Sodium Bicarbonate Infusion Rate for Severe Metabolic Acidosis
For severe metabolic acidosis (pH <7.1), administer sodium bicarbonate as an initial IV bolus of 1-2 mEq/kg (typically 50-100 mL of 8.4% solution) given slowly over several minutes, followed by a continuous infusion of 150 mEq/L solution at 1-3 mL/kg/hour if ongoing alkalinization is needed. 1, 2, 3
Initial Bolus Administration
Standard adult dosing: Administer 1-2 mEq/kg IV (equivalent to 50-100 mEq or 50-100 mL of 8.4% solution) as a slow IV push over several minutes. 1, 2, 3 The FDA label specifies that in cardiac arrest, one to two 50 mL vials (44.6 to 100 mEq) may be given initially and continued at a rate of 50 mL every 5 to 10 minutes if necessary, as indicated by arterial pH and blood gas monitoring. 3
Pediatric dosing: Children require 1-2 mEq/kg IV administered slowly, with newborn infants requiring only 0.5 mEq/mL (4.2%) concentration achieved by diluting 8.4% solution 1:1 with normal saline or sterile water. 1, 4
Continuous Infusion Rate
After the initial bolus, continue with an infusion of 150 mEq/L solution at 1-3 mL/kg/hour to maintain alkalinization. 1 This rate applies to both adults and children requiring ongoing therapy for severe acidosis or sodium channel blocker toxicity. 1
For diabetic ketoacidosis with pH <6.9, the American Diabetes Association recommends infusing 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/hour. 1 For pH 6.9-7.0, infuse 50 mmol sodium bicarbonate in 200 mL sterile water at 200 mL/hour. 1
Critical pH Thresholds for Treatment
Only administer bicarbonate when pH is <7.0-7.1 with severe acidosis. 1, 2, 5 The Surviving Sepsis Campaign explicitly recommends against sodium bicarbonate therapy for hypoperfusion-induced lactic acidemia when pH ≥7.15, as multiple trials show no benefit in hemodynamic variables or vasopressor requirements. 1
For diabetic ketoacidosis specifically, bicarbonate may be beneficial only in patients with pH <6.9, and is not necessary if pH ≥7.0. 1, 2
Concentration Selection and Preparation
Use 4.2% concentration (isotonic) rather than 8.4% (hypertonic) to reduce risk of hyperosmolar complications. 1 For pediatric patients under 2 years, 8.4% solution must be diluted 1:1 with normal saline to achieve 4.2% concentration before administration. 1, 4 Children ≥2 years and adults may use 8.4% solution, though dilution is often performed for safety. 1
The hypertonic 8.4% solution has an osmolality of 2 mOsmol/mL, making it extremely hypertonic and capable of producing hyperosmolarity that can compromise cerebral perfusion pressure. 1
Monitoring Requirements During Infusion
Monitor arterial blood gases and serum electrolytes every 2-4 hours during active therapy. 1, 2 Specific parameters to track include:
- Target pH: 7.2-7.3, not complete normalization. Avoid pH >7.50-7.55. 1
- Serum sodium: Keep <150-155 mEq/L to prevent hypernatremia. 1
- Serum potassium: Monitor closely as bicarbonate shifts potassium intracellularly, causing hypokalemia requiring replacement. 1
- Ionized calcium: Monitor especially with doses >50-100 mEq, as bicarbonate can decrease ionized calcium affecting cardiac contractility. 1
Essential Pre-Administration Requirements
Ensure effective ventilation is established before administering bicarbonate, as ventilation is needed to eliminate excess CO2 produced. 1, 2 Giving bicarbonate without adequate ventilation causes paradoxical intracellular acidosis, worsening cellular function. 1 In mechanically ventilated patients, establish a respiratory response similar to physiological compensation to extract excess CO2. 6
Administration Technique and Compatibility
Never mix sodium bicarbonate with calcium-containing solutions or vasoactive amines (norepinephrine, dobutamine), as precipitation or inactivation will occur. 1, 2, 4 Flush the IV line with normal saline before and after bicarbonate administration to prevent inactivation of simultaneously administered catecholamines. 1
Duration and Stopping Criteria
Continue sodium bicarbonate infusion until:
- Target pH of 7.2-7.3 is achieved 1
- Serum bicarbonate reaches ≥22 mmol/L 2, 4
- Resolution of QRS prolongation and hemodynamic stability in toxicity cases 1
- Development of hypernatremia (sodium >150-155 mEq/L) or excessive alkalemia (pH >7.50-7.55) 1
The FDA label emphasizes that it is unwise to attempt full correction of low total CO2 content during the first 24 hours of therapy, since this may be accompanied by unrecognized alkalosis due to delayed readjustment of ventilation. 3 Achievement of total CO2 content of about 20 mEq/L at the end of the first day will usually be associated with normal blood pH. 3
Specific Clinical Scenarios Requiring Different Rates
Sodium channel blocker/TCA toxicity: Administer initial bolus of 50-150 mEq using hypertonic solution (1000 mEq/L), followed by continuous infusion of 150 mEq/L solution at 1-3 mL/kg/hour, titrated to resolution of QRS prolongation and hypotension. 1, 4
Cardiac arrest: After first epinephrine dose fails, give 1 mmol/kg (50-100 mEq) as slow IV push, repeated every 5-10 minutes as guided by arterial blood gas monitoring. 1, 3
Common Pitfalls to Avoid
Do not give bicarbonate for hypoperfusion-induced lactic acidemia with pH ≥7.15. 1 Two blinded randomized controlled trials showed no difference in hemodynamic variables or vasopressor requirements compared to equimolar saline. 1
Do not administer bicarbonate for respiratory acidosis. 1 Treat respiratory acidosis with ventilation, not bicarbonate, as the underlying problem is CO2 retention. 1
Avoid rapid administration rates. 3, 6 The FDA label cautions that bicarbonate solutions are hypertonic and may produce an undesirable rise in plasma sodium concentration. 3 Rapid infusion can cause sodium and fluid overload, increased lactate production, and decreased ionized calcium. 1
Do not ignore the underlying cause. 1 The best method of reversing acidosis is to treat the underlying cause and restore adequate circulation—bicarbonate buys time but does not treat the disease. 1