What are the indications for emergent dialysis in patients with acute kidney injury (AKI)?

Indications for Emergent Dialysis in Acute Kidney Injury

Emergent dialysis should be initiated immediately when life-threatening changes in fluid, electrolyte, and acid-base balance exist in patients with acute kidney injury (AKI). 1

Absolute Indications for Emergent Dialysis

Electrolyte Abnormalities

• Severe hyperkalemia (K+ ≥6.5 mEq/L) or rapidly rising potassium levels, especially with ECG changes 1, 2
• Severe dysnatremia that is symptomatic or resistant to medical management 1

Acid-Base Disturbances

• Severe metabolic acidosis (pH <7.1) with impaired compensation 1, 3
• Lactic acidemia that is severe and refractory to medical management 1

Volume Overload

• Pulmonary edema unresponsive to diuretics 1, 4
• Severe fluid overload causing respiratory compromise 1, 5
• Anuria or oliguria with progressive volume overload 1

Uremic Complications

• Uremic encephalopathy 1
• Uremic pericarditis 1
• Uremic bleeding 1

Relative Indications (Context-Dependent)

• Rapidly rising blood urea nitrogen (BUN) and creatinine levels 1
• Drug overdose with dialyzable toxins 6
• Hyperthermia unresponsive to conventional cooling measures 6
• Rhabdomyolysis with progressive AKI and myoglobinuria 1

Special Considerations for Specific Patient Populations

Trauma-Associated AKI

• Earlier initiation of RRT may be associated with improved survival in trauma-associated AKI 1
• Crush-related AKI often requires earlier initiation and more frequent dialysis due to higher incidence of life-threatening complications such as hyperkalemia and acidosis 1

Patients with Brain Injury

• Continuous renal replacement therapy (CRRT) is preferred over intermittent hemodialysis for patients with acute brain injury or increased intracranial pressure 1, 5
• CRRT provides more stable hemodynamics and better control of intracranial pressure 1

Hemodynamically Unstable Patients

• CRRT is recommended over standard intermittent hemodialysis for hemodynamically unstable patients requiring vasopressor support 1, 5
• CRRT allows for gentler fluid removal and better hemodynamic tolerance 1

Modality Selection for Emergent Dialysis

• Intermittent hemodialysis is preferred for rapid correction of severe hyperkalemia due to faster clearance 1
• CRRT is preferred for hemodynamically unstable patients and those with increased intracranial pressure 1, 5
• Peritoneal dialysis may be considered in small children or when other options are not available, though rapid exchanges may be required for efficient potassium removal 1

Common Pitfalls to Avoid

• Delaying dialysis when absolute indications are present can increase mortality 2, 7
• Focusing solely on creatinine or BUN thresholds rather than considering the broader clinical context 1
• Failing to recognize AKI in patients with normal baseline renal function, which is associated with higher mortality than AKI superimposed on chronic kidney disease 2
• Inadequate monitoring of electrolytes during initial dialysis, which can lead to dialysis disequilibrium syndrome 3
• Inappropriate vascular access placement - right jugular or femoral veins are preferred first choices 1

Practical Implementation

• Use uncuffed non-tunneled dialysis catheters for initial access in emergent situations 1
• Deliver adequate dialysis dose: Kt/V of 3.9 per week for intermittent RRT or effluent volume of 20-25 mL/kg/h for CRRT 1
• Use bicarbonate-based dialysate rather than lactate, especially in patients with shock, liver failure, or lactic acidemia 1, 5
• Consider regional citrate anticoagulation for CRRT in patients without contraindications 1

By promptly recognizing these indications and initiating appropriate renal replacement therapy, clinicians can significantly improve outcomes in patients with acute kidney injury requiring emergent dialysis.