What is the recommended intravenous sodium bicarbonate dosing and administration protocol for severe metabolic acidosis (arterial pH ≤7.1 or ≤7.2 with hemodynamic instability) in adults and children?

Administration of Sodium Bicarbonate in Severe Metabolic Acidosis

For severe metabolic acidosis with arterial pH <7.1, administer 50 mmol (50 mL of 8.4% solution) intravenously as a slow push over several minutes, then reassess with arterial blood gas analysis before giving additional doses. 1, 2

Critical Decision Algorithm: When to Give Bicarbonate

DO NOT give bicarbonate if:

• pH ≥7.15 in sepsis or hypoperfusion-induced lactic acidosis – Multiple high-quality RCTs show no benefit in hemodynamics or vasopressor requirements, with potential harm including sodium overload, increased lactate, elevated PaCO2, and decreased ionized calcium 3, 1, 4
• Respiratory acidosis without metabolic component – treat with ventilation, not bicarbonate 1
• Adequate ventilation cannot be established – bicarbonate produces CO2 that must be eliminated to prevent paradoxical intracellular acidosis 1, 2

DO give bicarbonate for:

• Arterial pH <7.1 with base excess <-10 1, 2, 5
• Life-threatening sodium channel blocker or tricyclic antidepressant toxicity with QRS >120 ms: give 50-150 mEq bolus of hypertonic solution (1000 mEq/L), targeting pH 7.45-7.55 1, 2
• Severe hyperkalemia as temporizing measure: 1-2 mEq/kg IV while definitive therapy is initiated 1, 2
• Cardiac arrest after first epinephrine dose fails with documented severe acidosis: 1-2 mEq/kg (44.6-100 mEq) rapid IV bolus, repeatable every 5-10 minutes based on arterial pH 2, 6
• Diabetic ketoacidosis with pH <6.9: 100 mmol in 400 mL sterile water at 200 mL/h; for pH 6.9-7.0: 50 mmol in 200 mL sterile water at 200 mL/h 1

Dosing Protocol for Adults

Initial Bolus

• Standard dose: 50 mmol (50 mL of 8.4% solution) IV push over several minutes 1, 2
• Alternative calculation: 1-2 mEq/kg body weight 1, 2, 6
• For cardiac arrest: 44.6-100 mEq rapid bolus, repeatable every 5-10 minutes 2, 6

Continuous Infusion (if ongoing alkalinization needed)

• Prepare 150 mEq/L solution and infuse at 1-3 mL/kg/hour 1, 2
• For sodium channel blocker toxicity: continue infusion to maintain pH ≥7.30 1

Stepwise Approach for Non-Emergency Acidosis

• Initial: 2-5 mEq/kg over 4-8 hours 6, 7
• Reassess with arterial blood gas before additional doses 1, 2
• Target pH 7.2-7.3, NOT complete normalization 1, 2

Pediatric Dosing

Standard Dose

• 1-2 mEq/kg IV given slowly 1, 2
• Children <2 years: Use ONLY 0.5 mEq/mL (4.2%) concentration – dilute 8.4% solution 1:1 with normal saline or sterile water 1, 2
• Children ≥2 years: May use 8.4% solution, though dilution often performed for safety 1
• Maximum rate: 8 mEq/kg/day in neonates and young children 1

Critical Pre-Administration Requirements

Ensure Adequate Ventilation FIRST

• Bicarbonate generates CO2 that MUST be eliminated 1, 2, 7
• For mechanically ventilated patients: increase minute ventilation to achieve PaCO2 30-35 mmHg 1
• For spontaneously breathing patients: confirm respiratory rate and effort adequate before each dose 1
• Giving bicarbonate without adequate ventilation causes paradoxical intracellular acidosis and worsens outcomes 1, 2

Establish IV Access

• NEVER mix bicarbonate with calcium-containing solutions – causes precipitation 1, 2
• NEVER mix with vasoactive amines (norepinephrine, epinephrine, dopamine, dobutamine) – causes inactivation 1, 2
• Flush IV line with normal saline before and after bicarbonate 1

Mandatory Monitoring Protocol

Before Each Dose

• Arterial blood gas (pH, PaCO2, bicarbonate, base excess) 1, 2
• Serum sodium, potassium, ionized calcium 1, 2
• Clinical assessment of ventilation adequacy 1

During Therapy (Every 2-4 Hours)

