What is the indication for a lidocaine (anti-arrhythmic medication) drip in a code blue (cardiac arrest) situation?

Lidocaine Drip in Code Blue: Indications and Administration

Lidocaine drip is indicated in a code blue situation for ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) that is unresponsive to defibrillation attempts, particularly in witnessed cardiac arrests where time to drug administration is shorter. 1

Primary Indications

• Shock-refractory VF/pVT: Lidocaine is recommended for persistent ventricular fibrillation or pulseless ventricular tachycardia that has not responded to:

  • CPR
  • Initial defibrillation attempts
  • Vasopressor therapy (epinephrine)

• Post-bolus maintenance: After initial bolus administration, a lidocaine drip is used to maintain therapeutic levels and prevent recurrence of arrhythmias

Dosing Protocol

1. Initial bolus:

   • 1.0-1.5 mg/kg IV/IO 1
   • Typically 75-100 mg for average adult 1

2. Additional boluses if needed:

   • 0.5-0.75 mg/kg IV/IO (25-50 mg) every 5-10 minutes 1
   • Maximum total bolus dose: 3 mg/kg 1

3. Maintenance infusion:

   • Follow boluses with continuous infusion to maintain therapeutic levels
   • Adjust dosing in patients with heart failure or hepatic dysfunction due to altered metabolism 1

Clinical Evidence and Considerations

The 2018 American Heart Association guidelines place lidocaine alongside amiodarone as a treatment option for shock-refractory VF/pVT 1. This represents an update from earlier guidelines where lidocaine was considered secondary to amiodarone.

Key evidence supporting lidocaine use:

• Improved rates of return of spontaneous circulation (ROSC) in the ROC-ALPS trial 1
• Improved survival to hospital admission compared to placebo 1
• Particularly beneficial in witnessed cardiac arrests 1, 2

Important Caveats

1. Efficacy limitations: Neither lidocaine nor amiodarone has definitively demonstrated improved long-term survival or neurological outcomes 1, 2

2. Timing considerations: Do not delay defibrillation or CPR to administer antiarrhythmic medications 3

3. Potential adverse effects:

   • CNS toxicity at high doses
   • Myocardial depression, especially in patients with shock 4
   • May increase the propensity for asystole during cardiac arrest 4
   • Can potentially reduce defibrillation efficacy by increasing energy requirements 4

4. Special populations: Dosage adjustment needed in patients with heart failure as volume of distribution and clearance are reduced 1

Alternative Considerations

For specific arrhythmias like torsades de pointes (polymorphic VT with long QT interval), magnesium sulfate (1-2g IV/IO) should be considered instead of lidocaine 1, 3

Summary

Lidocaine drip in code blue is primarily indicated for shock-refractory VF/pVT after failed defibrillation attempts. While it may improve short-term outcomes like ROSC and survival to hospital admission, its impact on long-term survival remains limited. The decision to use lidocaine should be made quickly within the ACLS algorithm, with proper attention to dosing and potential adverse effects.