What is the management of metabolic acidosis?

Management of Metabolic Acidosis

Treat the Underlying Cause First—Not the pH

The primary management of metabolic acidosis is identifying and treating the underlying etiology, not routine bicarbonate administration. 1, 2 Sodium bicarbonate has not demonstrated mortality benefit in most acute organic acidoses and may worsen intracellular acidosis. 1

Algorithmic Approach Based on Etiology

Diabetic Ketoacidosis (DKA)

• Focus on insulin therapy, fluid resuscitation, and electrolyte replacement—NOT bicarbonate. 1, 2
• Continuous intravenous insulin is the standard of care for critically ill and mentally obtunded patients. 1
• Restoration of circulatory volume and tissue perfusion is the primary goal. 1
• Bicarbonate is only indicated if pH < 6.9 (some sources suggest < 7.0). 1, 3 Bicarbonate administration has not been shown to improve resolution of acidosis or time to discharge in DKA. 1
• For children with pH < 6.9, give 1-2 mEq/kg IV sodium bicarbonate slowly. 1

Chronic Kidney Disease (CKD)-Associated Acidosis

Treatment thresholds are based on serum bicarbonate levels: 1, 3, 2

• Bicarbonate ≥22 mmol/L: Monitor monthly without pharmacological intervention. 1, 3
• Bicarbonate 18-22 mmol/L: Consider oral alkali supplementation (sodium bicarbonate 2-4 g/day or 25-50 mEq/day divided into 2-3 doses) with or without dietary intervention. 1, 3
• Bicarbonate <18 mmol/L: Initiate pharmacological treatment with oral sodium bicarbonate to prevent bone and muscle metabolism abnormalities. 1, 2

Target maintenance is serum bicarbonate ≥22 mmol/L at all times. 1, 3 This prevents protein catabolism, bone demineralization, and may slow CKD progression. 1, 3

Typical oral dosing: 0.5-1.0 mEq/kg/day divided into 2-3 doses (or 2-4 g/day). 1, 3

Sepsis-Related Acidosis

• Prioritize fluid resuscitation and vasopressors over bicarbonate. 2
• Sodium bicarbonate should not be used to treat metabolic acidosis arising from tissue hypoperfusion in sepsis. 1
• Focus treatment on restoring tissue perfusion. 1

Severe Malaria in Children

• Metabolic acidosis resolves with correction of hypovolemia and treatment of anemia by adequate blood transfusion. 1
• Volume resuscitation with 20-40 ml/kg of 0.9% saline or 4.5% human albumin solution safely corrects hemodynamic features of shock. 4, 2
• No evidence supports sodium bicarbonate use. 1
• In children presenting with coma (Glasgow coma score ≤8) and shock, human albumin solution should be considered the resuscitation fluid of choice. 4

Lactic Acidosis

• The only effective treatment is cessation of acid production via improvement of tissue oxygenation. 5
• Treatment with sodium bicarbonate has failed to reduce morbidity and mortality despite improvement in acid-base parameters. 5

When to Use Intravenous Sodium Bicarbonate

Bicarbonate therapy is reserved for severe, life-threatening acidosis in specific situations: 6

Cardiac Arrest

• Rapid IV dose of 44.6 to 100 mEq (one to two 50 mL vials) may be given initially. 6
• Continue at 44.6 to 50 mEq every 5-10 minutes if necessary, guided by arterial pH and blood gas monitoring. 6
• In cardiac arrest, the risks from acidosis exceed those of hypernatremia. 6

Less Urgent Metabolic Acidosis

• For older children and adults: 2-5 mEq/kg body weight over 4-8 hours, depending on severity. 6
• Initial target is total CO₂ of approximately 20 mEq/L, NOT full correction to normal. 6
• It is unwise to attempt full correction of low total CO₂ during the first 24 hours, as this may be accompanied by unrecognized alkalosis due to delayed readjustment of ventilation. 6

Severe Acidosis with Acute Kidney Injury

• Hemodialysis is the definitive treatment for patients with severe acidosis (pH <7.20) and acute kidney injury. 1
• Dialysis should not be delayed while attempting medical management, as acidosis is refractory to conservative measures with this degree of renal impairment. 1

Critical Monitoring Requirements

Monitor these parameters closely during treatment: 1, 2

• Potassium levels: Acidosis causes transcellular potassium shift leading to hyperkalemia. 1, 2 As acidosis corrects, potassium shifts intracellularly and can cause life-threatening hypokalemia. 2
• Serum bicarbonate: Monthly initially in CKD patients, then at least every 4 months once stable. 1, 2
• Blood pressure and fluid status: Ensure treatment doesn't cause hypertension or volume overload. 1
• Arterial blood gases in severe cases to assess pH and response to treatment. 1, 6
• In shock-associated acidosis: blood gases, plasma osmolarity, arterial lactate, hemodynamics, and cardiac rhythm. 6

Common Pitfalls to Avoid

• Do NOT use furosemide unless hypervolemia, hyperkalemia, and/or renal acidosis are present. 1, 2
• Do NOT use dopamine in an attempt to improve renal function. 1, 2
• Do NOT use hypotonic fluids (e.g., glucose solutions) for fluid resuscitation. 1, 2
• Recognize that bicarbonate may worsen intracellular acidosis, reduce ionized calcium, and produce hyperosmolality. 1, 2
• Avoid citrate-containing alkali in CKD patients exposed to aluminum salts, as they may increase aluminum absorption. 1, 3
• Be cautious or avoid sodium bicarbonate in patients with advanced heart failure with volume overload, severe uncontrolled hypertension, or significant edema. 3

Special Populations

Children with CKD

• Pediatric clinicians may choose to treat milder acidosis (bicarbonate >18 mmol/L) more aggressively to optimize growth and bone health. 3
• Normalization of serum bicarbonate is important for normal growth parameters in children with renal tubular acidosis. 1

Dialysis Patients

• Maintain serum bicarbonate at or above 22 mmol/L through dialysate bicarbonate concentration adjustment. 1
• Higher dialysate bicarbonate concentrations (38 mmol/L) combined with oral supplementation may be needed. 3