Adult Medical-Surgical Adult Medical-Surgical Nursing Nursing

Renal Module: Renal Module:

Acute Renal FailureAcute Renal Failure

Acute Renal Failure: GFRAcute Renal Failure: GFR

The glomerular filtration rate (GFR) The glomerular filtration rate (GFR) indicates the efficiency of the kidney indicates the efficiency of the kidney nephrons:nephrons:

In concentrating urine to excrete toxins In concentrating urine to excrete toxins from the body from the body

In maintaining water and electrolyte In maintaining water and electrolyte balance in the bodybalance in the body

Average urine output is approximately Average urine output is approximately 1500 ml/ 24 hours1500 ml/ 24 hours

Acute Renal Failure: ClassificationAcute Renal Failure: Classification

A sudden decrease in the glomerular A sudden decrease in the glomerular filtration rate (occurring in hours to days)filtration rate (occurring in hours to days)

Oliguria: < 400ml urine output in 24 hoursOliguria: < 400ml urine output in 24 hours Anuria: < 50 ml in 24 hoursAnuria: < 50 ml in 24 hours There may be normal volume but failure to There may be normal volume but failure to

concentrate urine therefore inability to rid concentrate urine therefore inability to rid the body of waste productsthe body of waste products

Urine output should be at least 30ml/ hour Urine output should be at least 30ml/ hour (400 ml/24 hours) in order to excrete (400 ml/24 hours) in order to excrete metabolic waste metabolic waste

Acute Renal Failure: CausesAcute Renal Failure: Causes

Pre-renal (60% of cases)Pre-renal (60% of cases)

Acute Tubular Necrosis (35-40%)Acute Tubular Necrosis (35-40%)

Post-renal (5%)Post-renal (5%)

Acute Renal Failure:Acute Renal Failure:Pre-renal Causes (Hypoperfusion) Pre-renal Causes (Hypoperfusion)

Pre-renal: hypoperfusion of the Pre-renal: hypoperfusion of the kidneys. Impaired blood flow leads to kidneys. Impaired blood flow leads to ↓ GFR and urine output ↓ GFR and urine output

Caused by:Caused by: Hypovolaemia (haemorrhage, burns, Hypovolaemia (haemorrhage, burns,

diarrhoea and vomiting)diarrhoea and vomiting) Impaired cardiac functionImpaired cardiac function Vasodilation (anaphylactic or septic Vasodilation (anaphylactic or septic

shock)shock)

Acute Renal Failure: Acute Renal Failure: Acute Tubular NecrosisAcute Tubular Necrosis

Direct trauma or toxicity to kidney tissue Direct trauma or toxicity to kidney tissue (nephrons: glomeruli, tubules) from:(nephrons: glomeruli, tubules) from:

BurnsBurns } myoglobin from muscle } myoglobin from muscle Crush injuriesCrush injuries ABO incompatibility (agglutination RBCs)ABO incompatibility (agglutination RBCs) Drugs: including nephrotoxic chemotherapy Drugs: including nephrotoxic chemotherapy Severe infections/ auto-immune reactions: Severe infections/ auto-immune reactions:

pyelonephritis/ glomerulonephritis pyelonephritis/ glomerulonephritis

Acute Renal Failure: Acute Renal Failure: Post-renal CausesPost-renal Causes

Obstruction to urine flow in the renal Obstruction to urine flow in the renal tract leads to back-pressure, tract leads to back-pressure, progressing to hydronephrosis and progressing to hydronephrosis and ↓ GFR. Caused by:↓ GFR. Caused by:

TumoursTumours StricturesStrictures Calculi (stones)Calculi (stones) ClotsClots Prostatic hyperplasiaProstatic hyperplasia

Acute Renal Failure:Acute Renal Failure:Four Clinical PhasesFour Clinical Phases

Initiation phase:Initiation phase: from time of insult to oliguria from time of insult to oliguria (hours to days)(hours to days)

Oliguric period:Oliguric period: Period of most clinical Period of most clinical manifestations and abnormal kidney function manifestations and abnormal kidney function tests (KFT) (10-20 days but may be months)tests (KFT) (10-20 days but may be months)

Diuresis:Diuresis: ↑ urine output but urine may be ↑ urine output but urine may be mostly water. Risk of dehydration. mostly water. Risk of dehydration. Symptoms/ KFT begin to improve (2-3 weeks)Symptoms/ KFT begin to improve (2-3 weeks)

Recovery:Recovery: Symptoms/ KFT improved (3-12 Symptoms/ KFT improved (3-12 months) months)

Acute Renal Failure: OutcomeAcute Renal Failure: Outcome

Recovery is possible but may not be Recovery is possible but may not be complete: GFR 1-3% below normalcomplete: GFR 1-3% below normal

