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CRRT Prescription in Paediatric AKI

Dr Chor Yek Kee Sarawak General Hospital

Disclosure

Definition of AKI

The Burden of AKI in PICU

• 30 to 40% of patient admitted to PICU has AKI

• Patients with AKI are associated with higher mortality rate ( 40 to 50%).

• 5% of PICU patient has AKI requiring renal replacement therapy.

• The overall mortality of these patient is around 40 to 60%, • significant higher in patients with

• Multiple organ dysfunction and fluid overloaded

• Weighting less than 10Kg

• Those receiving stem cell transplantation

The trend of treatment for AKI

•1995 45% PD 18% CRRT

•1999 31% PD 36% CRRT

Warady BA, Bunchman T. Dialysis therapy for children with acute renal failure: survey results. Pediatr Nephrol 2000; 15:11–13.

Why CRRT in AKI?

• Critically ill patient

• Advantages • Slower blood flows • Slower UF rates • UF rates can be prescriptive (versus PD) • Adjust UF rates with hourly patient intake • Increased cytokine (bad humors) removal.

• Disadvantages • Increased cytokine (good humors) removal. • Non-dialysis personnel with many other bedside responsibilities required to

monitor circuit

Indication for Paediatric RRT

Hemofilter

Basic Components in CRRT

CRRT

Blood Warmer Vascular access

Anticoagulation

CRRT System

Solutions

Anatomy of a Hemofilter

Different Types of Filters

M60/M100/M150 • Polyacrylonitrile (AN69)

HF 20 • Polyarylethersulfone (PAES)

CRRT Transport Mechanism

•Ultra-filtration Fluid Transport

•Diffusion •Convection Solute transport •Absorption

Blood Out

Blood In to waste

(to patient)

(From patient)

HIGH PRESS LOW PRESS

Fluid Volume Reduction

Ultrafiltration

Hemodialysis: Diffusion

Dialysate In

Dialysate Out (to waste)

Blood Out

Blood In

(to patient)

(from patient)

HIGH CONC LOW CONC

to waste

HIGH PRESS LOW PRESS

Repl. Solution

Hemofiltration: Convection

Blood Out

Blood In

(to patient)

(from patient)

Adsorption

19

Molecular Weights

“Small”

“Middle”

“Large”

3 category of solutes for removal in CRRT.

Septic Mediators Interleukins TNF

Co

nve

ction

D

iffusio

n

CRRT Modes of Therapy

• SCUF - Slow Continuous Ultrafiltration

• CVVH - Continuous Veno-Venous Hemofiltration

• CVVHD - Continuous Veno-Venous HemoDialysis

• CVVHDF - Continuous Veno-Venous HemoDiaFiltration

Features of Solutes Removal in Each CRRT Modalities

Vascular access

Anticoagulant

• Choices of anticoagulant a) Heparin

b) Citrate

c) Prostacyclin

• Target • Activated clotting time : 160 to 200 seconds

• aPTT twice of normal value

Controversial issues in pCRRT

1. The optimal timing of pCRRT • Ongoing debate • It is now clear that pCRRT should be considered before fluid accumulates in

children

2. The dose and the level of adequate dialytic delivery in children • The dose for older child and neonate remain to be established

3. The longterm outcome of AKI in children undergoing CRRT • Evidence indicate the patient surviving CRRT often have reduced renal reserve

and do not achieve restoration of pre-morbid renal function.

Timing for pCRRT

• According to current evidence , reasonable to suggest pCRRT be instituted rapidly in • oligoanuric patients,

• especially those with significant fluid accumulation,

• before the fluid overload threshold of 10 to 20 % has been reached.

Analysis from nearly 600 children in 6 studies suggest that mortality increases from 40 to 60 % in children with more than 10 to 20% fluid overload at the RRT initiation

Crit Care Med 2014:42:943-953

Crit Care Med 2014:42:943-953

Early initiation of continuous renal replacement therapy was associated with

lower mortality in this cohort of critically ill children

If a patient has AKI, pCRRT has to be started within 5 days of ICU admission in order to

be effective in term of mortality

• The RENAL Trial clearly showed that the mortality rate of adult patient undergoing CRRT was affected by the level of fluid balance achieved after the initial 48 hours of therapy

(Crit Care Med 2012; 40: 1753–1760)

Would you dialyze ?

