Bicarbonate Therapy in Diabetic Ketoacidosis
Bicarbonate therapy in DKA is indicated only when arterial pH is below 6.9, and should not be administered when pH is 7.0 or higher. 1, 2
Specific Recommendations for Bicarbonate Administration
When bicarbonate therapy is deemed necessary, follow these guidelines:
- For pH < 6.9: Administer 100 mmol sodium bicarbonate diluted in 400 ml sterile water at a rate of 200 ml/h 1
- For pH 6.9-7.0: Administer 50 mmol sodium bicarbonate diluted in 200 ml sterile water at a rate of 200 ml/h 1
- For pH > 7.0: No bicarbonate therapy is necessary 1, 2
Rationale and Evidence
The use of bicarbonate in DKA remains controversial. The American Diabetes Association guidelines indicate that at pH ≥ 7.0, reestablishing insulin activity blocks lipolysis and resolves acidosis without bicarbonate supplementation 1. This recommendation is supported by evidence graded as "B" level, indicating well-conducted cohort studies support this approach.
The FDA label for sodium bicarbonate injection states it is indicated for metabolic acidosis in uncontrolled diabetes, but does not specify pH thresholds 3. However, the more specific diabetes guidelines should take precedence in DKA management.
Special Considerations
Pediatric Patients
- Bicarbonate should not be administered to children with DKA, except in cases of very severe acidemia with hemodynamic instability refractory to saline administration 4
- There are no randomized studies in pediatric patients with pH < 6.9 1
Adult Patients with Compounding Factors
Consider bicarbonate in adults with:
- Severe acidemia (pH < 7.20 and bicarbonate < 12 mmol/L) who are at risk for worsening acidemia 4
- Hemodynamic instability 4, 5
- Hyperkalemia 5
- Compounding acidosis due to acute kidney injury or normal anion gap acidosis 5
Monitoring During Bicarbonate Therapy
When administering bicarbonate:
- Monitor electrolytes, especially potassium, as bicarbonate therapy can worsen hypokalemia
- Assess arterial pH and bicarbonate levels frequently (every 2-4 hours) 2
- Monitor for signs of fluid overload, especially in patients with cardiac compromise
Potential Risks of Bicarbonate Therapy
- Paradoxical central nervous system acidosis
- Hypokalemia
- Fluid overload
- Delayed ketone clearance
- Potential contribution to cerebral edema (particularly in pediatric patients)
Resolution of DKA
DKA is considered resolved when:
The evidence clearly shows that bicarbonate therapy should be reserved for cases of severe acidemia (pH < 6.9) in adult patients, while focusing on the mainstays of DKA management: fluid resuscitation, insulin therapy, and electrolyte replacement.