Bicarbonate Therapy for Acidosis
Primary Recommendation
Bicarbonate therapy should be reserved for severe metabolic acidosis with pH < 7.0-7.1 in specific clinical scenarios: documented severe metabolic acidosis after establishing effective ventilation, life-threatening hyperkalemia, tricyclic antidepressant or sodium channel blocker overdose, and diabetic ketoacidosis with pH < 6.9. 1, 2, 3
Clinical Decision Algorithm
Step 1: Determine Type of Acidosis
- Respiratory acidosis: Treat with ventilation, NOT bicarbonate 1
- Metabolic acidosis: Proceed to Step 2 1
Step 2: Assess pH Threshold
- pH ≥ 7.15: Do NOT give bicarbonate, even in sepsis-related lactic acidosis 1, 4, 5
- pH 7.0-7.15: Generally avoid bicarbonate; focus on treating underlying cause 1, 6
- pH < 7.0: Consider bicarbonate therapy after Step 3 2, 6
Step 3: Identify Specific Indications (When pH < 7.0-7.1)
Strong indications for bicarbonate:
- Tricyclic antidepressant overdose with QRS > 120 ms: 50-150 mEq bolus of hypertonic solution (1000 mEq/L), followed by 150 mEq/L infusion at 1-3 mL/kg/h 1
- Sodium channel blocker toxicity: Same dosing as TCA overdose 1
- Life-threatening hyperkalemia: 1-2 mEq/kg IV as temporizing measure while definitive therapy initiated 1
- Diabetic ketoacidosis with pH < 6.9: 100 mmol in 400 mL sterile water at 200 mL/h 1, 2
- DKA with pH 6.9-7.0: 50 mmol in 200 mL sterile water at 200 mL/h 1, 2
Contraindications (do NOT give bicarbonate):
- Sepsis-related lactic acidosis with pH ≥ 7.15 1, 5
- Cardiac arrest (routine use not recommended) 1
- Tissue hypoperfusion-related acidosis without specific indication 1
- DKA with pH ≥ 7.0 2
Dosing and Administration
Standard Adult Dosing
- Initial bolus: 1-2 mEq/kg IV (50-100 mL of 8.4% solution) given slowly over several minutes 1, 3
- Cardiac arrest: 44.6-100 mEq initially, then 44.6-50 mEq every 5-10 minutes guided by arterial pH 3
- Target pH: 7.2-7.3, NOT complete normalization 1, 3
Pediatric Dosing
- Standard dose: 1-2 mEq/kg IV given slowly 1
- Infants < 2 years: Use only 0.5 mEq/mL (4.2%) concentration—dilute 8.4% solution 1:1 with normal saline 1
- Children ≥ 2 years: May use 8.4% solution, though dilution often performed for safety 1
Continuous Infusion (When Indicated)
Critical Safety Requirements
Before Administration
- Ensure effective ventilation FIRST—bicarbonate produces CO2 that must be eliminated to prevent paradoxical intracellular acidosis 1
- Never mix with calcium-containing solutions or vasoactive amines (causes precipitation/inactivation) 1
- Flush IV line with normal saline before and after administration 1
Monitoring During Therapy (Every 2-4 Hours)
- Arterial blood gases: pH, PaCO2, bicarbonate 1
- Serum sodium: Target < 150-155 mEq/L 1
- Serum potassium: Bicarbonate shifts K+ intracellularly; replace as needed 1, 2
- Ionized calcium: Large doses can decrease levels, impairing cardiac contractility 1, 5
Stop Bicarbonate If:
- pH exceeds 7.50-7.55 1
- Serum sodium exceeds 150-155 mEq/L 1
- Severe hypokalemia develops 1
- Target pH of 7.2-7.3 achieved 1
Common Pitfalls and How to Avoid Them
Pitfall 1: Giving Bicarbonate Without Adequate Ventilation
- Risk: Paradoxical intracellular acidosis from CO2 accumulation 1
- Solution: Establish effective ventilation before or simultaneously with bicarbonate administration 1
Pitfall 2: Routine Use in Sepsis-Related Lactic Acidosis
- Evidence: Multiple trials show no benefit in hemodynamic variables or vasopressor requirements when pH ≥ 7.15 1, 5
- Solution: Focus on treating underlying shock with fluids, vasopressors, and source control 1
Pitfall 3: Over-Correction of Acidosis
- Risk: Metabolic alkalosis, hypokalemia, decreased oxygen delivery 1
- Solution: Target pH 7.2-7.3, not complete normalization; avoid bringing total CO2 to normal within first 24 hours 3
Pitfall 4: Mixing with Incompatible Solutions
- Risk: Precipitation with calcium, inactivation of catecholamines 1
- Solution: Flush line with normal saline before and after; use separate IV access if possible 1
Pitfall 5: Using Hypertonic Solution in Vulnerable Populations
- Risk: Hyperosmolarity, hypernatremia, cerebral complications 1
- Solution: Use 4.2% concentration for infants < 2 years; consider dilution for all pediatric patients 1
Special Clinical Scenarios
Diabetic Ketoacidosis
- pH < 6.9: Give bicarbonate (100 mmol in 400 mL sterile water at 200 mL/h) 2
- pH 6.9-7.0: Consider bicarbonate (50 mmol in 200 mL sterile water at 200 mL/h) 2
- pH ≥ 7.0: Do NOT give bicarbonate—insulin therapy alone resolves acidosis 2
- Rationale: Prospective studies show no benefit at pH > 6.9 2, 7
Chronic Kidney Disease
- Indication: Maintain serum bicarbonate ≥ 22 mmol/L 1
- Dosing: Oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) 1
- Benefits: Increased serum albumin, decreased protein degradation, fewer hospitalizations 1
Cardiac Arrest
- Not routinely recommended 1
- Consider after first epinephrine dose fails in asystolic arrest with documented severe acidosis 1
- Dose: 1 mEq/kg as single bolus before second epinephrine dose 1
Evidence Quality Assessment
The strongest evidence against routine bicarbonate use comes from the Surviving Sepsis Campaign guidelines, which explicitly recommend against bicarbonate for pH ≥ 7.15 in sepsis-related lactic acidosis 1, 5. This is supported by multiple blinded randomized controlled trials showing no difference in hemodynamic outcomes 1.
For severe acidosis (pH < 7.0), evidence is limited to observational data and expert consensus 8, 6. The recommendation for bicarbonate at this threshold is based on theoretical concerns about severe acidemia's effects on cardiac function and the lack of data showing harm at this extreme pH 6, 9.
The FDA label supports use in severe metabolic acidosis but emphasizes stepwise therapy and careful monitoring 3. The most recent guidelines (2025) from multiple societies converge on pH < 7.0-7.1 as the threshold for consideration, with specific exceptions for toxicologic emergencies regardless of pH 1.