Acute Renal Failure

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Acute Renal Failure
2011-01-13 13:04:05
Acute Renal Failure PHPR521

Acute Renal Failure
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  1. What is the definition of anuric?
    urine output < 50mL/d
  2. What is the definition of oliguric?
    urine output < 500mL/d
  3. What is the definition of nonoliguric?
    urine output >500mL/d
  4. What are the characteristics of RIFLE?
    • R = risk of dysfunction; SrCr up 50%; GFR down 25%, UO < 0.5mL/kg/h for 6h
    • I = injury to kidney; SrCr up 100%; GFR down 50%; UO < 0.5mL/kg/h for 12h
    • F = failure of kidney; SrCr up 200%; GFR down 75%; UO < 0.3mL/kg/h for 24h or anuria for 12h
    • L = Loss of function; persistent ARF > 4wks
    • E = End-stage renal disease; ESRD > 3mo
  5. What is the definition of prerenal ARF?
    • decreased renal perfusion in the setting of undamaged parenchymal tissue
    • NSAIDS, ACE, ARB, dehydration, B-blockers
  6. What is the definition of intrinsic ARF?
    • result of structural damage to the kidney - most commonly the tubule from ischemic or toxic insult
    • nafcillin
  7. What is the definition of postrenal ARF?
    • caused by obstruction of urine flow downstream from the kidney
    • obstruction d/t prostatic process (enlarged prostate)
    • improperly placed urinary catheter
    • neurogenic bladder
    • too many anticholinergics
  8. What are the causes of decline in IV blood volume leading to prerenal azotemia?
    • acute blood loss
    • dehydration
    • hypoalbuminemia
    • diuretic therapy
  9. How is renal vascular damage usually caused?
    atherothrombi dislodged during a procedure or thromboemboli from pts with severe heart failure or atrial fibrillation
  10. What is the cause of glomerular damage?
    • severe inflammatory processes as seen in SLE and poststreptococcal glomerulonephritis
    • emboli
  11. What is the cause of 85% of ARF?
    tubule damage (acute tubular necrosis)
  12. What is the cause of 50% of ARF?
    renal ischemia
  13. What is the cause of 35% of ARF?
    • exposure to direct tubule toxins:
    • myoglobin
    • hemoglobin
    • uric acid
    • contrast dyes
    • heavy metals
    • aminoglycosides
  14. What are the effects of tubular injury?
    • inability to concentrate urine
    • defective distal sodium reabsorption
    • decrease in GFR
  15. What is the time frame for the maintenance and recovery phases of acute tubular necrosis (ATN)?
    2-3 wks per phase
  16. What are the most common causes of interstitial damage?
    • medications
    • bacterial or viral infections
  17. What type of dialysis should be used to treat hypokalemia?
  18. What is the mechanism for renal failure d/t concomittant use of NSAIDs and ACE/ARBs?
    constriction of afferent arterioles (NSAIDs) and dilation of efferent arterioles (ACEI)
  19. What is urine sodium in prerenal?
    < 20
  20. What is urine sodium in intrinsic and postrenal?
    > 40
  21. What is FENa % in prerenal?
  22. What is FENa % in intrinsic?
  23. What is FENa % in postrenal?
  24. What is osmolality in prerenal?
    > 1.5
  25. What is osmolality in intrinsic?
    < 1.3
  26. What is osmolality in postrenal?
    < 1.5
  27. What is urine/SCr in prerenal?
    > 40:1
  28. What is urine/SCr in intrinsic and postrenal?
    < 20:1
  29. What is BUN/SCr in prerenal?
    > 20
  30. What is BUN/SCr in intrinsic and postrenal?
    about 15
  31. What is the FENa equation?
    FENa = (UNa x SCr x 100)/(UCr x SNa)
  32. What meds disrupt the usefulness of FENa?
  33. At what [K] is immediate tx of hyperkalemia required?
    • > 7.0
    • b/w 6.1-6.9 if ECG changes present
  34. How do you treat hyperkalemia?
    • lasix
    • kayexelate (cation exchange for Na)
    • Calcium gluconate or chloride (stabilizes the heart)
    • sodium bicarb (pushes intracellular)
    • insulin and glucose (pushes intracellular
    • beta agonists (pushes intracellular)
    • dialysis
  35. What should be remembered about Metformin and ARF?
    Metformin doesn't cause ARF, but it does need to be stopped in ARF
  36. What is the Ca x Phosphorus product goal value?
    < 55 mg/dL
  37. At what Ca x Phosphorus product value does mortality increase?
    72 mg/dL
  38. What are the medical issues associated with hyperphosphatemia/hyperparthyroidism?
    • alterations in lipid metabolism and insulin secretion
    • resistance to erythropoieten tx
    • myocardial, skeletal muscle, neurologic and immune dysfunction
    • vascular calcification, renal osteodystrophy
  39. What drugs are used to treat hyperphosphatemia?
    • calcium acetate or carbonate (Phoslo)
    • Sevelamer
    • Lanthanum
  40. What is first line tx for hyperphoshpatemia?
    • sevelamer
    • calcium acetate/carbonate (Phoslo) if no insurance or if Ca < 8.2
  41. What drugs are used to tx hyperparathyroidism?
    • vitamin D3 (Calcitriol, Rocaltrol)
    • vitamin D2 (Zemplar)
    • Cinacalcet
  42. Why do pts with chronic renal failure have anemia?
    • blood draws
    • hemodialysis
    • iron deficiency
    • decreased erythropoietin production
    • uremia build-up
  43. When does work-up start for anemia?
    • Hgb < 12 premenopausal
    • Hgb < 13.5 postmenopausal and men
  44. What is the goal for CKD?
    • 11-12g/dL
    • begin tx at about 9g/dL
  45. What is the goal for transferrin saturation?
    > 20%
  46. What is the goal for serum ferritin?
    > 100ng/mL
  47. What is the goal for serum iron?
  48. What drugs are used to tx anemia secondary to renal failure?
    • epoetin alfa/darbepoetin alfa (Epogen, Procrit, Eprex)
    • Iron (Slow Fe, Ferrin-Sol, Feratab, Mol-Iron, Feosol)
  49. How should iron be taken?
    on an empty stomach to increase absorption
  50. What is SCUF (slow continuous ultrafiltration) used for?
    • only for fluid control
    • no dialysate
    • no replacement fluid
  51. What is CVVH (continuous venovenous hemofiltration) used for?
    • fluid and some solute removal
    • replacement fluid
    • no dialysate
  52. What is CVVHD (continuous venovenous hemodialysis) used for?
    • greater solute removal, less fluid removal
    • dialysate
    • no replacement fluid
  53. What is CVVHDF (continuous venovenous hemodiafiltration) used for?
    • fluid removal plus solute removal (small and large particles)
    • dialysate
    • replacement fluid
  54. What is the MW cutoff to get through the peritoneum in or out?
    5200 Dalton
  55. What is the MW cutoff for low efficiency, conventional dialysis?
    > 500 Dalton
  56. What is the MW cutoff for high efficiency, conventional dialysis?
    > 2,000 Dalton
  57. What is the MW cutoff for high efficiency, high flux dialysis?
    > 12,000 Dalton