What is the evidence for lidocaine (Lidocaine) vs amiodarone (Amiodarone) in traumatic cardiac arrest with ventricular arrhythmias?

From the Guidelines

In traumatic cardiac arrest with ventricular arrhythmias, amiodarone is generally preferred over lidocaine, though both medications can be used, as evidenced by the 2018 American Heart Association guidelines 1.

Key Considerations

• Amiodarone should be administered at 300 mg IV/IO bolus, with a possible second dose of 150 mg if needed, based on the recommendations from the 2018 American Heart Association focused update on advanced cardiovascular life support 1.
• Lidocaine can be given as an alternative at 1-1.5 mg/kg IV/IO initially, followed by 0.5-0.75 mg/kg every 5-10 minutes if necessary, up to a maximum of 3 mg/kg, as suggested by the same guidelines 1.

Rationale

The preference for amiodarone stems from its broader spectrum of antiarrhythmic effects and evidence suggesting slightly better outcomes in cardiac arrest scenarios, as noted in the 2018 evidence summary 1. Amiodarone works by blocking multiple ion channels and adrenergic receptors, providing more comprehensive control of ventricular arrhythmias. However, in traumatic cardiac arrest specifically, addressing the underlying cause (such as hypovolemia, tension pneumothorax, or cardiac tamponade) takes precedence over antiarrhythmic medications. If amiodarone is unavailable or contraindicated, lidocaine remains a reasonable alternative, particularly in patients with liver dysfunction where amiodarone's metabolism may be problematic. Both medications should be considered as part of a comprehensive resuscitation approach that prioritizes treating reversible causes of traumatic arrest.

Important Notes

• The choice between amiodarone and lidocaine should be made based on the individual patient's circumstances and the availability of the medications, considering the latest guidelines and evidence 1.
• The use of magnesium in cardiac arrest management is not routinely recommended but may be considered for torsades de pointes, as stated in the 2018 American Heart Association guidelines 1.

From the Research

Evidence for Lidocaine vs Amiodarone in Traumatic Cardiac Arrest with Ventricular Arrhythmias

• The provided studies do not specifically address traumatic cardiac arrest, but rather out-of-hospital or in-hospital cardiac arrest due to ventricular arrhythmias.
• A study published in 2016 2 compared amiodarone, lidocaine, and placebo in out-of-hospital cardiac arrest, and found no significant difference in survival to hospital discharge between the three groups.
• A 2023 study 3 compared amiodarone and lidocaine in in-hospital cardiac arrest, and found that lidocaine was associated with higher rates of return of spontaneous circulation, 24-hour survival, survival to hospital discharge, and favorable neurologic outcome.
• A systematic review published in 2017 4 found that the evidence for amiodarone or lidocaine in pediatric cardiac arrest due to ventricular arrhythmias was limited and of low quality.
• A Bayesian analysis published in 2022 5 reanalyzed the data from the 2016 study 2 and found that amiodarone had a high probability of improved survival and neurological outcome compared to placebo, while lidocaine had a more modest benefit.
• A 2020 study 6 found that amiodarone was associated with a higher likelihood of terminating ventricular fibrillation/pulseless ventricular tachycardia within three shocks, but there was no significant difference in long-term outcomes between amiodarone and lidocaine.

Comparison of Amiodarone and Lidocaine

• The studies suggest that both amiodarone and lidocaine may be effective in treating ventricular arrhythmias, but the evidence is not consistent and more research is needed to determine the optimal treatment.
• Amiodarone may have a higher probability of improved survival and neurological outcome compared to placebo, but the evidence for lidocaine is less clear.
• The choice between amiodarone and lidocaine may depend on individual patient factors and the specific clinical context.

Limitations of the Evidence

• The studies were conducted in different populations (out-of-hospital, in-hospital, pediatric, adult) and may not be generalizable to traumatic cardiac arrest.
• The evidence is limited by the quality of the studies, with many having small sample sizes or methodological limitations.
• More research is needed to determine the optimal treatment for traumatic cardiac arrest with ventricular arrhythmias.