Sodium Bicarbonate Infusion Rate for Metabolic Acidosis
For severe metabolic acidosis (pH <7.1), administer sodium bicarbonate as an initial IV bolus of 1-2 mEq/kg (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
Initial Bolus Administration
The standard initial dose is 1-2 mEq/kg IV administered slowly over several minutes for adults, which typically translates to 50-100 mEq or 50-100 mL of 8.4% solution. 1, 2 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. 2
- For pediatric patients, the dose is 1-2 mEq/kg IV given slowly. 1, 3
- For newborn infants, use only 0.5 mEq/mL (4.2%) concentration, achieved by diluting 8.4% solution 1:1 with normal saline or sterile water. 1
- For children under 2 years, dilute 8.4% bicarbonate 1:1 with normal saline to achieve 4.2% concentration before administration. 1
Continuous Infusion Rate
After the initial bolus, continue with an infusion of 150 mEq/L solution at 1-3 mL/kg/hour to maintain alkalosis in cases requiring ongoing therapy, such as sodium channel blocker overdose or persistent severe acidosis. 1, 3 This infusion rate allows for controlled correction while minimizing complications.
- For sodium channel blocker toxicity specifically, give a bolus of 50-150 mEq followed by an infusion of 150 mEq/L solution at 1-3 mL/kg/hour. 1, 3
- The FDA label recommends that for less urgent forms of metabolic acidosis, approximately 2 to 5 mEq/kg body weight should be given over a four-to-eight-hour period, depending on severity. 2
Specific Clinical Scenarios
Diabetic Ketoacidosis
For DKA with pH <6.9, infuse 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 Bicarbonate is not indicated if pH ≥7.0 in DKA. 1
Cardiac Arrest
In cardiac arrest, the FDA label permits rapid infusion of 50 mL (44.6 to 50 mEq) every 5 to 10 minutes as needed, though caution is advised regarding the hypertonic nature of the solution. 2 However, bicarbonate should only be given after the first dose of epinephrine has been ineffective. 1
Critical Monitoring Requirements
Monitor arterial blood gases, serum electrolytes (sodium, potassium, ionized calcium), and pH every 2-4 hours during active bicarbonate therapy. 1, 4
- Target pH of 7.2-7.3, not complete normalization. 1
- Avoid serum sodium >150-155 mEq/L. 1
- Avoid pH >7.50-7.55. 1
- Monitor and replace potassium as bicarbonate shifts potassium intracellularly. 1
Important Contraindications and Cautions
Do not use bicarbonate for hypoperfusion-induced lactic acidemia when pH ≥7.15, as multiple trials show no benefit and potential harm. 1 The Surviving Sepsis Campaign explicitly recommends against sodium bicarbonate therapy in this scenario. 1
- Never mix sodium bicarbonate with calcium-containing solutions or vasoactive amines (causes precipitation or inactivation). 1, 3
- Flush IV line with normal saline before and after bicarbonate administration. 1
- Ensure adequate ventilation before giving bicarbonate, as it produces CO2 that must be eliminated to prevent paradoxical intracellular acidosis. 1
Duration of Therapy
Continue sodium bicarbonate infusion until serum bicarbonate reaches ≥22 mmol/L or pH rises above 7.2-7.3, then reassess the need for further therapy. 4 The FDA label emphasizes that it is generally unwise to attempt full correction of low total CO2 content during the first 24 hours, as this may be accompanied by unrecognized alkalosis. 2
Common Pitfalls
The most critical error is administering bicarbonate without ensuring adequate ventilation, which can worsen intracellular acidosis. 1 Another common mistake is using bicarbonate routinely in sepsis-related lactic acidosis with pH ≥7.15, where evidence shows no benefit. 1 Rapid administration of hypertonic solutions can cause dangerous hypernatremia and hyperosmolarity. 2 Finally, failing to monitor and replace potassium during therapy can lead to life-threatening hypokalemia. 1