Nursing 4 Lecture 5 Acute Renal Failure

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Nursing 4 Lecture 5 Acute Renal Failure
2012-02-04 23:43:16

Nursing 4 Lecture 5 Acute Renal Failure
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  1. Pathophysiology:
    • -Rapid decrease in kidney function, leading to the collection of metabolic wastes in the body
    • -Acute syndrome may be reversible, esp with prompt intervention
    • -Occurs suddenly (over hours to a few days)

    • *GFR decreases
    • *Serum creatinine and BUN increase
    • *Most common cause: hypotension & pre-renal hypovolemia

    • Prerenal Failure:
    • -Results from conditions that reduce blood flow to the kidneys ( ex. hypovolemia)

    • Intrarenal/Intrinsic Renal Failure:
    • -Damage to the glomeruli, interstitial tissue, or tubules

    • Postrenal Failure:
    • -Obstruction of urine flow
  2. Prerenal Azotemia:
    • -Any condition decreasing blood flow to the kidneys and leading to ischemia in the nephrons
    • -Caused by poor blood flow to the kidneys
    • -Kidneys depend on a adequate supply of blood to be filtered by the glomeruli
    • -Reduced blood flow lowers the GFR and can lead to ARF
    • -If the prerenal condition is prolonged it can progress to intrarenal damage

    • Causes:
    • -Shock
    • -Heart failure
    • -Pulmonary embolism
    • -Anaphylaxis
    • -Sepsis
    • -Pericardial tamponade
  3. Intrarenal (Intrinsic) ARF:
    -Actual physical, chemical, hypoxic, or immunologic tissue damage to the kidneys

    • Examples:
    • -Acute interstitial nephritis
    • -Exposure to nephrotoxins
    • -Acute glomerulonephritis
    • -Vasculitis
    • -Acute tubular necrosis
    • -Renal artery or vein stenosis
    • -Renal artery or vein thrombosis
    • -Formation of crystals or precipitates in the nephron tubules
  4. Postrenal Azotemia:
    -Obstruction to the urine collection system anywhere from the calyces to the urethal meatus

    • Causes:
    • -Ureter, bladder, or urethral cancer
    • -Kidney, ureter, or bladder stones
    • -Bladder atony (atonic bladder: a large, dialated, and non emptying urinary bladder; usually attributable to disturbance of innerbation or to chronic obstruction)
    • -BPH or cancer
    • -Urethral stricture
    • -Cervical cancer
  5. Onset Phase:
    • Description:
    • -Begins with the precipitating event and continues until oliguria develops
    • -Lasts hours to days

    • Characteristics:
    • -The gradual accumulation of nitrogenous wastes, such as serum creatinine and BUN
  6. Oliguric Phase:
    • Description:
    • -Characterized by a urine ouput of 100 to 400 mL/24 hours that does not respond to fluid challenges or diuretics
    • -Lasts 1 to 3 weeks

    • Characteristics:
    • -Laboratory data include increasing serum creatinine and BUN levels, hyperkalemia, bicarbonate deficit (metabolic acidosis), hyperphosphatemia, hypocalcemia, and hypermagnesemia
    • -Sodium retention occurs, but this is masked by the dilutional effects of water retention
    • -Urinary indices are typically low and fixed; regulation of water balance by the kidneys is impaired, so urine specific gravity and urine osmolarity do not vary as plasma osmolarity changes
  7. Diuretic Phase (high output phase):
    • Description:
    • -Often has a sudden onset within 2 to 6 weeks after oliguric stage
    • -Urine flow increases rapidly over a period of several days
    • -The diuresis can result in an ouput of up to 10 L/day of dilute urine

    • Characteristics:
    • -Electrolyte losses typically precede clearance of nitrogenous wastes
    • -Later in the diuretic phase the BUN level starts to fall and continues to fall until the level reaches normal limits
    • -Normal renal tubular function is re-established during this phase
  8. Recovery Phase (convalescent phase):
    • Description:
    • -The patient begins to return to normal levels of activity
    • -Complete recovery may take up to 12 months

    • Characteristics:
    • -The patient functions at a lower energy level and has less stamina than before the illness
    • -Residual renal insufficiency may be noted through regular monitoring of renal function
    • -Renal function may never return to pre-illness levels, but renal function sufficient for a long and healthy life is likely
  9. Health Promotion and Maintenance:
    -Severe blood volume depletionan lead to renal failure even in people who have no known kidney problems

    -Continual assessment of I&O, blood volume depletion, laboratory values, and use of nephrotoxic substances

    • -Need to avoid dehydration
    • -Encourage everyone to drunk 2 to 3 liters of fluid a day
    • -Decreased urine specific gravity indicates a loss of urine concentrating ability and is the earliest sign of renal tubular damage
  10. Assessment: History
    • -Exposure to nephrotoxins
    • -Recent surgery or trauma
    • -Transfusions
    • -Obtain a drug hx especially tx w/ antibiotics, ace inhibitors, and NSAIDS
    • -Recent imaging requiring contrast dye because they can cause ARF
    • -Ask about diseases that impair renal function such as DM, long term HTN, and systemic lupus
  11. Assessment: Physical/Clinical Manifestations
    • Prerenal:
    • -Hypotenstion
    • -Tachycardia
    • -Decreased urine output
    • -Decreased cardiac output
    • -Lethargy

