From the Guidelines
Sodium bicarbonate treatment should not be used to improve hemodynamics or reduce vasopressor requirements in patients after Coronary Artery Bypass Grafting (CABG) with pH ≥ 7.15, as evidenced by the 2017 Surviving Sepsis Campaign guidelines 1. The use of sodium bicarbonate in post-CABG patients is a topic of debate, with some advocating for its use in managing metabolic acidosis. However, the current evidence suggests that bicarbonate therapy may not be beneficial in patients with hypoperfusion-induced lactic acidemia and a pH ≥ 7.15.
- The 2017 guidelines suggest against the use of sodium bicarbonate therapy in this context, citing moderate quality of evidence and a weak recommendation 1.
- The rationale behind this recommendation is that sodium bicarbonate therapy has not been shown to improve hemodynamics or reduce vasopressor requirements in patients with lactic acidosis, and may even be associated with adverse effects such as sodium and fluid overload, increased lactate and Paco2, and decreased serum ionized calcium.
- Key considerations in the management of post-CABG patients include:
- Monitoring arterial blood gas measurements to guide treatment
- Addressing the underlying cause of acidosis, such as improving cardiac output or optimizing ventilation
- Using bicarbonate therapy judiciously, if at all, and reserving it for severe acidosis (pH < 7.2)
- Carefully monitoring serum electrolytes, particularly sodium and potassium, during treatment. The evidence from the 2017 Surviving Sepsis Campaign guidelines 1 takes precedence in guiding the use of sodium bicarbonate in post-CABG patients, and its recommendation against routine use of bicarbonate therapy in patients with pH ≥ 7.15 should be prioritized.
From the Research
Role of Bicarbonate Treatment in Patients after CABG
There is limited research directly addressing the role of bicarbonate (sodium bicarbonate) treatment in patients after Coronary Artery Bypass Grafting (CABG). However, we can look at the general use of bicarbonate in treating metabolic acidosis, which may occur in critically ill patients, including those post-CABG.
Use of Bicarbonate in Metabolic Acidosis
- Bicarbonate therapy is used to treat severe metabolic acidosis, but its utility remains controversial 2.
- The current literature suggests limited benefit from bicarbonate therapy for patients with severe metabolic acidosis (pH < 7.1 and bicarbonate < 6 mEq/L) 3.
- However, bicarbonate therapy may yield improvement in survival for patients with accompanying acute kidney injury 3.
- Sodium bicarbonate has been used in various pathologies, including hyperkalemia, cardiac arrest, and acute acidosis, but its efficacy and potential harm are debated 4.
Administration and Effects of Bicarbonate
- Bicarbonate should be given at an arterial blood pH of ≤7.0, and the amount given should be calculated to bring the pH up to 7.2 2.
- The use of sodium bicarbonate may cause paradoxical respiratory acidosis, intracellular acidosis, hypokalemia, hypocalcemia, alkalosis, and impaired oxygen delivery 4.
- In patients with chronic kidney disease and metabolic acidosis, sodium bicarbonate supplementation did not significantly increase blood pressure measured by 24-hour ambulatory blood pressure monitoring 5.
- Early sodium bicarbonate administration in ICU patients with metabolic acidosis was associated with an adjusted odds ratio of 0.85 for ICU mortality, but may be beneficial in patients with vasopressor dependency 6.
Considerations for Bicarbonate Treatment
- The decision to use bicarbonate therapy should be individualized, considering the underlying cause of metabolic acidosis and the patient's clinical situation 2, 3.
- The potential benefits and risks of sodium bicarbonate administration should be carefully weighed, and its use should be guided by evidence-based guidelines and clinical judgment 4.