What is the treatment for lactic acidosis?

Treatment of Lactic Acidosis

The primary treatment for lactic acidosis is to identify and address the underlying cause, with specific interventions determined by the type of lactic acidosis (Type A or Type B), while avoiding bicarbonate therapy in most cases unless pH is <7.15 with hemodynamic instability. 1

Types of Lactic Acidosis and Initial Approach

Type A (Hypoxic) Lactic Acidosis

• Caused by: Tissue hypoperfusion, shock, severe dehydration, cardiac arrest
• Primary treatment:
  • Restore tissue perfusion and oxygen delivery
  • Fluid resuscitation to maintain adequate intravascular volume
  • Maintain mean arterial pressure >65 mmHg using vasopressors if needed 1
  • For sepsis-induced lactic acidosis, follow Surviving Sepsis Campaign guidelines with early antibiotics and source control 2

Type B (Non-hypoxic) Lactic Acidosis

• Caused by: Medications (metformin, NRTIs), liver failure, diabetic ketoacidosis, malignancy
• Primary treatment:
  • Immediately discontinue offending medications 1
  • For metformin-associated lactic acidosis, prompt hemodialysis is recommended 2
  • Treat underlying conditions (e.g., diabetic ketoacidosis, liver failure) 1

Specific Interventions Based on Severity

For Severe Lactic Acidosis (pH <7.15)

1. Consider renal replacement therapy:

   • Continuous renal replacement therapy (CRRT) or hemodialysis is indicated for:
     • Severe metabolic acidosis unresponsive to medical management
     • Metformin-associated lactic acidosis
     • When pH <7.15 with hemodynamic instability 1
   • CRRT with high-volume hemofiltration has limited effectiveness for severe lactic acidosis 3

2. Bicarbonate therapy:

   • Generally not recommended for routine treatment of lactic acidosis 2
   • Consider only when pH <7.15 with hemodynamic instability 1
   • FDA indication: "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" 4
   • Dosing: Initial 1-2 vials (44.6-100 mEq) IV, may continue at 50 mL (44.6-50 mEq) every 5-10 minutes as indicated by arterial pH 4
   • Caution: Monitor for complications like hypocalcemia, volume overload, and paradoxical intracellular acidosis 1

For Cardiac Arrest with Lactic Acidosis

• Rapid IV administration of sodium bicarbonate (1-2 vials, 44.6-100 mEq)
• May continue at 50 mL every 5-10 minutes if necessary based on arterial pH 4
• In this setting, risks from acidosis exceed those of hypernatremia 4

For Less Urgent Forms of Metabolic Acidosis

• Sodium bicarbonate may be added to IV fluids
• Dosage: 2-5 mEq/kg body weight over 4-8 hours 4
• Plan therapy in a stepwise fashion, as response is not precisely predictable
• Avoid full correction of low total CO2 content during first 24 hours to prevent unrecognized alkalosis 4

Monitoring and Follow-up

1. Regular monitoring of:

   • Arterial blood gases
   • Plasma osmolarity
   • Arterial blood lactate levels
   • Hemodynamics and cardiac rhythm
   • Electrolytes and renal function 1, 4

2. Lactate clearance:

   • Serial lactate measurements to assess response to treatment
   • Failure to clear lactate within 6 hours is associated with increased mortality 5

Important Caveats

• Mortality rates for severe lactic acidosis remain high, especially with delayed recognition 6
• CRRT alone has limited effectiveness for severe lactic acidosis and should not be considered a primary treatment 3
• Lactic acidosis in sepsis is not entirely due to tissue hypoxia and may not be reversible solely by increasing oxygen delivery 7
• Early identification and treatment of the underlying cause is crucial for improving outcomes 5

Special Considerations

• In pediatric patients with unexplained lactic acidosis, consider rare causes such as malignancy-related type B lactic acidosis 8
• For drug-induced lactic acidosis (e.g., metformin), prompt discontinuation of the medication and consideration of hemodialysis is essential 2, 1