What is the recommended dose and administration of sodium bicarbonate (NaHCO3) for correcting metabolic acidosis?

Sodium Bicarbonate Correction for Metabolic Acidosis

Recommended Dose and Administration

For severe metabolic acidosis (pH < 7.1), administer sodium bicarbonate 1-2 mEq/kg IV (typically 50-100 mL of 8.4% solution) given slowly over several minutes, with a target pH of 7.2-7.3, not complete normalization. 1, 2

Initial Dosing by Population

Adults:

• Standard dose: 1-2 mEq/kg IV (50-100 mEq or 50-100 mL of 8.4% solution) administered slowly over several minutes 1, 2
• In cardiac arrest: One to two 50 mL vials (44.6-100 mEq) initially, then 50 mL every 5-10 minutes as indicated by arterial blood gas monitoring 2
• For less urgent metabolic acidosis: 2-5 mEq/kg over 4-8 hours 2

Pediatric Patients:

• Children: 1-2 mEq/kg IV given slowly 1
• Infants under 2 years: Use only 0.5 mEq/mL (4.2%) concentration—dilute 8.4% solution 1:1 with normal saline 1
• Newborns: Mandatory 4.2% concentration with dilution of stock solutions 1

Concentration Selection

Use 4.2% (0.5 mEq/mL) concentration for all pediatric patients under 2 years to reduce hyperosmolar complications. 1 The 8.4% hypertonic solution has an osmolality of 2 mOsmol/mL, creating significant risk for cerebral perfusion compromise in vulnerable populations 1. Adults may receive undiluted 8.4% solution, though dilution is often performed for safety 1.

Specific Clinical Indications

When to Give Bicarbonate

Definite indications:

• pH < 7.0-7.1 with base deficit < -10 1
• Life-threatening hyperkalemia (as temporizing measure) 1
• Tricyclic antidepressant overdose with QRS > 120 ms: 50-150 mEq bolus, target pH 7.45-7.55 1
• Sodium channel blocker toxicity: 50-150 mEq bolus followed by 150 mEq/L infusion at 1-3 mL/kg/hour 1
• Diabetic ketoacidosis with pH < 6.9: 100 mmol in 400 mL sterile water at 200 mL/hour 1
• Diabetic ketoacidosis with pH 6.9-7.0: 50 mmol in 200 mL sterile water at 200 mL/hour 1

When NOT to Give Bicarbonate

Do not administer sodium bicarbonate for hypoperfusion-induced lactic acidemia when pH ≥ 7.15 in sepsis—multiple trials show no benefit in hemodynamic variables or vasopressor requirements. 1 The Surviving Sepsis Campaign explicitly recommends against routine use in this setting 1.

Additional contraindications:

• Routine use in cardiac arrest (unless specific indications present) 1
• Tissue hypoperfusion-related acidosis as routine therapy 1
• Diabetic ketoacidosis with pH ≥ 7.0 1
• Respiratory acidosis without adequate ventilation 1

Critical Safety Requirements

Pre-Administration Checklist

Ensure effective ventilation is established BEFORE giving bicarbonate—this is non-negotiable. 1 Bicarbonate produces CO2 that must be eliminated; giving it without adequate ventilation causes paradoxical intracellular acidosis, worsening outcomes 1.

Never mix sodium bicarbonate with:

• Calcium-containing solutions (causes precipitation) 1
• Vasoactive amines like norepinephrine or dobutamine (causes inactivation) 1
• Flush IV line with normal saline before and after administration 1

Monitoring Requirements

Monitor every 2-4 hours during active therapy: 1

• Arterial blood gases (pH, PaCO2, bicarbonate)
• Serum sodium (keep < 150-155 mEq/L)
• Serum potassium (bicarbonate shifts K+ intracellularly, causing hypokalemia)
• Ionized calcium (large doses decrease free calcium)

Target Goals

Aim for pH 7.2-7.3, NOT complete normalization. 1, 2 Attempting full correction within 24 hours risks unrecognized alkalosis due to delayed ventilatory readjustment 2. Achieving total CO2 of approximately 20 mEq/L at end of first day usually associates with normal blood pH 2.

Continuous Infusion Protocol

For ongoing alkalinization needs (e.g., sodium channel blocker toxicity):

• Prepare 150 mEq/L solution 1
• Infuse at 1-3 mL/kg/hour 1
• Continue until pH ≥ 7.30 or QRS normalization in toxicity cases 1
• Monitor for hypernatremia (stop if Na+ > 150-155 mEq/L) 1
• Monitor for excessive alkalemia (stop if pH > 7.50-7.55) 1

Common Pitfalls and Complications

Major adverse effects to anticipate: 1

• Hypernatremia and hyperosmolarity (especially with hypertonic solutions)
• Hypokalemia requiring aggressive replacement
• Ionized hypocalcemia (worsens cardiac contractility)
• Paradoxical intracellular acidosis (if ventilation inadequate)
• Sodium and fluid overload
• Increased lactate production
• Rebound metabolic alkalosis with overcorrection

The single most important pitfall is administering bicarbonate without ensuring adequate ventilation—this converts extracellular alkalosis into intracellular acidosis, inhibits oxygen release via leftward oxyhemoglobin shift, and worsens outcomes. 1

Special Populations

Chronic kidney disease patients:

• Oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) for outpatient management 1
• Target serum bicarbonate ≥ 22 mmol/L 1, 3
• Benefits include increased serum albumin, decreased protein degradation, fewer hospitalizations 1

Cardiac arrest:

• Give only after first epinephrine dose fails 1
• Dose: 1 mEq/kg as single bolus before second epinephrine 1
• Repeat every 5-10 minutes guided by arterial pH 2

Duration of Therapy

Continue sodium bicarbonate infusion until: 3

• Serum bicarbonate reaches ≥ 22 mmol/L in metabolic acidosis
• pH rises above 7.0 in severe acidosis (pH < 7.0), then reassess
• QRS normalization and hemodynamic stability in toxicity cases
• Development of hypernatremia (Na+ > 150-155 mEq/L) or alkalemia (pH > 7.50-7.55)

Monitor serum bicarbonate every 2-4 hours during active infusion, then at least monthly in maintenance dialysis patients. 3

The best treatment for metabolic acidosis remains correcting the underlying cause and restoring adequate circulation—bicarbonate buys time but does not treat the disease 1.