Renal Failure

• • Oliguric (urinary output < 400 mL/d) and nonoliguric

  • Mortality in surgical ICU of 50-90%

  • Etiologies of parenchymal disease include:

  • -Acute tubular necrosis

    -Pigment nephropathy

    -Nephrotoxic agents

    -Acute rejection following transplantation

    -Prerenal and postrenal causes

Symptoms and Signs

• • Diminished urinary output

  • Altered mental status

  • Abdominal pain

  • Edema

  • Prolonged bleeding time secondary to platelet dysfunction

  • Tenderness over transplant allograft

  • Hypertension

Laboratory Findings

• • Elevated creatinine

  • Hyperkalemia

  • Hyperphosphatemia

  • Elevated blood urea nitrogen

  • Urine osmolarity isotonic with serum levels

  • Urine sodium > 40

  • Fractional excretion of sodium > 3%

  • Hyponatremia

  • Hypocalcemia

  • Metabolic acidosis

  • Anemia

Imaging Findings

• • Renal US: Shows dampened waveform in arterial thrombosis or diastolic reversal of flow in venous obstruction or allograft rejection post-transplantation

• • Duration since transplantation

  • Underlying critical illness in acute renal failure

Rule Out

• • Renal artery or vein thrombosis immediately post-transplant

  • Ureter obstruction or leak post-transplant

• • History and physical exam

  • Serum and urine creatinine

  • Serum and urine sodium

  • Serum potassium

  • Serum phosphate

  • Renal US

Surgery

Indications

• • Removal of allograft if hyperacute rejection

Medications

• • Optimization of cardiac output

  • Diuresis and renal replacement therapy (intermittent hemodialysis, continuous venovenous hemofiltration and dialysis if hemodynamically unstable)

  • Adequate nutrition

  • Treatment of underlying disease

  • Pulse corticosteroids and/or OKT3 for acute allograft rejection

Prognosis

• • 50-90% mortality (highest if oliguric)

  • 90% recover renal function if survive underlying inciting illness (recovery unlikely if > 6 weeks postresolution of illness)

Prevention

• • Avoidance of nephrotoxic agents and maintain organ perfusion in critically ill

  • Adequate immunosuppression and compliance post-renal transplant

References