diuretic sensitive)
–BUN >76 mg/dl (27 mmol/l)
–[Serum Na+] < 110 and >160 mmol/L
–Oligurea: RIFLE class R, I, F.
INDICATIONS

Figure 1
Kidney International 2009 76, 422-427DOI: (10.1038/ki.2009.159)
Copyright © 2009 International Society of Nephrology Terms and Conditions

Figure 2

Figure 3

Figure 4

Non Renal Indications (ICU)
• Cardiac failure.
• Large amount of IV intake.
• Hyperthermia (core temperature >39.5°C) or
hypothermia (core temperature <37°C)
• Overdose with a dialyzable toxin (e.g. Lithium)

•
– Hemodynamic instability
– Combined acute renal and hepatic failure
– Acute brain injury: Decreases cerebral edema
Non Renal Indications (ICU)

• Patients with intra cranial hypertension or cerebral edema
– Autoregulation is lost!
– Sudden changes in systemic or intra-abdominal pressure change
intracranial pressure
• Patients with abdominal compartment syndrome
• Correct azotemia slowly, to avoid dialysis disequilibrium
and worsened brain edema
• Urea protects against osmotic demyelination syndrome
• Patients with hyponatremia
– Correct Na very slowly to avoid osmotic demyelination
syndrome
Special Circumstances

Special Circumstances
• Acute fulminant liver failure or acute-on chronic
liver failure
• Partly determined by brain edema, so avoid brain
swelling
• Hyponatremia is common, causes brain edema
• Low blood urea concentration increases risk of
ODS.

• Initially, high volume hemofiltration offered
benefit over conventional hemodialysis.
• Meta-analysis (IVOIRE) suggested no
benefit (Borthwick et al, Cochrane Database Syst Rev. 2013, Joannes-Boyau et
al Intensive Care Med. 2013)
• High dose 80ml/kg/h was found to decrease level
of IL 1B, 6, 8 and 10 with no effect on mortality
than conventional dos of 40ml/kg/h
(Park et al, Am J Kidney Dis, 2016)
CRRT and Sepsis

• Use of hemoperfusion with Polymyxin B fiber
column was found to improve hemodynamics
and organ dysfunction and reduced 28-day
mortality (EUPHAS randomized controlled trial, JAMA ,2009).
• Use of some dialyzers was suggested to be of
benefit: AN69 Surface Treated (ST), SEPTEX,
polymethylmetacrylate. Oxiris® orToraymyxin®
CRRT and Sepsis

Early or Late????

• Early initiation of RRT significantly reduced
– Occurrence of major adverse kidney events,
– Mortality, and
– Enhanced renal recovery at 1 year.
(Meersch et al, J Am Soc Nephrol. 2018)

ELAIN Trial

• 231 patients, early group (n = 112), 108 of 119
patients (90.8%) in the delayed group received
RRT.
• Early initiation of RRT significantly reduced 90-
day mortality
• More patients in the early group recovered
renal function by day 90
• Duration of RRT and length of hospital stay
were significantly shorter in the early group
• No significant effect on requirement of RRT
after day 90, organ dysfunction, and length of
ICU stay.

• Conclusion: Among critically ill patients with
AKI, early RRT compared with delayed
initiation of RRT reduced mortality over the
first 90 days. Further multicenter trials of this
intervention are warranted.

• A total of 620 patients
• Conclusion: we found no significant difference
with regard to mortality between an early and
a delayed strategy for the initiation of renal-
replacement therapy. A delayed strategy
averted the need for renal-replacement
therapy in an appreciable number of patients.

• A total of 488 patients
• Conclusion: there was no significant difference
in overall mortality at 90 days between
patients who were assigned to an early
strategy for the initiation of renal-replacement
therapy and those who were assigned to a
delayed strategy. (Barbar etl,IDEAL-ICU Trial Investigators
and the CRICS TRIGGERSEP Network, NEJM 2018)

• Despite the presence of a plethora of studies in
this field, the lack of uniformity in study design,
patient population types, definition of early and
late initiation, modality of RRT, and results, the
optimal time for starting RRT in AKI still remains
unknown. (Nithin Karakala MD, Ashita J. Tolwani, MD, MSE, Journal
of Intensive Care Medicine, 2018)

Several trials have been largely disappointing
– Ant-inflammatory and pleiotropic drugs
(corticosteroids, statins, aspirin)
– Vasoactive or antiplatelet drugs
– Different fluid administration strategies
(Dr Chertow GM, Winkelmayer WC JAMA 2016;325:2171)
• Definition of early intervention

KDIGO
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 broader clinical context, the
presence of conditions that can be modified with RRT,
and trends of laboratory tests, rather than single BUN
and creatinine thresholds alone, when making the
decision to start RRT. (Not Graded)

• Modalities

• The main mechanism with which clearance is
achieved.

Ideal Treatment Modality
• Preserves homeostasis
• Does not increase co-morbidity
• Does not worsen patient’s underlying
condition
• Is inexpensive
• Is simple to manage
• Is not burdensome to the ICU staff

CRRT Modalities
(Cerda´ and Ronco, Seminars in Dialysis, 2009)

• Many intensivists and nephrologists prefer to
use CVVH in the belief that pure convection
will remove a greater number of larger
molecules than diffusion-base CVVHD.
• CVVHDF in a safe combination
(Ricci et al, Crit Care, 2006)

Indications for specific Therapy
(Cerda´ and Ronco, Seminars in Dialysis, 2009)

CRRT Modalities

Criteria of Different Therapies
(Cerda´ and Ronco, Seminars in Dialysis, 2009)Prof. Yasse Abdelhamid

Conclusion

CRRT Prescription
van Bommel EF, Neth J Med. 2003

Conclusion
• Please Don't hesitate to use CRRT if facilities
are available

Yasser Abdelhamid

Crrt indications and modalities [autosaved]

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