JULIE SCHAEFFER
JEMS Magazine
Data presented at the American Heart Association's (AHA) Scientific Sessions 2001 in Anaheim, Calif., demonstrated that the antiarrythmic agent IV amiodarone (marketed as Cordarone I.V.) is almost twice as effective as lidocaine in keeping cardiac arrest patients alive until they reach a hospital.
Traditionally, lidocaine has been used to treat cardiac arrest victims when other resuscitation techniques, such as defibrillation, have failed. However, the 2000 Advanced Cardiac Life Support (ACLS) Guidelines (published in Circulation, August 2000) recommended use of amiodarone for the treatment of ventricular tachycardia (VT), classifying its use as acceptable and useful with good to very good evidence (Class IIA). This rating was based in part on the study, "Amiodarone in Out-of-Hospital Resuscitation of Refractory Sustained Ventricular Tachyarrhythmias" (ARREST). The ARREST trial demonstrated survival-to-hospital rates for IV amiodarone at 29%. However, it compared IV amiodarone with placebo treatment, not lidocaine.
Although the 2000 guidelines did not rule out use of lidocaine for VT and ventricular fibrillation (VF), they stated that evidence for its efficacy is poor and gave it an indeterminant recommendation. Now a new study, "Amiodarone vs. Lidocaine in Prehospital Ventricular Fibrillation Evaluation" (ALIVE), reinforces those recommendations.
In the ALIVE trial, researchers studied the effectiveness of lidocaine vs. IV amiodarone by following 347 randomized patients who had suffered cardiac arrest and did not respond to three defibrillation shocks. In the blind trial, Toronto EMS paramedics administered one of the two drugs to each patient.
The trial found that 22.8% of cardiac arrest patients treated with IV amiodarone survived to hospital admission compared with 12% of patients treated with lidocaine. Among patients who received drug treatment within 24 minutes, IV amiodarone proved twice as effective (28%) as lidocaine (14%) in improving survival to hospital admission. Among patients treated more than 24 minutes after cardiac arrest, IV amiodarone proved three times more effective (18%) than lidocaine (6%).
Dosages: Amiodarone IV was administered as a bolus dose of 5 mg/kg, whereas 1.5 mg/kg of lidocaine was administered. When necessary, a second bolus dose of study drug was administered (2.5 mg/kg of amiodarone IV or 1.5 mg/kg of lidocaine).
Although the 2000 guidelines maintain that lidocaine is acceptable treatment, ALIVE's lead investigator, Paul Dorian, MD, says there are sufficient questions to challenge support of lidocaine as a first-line antiarrhythmic agent in the acute treatment of VF. "It's essential that we have the most effective medications available should defibrillation fail," says Dorian, a staff cardiologist and director of the Arrhythmia Service at St. Michael's Hospital, Toronto, Ontario, Canada. "Although lidocaine has always been an important tool, this study tells us that IV amiodarone offers better insurance of getting a patient to the hospital, where we can then use sophisticated lifesaving tools."
The Council on Cardiopulmonary and Critical Care awarded the ALIVE trial the "2001 Critical Care Best Abstract Award" at the AHA Scientific Sessions.
