Management Of Acute Renal Injury In Pediatrics

ProfSonia Elsharkawy

Head of pediatric departmentSuez canal university

Objectives

Acute renal failure.•

•Definition of ARF.Definition of ARF.

• Classification of ARF.

• Causes of ARF.

• Symptoms & sings Of ARF.• Diagnosis Of ARF.& prevention

Indications and goals for acute renal replacement therapy

• Modalities for renal replacement therapy– Peritoneal dialysis– Intermittent hemodialysis– Continuous renal replacement therapy

(CRRT)

Special issues related to the infant

The Problematic Definition of The Problematic Definition of ARFARF

• The Conceptual Definition of Acute Renal Failure:

– “Sudden loss of renal function resulting in the loss of the kidneys’ ability to regulate electrolyte and fluid homeostasis”

The Problematic Definition of The Problematic Definition of ARFARF

• Pediatric AKI definition: a moving target

• Infants– Cr in the first few weeks of life may reflect

maternal values

• Children– Low baseline Cr makes 0.2-0.3 changes in Cr

significant– Varying muscle mass

• Adolescents– Similar to adults

ARF• Pre renal (functional)

• Renal-intrinsic (structural)

• Post renal (obstruction)

ARF Pirouz Daeihagh, M.D.Internal medicine/Nephrology Wake Forest University School of Medicine. Downloaded 4.6.09

Causes of ARF

Pre-renal Renal Post-renal Absolute hypovolaemia

Glomerular (RPGN)

Pelvi-calyceal

Relative hypovolaemia

Tubular (ATN)

Ureteric

Reduced cardiac output

Interstitial (AIN)

VUJ-bladder

Reno-vascular occlusion

Vascular (atheroemboli)

Bladder neck-urethra

ARF Pre renal

•Decreased renal perfusion without cellular injury

– 70% of community acquired cases– 30% hospital acquired cases

ARF Intrinsic• Acute tubular necrosis (ATN)

– Ischaemia

– Toxin

– Tubular factors

• Acute interstitial Necrosis (AIN)– Inflammation

– oedema

• Glomerulonephritis (GN)

ARF Post renal

• Post renal obstruction

• Obstruction to the urinary outflow tract

Blocked catheter– Malignancy

Contrast-Induced ARF

• Prevalence• Less than 1% in patients with normal

renal function

• Increases significantly with renal insufficiency

Contrast-Induced ARF• Risk Factors

• Renal insufficiency

• Diabetes mellitus

• Multiple myeloma

• High osmolar (ionic) contrast media

• Contrast medium volume

Contrast-induced ARF

Clinical Characteristics

• Onset - 24 to 48 hrs. after exposure

• Duration - 5 to 7 days

• Non-oliguric (majority)

• Dialysis - rarely needed

• Urinary sediment - variable

• Low fractional excretion of Na

Contrast-induced ARFProphylactic Strategies

• Use I.V. contrast only when necessary

• Hydration

• Minimize contrast volume

• Low-osmolar (nonionic) contrast media

• N-acetylcysteine.

Pediatric Modified RIFLE--Pediatric Modified RIFLE--definitiondefinition

Ackan-Arikan et al: Kid Int 2010

Pediatric Modified RIFLE Criteria

CrCl Urine output

Risk GFR decrease by 25% <0.5ml/kg/hour for 8 hours

Injury GFR decrease by 50% <0.5ml/kg/hour for 16 hours

Failure GFR decrease by 75% or GFR<35ml/min/1.73m 2

<0.3 ml/kg/hour for 24 hours or anuric for 12 hours

Loss Persistent ARF > 4 weeks

End stage

End Stage Renal Disease (>3 months)

GFR per Schwartz equation: GFR= Ht (cm) X constant / serum creat (mg/dl)

Acute Kidney Injury

AKI can be prevented by early recognition and treatment of the underlying cause, for example:

-Early treatment of infections/sepsis– Early treatment/prevention of dehydration– Correcting hypovolaemia

