How to clear lactic acidosis?

Management of Lactic Acidosis

The most effective approach to clearing lactic acidosis is to identify and treat the underlying cause while providing supportive care, including discontinuation of contributing medications, fluid resuscitation, and judicious use of sodium bicarbonate in severe cases. 1

Diagnosis and Assessment

• Lactic acidosis presents with:

  • Elevated blood lactate concentrations
  • Anion gap acidosis
  • Increased lactate:pyruvate ratio
  • Early symptoms: malaise, myalgias, abdominal pain
  • Advanced symptoms: tachypnea, dyspnea, hypotension 1

• Laboratory findings typically include:

  • Elevated aminotransferases
  • Increased creatine phosphokinase
  • Elevated lactic dehydrogenase, lipase, and amylase 1

Treatment Algorithm

Step 1: Address the Underlying Cause

• Identify and treat the primary etiology:
  • Tissue hypoxia (circulatory, pulmonary disorders)
  • Medication-induced (metformin, NRTIs)
  • Sepsis
  • Liver disease
  • Thiamine deficiency 1, 2

Step 2: Discontinue Contributing Medications

• Immediately stop medications that may contribute to lactic acidosis:
  • Metformin: Discontinue in patients with suspected lactic acidosis 1
  • NRTIs: Discontinue if clinical manifestations of lactic acidosis occur 1
  • SGLT2 inhibitors: Stop in patients with severe acute illness 1

Step 3: Supportive Care

• Fluid resuscitation to improve tissue perfusion
• Ensure adequate oxygenation
• Consider thiamine and riboflavin administration based on pathophysiologic rationale 1

Step 4: Bicarbonate Therapy (for severe acidosis)

• For severe acidosis (pH < 7.1) or cardiac arrest:
  • Initial dose: 1-2 vials (44.6-100 mEq) IV
  • May continue at 50 mL (44.6-50 mEq) every 5-10 minutes if necessary
  • Monitor with arterial pH and blood gas measurements 3
• For less urgent metabolic acidosis:
  • 2-5 mEq/kg body weight over 4-8 hours 3
  • Target partial correction initially (aim for total CO2 content of about 20 mEq/L in first 24 hours) 3

Step 5: Consider Renal Replacement Therapy

• Indications for hemodialysis:
  • Severe, refractory acidosis
  • Metformin-associated lactic acidosis
  • Hemodynamic instability with acidosis 1, 4
• Continuous venovenous hemodiafiltration (CVVHDF) is preferred for hemodynamically unstable patients 1

Important Caveats and Pitfalls

1. Bicarbonate therapy limitations:

   • May increase lactate production
   • Can cause hypernatremia and fluid overload
   • Risks from severe acidosis may exceed those of hypernatremia in cardiac arrest 3, 2

2. Renal replacement therapy considerations:

   • High-volume hemofiltration has limited effectiveness for severe lactic acidosis
   • Lactate clearance (approximately 79 mL/min) is small compared to rates of lactate overproduction in septic shock 4
   • Lactic acidosis alone should not be considered a non-renal indication for CRRT 4

3. Avoid complete correction of acidosis too rapidly:

   • Full correction within 24 hours may lead to unrecognized alkalosis
   • Stepwise approach is recommended as response is not precisely predictable 3

4. Prevention strategies:

   • Avoid metformin in patients with eGFR <30 mL/min/1.73m²
   • Reduce metformin dose in patients with eGFR 30-45 mL/min/1.73m²
   • Temporarily discontinue metformin during acute illness, iodinated contrast procedures, or major surgery 1

Remember that prompt recognition and treatment of the underlying causes remain the cornerstone of effective management of lactic acidosis 5. No therapy specifically designed to lower arterial blood lactate levels has been shown to significantly reduce mortality without addressing the primary cause 5.