• Arterial blood gases to assess pH response and PaCO2 1, 2
• Serum sodium – STOP if >150-155 mEq/L 1, 2
• Serum potassium – bicarbonate shifts K+ intracellularly, causing hypokalemia requiring replacement 1, 2
• Ionized calcium – large doses decrease ionized calcium, impairing cardiac contractility 1, 2
• Arterial pH – STOP if >7.50-7.55 to avoid excessive alkalemia 1, 2

Clinical Monitoring

• Hemodynamics (blood pressure, heart rate, cardiac output) 1
• Urine output and fluid balance 5
• Signs of fluid overload (especially in oliguric patients) 1, 5

Common Pitfalls and How to Avoid Them

Pitfall #1: Giving bicarbonate for pH ≥7.15 in septic shock

• Evidence shows NO benefit and potential harm – two blinded RCTs demonstrated no improvement in hemodynamics or vasopressor requirements 3, 1
• Focus instead on fluid resuscitation, vasopressors, and source control 1

Pitfall #2: Inadequate ventilation before/during bicarbonate

• Each 1 mEq of bicarbonate generates 1 mEq of CO2 1, 7
• Without adequate CO2 elimination, intracellular pH paradoxically WORSENS 1, 2
• Confirm mechanical ventilation settings or spontaneous respiratory effort before EVERY dose 1

Pitfall #3: Attempting complete pH normalization in first 24 hours

• Target pH 7.2-7.3, NOT 7.4 1, 2, 6
• Overshoot causes metabolic alkalosis, hypokalemia, cerebral vasoconstriction, and leftward shift of oxyhemoglobin curve 1, 2
• Ventilation lags behind pH correction, causing unrecognized alkalosis 6

Pitfall #4: Ignoring sodium load

• Each 50 mL of 8.4% solution contains 50 mEq sodium 6, 7
• Causes hypernatremia, hyperosmolarity, and fluid overload (especially in oliguric AKI) 1, 7
• Monitor serum sodium closely; stop if >150-155 mEq/L 1, 2

Pitfall #5: Not replacing potassium

• Bicarbonate shifts K+ intracellularly, causing severe hypokalemia 1, 2
• Monitor potassium every 2-4 hours and replace aggressively 1, 2
• Hypokalemia during alkalemia increases risk of arrhythmias 1

Pitfall #6: Mixing with incompatible medications

• Bicarbonate precipitates with calcium and inactivates catecholamines 1, 2
• Use dedicated IV line or flush thoroughly with normal saline before/after 1

Stopping Criteria

Discontinue bicarbonate when:

• pH reaches 7.2-7.3 1, 2
• Serum sodium >150-155 mEq/L 1, 2
• pH >7.50-7.55 (excessive alkalemia) 1, 2
• Severe hypokalemia develops despite replacement 1
• Underlying cause corrected and patient hemodynamically stable 1
• Fluid overload in oliguric patient 1, 5

Special Clinical Scenarios

Diabetic Ketoacidosis

• Give bicarbonate ONLY if pH <6.9 1
• pH 6.9-7.0: 50 mmol in 200 mL sterile water at 200 mL/h 1
• pH <6.9: 100 mmol in 400 mL sterile water at 200 mL/h 1
• Do NOT give if pH ≥7.0 – no evidence of benefit 1

Chronic Kidney Disease (Outpatient Management)

• Oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) to maintain serum bicarbonate ≥22 mmol/L 1, 5
• Benefits include increased serum albumin, decreased protein degradation, fewer hospitalizations 1

Renal Replacement Therapy

• Use bicarbonate-based (not lactate-based) replacement fluid in patients with lactic acidosis or liver failure 1, 5
• CRRT removes lactate while providing bicarbonate, making it attractive for severe refractory lactic acidosis 1

Rhabdomyolysis with Myoglobinuria

• Use bicarbonate to alkalinize urine and prevent acute tubular necrosis 1
• Target urine output >2 mL/kg/h 1

What NOT to Do

• Do NOT give bicarbonate routinely in cardiac arrest – no improvement in hospital admission or discharge rates 1, 2
• Do NOT calculate total bicarbonate deficit and give it all at once – response is unpredictable; use stepwise approach 6, 7
• Do NOT exceed 6 mEq/kg total dose – commonly causes hypernatremia, fluid overload, metabolic alkalosis, cerebral edema 1
• Do NOT use in severe malaria – no evidence of benefit; acidosis resolves with volume correction and blood transfusion 1