• a non-oliguric patient

• Creatinine 200 mmol/L

• Urea 20 mmol/L

• Bicarbonate 18 mmol/L

• Potassium 4.4 mmol/L

• Intubated

• Septic

• On Vasopressor

Earlier initiation of RRT may produce benefits by avoiding hypervolemia, eliminating of toxins, establishing acid-base homeostasis, and preventing other complications attributable to AKI. However, early initiation of RRT may unnecessarily expose some patients to potential harm because some patients will spontaneously recover renal function. — Zarbock, et al

EinitiaRT may produce benefits by avoiding hypervolemia, eliminating of toxins, establishing acid-base homeostasis, and preventing other complications attributable to AKI. However, early initiation of RRT may unnecessarily expose some patients to potential harm because some patients will spontaneously recover renal function. — Zarbock, et al

Effect of Early vs Delayed Initiation of Renal Replacement Therapy on Mortality in Critically Ill Patients With Acute Kidney InjuryThe ELAIN Randomized Clinical Trial Alexander Zarbock, MD1; John A. Kellum, MD2; Christoph Schmidt, MD1; Hugo Van Aken, MD1; Carola Wempe, PhD1; Hermann Pavenstädt, MD3; Andreea Boanta, MD1; Joachim Gerß, PhD4; Melanie Meersch, MD1 JAMA. 2016;315(20):2190-2199.

Timing for pCRRT

• According to current evidence , reasonable to suggest pCRRT be instituted rapidly in • oligoanuric patients,

• especially those with significant fluid accumulation,

• before the fluid overload threshold of 10 to 20 % has been reached.

The dose and the level of adequate dialytic delivery in children

• Remain to be established

• To date , there have been no randomized trials guiding the prescription of CRRT in children.

• A small solute clearance of 2 to 3 litre/H/1.73m2 ( 25 to 40 ml/Kg/H ) may be recommended

Treatment Dosing in CVVHDF at PICU, SGH

• Blood flow rate : 3 to 10 ml/Kg/min

• Dosing : 25 to 100 ml/Kg/H • 50% Dialysis

• 50% Convection: • 2/3 pre-dilution

• 1/3 post dilution

• Fluid removal : 1 to 2 ml/Kg/H

Lancet 2000 : Ronco et al

35ml/Kg/H

25ml/Kg/H

40ml/kg/H

25ml/Kg/H

The dose and the level of adequate dialytic delivery in children

• Remain to be established

• To date , there have been no randomized trials guiding the prescription of CRRT in children.

• A small solute clearance of 2 to 3 litre/H/1.73m2 ( 25 to 40 ml/Kg/H ) may be recommended

1. Electrolyte and Divalent Ion losses a) Hypokalaemia 5 - 25% b) Hypophosphataemia 10.9 – 65% c) Hypomagneaemia < 3%

2. Acid/Base Disorder • Buffering substances Citrate, bicarbonate and lactate • Excessive metabolic alkalosis • Hyperlactataemia with liver impairment • Increase glucose intolerance in hyperlactataemia

3. Nitrogen

• Significant nitrogen loss in CRRT • European Society of Parenteral and Enteral Nutrition Society suggest additional of

glutamine during CRRT ( 0.3 to 0.6g/Kg/day Alanyl Glutamine Dipeptide )

1. Drug and specifically antibiotic • Always check with pharmacist regarding dose adjustment

2. Heat loss • CRRT provoke greater heat loss than IHD • Higher dose associated with higher incidence of hypothermia

3. Complication related to vascular access

4. Clotting and bleeding problem

5. Hemodynamic monitor disturbances

CRRT in smaller child

Children who were able to achieve dry weight during their CRRT course more likely to survive than children remaining fluid overload ( 78% Vs 35%, P = 0.002 )

• Weight between 1880gm to 8 Kg

• Single lumen line

• Without blood prime

• With microliter UF control

Changes can be made

Thank you