Monitoring use of drugs such as NSAIDs and ACE inhibitors, especially if a patient is acutely unwell

• Taking care with at-risk patients who need iodinated contrast agents with scans

BIOMARKERS

Biomarkers for Acute Kidney InjuryBiomarkers for Acute Kidney Injury

• Ideally AKI would have a biomarkers like myocardial infarction (i.e. troponin-1)

• Currently no Troponin-I like marker to identify the site or severity of injury, although various markers are being evaluated

– Kidney Injury Molecule (KIM-1)

– Neutrophil gelatinase-associated lipocalcin (NGAL)

– IL-18

– Cystatin C

(Changes in SCr may be a very late indicator of renal injury)

AKI in the ICU

• Treatment of acute kidney injury (AKI) is principally supportive -- renal replacement therapy (RRT) indicated in patients with severe kidney injury.

• Goal: optimization of fluid & electrolyte balance

Use an early warning score

that recognises and responds to

deterioration and acute illness

Staff should have competencies in:

• Monitoring • Measurement• Interpretation

Observations and assessment

Neonatal Renal Failure

In term neonates, renal failure is suspected when the plasma creatinine concentration is greater than 15 mg/L, for at least twenty four to forty eight hours, while maternal renal function is normal

Incidence

Precise incidence and prevalence of ARF in the newborn is

unknown , 6%- 24% (Andreoli, 2013).

In developing countries, the incidence and epidemiology of

acute renal failure in newborns was 3.9% of 1.000 live births

and 34.5% of 1.000 newborns admitted to the neonatal unit

(Andreoli, 2013).

The mortality of acute renal failure is still very high (30%-

60%) (Drukker & Guingard, 2012).

Etiology

Variety of congenital, developmental, and acquired conditions

(Mercado-Deane et al, 2012).

Prenatal injury/vascular damage: - Maternal

- Congenital renal diseases

Postnatal:

1- Prerenal: - Decreased true intravascular volume

- Decreased effective intravascular volume

2- Intrinsic: -ATN

-Interstitial nephritis

3- Postrenal (obstructive)

Management

Immediate Measures:Immediate Measures:

1- 1- volume trials.

2- Diuretics

3- Dopaminergic (Vasoactive) Agents

Conservative treatment.Conservative treatment.

Renal replacement therapyRenal replacement therapy

Renal TransplantationRenal Transplantation

Indications for Renal Replacement

• Volume overload

• Metabolic imbalance

• Toxins (endogenous or exogenous)

• Inability to provide needed daily fluids due to insufficient urinary excretion

Goals of Renal Replacement

• Restore fluid, electrolyte and metabolic balance

• Remove endogenous or exogenous toxins as rapidly as possible

• Permit needed therapy and nutrition

• Limit complications

R R T Includes: •Traditional intermittent hemodialysis,

• Peritoneal dialysis

• Variety of other intermittent and continuous therapy,

•Renal transplant

Indications to start RRT

• Anuria – oliguria(diuresis <200 ml in 12 hr)

• Severe metabolic acidosis(pH<7.10)

• Hyperazotemia(BUN> 80mg/dl) or creatinine >4mg/dl

• Hyperkalemia K >6.5mEq/l

• Clinical signs of uremic toxicity

• Severe dysnatremia Na<115 or Na>160mEq/l

• Hyperthermia (>40 deg.C without response to medical therapy)

• Anasarca or severe fluid overload

• Multiple organ failure with renal dysfunction and /SIRS, sepsis, or septic shock with renal dysfunction

BUT• The optimal timing of RRT for AKI is not

defined

• Timing of renal replacement therapy initiation in acute renal failure: a meta-analysis

Meta-analysis of randomized trials, early RRT was associated with a nonsignificant 36% mortality risk reduction (RR, 0.64; 95% confidence interval, 0.40 to 1.05; P = 0.08)

In cohort studies, early RRT was associated with a statistically significant 28% mortality risk reduction (RR, 0.72; 95% confidence interval, 0.64 to 0.82; P < 0.001).

