Does the patient need sodium bicarbonate (NaHCO3)?

Sodium Bicarbonate for Metabolic Acidosis

Sodium bicarbonate should NOT be used routinely for metabolic acidosis in sepsis or lactic acidosis when pH ≥ 7.15, but IS indicated for severe metabolic acidosis (pH < 7.1-7.2), specific toxicological emergencies (tricyclic antidepressants, sodium channel blockers), life-threatening hyperkalemia, and diabetic ketoacidosis with pH < 6.9. 1, 2, 3

When NOT to Use Sodium Bicarbonate

Sepsis and Lactic Acidosis

• The Surviving Sepsis Campaign explicitly recommends AGAINST sodium bicarbonate for hypoperfusion-induced lactic acidemia when pH ≥ 7.15. 1, 2
• Two randomized controlled trials comparing bicarbonate versus equimolar saline showed no difference in hemodynamic variables or vasopressor requirements. 1, 2
• Bicarbonate does not improve outcomes in sepsis-related hyperlactatemia and may cause harm. 2, 4
• The rationale that bicarbonate ameliorates hemodynamic depression from acidemia has been convincingly disproved. 4

General Contraindications

• Do NOT use bicarbonate for tissue hypoperfusion-related acidosis as routine therapy. 1, 2
• Avoid in diabetic ketoacidosis when pH ≥ 7.0. 2
• The best treatment for metabolic acidosis is correcting the underlying cause and restoring adequate circulation. 1, 2

When TO Use Sodium Bicarbonate

Severe Metabolic Acidosis

• Administer bicarbonate when arterial pH < 7.0-7.1 with base deficit < -10. 2, 3, 5
• The FDA label indicates use in severe metabolic acidosis from renal disease, uncontrolled diabetes, circulatory insufficiency, cardiac arrest, and severe primary lactic acidosis. 3
• Vigorous bicarbonate therapy is required when rapid increase in plasma CO2 content is crucial (cardiac arrest, severe shock, severe diabetic acidosis). 3

Specific Toxicological Emergencies

• Tricyclic antidepressant overdose with QRS prolongation > 120 ms: Give 1-2 mEq/kg IV bolus of hypertonic sodium bicarbonate (Class I recommendation), targeting arterial pH 7.45-7.55. 2
• Sodium channel blocker toxicity: Administer 50-150 mEq bolus followed by continuous infusion of 150 mEq/L solution at 1-3 mL/kg/hour. 2
• Barbiturate intoxication, salicylate poisoning, and methyl alcohol poisoning. 3

Life-Threatening Hyperkalemia

• Use bicarbonate as adjunct therapy to shift potassium intracellularly while definitive treatments are initiated. 2
• Always combine with glucose/insulin; never use as monotherapy. 2

Diabetic Ketoacidosis

• Give bicarbonate ONLY if pH < 6.9 in adult DKA patients. 2
• For pH < 6.9: Infuse 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/hour. 2
• For pH 6.9-7.0: Infuse 50 mmol sodium bicarbonate in 200 mL sterile water at 200 mL/hour. 2

Other Indications

• Severe diarrhea with significant bicarbonate loss. 3
• Hemolytic reactions requiring urine alkalinization. 3
• Rhabdomyolysis with myoglobinuria (alkalinize urine to prevent acute tubular necrosis). 2

Dosing and Administration

Standard Adult Dosing

• Initial dose: 1-2 mEq/kg IV (typically 50-100 mEq or 50-100 mL of 8.4% solution) given slowly over several minutes. 2
• Target pH 7.2-7.3, NOT complete normalization. 2
• Repeat dosing should be guided by arterial blood gas analysis, not empirically. 2

Pediatric Dosing

• Children: 1-2 mEq/kg IV given slowly. 2
• Newborn infants: Use ONLY 0.5 mEq/mL (4.2%) concentration—dilute 8.4% solution 1:1 with normal saline or sterile water. 2
• Children < 2 years: Dilute 8.4% solution 1:1 to achieve 4.2% concentration. 2

Concentration Considerations

• Prefer 4.2% (isotonic) over 8.4% (hypertonic) solution to reduce risk of hyperosmolar complications. 2
• Hypertonic bicarbonate (8.4%) has osmolality of 2 mOsmol/mL, creating substantial risk for cerebral perfusion compromise. 2
• No commercially available isotonic bicarbonate solutions exist in the US, requiring pharmacy compounding. 2

