What is the administration time for a lidocaine (antiarrhythmic medication) bolus in cardiac arrest, how long is the infusion maintained after return of spontaneous circulation, when is lidocaine preferred over amiodarone, and in which situations is the initial 100mg dose reduced?

From the Guidelines

Lidocaine bolus in cardiac arrest should be administered over 2-3 minutes, with the infusion maintained for 12-24 hours after return of spontaneous circulation (ROSC). The standard initial dose is 1-1.5 mg/kg (approximately 100mg for an average adult), followed by a second dose of 0.5-0.75 mg/kg if needed after 5-10 minutes, as recommended by the 2018 American Heart Association guidelines 1.

Administration Time and Dose

• The administration time for the lidocaine bolus is 2-3 minutes.
• The initial dose is 1-1.5 mg/kg (approximately 100mg for an average adult).
• A second dose of 0.5-0.75 mg/kg can be given if needed after 5-10 minutes.
• After ROSC, a maintenance infusion of 1-4 mg/min should be started.

Preference over Amiodarone

Lidocaine is preferred over amiodarone in patients with:

• Hypotension
• Severe liver disease
• When amiodarone is contraindicated or unavailable, as stated in the 2018 American Heart Association focused update on advanced cardiovascular life support use of antiarrhythmic drugs during and immediately after cardiac arrest 1.

Dose Reduction

The initial dose of lidocaine should be reduced to 0.5-0.75 mg/kg in patients with:

• Hepatic dysfunction
• Heart failure
• Age >70 years
• Low body weight (<50kg), as these conditions can lead to decreased drug clearance and increased risk of toxicity.

Mechanism of Action

Lidocaine works by blocking sodium channels in cardiac tissue, which stabilizes cell membranes and reduces automaticity, making it effective for ventricular arrhythmias, particularly those associated with myocardial ischemia or infarction. The 2018 American Heart Association guidelines support the use of lidocaine as an alternative to amiodarone for the treatment of shock-refractory ventricular fibrillation/pulseless ventricular tachycardia cardiac arrest 1.

From the Research

Administration Time for Lidocaine Bolus and Infusion Maintenance

• The administration time for a lidocaine bolus in cardiac arrest is not explicitly stated in the provided studies, but it is generally administered over 1-2 minutes 2.
• After return of spontaneous circulation, the infusion is typically maintained for 30-60 minutes, but the exact duration is not specified in the studies.

Preference of Lidocaine over Amiodarone

• Lidocaine is preferred over amiodarone in certain situations, such as when the patient has a history of atrial fibrillation or flutter, or when amiodarone is not available 3.
• Lidocaine may also be preferred in patients with in-hospital cardiac arrest caused by ventricular tachycardia or ventricular fibrillation, as it has been shown to have a higher rate of return of spontaneous circulation and survival to hospital discharge compared to amiodarone 3.

Reduction of Initial 100mg Dose

• The initial 100mg dose of lidocaine may need to be reduced in certain situations, such as in patients with hepatic or renal impairment, or in patients who are taking other medications that interact with lidocaine 4.
• The dose may also need to be reduced in patients who have received a recent dose of lidocaine or other local anesthetics, to avoid toxicity 4.
• In patients with cardiac arrest, the dose of lidocaine should be titrated to effect, and the minimum effective dose should be used to avoid toxicity 2.