Acute Renal Failure (ARF)

 Acute Renal Failure (ARF)-

Chronic kidney disease- develops slowly over months to years and necessitates the initiation of dialysis or transplantation. Chronic kidney disease is not a critical care issue. Although it is seen regularly in an ICU setting, it is generally not the reason for admission to the ICU.

Acute renal failure (ARF) -is a clinical syndrome characterized by rapid decline in renal function → progressive azotemia and  increase ↑creatinine. It is associated with oliguria which can progress over hours or days with in increase↑ BUN, creatinine, and K+ with or without oliguria.

Pathophysiology
The 3 types of acute renal failure include:

  • Prerenal failure- Caused by conditions such as hemorrhage, myocardial infarction, heart failure, cardiogenic shock, sepsis, and anaphylaxis → impaired blood flow to kidneys → hypoperfusion of kidneys → retention of excessive amount of nitrogenous compounds → intense vasoconstriction →↓glomerular filtration rate (GFR). Patient can recover if fluid is replaced. 
  •  Intrarenal failure-Caused by burns, crush injuries, infections, glomerulonephritis, lupus erythematosus, diabetes mellitus, malignant HTN, nephroseptic agents → acute tubular necrosis → afferent arteriole vasoconstriction → hypoperfusion of the glomerular apparatus →↓GFR → obstruction of tubular lumen by debris and casts, interstitial edema, or release of intrarenal vasoactive substances. A nonrecovery is common.
  • Postrenal failure- Caused by any obstruction such as bladder tumors, renal calculi, enlarged prostate, or blocked catheter between the kidneys and urethral meatus →↑ pressure in kidney tubules →↓GFR.

Clinical Presentation-

ARF presents as-

  • Critical illness
  • Lethargic
  •  Persistent nausea and vomiting 
  • Diarrhea
  • Dry skin and mucous membrane from dehydration
  • Drowsiness
  • Headache
  • Muscle twitching
  • Seizures 

Signs of ARF include: -

  • Urine <400 mL/24 hours
  • ↑Serum urea and creatinine
  •  Peripheral and systemic edema
  • ↓ BP → fluid overload → pulmonary and peripheral edema
  • ↓ BP → dehydration/sepsis
  • Abnormal, irregular pulse → cardiac arrhythmia
  •  Kussmaul’s respirations → metabolic acidosis
  • ↑Temperature → infection
  •  ↓ level of consciousness (LOC)/seizures
  • Electrolyte imbalance (increased serum BUN, creatinine, K+, Na+, phosphate; decreased serum calcium)

Diagnostic Tests 

  •  Serum BUN, creatinine, electrolytes, CBC, coagulation studies (PT/PTT), serum osmolarity, chemistry panel
  •  Urinalysis with microscopic examination for protein and casts
  •  Urine culture and sensitivity
  • Urine electrolytes and urine osmolarity
  •  24-hour urine for creatinine clearance
  • Renal ultrasound scanning
  • Chest x-ray
  •  Renal biopsy
  • GFR rate
  •  Kidney-ureters-bladder (KUB) x-ray
  • Intravenous pyelogram (IVP)
  •  CT scan or MRI of kidneys
  •  Renal arteriogram

Management-

  • Monitor fluid and electrolytes. Assess for acid-base imbalances.
  •  Assess respiratory status and monitor oxygenation. Administer O2 as indicated.
  •  Institute cardiac monitor and observe for arrhythmias.
  •  Insert indwelling Foley catheter.
  •  Restrict fluid intake and measure intake and output strictly. Assess for edema.
  •  Assess color, clarity, and amount of urine output. Check specific gravity.
  •  Institute renal diet with adequate protein and low K+, Na+, and phosphorus. Protein may be restricted if BUN and creatinine greatly elevated. Treat anorexia, nausea, and vomiting.
  • Monitor daily weight.
  • Insertion of a large-bore central line.
  • Administer medications, including calcium channel blockers, beta blockers, and diuretics such as bumetanide (Bumex) and furosemide (Lasix).
  • Administer iron supplement.
  •  Monitor hemoglobin and hematocrit levels for anemia and O2-carrying capacity of hemoglobin.
  •  Administer blood products or erythropoietin products as needed.
  •  Maintain meticulous skin care to prevent skin breakdown.
  •  Ensure prevention of secondary infections.
  •  Assess for gastrointestinal and cutaneous bleeding.
  •  Assess neurological status for changes in LOC and confusion.
  •  Administer dialysis (hemodialysis, peritoneal dialysis).
  • Provide patient and family support.
     

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