How is lactic acidosis managed in patients with hepatic (liver) failure?

From the Guidelines

Lactic acidosis in patients with hepatic failure should be managed with bicarbonate as the preferred buffer in continuous renal replacement therapy (CRRT), as lactate can worsen acidosis in these patients. Management of lactic acidosis in patients with hepatic failure requires a multifaceted approach targeting both the underlying liver dysfunction and the acid-base disturbance. The primary treatment focuses on addressing the cause of lactic acidosis while supporting liver function.

• Intravenous fluid resuscitation with crystalloids like normal saline at 10-20 ml/kg should be initiated promptly to improve tissue perfusion and oxygen delivery.
• Sodium bicarbonate (1-2 mEq/kg IV) may be considered for severe acidosis (pH < 7.1) but should be used cautiously as it can worsen intracellular acidosis and sodium overload, as suggested by the use of bicarbonate in CRRT patients with lactic acidosis or liver failure 1.
• Continuous renal replacement therapy may be necessary in cases refractory to medical management, with bicarbonate being the preferred buffer in patients with lactic acidosis and/or liver failure 1.
• Specific to liver failure patients, lactulose (20-30g orally or via nasogastric tube every 6-8 hours) helps reduce ammonia levels, while rifaximin (550mg twice daily) decreases bacterial production of toxins.
• Thiamine supplementation (100mg IV daily for 3-5 days) is crucial as deficiency can worsen lactic acidosis.
• Vasopressors like norepinephrine (starting at 0.05-0.1 mcg/kg/min) may be needed to maintain adequate mean arterial pressure.
• Careful monitoring of serum lactate, arterial blood gases, electrolytes, and liver function tests is essential to guide therapy. The underlying pathophysiology involves impaired lactate clearance by the damaged liver combined with tissue hypoxia, making both supportive care and addressing the primary liver condition critical components of management.

From the FDA Drug Label

In the treatment of metabolic acidosis which may occur in severe renal disease, uncontrolled diabetes, circulatory insufficiency due to shock or severe dehydration, extracorporeal circulation of blood, cardiac arrest and severe primary lactic acidosis Sodium bicarbonate is further indicated in the treatment of certain drug intoxications, including barbiturates (where dissociation of the barbiturate-protein complex is desired), in poisoning by salicylates or methyl alcohol and in hemolytic reactions requiring alkalinization of the urine to diminish nephrotoxicity of hemoglobin and its breakdown products Vigorous bicarbonate therapy is required in any form of metabolic acidosis where a rapid increase in plasma total CO2 content is crucial - e. g., cardiac arrest, circulatory insufficiency due to shock or severe dehydration, and in severe primary lactic acidosis or severe diabetic acidosis.

Management of Lactic Acidosis in Hepatic Failure:

• The FDA drug label indicates that sodium bicarbonate can be used to treat severe primary lactic acidosis.
• However, it does not specifically address the management of lactic acidosis in patients with hepatic failure.
• The label does provide guidance on the use of sodium bicarbonate in the treatment of metabolic acidosis, which may be applicable to patients with lactic acidosis.
• The dosage and administration of sodium bicarbonate are provided, but the label advises that therapy should be planned in a stepwise fashion and monitored by measuring blood gases, plasma osmolarity, arterial blood lactate, hemodynamics, and cardiac rhythm 2, 2. The FDA drug label does not answer the question.

From the Research

Management of Lactic Acidosis in Hepatic Failure

• Lactic acidosis is a serious condition that can occur in patients with hepatic failure, and its management is crucial to improve patient outcomes.
• According to 3, in patients with severe liver failure or lactic acidosis, solutions with lactate buffer are not indicated, and bicarbonate-buffered solutions should be used instead.
• The use of bicarbonate-buffered solutions can help control metabolic acidosis and reduce lactate levels in patients with hepatic failure, as shown in 4.
• However, the effectiveness of bicarbonate therapy in severe metabolic acidosis remains controversial, and its use should be individualized, as discussed in 5.

Treatment Options

• Eliminating the triggering conditions remains the most effective therapy for lactic acidosis, as stated in 6.
• Sodium bicarbonate administration is not recommended as a first-line treatment, as it can have negative effects, such as reducing serum calcium concentration and generating excess carbon dioxide, as mentioned in 6.
• Other buffers, such as THAM or Carbicarb, or dialysis might provide base with fewer untoward effects, as suggested in 6.
• Selective NHE1 inhibitors have shown promise in improving cardiovascular function and reducing mortality in animal studies, as reported in 6.

Considerations in Hepatic Failure

• Patients with hepatic failure have reduced lactate metabolism, making them more susceptible to lactic acidosis, as noted in 3.
• The use of lactate-buffered solutions can exacerbate lactic acidosis in patients with hepatic failure, as warned in 7.
• Bicarbonate-buffered solutions are preferred in patients with hepatic failure, as they can help control metabolic acidosis and reduce lactate levels, as shown in 4.