    • Intrarenal:
    • -Oliguria or anuria
    • -Edema
    • -Hypertensioin
    • -Tachycardia
    • -SOB
    • -Distended neck veins
    • -Weight gain
    • -Resp crackles
    • -Anorexia
    • -N/V
    • -Lethargy
    • -Electrolytes:elevated potassium, low calcium

    • Postrenal:
    • -Oliguria
    • -Sx of uremia and lethargy
    • -Report changes in urine flow or difficulty starting urination
  12. Assessment: Laboratory
    • -Serum creatinine
    • -BUN
    • -Serum sodium (or decreased or normal)
    • -Serum potassium
    • -Serum phosphorus
    • -Serum magnesium

    • -Serum calcium
    • -Bicarbonate
    • -Arterial blood PaCO2
    • -Hemoglobin
    • -Hematocrit
  13. Specific Gravity:
    • Prerenal:
    • -Urine is concentrated
    • -Greater than 1.030

    • Intrarenal:
    • -Less than 1.010

    • Postrenal:
    • -1.000 to 1.010
  14. Assessment: Imaging
    • -KUB
    • -Ultrasound
    • -CT scans (without contrast dye)
  15. Assessment: Diagnostic
    -Renal biopsy
  16. Nursing Management:
    • -I&O and daily weights are vital interventions
    • -1kg weight gain = 1000 mL of fluid
    • -1lb=500 mL
    • -Administer IV fluid as ordered prior to procedures with radiocontrast agents
    • -Prevent infection
    • -Monitor Peak & Trough levels to measure toxicity
  17. Drug Therapy:
    • Cardiac Glycosides: Digoxin
    • -Improves ventricular contraction, increasing stroke volume and cardiac output

    • Vitamins and Minerals: Folic acid, ferrous sulfate
    • -Used to replace essential vitamins and minerals removed with dialysis

    • Sythetic Erythropoietin: Epogen, procrit
    • -Prevents anemia by stimulating RBC growth and maturation in bone marrow

    • Phosphate Binders: Aluminum hydroxide gel
    • -Increase blood phosphate and causes decreased calcium
    • -Drugs bind to phosphorus in food and lower serum levels
  18. Nutrition Therapy:
    • -Pts have a high rate of protein breakdown
    • -Exact cause is not known
    • -Rate of protein breakdown correlates with the severity of uremia (build up of urea) and azotemia (build up of nitrogen)

    • Protein:
    • -No dialysis: 0.6g/kg/day
    • -With dialysis: 1 to 1.5g/kg/day

    • Sodium and Potassium:
    • -Dietary sodium ranges from 60 to 90 mEq
    • -If potassium levels are high, that is restricted to 60 to 70 mEq

    • Fluid:
    • -Urine output plus 500 to 600 mL

    If the patient is to ill to eat, TPN or hyperalimentation is needed. Lipids are a good form of non-protein calories

    • Hyperalimentation:
    • -The administration of nutrients by EV feeding, especially to individuals unable to take in food through the alimentary tract
  19. Dialysis Therapies:
    • Indications:
    • -Presence of anemia
    • -Persistent high potassium
    • -Metabolic acidosis
    • -Continued fluid volume excess
    • -Uremic pericarditis
    • -Encephalopathy

    • Immediate vascular access for HD is made by placement of a dula or triple lumen catheter made specifically for HD, preferably in the subclavian or internal jugular vein

      -Continuous renal replacement therapy
    • -Continuous arteriovenou hemofiltration (CAVHD)
    • -Continuous arteriovenous hemodyalysis and filtration (CAVHD)
    • -Hemodialysis (HD)
    • -Peritoneal dialysis (PD)
  20. Subclavian Dialysis Catheters:
    Mahurkar catheters made of polyurethan are used for short term access

    • PermCath catheter made of silicone is used for long term access
    • Assess for complications:
    • -Pneumothorax (reduced breath sounds, tracheal deviation away from midline, prominence and poor movement of one side of the chest)
    • -Subcutaneous emphysema (crackling and swelling of tissue around the site)
  21. Tunnelled Haemodialysis Catheters:
    • -Most common type of catheter used within the dialysis unit and can stay in position for several months or even years
    • -Catheter has a tunnelled section which lies under the skin and has a holding cuff which helps anchor the catheter in place and helps prevent infection by acting as a barrier against bacteria

    • Most commonly used: Tesio Catheter
    • -It consists of two seperate lines that sit close to each other in the vein and lie side by side under the skin
    • -Both come out lower down on your chest and have a dressing placed over the exit site to prevent infection
  22. Continuous Renal Replacement Therapy:
    -Better tolerated than hemodialysis for critically ill patients because this method avoids rapid shifts of fluid and electrolytes

    • CAVH:
    • -Used for patients with fluid volume overload, are resistent to diuretics, or who have unstable BP's and cardiac output
    • -Continuously removed large amounts of plasma water, wastes and electrolytes
    • -Electrolytes are replaced through prescribed amounts of IV electrolyte solutions

    • CVVH:
    • -Uses a pump making the rate of filtration more reliable than methods useing mean arterial pressure
  23. Posthospital Care:
    • -If renal failure is resolving, follow up care my be required
    • -There may be permanent renal damage and the need for chronic dialysis or even transplantation
    • -Temporary dialysis is appropriate for some patients