How to manage anuria in a patient with acute liver failure?

Management of Anuria in Acute Liver Failure

In patients with acute liver failure and anuria, continuous renal replacement therapy (CRRT) should be initiated immediately, with aggressive fluid resuscitation using albumin to maintain mean arterial pressure of 50-60 mm Hg, while avoiding intermittent hemodialysis due to hemodynamic instability. 1, 2

Renal Replacement Therapy Strategy

Continuous modes of dialysis are strongly preferred over intermittent hemodialysis in acute liver failure with anuria. 1, 2 The hemodynamic instability inherent to acute liver failure makes intermittent hemodialysis poorly tolerated, as it can precipitate further circulatory collapse and worsen cerebral perfusion. 3, 4

Key Technical Considerations:

• Regional citrate anticoagulation requires careful monitoring because the failing liver cannot adequately metabolize citrate, leading to potential citrate accumulation and metabolic complications. 1, 2
• Continuous venovenous hemofiltration (CVVH) or continuous venovenous hemodiafiltration (CVVHDF) are the preferred modalities. 3, 5
• CRRT provides gradual fluid removal without hemodynamic fluctuations, which is critical for maintaining cerebral perfusion pressure. 3, 4

Hemodynamic Management Before and During Dialysis

Aggressive volume resuscitation with albumin (colloid) must precede any consideration of vasopressor support. 1, 2 This is a critical pitfall—many clinicians prematurely escalate to vasopressors without ensuring adequate intravascular volume.

Fluid Resuscitation Protocol:

• Use albumin preferentially over crystalloid solutions for volume expansion in acute liver failure patients with acute kidney injury. 2, 6
• All resuscitation fluids should contain dextrose to prevent hypoglycemia, which can be masked by encephalopathy. 1, 7
• Consider pulmonary artery catheterization in hemodynamically unstable patients to objectively assess volume status before escalating therapy. 1, 2

Vasopressor Support:

• If mean arterial pressure remains <50-60 mm Hg despite adequate fluid resuscitation, initiate norepinephrine, epinephrine, or dopamine—but never vasopressin. 1, 2, 6
• Dopamine has been associated with increased systemic oxygen delivery in acute liver failure specifically. 1
• Target mean arterial pressure of 50-60 mm Hg to maintain renal and cerebral perfusion. 1, 2

Critical Metabolic Management During Anuria

Sodium Management:

Maintain serum sodium between 140-145 mmol/L, correcting no faster than 10 mmol/L per 24 hours. 1, 2 This is particularly important because:

• Hyponatremia correlates with increased intracranial pressure in acute liver failure. 1
• Overly rapid correction risks osmotic demyelination syndrome. 2
• Hypertonic saline (3%) can be used to manage intracranial pressure, but serum sodium >150 mmol/L should be avoided. 1

Glucose Monitoring:

Monitor blood glucose at least every 2 hours due to the high risk of hypoglycemia in acute liver failure, which can be confused with worsening encephalopathy. 1, 2, 7

Electrolyte Supplementation:

• Phosphate, magnesium, and potassium levels frequently drop and require repeated supplementation throughout the hospital course. 1, 7

Infection Prevention and Treatment

Empirical broad-spectrum antibiotics should be administered immediately if there are signs of sepsis or worsening encephalopathy. 1, 2 This is critical because:

• Bacterial infections occur in 60-80% of acute liver failure patients. 1
• Sepsis is a common precipitant of acute kidney injury in this population. 8
• Coverage should include enterobacteria, staphylococcal, and streptococcal species based on local ecology. 1, 2

Common Pitfalls to Avoid

Nephrotoxic Agent Exposure:

Avoid all nephrotoxic medications including NSAIDs and aminoglycosides. 7, 8 These agents are particularly dangerous in acute liver failure where renal perfusion is already compromised. 8, 5

Volume Depletion:

Avoid diuretics, which are a common cause of acute kidney injury progression in acute liver failure. 8 Even in the setting of volume overload, CRRT should be used for fluid removal rather than diuretics. 4

Coagulation Factor Administration:

Do not prophylactically administer fresh frozen plasma or coagulation factors unless there is active bleeding or an invasive procedure is planned. 1, 7 Most acute liver failure patients have rebalanced hemostasis, and prophylactic correction precludes assessment of disease progression. 1

Urgent Liver Transplantation Evaluation

Contact a liver transplant center immediately upon diagnosis of anuria in acute liver failure. 1, 7, 6 The "transplantation window" is often narrow, and 10% of listed patients die on the waiting list despite UNOS status 1 priority. 1, 2

Poor Prognostic Indicators Requiring Urgent Listing:

• Idiosyncratic drug injury, non-hepatitis A viral infections, autoimmune hepatitis, mushroom poisoning, Wilson disease, Budd-Chiari syndrome, or indeterminate cause. 7, 6
• Post-transplant survival rates reach 80-90% even in patients with multiple organ failures. 1, 2, 7

Nutritional Support During Anuria

Initiate enteral feedings early with moderate protein intake (approximately 60 grams per day). 1, 7 Severe protein restrictions should be avoided despite the presence of encephalopathy. 1 If enteral feeding is contraindicated, parenteral nutrition is acceptable despite increased fungal infection risk. 1, 7

Gastrointestinal Bleeding Prophylaxis

Administer H2 blocking agents or proton pump inhibitors for stress ulcer prophylaxis. 2, 7 Sucralfate is an acceptable second-line option. 7 This is important because upper gastrointestinal bleeding is a common complication and can worsen hemodynamic instability. 1