ACUTE RENAL FAILURE

Dr .Shabbir2nd year PG

MD Emergency Medicine

Introduction

• Acute renal failure (ARF) is seen commonly in the perioperative period and in the ICU.

• It is associated with a high morbidity and mortality ( oliguric 50-80% and non oliguric 10-40%).

Urine Volume

• Anuria (< 100 ml/24h)• Oliguria (100-500 ml/24h)• Non-Oliguria (> 500 ml/24h)

Definition

• sudden and rapid decline in renal function,causing retention of nitrogenous waste products such as blood urea nitrogen and creatinine.

• The term ‘acute kidney injury (AKI)’ has now replaced the previously used ‘acute renal failure (ARF)’.

Classification

• RIFLE criteria• Acute Kidney Injury Network

definition

GFR URINE OUT PUT serum creatinine

RIFLE criteria

Acute Kidney Injury Network definition

• Renal ultrasonography may show small (,9 cm) kidneys, often with cortical scarring and possibly cyst formation, in which case chronic disease is probable.

• Evidence of current—or a history suggestive of recent—volume depletion implies a pre-renal cause or ATN, and response to treatment differentiates between the two.

Acute Chronic

History Short (days-week) Long (month-years)

Haemoglobin concentration Normal Low

Renal size Normal Reduced

Renal osteodystrophy Absent Present

Peripheral neuropathy Absent Present

Serum Creatinine concentration

Acute reversible increase

Chronic irreversible

Etiology

Causes of acute renal failure

• Pre-renal• Intrinsic renal• Post-renal

• Oliguric• Non- oliguric

Pathogenesis

• Oliguric• Non-oliguric

Diagnosis

Clinical examination Investigations

5

Clinical feature

• Sign and symptoms resulting from loss of kidney function:

• decreased or no urine output, flank pain, oedema, hypertension, or discoloured urine

• Asymptomatic• elevations in the plasma creatinine • abnormalities on urinalysis

Treatment

PRACTICAL MANAGEMENT

• Management is directed at treating any life threatening features, Hyperkalaemia, pulmonary oedema, and severe acidosis.

• Fluid balance, the treatment of less severe acidosis, the use of diuretics and dopamine, as well as the relief of obstruction are all issues in the further management of the patient.

Pulmonary oedema

• Pulmonary oedema is often the result of excessive fluid resuscitation ,cardiac dysfunction.

• furosemide 250 mg in 50 ml 0.9% saline over one hour.• Furosemide 1mg/kg iv over 1to 2 min. if no

response after 1 hour increase to 2 mg/kg over 1 to 2 min.

ACIDOSIS• Severe metabolic acidosis (blood pH ,7.2) or

HCO3 <15 meq/L.• Reversing acidosis through administration of an

alkaline solution—sodium bicarbonate—would seem to be sensible, but there is very little evidence to show that it provides benefit.

• Haemodialysis or haemofiltration will usually be required to treat severe acidosis in oligoanuric patients

Treatment of oliguric renal faiure

• Fluid challenge- fluid bolus (250-500 ml of normal saline) over 10–15 minutes may help to differentiate between Pre-renal to other renal causes.

• Drugs used are:-1. Diuretics2. Dopamine3. Calcium channel blockers

Calculation of GFR

• Cockcroft-Gault equation Estimated creatine clearnce (ml/min)= (140-Age )x Weight 72 x pcrAge – in yearsWeight- kgsPcr- mg/dl

Calculation of GFR

Diuretics

Rationale for use:-• loop diuretics may vasodilate cortical vessels

and improve oxygenation.• augmentation of tubular blood flow may

reduce intratubular obstruction back leak of filtrate thus rapidly accelerating resolution of ARF

Dosage of furosemide

• 250 mg in 250 ml of NS IV over 1 hour. • If out put not good, 500mg in 400ml of

NS IV over 2 hours.• If no response , 1g in 400ml NS IV 4

hours .• No response –hemodialysis• Rate of infusion -<4mg/min.• C/i:-volume depletion, hypotension,hypokelamia,

hyperuricemia

“PREVENTION IS BETTER THEN CURE”

THANK YOU