Critical Safety Considerations and Adverse Effects

Major Complications

• Sodium and fluid overload. 1, 2
• Hypernatremia—monitor to keep serum sodium < 150-155 mEq/L. 2
• Hypokalemia—bicarbonate shifts potassium intracellularly; monitor every 2-4 hours and replace as needed. 2
• Decreased ionized calcium—can worsen cardiac contractility; monitor levels especially with doses > 50-100 mEq. 1, 2
• Paradoxical intracellular acidosis—bicarbonate produces CO2 that must be eliminated through adequate ventilation. 2
• Rebound alkalosis—avoid pH > 7.50-7.55. 2
• Increased lactate production. 1, 2

Administration Precautions

• NEVER mix sodium bicarbonate with calcium-containing solutions or vasoactive amines (catecholamines). 2
• Flush IV cannula with normal saline before and after bicarbonate to prevent catecholamine inactivation. 2
• Ensure effective ventilation BEFORE administering bicarbonate—ventilation is needed to eliminate excess CO2. 2
• Administer as slow IV push, not rapid bolus. 2

Monitoring Requirements

Essential Parameters

• Arterial blood gases every 2-4 hours to assess pH, PaCO2, and bicarbonate response. 2
• Serum electrolytes every 2-4 hours (sodium, potassium, chloride). 2
• Ionized calcium levels, particularly with large doses or renal dysfunction. 2
• Anion gap to monitor resolution of underlying acidosis. 2

Treatment Goals

• Target pH 7.2-7.3, not complete normalization. 2
• Serum sodium < 150-155 mEq/L. 2
• Serum pH < 7.50-7.55. 2
• In DKA: glucose < 200 mg/dL, bicarbonate ≥ 18 mEq/L, venous pH > 7.3. 2

Clinical Decision Algorithm

Step 1: Identify the pH threshold

• If pH ≥ 7.15 in sepsis/lactic acidosis → DO NOT give bicarbonate. 1, 2
• If pH 7.0-7.15 → Consider ONLY in specific contexts (see below). 2, 5
• If pH < 7.0-7.1 → Bicarbonate indicated. 2, 5

Step 2: Ensure adequate ventilation

• Confirm patient can eliminate CO2 (spontaneous adequate ventilation or mechanical ventilation). 2
• If inadequate ventilation, optimize this FIRST before bicarbonate. 2

Step 3: Identify specific indications

• TCA/sodium channel blocker toxicity with QRS > 120 ms → Give bicarbonate regardless of pH. 2
• Life-threatening hyperkalemia → Give bicarbonate as temporizing measure. 2
• DKA with pH < 6.9 → Give bicarbonate per protocol. 2
• Severe metabolic acidosis pH < 7.1 → Give bicarbonate. 2, 5

Step 4: Optimize hemodynamics FIRST

• Ensure adequate fluid resuscitation and treat underlying shock before bicarbonate. 2
• Bicarbonate is NOT a substitute for addressing the underlying cause. 1, 2

Step 5: Administer and monitor

• Give 1-2 mEq/kg IV slowly. 2
• Monitor ABG, electrolytes, ionized calcium every 2-4 hours. 2
• Repeat dosing based on serial ABG, targeting pH 7.2-7.3. 2

Common Pitfalls to Avoid

• Do NOT use bicarbonate routinely in sepsis or lactic acidosis with pH ≥ 7.15—this is explicitly contraindicated and lacks evidence for benefit. 1, 2
• Do NOT give bicarbonate without ensuring adequate ventilation—this causes paradoxical intracellular acidosis. 2
• Do NOT mix with calcium or catecholamines—causes precipitation and inactivation. 2
• Do NOT forget to monitor and replace potassium—bicarbonate causes intracellular shift leading to severe hypokalemia. 2
• Do NOT target complete pH normalization—aim for pH 7.2-7.3 only. 2
• Do NOT use hypertonic 8.4% solution in neonates or young children without dilution. 2
• Do NOT ignore the underlying cause—bicarbonate buys time but does not treat the disease. 1, 2, 3