Renal failure

WELCOME

w. akpaloo

Objectives

By the end of this lecture, the student should be able to:

• Describe what constitutes renal failure
• Enumerate and explain the clinical manifestations of renal failure
• Describe the pathophysiology, diagnosis and medical management of renal failure
• Explain with rational nursing responsibilities for patients suffering from renal failure

Renal failure (RF)

• RF results when the kidneys cannot remove the body’s metabolic wastes or perform their regulatory function
• Metabolites then accumulate in the blood leading to alteration in fluid, electrolyte, and acid-base balance.

RF

• RF may occur as a result of primary kidney disorder or secondary to a systemic disease or other urologic defects.
• RF may be acute or chronic

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Acute renal failure (ARF)/acute kidney injury (AKI)

• ARF/AKI has an abrupt onset and is often reversible with prompt intervention
• It is a rapid decline in renal function with azotemia and fluid & electrolyte imbalances
• Ischemia and nephrotoxins are known to be the most common causes of ARF

Risk factors for ARF

• Major trauma
• Major surgery
• Haemorrhage
• Infection – septic abortion
• Nephrotoxic drugs
• Nephrotoxic radiologic contrast
• Severe liver disease
• Severe heart failure
• Lower urinary tract obstruction

Categories of ARF and pathophysiology

• Causes and pathophysiology of ARF often categorized as
• Prerenal
• Intrinsic/intrarenal
• Postrenal
• Prerenal is the most common cause – about 55%

Prerenal ARF

• Results from conditions that affects renal blood flow and perfusion
• Thus any disorder that decreases vascular volume, cardiac output, or systemic vascular resistance affects renal blood flow
• In prerenal ARF, hypo-perfusion leads to ARF without directly affecting the integrity of the kidney tissues

Prerenal ARF

• This type of ARF is quickly reversed when blood flow is restored and renal parenchyma remains undamaged
• It is common in trauma, surgical and critically ill patients
• Without prompt treatment is leads to ischemic acute tubular necrosis and intrarenal or intrinsic ARF

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Intrinsic/intrarenal ARF

• This occurs when there is direct damage to the functional kidney tissues
• It is characterised by acute damage to the renal parenchyma and nephrons
• Intrarenal cause: diseases of the kidney itself and acute tubular necrosis
• The second commonest form of ARF – about 40%

Postrenal ARF

• Urinary tract obstruction which results in kidney damage is what causes post-renal ARF
• Any condition that prevents urine excretion can precipitate post renal ARF
• Benign prostrate hypertrophy is the most common precipitating factor
• Other precipitating factors: urinary or renal calculi and tumours

Causes of ARF

Acute tubular necrosis (ATN)

• Read on the above topic under ARF

Phases of ARF

• There are 4 phases of ARF namely:
• Initiation
• Oligouria
• Diuresis
• Recovery

Initiation phase

• This period begins with the initial result/initiating event eg haemorrhage and ends when tubular injury occurs and oligouria develops
• May last hours to days
• If recognized early and initiating event is adequately managed during this phase, prognosis is good.

Oligouria period

• This phase is accompanied by a rise in serum concentration of waste products usually excreted by the kidney (urea, creatinine, uric acid etc)
• Uremic symptoms first appear in this phase and hyperkalaemia also develops

Oligouria period

• Minimum amount of urine needed to excrete the waste substances is 400mL

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• Some patients may have decreased renal function with increasing nitrogen retention yet may excrete normal urine volume of say 2L/day or more – the non-oligouric form of renal failure may occur with burns, traumatic injury and use of halothane anaesthetic agent etc

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Diuresis period

• Patient experiences gradual increase in urine output – signal of glomerular recovery
• Lab values stop rising and eventually decrease
• Urine volume may be normal but renal function may be abnormal
• Patient must be closely observed at this phase especially for dehydration which could worsen uremic symptoms

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Recovery period

• This phase is characterised by a process of tubule cell repair and regeneration and gradual return of GFR to normal or pre-ARF levels
• Indication of improvement in renal function
• May take 3 to 12 months
• Lab values return to normal levels

Manifestations

• Almost every system of the body is affected when normal renal regulation is impaired
• Patient appears very ill
• Lethergic
• Nausea & vomiting
• Diarrhoea
• Dry skin and mucous membranes – dehydration
• Breath may have odour of urine (uremic fetor)
• Drowsiness
• Headache
• Muscle twitching
• Seizures
• Oligouria
• Anuria
• Nocturia
• Oedema
• Decreased appetite
• Metallic taste in mouth
• Hiccups
• Change in mood
• Flank pain
• Fatigue

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Diagnosis

• Urinalysis
• Serume creatinine and , BUN
• Serum electrolyes
• ABGs
• Blood culture
• Urine culture
• Abdominal/Renal ultrasound scan to exclude urinary tract obstruction
• Renal biopsy
• Plain X-ray of abdomen
• FBC
• Kidney biopsy
• 24-hour urine test
• ECG
• Excretory urography
• MRI
• CT scan
• Retrograde pyelogram
• KUB

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Management

PREVENTION

• Instituting measures that will prevent ARF should be the goal when caring for all patients especially the high risk groups
• Ensure the ff:
• Adequate vascular volume
• Cardiac output and
• Blood pressure
• Is vital to preserving kidney perfusion and function

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Medical management

Treatment goals for ARF are to:

• To recognise and correct underlying reversible causes
• To prevent further kidney injury
• Restore the urine output and kidney function
• To maintain a normal electrolyte and fluid volume milieu

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Non-pharmacological treatment�

• Nutrition: Give protein of high biological value at 40 g protein/day; increase carbohydrate
• Strict fluid input and output chart
• Daily weighing

