What is the treatment for metabolic acidosis?

Treatment of Metabolic Acidosis

The treatment of metabolic acidosis must prioritize treating the underlying cause first, with sodium bicarbonate reserved for severe acidosis (pH <7.0-7.1) or specific clinical scenarios including diabetic ketoacidosis with pH <6.9, life-threatening sodium channel blocker toxicity, and severe hyperkalemia. 1, 2, 3

Primary Treatment Approach: Address the Underlying Cause

The most effective treatment for metabolic acidosis is correcting the underlying disorder and restoring adequate tissue perfusion—not routine bicarbonate administration. 1, 2 This means:

• Diabetic ketoacidosis: Continuous intravenous insulin, fluid resuscitation, and electrolyte replacement are the cornerstones of therapy 1, 2
• Shock/hypoperfusion: Restore circulatory volume and tissue perfusion 1, 2
• Chronic kidney disease: Oral sodium bicarbonate 2-4 g/day (25-50 mEq/day) when serum bicarbonate is consistently <18 mmol/L 2
• Renal tubular acidosis: Chronic bicarbonate replacement to normalize serum bicarbonate for normal growth in children 2

When to Use Sodium Bicarbonate

Clear Indications for IV Bicarbonate

Administer sodium bicarbonate only in these specific situations:

• Severe metabolic acidosis with pH <7.0-7.1 after ensuring adequate ventilation 2, 3, 4
• Diabetic ketoacidosis with pH <6.9: Give 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/hour 1, 2, 3
• Diabetic ketoacidosis with pH 6.9-7.0: Give 50 mmol sodium bicarbonate in 200 mL sterile water at 200 mL/hour 1, 2, 3
• Life-threatening sodium channel blocker/tricyclic antidepressant toxicity with QRS >120 ms: Initial bolus of 50-150 mEq, then continuous infusion of 150 mEq/L solution at 1-3 mL/kg/hour 2, 3
• Life-threatening hyperkalemia: Use as temporizing measure while definitive therapy is initiated 2, 3

When NOT to Use Bicarbonate

Do not administer sodium bicarbonate in these situations:

• Hypoperfusion-induced lactic acidemia with pH ≥7.15: Two randomized controlled trials showed no difference in hemodynamic variables or vasopressor requirements compared to saline 2, 3
• Routine cardiac arrest: Not recommended unless specific indications present (severe documented acidosis, hyperkalemia, or toxicologic emergency) 2, 3
• Diabetic ketoacidosis with pH ≥7.0: No evidence of benefit 1, 2, 3

Dosing and Administration

Standard Adult Dosing

• Initial bolus: 1-2 mEq/kg IV (50-100 mEq or 50-100 mL of 8.4% solution) given slowly over several minutes 3, 4
• Cardiac arrest: 50 mL (44.6-50 mEq) every 5-10 minutes as indicated by arterial pH monitoring 4
• Target pH: 7.2-7.3, not complete normalization 3, 4

Pediatric Dosing

• Children: 1-2 mEq/kg IV given slowly 1, 2, 3
• Infants <2 years: Use only 0.5 mEq/mL (4.2%) concentration—dilute 8.4% solution 1:1 with normal saline 2, 3
• Never mix with calcium-containing solutions or vasoactive amines 2, 3

Chronic Kidney Disease

• Oral sodium bicarbonate: 2-4 g/day (25-50 mEq/day) to maintain serum bicarbonate ≥22 mmol/L 2
• Maintenance dialysis patients: Target serum bicarbonate ≥22 mmol/L 2

Critical Monitoring Requirements

Monitor the following every 2-4 hours during active bicarbonate therapy:

• Arterial blood gases: Assess pH, PaCO2, and bicarbonate response 3
• Serum electrolytes: Sodium (target <150-155 mEq/L), potassium, and ionized calcium 2, 3
• Avoid: Serum sodium >150-155 mEq/L and pH >7.50-7.55 2, 3

Important Safety Considerations and Pitfalls

Common Adverse Effects

Sodium bicarbonate administration can cause:

• Paradoxical intracellular acidosis: Bicarbonate produces CO2 that must be eliminated through adequate ventilation 2, 3
• Hypernatremia and hyperosmolality: Bicarbonate solutions are hypertonic 3, 4
• Decreased ionized calcium: Can worsen cardiac contractility 2, 3
• Hypokalemia: Bicarbonate shifts potassium intracellularly—monitor and replace as needed 2, 3
• Sodium and fluid overload 2, 3

Critical Safety Steps

Before administering bicarbonate:

1. Ensure adequate ventilation first: Bicarbonate produces CO2 that requires elimination to prevent worsening intracellular acidosis 2, 3
2. Flush IV line with normal saline before and after administration to prevent catecholamine inactivation 3
3. Never mix with calcium or vasoactive amines 2, 3

Special Clinical Scenarios

Diabetic Ketoacidosis Management

The American Diabetes Association recommends:

• Continuous IV insulin is the standard of care for critically ill patients 1, 2
• Bicarbonate use has not improved resolution of acidosis or time to discharge 1, 2
• When transitioning from IV to subcutaneous insulin, administer basal insulin 2-4 hours before stopping IV insulin to prevent rebound ketoacidosis 1

Chronic Kidney Disease

Correction of acidemia in CKD patients has been associated with:

• Increased serum albumin and decreased protein degradation 2
• Improved bone histology 2
• Fewer hospitalizations 2

Contrast-Induced Nephropathy Prevention

• Either lactate or bicarbonate can be used as buffer in CRRT patients 2
• Bicarbonate is preferred in patients with lactic acidosis and/or liver failure 2