Plasma Exchange in Acute Liver Failure

Indications for Plasma Exchange

• Hyperammonemia (ammonia > 150 µmol/L) in adult acute liver failure (ALF) warrants plasma exchange as adjunctive therapy – conditional recommendation based on low‑quality evidence from the American College of Critical Care Medicine. 1
• Wilson disease‑related ALF requires immediate initiation of plasma exchange to serve as a bridge to transplantation, because the condition is uniformly fatal without transplant. 1
• High‑volume plasma exchange (8–12 L per session) may be considered for patients with severe disease (e.g., CLIF‑C ACLF score ≥ 13 or Grade 4 encephalopathy), as it has shown additional benefit in a multicenter randomized trial. 1

Diagnostic Criterion Supporting Decision‑Making

• ALF is defined by the absence of known chronic liver disease together with liver‑derived coagulopathy (INR ≥ 1.5) and hepatic encephalopathy. This definition guides the identification of patients eligible for plasma exchange. 2

Evidence of Survival Benefit

• The above trial demonstrated a statistically significant improvement in transplant‑free survival with high‑volume plasma exchange.

Implementation Considerations

• Resource and expertise requirements – plasma exchange should be performed only at centers with experienced operators and appropriate infrastructure; the conditional nature of the recommendation allows adaptation to local resource availability. 1
• Bridge to liver transplantation – patients receiving plasma exchange should simultaneously be listed for transplantation, as exchange therapy is not curative. 1

Contraindications / Distinctions

• Plasma exchange is not recommended for acute‑on‑chronic liver failure (ACLF); the European Association for the Study of the Liver advises against routine use outside research settings, and the American Association for the Study of Liver Diseases limits its use to ALF with hyperammonemia. [3][4]
• Standard chronic liver failure therapies (e.g., lactulose, rifaximin) have not shown benefit in ALF and should not be relied upon as primary treatment. 1

Plasma Exchange Preferred for Severe Hyperammonemia in Acute Liver Failure

Guideline Recommendation

• In adult acute liver failure (ALF) patients with severe hyperammonemia (ammonia > 150 µmol/L), the Society of Critical Care Medicine recommends plasma exchange as the preferred extracorporeal therapy over continuous renal replacement therapy (CRRT) alone. This recommendation is conditional and based on low‑quality evidence. [5][6]

Evidence Strength and Details

• The 2023 Critical Care Medicine guideline (Society of Critical Care Medicine) issues a conditional recommendation for plasma exchange in ALF with hyperammonemia, acknowledging that the supporting evidence is of low quality. [5][6]
• High‑volume plasma exchange (8–12 L per session) is specifically advised for patients with ammonia > 150 µmol/L, providing the most effective reduction of both ammonia and inflammatory mediators. [5][6]

Clinical Decision Algorithm (Cited Steps)

• Ammonia measurement is required to guide therapy; levels ≥150 µmol/L trigger the plasma‑exchange pathway. 6
• If ammonia ≥ 150 µmol/L and plasma‑exchange capability is available, initiate plasma exchange immediately. [5][6]
• If ammonia ≥ 150 µmol/L and plasma exchange is unavailable, start CRRT with a bicarbonate‑buffered solution as a secondary measure. (cited by the same guideline) [5][6]

Contra‑indicated or Ineffective Therapies (Cited)

• Lactulose and rifaximin have not shown benefit for hyperammonemia in ALF and should not be used in this setting. This statement is supported by the same conditional recommendation. [5][6]