management of acute renal injury in pediatrics

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!