What are the indications for hemodialysis in patients presenting to the emergency department (ED) with acute kidney injury or severe chronic kidney disease?

Indications for Hemodialysis in Emergency Department Patients with Acute Kidney Injury or Severe CKD

Renal replacement therapy (RRT) should be initiated immediately in patients with life-threatening complications of acute kidney injury (AKI) or severe chronic kidney disease (CKD), rather than waiting for conservative management when metabolic demands exceed kidney capacity. 1

Absolute Indications for Emergency Hemodialysis

1. Life-threatening Electrolyte Abnormalities

• Severe hyperkalemia (K+ ≥6.5 mEq/L) with ECG changes 1, 2
• Severe hyponatremia or hypernatremia causing neurological symptoms
• Severe hypercalcemia causing hemodynamic instability or altered mental status

2. Severe Acid-Base Disturbances

• Severe metabolic acidosis (pH <7.1) refractory to medical management 1
• Lactic acidosis with hemodynamic compromise

3. Volume Overload

• Pulmonary edema unresponsive to diuretics 1
• Respiratory compromise due to fluid overload
• Refractory heart failure exacerbation with volume overload

4. Uremic Complications

• Uremic encephalopathy (altered mental status, seizures)
• Uremic pericarditis (chest pain, friction rub, ECG changes)
• Uremic bleeding (platelet dysfunction causing hemorrhage)

5. Toxin Removal

• Poisoning or drug overdose with dialyzable toxins (lithium, salicylates, methanol, ethylene glycol)

Modality Selection Based on Patient Status

Hemodynamically Unstable Patients

• Continuous RRT (CRRT) is preferred for:
  • Patients requiring vasopressor support
  • Patients with increased intracranial pressure
  • Patients with septic shock 1
• Target effluent volume: 20-25 mL/kg/h 1

Hemodynamically Stable Patients

• Intermittent hemodialysis (IHD) may be used when:
  • Vasopressor support has been discontinued
  • Intracranial hypertension has resolved
  • Fluid balance can be controlled with intermittent therapy 1
• Target Kt/V: at least 1.2 per treatment three times weekly 1

Vascular Access Considerations

• First choice: Right jugular vein or femoral vein 1
• Second choice: Left jugular vein
• Avoid: Subclavian veins due to risk of stenosis 1
• Use ultrasound guidance for insertion to minimize complications 1

Special Considerations

Electrolyte Management During RRT

• Use dialysis solutions containing potassium, phosphate, and magnesium to prevent electrolyte disorders 3
• Monitor for common electrolyte abnormalities during intensive/prolonged RRT:
  • Hypophosphatemia
  • Hypokalemia
  • Hypomagnesemia 3

Nutritional Support

• For critically ill patients on CRRT: Provide 1.5-1.7 g/kg/day of protein 1
• Do not reduce protein intake to delay RRT initiation 1

Discontinuation of RRT

RRT should be discontinued when:

• Kidney function has recovered sufficiently
• RRT becomes inconsistent with shared care goals
• Increasing urine output indicates potential for recovery 1

Caution and Pitfalls

1. Avoid unnecessary RRT: Evidence suggests that unnecessary RRT may be independently associated with impaired kidney recovery 4

2. Higher mortality risk factors to consider when initiating RRT:

   • Cardiac arrest at time of diagnosis
   • Multi-organ failure
   • Acute kidney injury in patients with previously normal renal function 2

3. Careful monitoring required for patients with:

   • Underlying malignancy
   • Active infection
   • Ongoing bleeding 2

4. Post-discharge follow-up: Patients who received RRT for AKI should have kidney function assessed within 3-7 days after the last RRT session 3

By following these guidelines, emergency physicians can appropriately identify patients requiring urgent hemodialysis while avoiding unnecessary RRT that might impair kidney recovery.