Renal Failure

Definition: acute kidney injury (AKI) is failure of the kidneys to regulate electrolyte, acid-base and fluid homeostasis adequately with concomitant reduction in glomerular filtration rate (GFR). pRIFLE (paediatric Risk, Injury, Failure, Loss, End-Stage Criteria).

Chronic renal failure: hyperfiltration, estimated creatinine clearance <75 ml/min/1.73m2 , hypertension, microalbuminuria.

Causes:

Multi-organ failure, congenital heart surgery, nephrotoxic substances, stem-cell transplantation, sepsis, HUS.

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pRIFLE
Grade	estimated Crea Clearance	Urine Output
Risk	decrease by 25 %	< 0.5 ml/kg/hr for 8 hours
Injury	decrease by 50 %	< 0.5 ml/kg/hr for 16 hours
Failure	decrease by 75 % or< 35 ml/min/1.73m2	< 0.3 ml/kg/hr for 24 hours or anuric for 12 hours
Loss	persistent failure > 4 w
End Stage	persistent failure > 3 mo

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Causes:

AKI, dysplasia, renal reflux, obstructive nephropathy, chronic GN.

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Options for renal replacement therapy (RRT):

CVVHD (continuous venovenous haemodialysis – clearance via diffusion)

CVVH (continuous venovenous haemofiltration – clearance via convection)

CVVHDF (continuous venovenous haemodiafiltration – clearance via convection and diffusion), most commonly done, PD (peritoneal Dialysis), SCUF, IHD (intermittent haemodialysis).

Comparison of Renal Replacement Therapy
Variable	PD	CRRT	IHD
Convection	+		+++
Diffusion	++		++
Fluid control	–	++	++
Uraemia control	–	++	+
Vascular access	Tenkhoff	required	required
Anitcoagulation	not applicable	required	required

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References:

[1] Kidney International 71, 2007, 1028 – 1035, Akcan-Arikan et al: Modified RIFLE criteria in critically ill children with acute kidney injuryAKI in critically ill children

[2] Am J Kidney Dis. 2005, Jan;45(1):96-101: Hui-Stickle et al: Pediatric ARF epidemiology at a tertiary care center from 1999 to 2001

[3] Adv Chronic Kidney Dis, 2008 July ; 15(3): 278-283: Goldstein et al: PROGRESSION FROM ACUTE KIDNEY INJURY TO CHRONIC KIDNEY DISEASE: A PEDIATRIC PERSPECTIVE: An invited review for Advances in Chronic Kidney Disease

[4] Pediatr Nephrol, 2009, 24: 37-49: Walters et al: Dialysis and pediatric acute kidney injury: choice of renal support modality

[5] Pediatr Nephrol. 2005 Jul;20(7):972-6: McNiece et al: Adequacy of peritoneal dialysis in children following cardiopulmonary bypass surgery

[6] Schrier: www.kidneyatlas.org

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