50% of patients do not recover: 50% of patients do not recover: acute renal failure may result in acute renal failure may result in death or chronic renal failure death or chronic renal failure

Acute Renal Failure: EffectsAcute Renal Failure: Effects

Failure of kidney function causes:Failure of kidney function causes: Reduced urine volume, fluid retention, Reduced urine volume, fluid retention,

circulatory overload, circulatory overload, ↑ ↑ BPBP Reduced urine concentration and Reduced urine concentration and

excretion of toxic waste products of excretion of toxic waste products of metabolism, most significantly:metabolism, most significantly:

Raised blood urea/ creatinineRaised blood urea/ creatinine Raised potassium: dysrhythmiasRaised potassium: dysrhythmias Acidic substances: metabolic acidosis Acidic substances: metabolic acidosis

Acute Renal Failure: Acute Renal Failure: Clinical ManifestationsClinical Manifestations

Reduced urine outputReduced urine output Weight gain and oedema; hypertensionWeight gain and oedema; hypertension Lethargy, drowsiness, sleep disturbance, Lethargy, drowsiness, sleep disturbance,

convulsions, comaconvulsions, coma Nausea, vomiting, cramps, diarrhoeaNausea, vomiting, cramps, diarrhoea Hiccoughs, muscle twitching, restlessnessHiccoughs, muscle twitching, restlessness Cardiac dysrhythmias Cardiac dysrhythmias Hyperventilation (acidosis)Hyperventilation (acidosis) Dry skin/ mucous membranes, fetor on Dry skin/ mucous membranes, fetor on

breathbreath

Acute Renal Failure: DiagnosisAcute Renal Failure: Diagnosis

History and clinical pictureHistory and clinical picture OliguriaOliguria Altered KFT:Altered KFT: Raised blood urea, creatinine, potassium, uric Raised blood urea, creatinine, potassium, uric

acid, phosphatesacid, phosphates Low serum calcium Low serum calcium Changes in urine specific gravity Changes in urine specific gravity ↑ ↑ urine sodium, cellular debris, RBC, WBC, urine sodium, cellular debris, RBC, WBC,

castscasts Metabolic acidosis (basal deficit; bicarb ↓) Metabolic acidosis (basal deficit; bicarb ↓)

Acute Renal Failure:Acute Renal Failure:Clinical ManagementClinical Management

Treat the causeTreat the cause Support the patient (ICU) until recovery Support the patient (ICU) until recovery

by:by: Dialysis (usually via temporary central Dialysis (usually via temporary central

line)line) Ventilation if necessaryVentilation if necessary Strict fluid intake restrictionStrict fluid intake restriction Foley catheter Foley catheter Diuretics to stimulate kidney functionDiuretics to stimulate kidney function Monitor for dysrhythmias and overload Monitor for dysrhythmias and overload MedicationsMedications

Acute Renal Failure:Acute Renal Failure:Nursing ConsiderationsNursing Considerations

Care in ICU; on ventilator if necessary Care in ICU; on ventilator if necessary Continuous ECG monitoring Continuous ECG monitoring Monitor BP, JVP, oedema (overload)Monitor BP, JVP, oedema (overload) Strict monitoring of intake/ outputStrict monitoring of intake/ output Care of Foley catheter; hourly output Care of Foley catheter; hourly output

(report <30ml)(report <30ml) Monitor progress through general Monitor progress through general

condition, urine output, lab testscondition, urine output, lab tests Support relativesSupport relatives

Acute Renal Failure: MedicationsAcute Renal Failure: Medications

Diuretics: stimulate renal functionDiuretics: stimulate renal function Insulin and Dextrose } ↓ high bloodInsulin and Dextrose } ↓ high blood KayexalateKayexalate potassium levelpotassium level Calcium GluconateCalcium Gluconate Sodium Bicarbonate: correct aciditySodium Bicarbonate: correct acidity Aluminium hydroxide } correct Aluminium hydroxide } correct Calcium carbonate phosphate/ Calcium carbonate phosphate/

calcium levelscalcium levels

Acute Renal Failure: Follow-upAcute Renal Failure: Follow-up

Diet: Fluid restriction Diet: Fluid restriction Increased CHO (protein-sparing)Increased CHO (protein-sparing) Reduced protein initiallyReduced protein initially Reduced potassium-containing foodsReduced potassium-containing foods Reduced medication doses as toxicReduced medication doses as toxic Monitor progress: urine output, Monitor progress: urine output,

weight, BP, KFT weight, BP, KFT Monitor for anaemia: erythropoietin ↓ Monitor for anaemia: erythropoietin ↓