From the Guidelines
Bicarbonate administration is advisable when arterial pH falls below 7.1, as this indicates severe acidosis that may require buffering to mitigate its negative effects on the body. The decision to administer bicarbonate should be based on the severity of acidosis and the underlying cause, with consideration of the potential risks and benefits. According to the European Resuscitation Council guidelines 1, the judicious use of sodium bicarbonate is limited to patients with severe acidosis (arterial pH less than 7.1 and base deficit less than 10) and to cardiac arrest occurring in special circumstances, such as hyperkalaemia or tricyclic antidepressant overdose. Some key points to consider when deciding to administer bicarbonate include:
- The severity of acidosis, as indicated by arterial pH and base deficit
- The underlying cause of acidosis, such as diabetic ketoacidosis, lactic acidosis, or cardiac arrest
- The potential risks of bicarbonate administration, including paradoxical intracellular acidosis, hypernatremia, volume overload, and hyperosmolarity
- The need for individualized treatment, with dosing guided by serial blood gas measurements to monitor response, as suggested by the 1998 European Resuscitation Council guidelines 1. It is essential to weigh the potential benefits of bicarbonate administration against its risks and to reserve its use for severe cases where the benefits outweigh the potential complications.
From the FDA Drug Label
In cardiac arrest, a rapid intravenous dose of one to two 50 mL syringes (44.6 to 100 mEq) may be given initially and continued at a rate of 50 mL (44. 6 to 50 mEq) every 5 to 10 minutes if necessary (as indicated by arterial pH and blood gas monitoring) to reverse the acidosis.
The decision to administer bicarbonate should be based on arterial pH and blood gas monitoring. However, the FDA drug label does not specify an exact arterial pH level at which it is advisable to administer bicarbonate.
- The label mentions that bicarbonate therapy should be planned in a stepwise fashion and monitored by measuring blood gases, plasma osmolarity, arterial blood lactate, hemodynamics, and cardiac rhythm 2.
- It is recommended to aim for a total CO2 content of about 20 mEq/liter at the end of the first day of therapy, which will usually be associated with a normal blood pH. The FDA drug label does not answer the question of the specific arterial pH level.
From the Research
Arterial pH Level for Bicarbonate Administration
The administration of bicarbonate is a topic of controversy, particularly in the context of severe metabolic acidosis. According to 3, bicarbonate should be given at an arterial blood pH of ≤7.0, with the amount administered calculated to bring the pH up to 7.2.
Key Considerations
- The decision to administer bicarbonate should be individualized, taking into account the patient's clinical situation and the underlying cause of the acidosis.
- Some studies suggest that bicarbonate administration may not improve hemodynamics in critically ill patients with lactic acidosis or ketoacidosis 4.
- Other research has investigated the use of bicarbonate in patients with severe metabolic acidosis and acute kidney injury, with some studies suggesting potential benefits 5.
pH Thresholds
- A study published in 2009 recommended bicarbonate administration at a pH of ≤7.0 3.
- Another study published in 2023 discussed a trial investigating the use of sodium bicarbonate in patients with severe metabolic acidosis and moderate or severe acute kidney injury, with a target pH of ≥7.30 5.
Additional Factors
- The calculation of the serum anion gap can aid in the diagnosis and classification of metabolic acidosis 6.
- The use of bicarbonate versus acetate hemodialysis has been compared in terms of effects on acid-base status, with bicarbonate appearing to be more efficient in correcting metabolic acidosis 7.