Administration Rate and Method for Sodium Bicarbonate in Severe Acidosis
For severe metabolic acidosis with pH < 6.9, administer 100 mmol sodium bicarbonate diluted in 400 mL sterile water at 200 mL/hour; for pH 6.9-7.0, give 50 mmol in 200 mL sterile water at 200 mL/hour. 1, 2
Concentration and Dilution Requirements
Use isotonic (4.2%) rather than hypertonic (8.4%) sodium bicarbonate solutions to minimize complications:
- Dilute standard 8.4% solution 1:1 with normal saline or sterile water to achieve 4.2% concentration before administration 2
- For pediatric patients under 2 years, mandatory 1:1 dilution is required 2
- Adults may receive 8.4% undiluted in cardiac arrest, but isotonic preparations are safer for metabolic acidosis management 2
- Hypertonic solutions risk hyperosmolarity, compromising cerebral perfusion and worsening outcomes 2
Specific Dosing by Clinical Scenario
Diabetic Ketoacidosis (DKA)
- pH < 6.9: Infuse 100 mmol (2 ampules) in 400 mL sterile water at 200 mL/hour 1, 3
- pH 6.9-7.0: Infuse 50 mmol (1 ampule) in 200 mL sterile water at 200 mL/hour 1, 3
- pH ≥ 7.0: No bicarbonate indicated; insulin therapy alone resolves ketoacidosis 1, 3
- Pediatric DKA: If pH remains < 7.0 after initial hour of hydration, give 1-2 mEq/kg over 1 hour 1
Cardiac Arrest
- Initial bolus: 50 mL of 8.4% solution (44.6-50 mEq) given rapidly IV push 4
- Repeat every 5-10 minutes as needed, guided by arterial blood gas monitoring 4
- Target pH 7.2-7.3, not complete normalization 2
Sodium Channel Blocker/TCA Toxicity
- Initial bolus: 50-150 mEq of hypertonic solution (1000 mEq/L) 2
- Continuous infusion: 150 mEq/L solution at 1-3 mL/kg/hour 2
- Titrate to QRS narrowing and resolution of hypotension 2
General Severe Metabolic Acidosis (Non-DKA)
- Initial dose: 1-2 mEq/kg (50-100 mEq for average adult) IV over several minutes 2, 4
- For ongoing therapy: 2-5 mEq/kg over 4-8 hours 4
- Administer as slow infusion, not rapid bolus, to minimize complications 2
Critical Administration Guidelines
Never mix sodium bicarbonate with:
- Calcium-containing solutions (causes precipitation) 2
- Vasoactive amines/catecholamines (causes inactivation) 1, 2
- Flush IV line with normal saline before and after bicarbonate 2
Ensure adequate ventilation before administration:
- Bicarbonate generates CO2 that must be eliminated to prevent paradoxical intracellular acidosis 1, 2
- In mechanically ventilated patients, increase minute ventilation to match physiologic respiratory compensation 5
Monitoring Requirements During Infusion
Check arterial blood gases every 2-4 hours: 2
Monitor serum electrolytes every 2-4 hours: 2, 3
- Sodium: Keep < 150-155 mEq/L to avoid hypernatremia 2
- Potassium: Bicarbonate shifts K+ intracellularly; replace aggressively once < 5.0 mEq/L 1, 3
- Ionized calcium: Monitor and replace if decreased, especially with doses > 50-100 mEq 2
Assess hemodynamic parameters continuously: 3
- Blood pressure, heart rate, cardiac rhythm
- Urine output and fluid balance
When NOT to Give Bicarbonate
Absolute contraindications based on evidence:
- pH ≥ 7.15 in sepsis-related lactic acidosis (no benefit demonstrated) 1, 2
- pH ≥ 7.0 in DKA (insulin therapy alone is sufficient) 1, 3
- Inadequate ventilation (will worsen intracellular acidosis) 1, 2
Common Pitfalls to Avoid
- Giving too rapidly: Causes hyperosmolarity, cerebral edema risk, and ionized calcium drop 2, 6
- Using hypertonic solutions routinely: Isotonic preparations are safer for non-arrest situations 2
- Ignoring potassium: Bicarbonate + insulin cause profound hypokalemia requiring aggressive replacement 1, 3
- Attempting full correction in first 24 hours: Lag in ventilatory adjustment causes rebound alkalosis 4
- Neglecting underlying cause: Bicarbonate buys time but doesn't treat the disease 2
Special Population Considerations
Pediatric patients:
- Use only 0.5 mEq/mL (4.2%) concentration for newborns 1, 2
- Standard dose: 1-2 mEq/kg IV given slowly 1, 2
Chronic kidney disease: