When is bicarbonate infusion recommended for metabolic acidosis?

Bicarbonate Infusion for Metabolic Acidosis

Bicarbonate infusion is generally not recommended for metabolic acidosis except in specific circumstances such as severe acidosis with pH < 7.1, hyperkalemia, tricyclic antidepressant overdose, or documented metabolic acidosis in patients with chronic kidney disease. 1, 2

Indications for Bicarbonate Therapy

• Recommended uses:

  • Severe metabolic acidosis with pH < 7.1 and base deficit < 10 1
  • Hyperkalemia (helps shift potassium into cells) 1
  • Tricyclic antidepressant overdose 1
  • Documented metabolic acidosis in maintenance dialysis patients (target serum bicarbonate ≥ 22 mmol/L) 2, 1
  • Sodium channel blocker overdose 1

• Not recommended for:

  • Hypoperfusion-induced lactic acidemia with pH ≥ 7.15 in sepsis 2
  • Routine use in cardiac arrest 1
  • Diabetic ketoacidosis (may cause harm in pediatric patients) 3
  • Rhabdomyolysis (no improvement in patient-centered outcomes) 3

Administration Guidelines

• Dosing for severe acidosis:

  • In cardiac arrest: 1-2 vials (44.6 to 100 mEq) initially, followed by 44.6-50 mEq every 5-10 minutes if necessary 4
  • For less urgent metabolic acidosis: 2-5 mEq/kg body weight over 4-8 hours 4
  • Stepwise approach recommended as response is not precisely predictable 4

• Monitoring:

  • Arterial pH and blood gas monitoring should guide therapy 4
  • Avoid complete correction of low total CO2 content during first 24 hours to prevent unrecognized alkalosis 4
  • Target total CO2 content of about 20 mEq/liter at end of first day 4

Potential Adverse Effects

• Sodium and fluid overload 2
• Increase in lactate and PCO2 2
• Decrease in serum ionized calcium 2
• Extracellular alkalosis (shifts oxyhemoglobin curve, inhibiting oxygen release) 1
• Hypernatremia and hyperosmolarity 1
• Paradoxical intracellular acidosis due to excess CO2 production 1
• Inactivation of simultaneously administered catecholamines 1

Special Considerations

• Caution in:

  • Patients with congestive heart failure or sodium-retaining states 4
  • Patients with oliguria or anuria 4
  • Patients receiving corticosteroids or corticotropin 4
  • Neonates and children under two years (risk of hypernatremia, decreased CSF pressure, and intracranial hemorrhage) 4

• Contraindications:

  • Do not use unless solution is clear and container/seal intact 4
  • Avoid mixing with calcium-containing solutions (precipitation may occur) 4
  • Incompatible with norepinephrine and dobutamine 4

Recent Evidence

• A 2019 systematic review found limited benefit from bicarbonate therapy for severe metabolic acidosis (pH < 7.1), but noted improvement in survival for patients with accompanying acute kidney injury 5
• A 2021 international observational study showed that early sodium bicarbonate administration in acidotic vasopressor-dependent patients may be beneficial 6
• However, a 2013 retrospective analysis found that sodium bicarbonate administration was associated with higher mortality in patients with lactic acidosis 7

Best Approach to Metabolic Acidosis

• The primary treatment should focus on addressing the underlying cause of acidosis 1
• Restore adequate circulation when acidosis is due to tissue hypoperfusion 1
• Consider bicarbonate therapy only when specific indications are present and pH is severely compromised 1, 3
• For chronic kidney disease patients, oral sodium bicarbonate at 2-4 g/day (25-50 mEq/day) can effectively increase serum bicarbonate concentrations 2