When should bicarbonate be used during cardiac arrest?

From the Guidelines

Bicarbonate should not be routinely used during cardiac arrest, but may be considered in specific situations such as hyperkalemia, tricyclic antidepressant overdose, or severe metabolic acidosis (pH < 7.2) 1. The use of bicarbonate during cardiac arrest is a topic of ongoing debate, with some studies suggesting potential benefits in specific situations, while others highlight the risks of adverse effects.

• The 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care recommend against the routine use of sodium bicarbonate in cardiac arrest, citing a lack of evidence for its effectiveness and potential risks such as hypernatremia, hyperosmolarity, and intracellular acidosis 1.
• The guidelines do suggest that bicarbonate may be beneficial in certain special situations, such as preexisting metabolic acidosis, hyperkalemia, or tricyclic antidepressant overdose 1.
• If bicarbonate is used, it is typically administered as a 1 mEq/kg IV bolus, with further administration guided by blood gas analysis or laboratory measurement 1.
• Other non-CO2-generating buffers, such as THAM or tribonate, may also be considered as alternatives to sodium bicarbonate, although clinical experience and outcome studies are limited 1.
• The focus during cardiac arrest should remain on high-quality CPR, appropriate ventilation, defibrillation when indicated, and addressing the underlying cause rather than correcting acidosis with bicarbonate 1. Key points to consider when deciding whether to use bicarbonate during cardiac arrest include:
• The presence of severe metabolic acidosis (pH < 7.2)
• Hyperkalemia or other electrolyte imbalances
• Tricyclic antidepressant overdose or other toxic ingestions
• The potential risks and benefits of bicarbonate administration in the individual patient
• The availability of alternative treatments and the underlying cause of the cardiac arrest.

From the FDA Drug Label

In cardiac arrest, a rapid intravenous dose of one to two 50 mL vials (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.

Bicarbonate should be used during cardiac arrest to reverse acidosis, as indicated by arterial pH and blood gas monitoring. It can be given initially in a rapid intravenous dose of one to two 50 mL vials (44.6 to 100 mEq) and continued at a rate of 50 mL (44.6 to 50 mEq) every 5 to 10 minutes if necessary.

• The use of bicarbonate is not empirical, but rather guided by arterial pH and blood gas monitoring.
• Key considerations for bicarbonate use in cardiac arrest include:
  • Reversing acidosis
  • Monitoring arterial pH and blood gas
  • Administering in a stepwise fashion 2

From the Research

Bicarbonate Administration in Cardiac Arrest

• The use of bicarbonate during cardiac arrest is a topic of ongoing debate, with various studies and guidelines providing different recommendations 3, 4, 5, 6, 7.
• According to the American Heart Association's revised "Standards and Guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiac Care (ECC)", bicarbonate should be used only at the discretion of the physician directing the resuscitation, and reliance upon arterial blood gases is suggested for bicarbonate administration 3.
• However, some studies suggest that arterial blood gases may not reflect the severe cellular acidosis that occurs at the tissue level during cardiac arrest, and that bicarbonate administration may not be beneficial in all cases 4, 5.
• The current guidelines recommend sodium bicarbonate injection in patients with existing metabolic acidosis, but clinical trials, particularly those involving patients with acidosis, are limited 4.
• A double-blind, randomized, placebo-controlled pilot study found that sodium bicarbonate administration improved acid-base status, but did not improve the rate of return of spontaneous circulation (ROSC) and good neurologic survival 4.
• Another study suggested that sodium bicarbonate should not be used during resuscitation in the absence of effective hyperventilation or where carbon dioxide removal is inadequate despite adequate ventilation, or in repeated doses without confirmation of substantial acidosis 5.
• A review of the literature over the last 25 years regarding bicarbonate administration in out-of-hospital cardiac arrest found that the debate is ongoing, but at the present time, sodium bicarbonate administration is only recommended for cardiac arrest related to hypokalemia or overdose of tricyclic antidepressants 7.

Situations for Bicarbonate Use

• Bicarbonate may be considered in cases of severe metabolic acidosis, as defined by a pH < 7.1 or bicarbonate < 10 mEq/L 4.
• It may also be considered in cases of cardiac arrest related to hypokalemia or overdose of tricyclic antidepressants 7.
• However, the use of bicarbonate should be individualized and based on the specific clinical scenario, taking into account the patient's underlying condition, the duration of cardiac arrest, and the presence of any preexisting acidosis 3, 6.

Empirical Use of Bicarbonate

• The empirical use of bicarbonate is not recommended, and its administration should be guided by arterial blood gas analysis and clinical judgment 3, 5.
• A reappraisal of the empirical use of bicarbonate or other buffer agents in the appropriate "therapeutic window" for cardiac patients may be warranted, but this should be based on careful consideration of the available evidence and individual patient factors 6.