What are the indications for emergent dialysis?

Indications for Emergent Dialysis

Initiate dialysis emergently when life-threatening metabolic derangements exist, specifically: severe hyperkalemia (>6.5 mmol/L), refractory metabolic acidosis, volume overload unresponsive to diuretics, or overt uremic symptoms including pericarditis and encephalopathy. 1

Life-Threatening Metabolic Indications

Hyperkalemia

• Persistent hyperkalemia requiring immediate dialysis is defined as serum potassium >6.5 mmol/L that fails to respond to medical management (calcium gluconate, insulin with glucose, beta-agonists) 1, 2
• This threshold represents the point where cardiac arrhythmias become imminent and life-threatening 1

Severe Metabolic Acidosis

• Dialysis is indicated for severe metabolic acidosis that is refractory to bicarbonate therapy, particularly when pH remains critically low despite medical intervention 1
• In toxic alcohol poisoning (methanol/ethylene glycol), specific thresholds apply: anion gap >27 mmol/L warrants emergent dialysis 1
• An anion gap of 23-27 mmol/L should prompt strong consideration for dialysis 1

Volume Overload

• Pulmonary edema or severe volume overload unresponsive to diuretic therapy constitutes an emergent indication 1
• This is particularly critical when respiratory compromise develops from fluid accumulation 1

Uremic Complications

Neurological Manifestations

• Uremic encephalopathy with altered mental status, confusion, or seizures requires immediate dialysis 1, 3
• Coma in the setting of uremia is an absolute indication for emergent dialysis 1, 3
• Seizures related to uremia mandate dialysis initiation 1, 3

Pericarditis

• Uremic pericarditis is an absolute indication for emergent dialysis due to risk of cardiac tamponade 1

Acute Kidney Injury Specific Indications

Severe AKI

• KDIGO stage 2 or 3 AKI with any of the above metabolic derangements warrants dialysis 1
• Blood urea nitrogen >30 mmol/L (approximately 84 mg/dL) combined with clinical uremic symptoms indicates need for dialysis 2

Progressive Hyperphosphatemia

• In tumor lysis syndrome, severe progressive hyperphosphatemia >6 mg/dL may warrant prophylactic dialysis before overt uremic symptoms develop 1
• Severe symptomatic hypocalcemia secondary to hyperphosphatemia is another indication 1

Toxic Ingestion Specific Indications

Ethylene Glycol Poisoning

• Dialysis is mandatory when ethylene glycol concentration is >50 mmol/L (>310 mg/dL) regardless of antidote availability 1
• With no antidote available, dialysis is required at >10 mmol/L (>62 mg/dL) 1
• Osmolar gap >50 (when fomepizole or ethanol used) or >10 (no antidote) indicates need for dialysis 1
• Coma or seizures from ethylene glycol poisoning require immediate dialysis 1
• Measured glycolate concentration >12 mmol/L mandates dialysis 1

Methanol Poisoning

• Similar thresholds apply: concentration ≥50 mg/dL, significant metabolic acidosis, or renal failure warrant hemodialysis 4, 5
• Visual disturbances with documented methanol ingestion should prompt dialysis consideration 4

Critical Pitfalls to Avoid

• Do not rely solely on estimated GFR or single creatinine values to determine dialysis timing - the broader clinical context including trends and symptoms must guide decisions 1
• Do not delay dialysis in toxic ingestions waiting for confirmatory levels - initiate based on clinical suspicion with anion gap metabolic acidosis, increased osmolar gap, or visual disturbances 4
• Do not use peritoneal dialysis for emergent indications - it is too inefficient for removing solutes and managing acute life-threatening complications 1
• In hemodynamically unstable patients, continuous renal replacement therapy is preferred over intermittent hemodialysis to avoid exacerbating hypotension 1, 3
• For toxic ingestions requiring hemodialysis, intermittent hemodialysis is superior to CRRT due to more efficient toxin removal 1

Modality Selection

• Intermittent hemodialysis is the preferred modality for most emergent indications when hemodynamic stability permits 1
• CRRT should be used for hemodynamically unstable patients or those at risk for cerebral edema 1, 3
• In tumor lysis syndrome, frequent (daily) dialysis is recommended due to continuous metabolite release 1