Non-pharmacological treatment

• In adults restrict fluid intake to 600 ml plus previous day's 24hr urine output
• Beware of hyperkalaemia - avoid potassium containing foods e.g. banana
• Dialysis – haemodialysis or peritoneal dialysis

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Pharmacological treatment

• The primary focus in drug management in ARF is to restore and maintain renal perfusion and
• To eliminate nephrotoxic drugs from patient’s medication regimen

Pharmacological treatment

• IVF and volume expanders are given as required to restore kidney perfusion
• Dopamine given by IV infusion in low doses to increase renal perfusion – it improves cardiac output and dilates blood vessels of kidney

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Pharmacological treatment

• Diuretics – Furosemide (Laxis) or osmotic diuretics eg mannitol
• Purpose of IVF + diuretic – to “wash out” the nephrons of toxins if any and to establish urine output which will reduce level of azotemia and prevent fluid and electrolyte imbalances

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Pharmacological treatment

• All potential nephrotoxic drugs discontinued – NSAIDs, nephrotoxic antibiotics are avoided
• ARF client has a likely risk for GIT bleeding probably from stress response and impaired platelet function – patient may need antacids, H2-antagonist or PPIs

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Pharmacological treatment

• Hyperkalaemia – may require administration of biocarbonate, calcium chloride, insulin and glucose intravenously to reduce serum potassium levels by moving potassium into the cells.
• Aliminium hydroxide – may be given to control hyperphosphatemia.
• Dosage of medication in general need to be reduced in ARF clients to prevent toxicity

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Pharmacological treatment

Treatment of fluid losses

• Correct fluid losses vigorously and early with appropriate fluid replacement as follows:
• 0.9% Sodium Chloride, IV, in cases of diarrhoea and vomiting
• Blood transfusion in severe bleeding
• Plasma replacement in cases of severe burns
• Furosemide (Furosemide), IV, when fluid volume has been replaced adequately

Nursing

Nursing Priorities

• Re-establish or maintain fluid and electrolyte balance.
• Prevent complications.
• Provide emotional support for client and significant other.
• Provide information about disease process, prognosis, and treatment needs.

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Nursing

• Nursing management is organized on the following major areas
• Nursing role regarding medication
• Monitoring fluid and electrolyte balance
• Reducing metabolic rate
• Promoting pulmonary function
• Preventing infection
• Provision of skin care
• Providing support

Nursing - responsibilities regarding drug administrations

Loop diuretics - Works in the loop of Henle. Response increases with increasing doses. They are highly effective diuretics used in ARF to establish urine flow

Nursing - responsibilities regarding drug administrations

Loop diuretics - Nursing responsibilities

• Assess weight + baseline vital signs
• Administer correct dosage
• Monitor intake and output
• Daily weighing
• Asses for fluid volume status eg skin turgor
• Ensure lab investigations are done eg serum elctrolytes
• Assess response – urine output typically increases within 10min post IV administration
• Advise and assist client in getting out of bed slowly – risk of orthostatic hypotension
• NSAIDs should be avoided – interfere with effectiveness of loop diuretics

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Nursing - responsibilities regarding drug administrations

Osmotic diuretics – acts by increasing the osmotic draw in blood and urine. Effect is to increase urine volume and flow

Nursing

• Assess urine output
• Not good for patient with heart failure or dehydration
• Monitor VS, breath sounds
• Discontinue if sign of heart failure or pulmonary oedema develop

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General nursing responsibilities

Nursing Management

• Monitor for potential complications.
• Assist in emergency treatment of fluid and electrolyte imbalances.
• Assess progress and response to treatment; provide physical and emotional support.
• Keep family informed about condition and provide support�

Monitoring fluid and Electrolyte Balance�

• Screen parenteral fluids, all oral intake, and all medications for hidden sources of potassium.
• Monitor cardiac function and musculoskeletal status for signs of hyperkalaemia.
• Pay careful attention to fluid intake (IV medications should be administered in the smallest volume possible),
• Fluid restrictions. Amount of fluids to be taken per day (600 ml (insensible fluid loss) + previous days urine output.
• Moisten the lips, give ice chips

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Monitoring fluid and Electrolyte Balance

• Monitor urine output, apparent oedema, distension of the jugular veins, alterations in heart sounds and breath sounds, and increasing difficulty in breathing.
• Maintain daily weight and intake and output records.
• Report indicators of deteriorating fluid and electrolyte status immediately. Prepare for emergency treatment of hyperkalaemia. Prepare patient for dialysis if indicated to correct fluid and electrolyte imbalances

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Promoting Pulmonary Function�

• Assist patient to turn and encourage to cough and take deep breaths frequently.
• Encourage and assist patient to move and turn.

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Reducing Metabolic Rate�

• Reduce exertion and metabolic rate with bed rest.
• Prevent or treat fever and infection promptly.

Preventing Infection

• Practice strict asepsis when working with invasive lines and catheters.
• Avoid indwelling catheters if possible or ensure frequent care of indwelling urethral catheters

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Providing Skin Care�

• Perform meticulous skin care
• Ensure frequent bathing and grooming
• Turn patient frequently,
• Keep the skin clean and well moisturized and fingernails trimmed for patient comfort and to prevent skin breakdown.

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Nursing Diagnosis�

• Excess fluid Volume related to compromised renal regulatory mechanism.
• Risk for Decreased Cardiac Output related to fluid overload, or fluid shifts, or fluid deficit.
• Risk for Imbalanced Nutrition: Less than Body Requirements
• Risk for Infection
• Deficient Knowledge

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