• Seabra VF, Balk EM, Liangos O, Sosa MA, Cendoroglo M, Jaber BL.

Am J Kidney Dis. 2012;52:272–284

whenInitiate RRT Initiate RRT EEmergentlymergently

Life-threatening changes in fluid

Electrolyte

Acid-base balance

Uremic complications: pericarditis, pleuritis, encephalopathy, coagulopathy

Kidney Disease: Improving Global Outcomes (KDIGO), 2012

Technique and modalities

Technique and modalities

• All RRT consist of blood purification by having the blood flow through SPM.

• Blood flow into hollow fibers composed by biocompatible synthetic materials.

• Wide range of substances( water , urea,and low, middle and high mol.wt. solutes)allow the blood across such membranes by diffusion (solutes) and by convection(solute and water)

Modalities for Renal Replacement

• Hemodialysis.

• Peritoneal dialysis.

• Continuous renal replacement therapy (CRRT)

• Heamofiltiration.

• Renal replacement.

Principles of dialysis

• Dialysis = diffusion = passive movement of solutes across a semi-permeable membrane down concentration gradient– Good for small molecules

• (Ultra)filtration = convection = solute + fluid removal across semi-permeable membrane down a pressure gradient (solvent drag)– Better for removal of fluid and

medium-size molecules

Faber. Nursing in Critical Care 2009; 14: 4Foot. Current Anaesthesia and Critical Care 2005; 16:321-329

Principles of dialysis

Hemodialysis = solute passively diffuses down concentration gradient Dialysate flows countercurrent to blood flow. Urea, creatinine, K move from blood to dialysate Ca and bicarb move from dialysate to blood.

Hemofiltration: uses hydrostatic pressure gradient to induce filtration / convection plasma water + solutes across membrane.

Hemodiafiltration: combination of dialysis and filtration.

Intermittent hemodialysis (IHD)

• Oldest and most common technique• Primarily diffusive treatment: blood and dialysate are

circulated in countercurrent manner

• Best for removal of small molecules• typically performed 4 hours 3x/wk or daily

Continuous RRT Introduced in 1980s• involve either dialysis (diffusion-based solute

removal) or filtration (convection-based solute and water removal) treatments in a continuous mode with slower rate of solute or fluid removal

• CRRT includes continuous hemofiltration, hemodialysis and hemodiafiltration, all of which can be performed using arteriovenous or venovenous extracorporeal circuits.

Peritoneal dialysis

Considerations for Infants

ADVANTAGES

• No vascular access• No extracorporeal

perfusion• Simplicity• ? Preferred modality

for cardiac patients?

DISADVANTAGES• Infectious risk• Leak• ? Respiratory

compromise?

Intermittent hemodialysis Considerations for Infants

ADVANTAGES

• Rapid particle and fluid removal; most efficient modality

• Does not require anticoagulation 24h/d

DISADVANTAGES

• Vascular access• Complicated• Large extracorporeal

volume• Adapted equipment• ? Poorly tolerated

Pediatric CRRT: Vicenza, 1984

CRRT for Infants: A Series of Challenges

• Small patient with small blood volume

• Equipment designed for bigger people

• No specific protocols

• Complications may be magnified

• No clear guidelines

• Limited outcome data

Potential Complications of Infant CRRT

• Volume related problems

• Biochemical and nutritional problems

• Hemorrhage, infection

• Thermic loss

• Technical problems

• Logistical problems

Role of RRT in different clinical situations

• Sepsis

• Congestive heart failure

•Miller's Anesthesia, 7th ed. 2009

RRT in congestive heart failure

• Slow continuous ultrafiltration (SCUF) effective for fluid removal in decompensated CHF..

Costanzo et al J Am Coll Cardiol 2010 49:675-683.

Discontinuation of RRT

• Until “evidence of recovery of kidney function”– Improved UOP in oliguria– Decreasing creatinine– Creatinine clearance minimum 12 mL/min,

some say 20 mL/min

Thanks!