Energy Waveforms and Dosing

Because first shock efficacy for monophasic shocks is lower than first shock efficacy for biphasic shocks [1], the AHA 2005 Guidelines recommend different initial shock dosages for monophasic defibrillators (360 Joules [J]) and biphasic defibrillators (150-200J). [1] The Guidelines also recommend subsequent biphasic doses at "equal or higher" energy settings. [1]

Clinical evidence shows the limitations of 200J and the benefits of having full energy biphasic available. [2] [3] [4] [5] [6] [7]

A recent out-of-hospital study showed that when energy dosage is limited to 200J biphasic, up to 12% of patients will fail to defibrillate. [7] A separate large out-of-hospital study showed that availability of higher dosage (up to 360J) was associated with a much lower rate of failure (just 0.5% of 416 patients) and good survival (27%). [2]

Challenges

• Will your responders always know which kind of device they are using-monophasic or biphasic?
• Will they be familiar with the appropriate protocol for either type of technology?
• Do your defibrillators provide higher dosage-beyond 200J-for difficult-to-treat patients?

Meeting the Challenges

By standardizing your hospital with the LIFEPAK family of defibrillators you can proactively address each of these challenges. LIFEPAK defibrillators use ADAPTIV™ biphasic technology, giving you a full range of energy dosing up to 360J and a dosing protocol that many responders are already familiar with from the traditional monophasic protocols.

[1]

"Guidelines 2005 for Cardiovascular Resuscitation and Emergency Cardiovascular Care." 2005. Circulation 112, IV-40

[2]

Chapman F, et al. 2005. "Use of 360 Joule Biphasic Shocks for Initial and Recurrent Ventricular Fibrillation in Prehospital Cardiac Arrest." Circulation 112 (17): II-1112-1113.

[3]

Kim, M.L., et al. 2004. "Comparison of rectilinear biphasic waveform energy versus truncated exponential biphasic waveform energy for transthoracic cardioversion of atrial fibrillation." American Journal of Cardiology; 94: 1438-1440

[4]

Al Atawi, F., et al. 2003. "Comparison of Biphasic Waveforms for the Transthoracic Conversion of Atrial Defibrillation: The Mayo Clinic Cardioversion Experience." Circulation: 108 IV-647

[5]

Neal, et al. 2003. "Comparison of the efficacy and safety of two biphasic defibrillator waveforms for the conversion of atrial fibrillation to sinus rhythm." American Journal of Cardiology; 92: 810-14

[6]

Khaykin Y, et al. 2003. "Biphasic versus monophasic cardioversion in shock-resistant atrial fibrillation." Journal of Cardiovascular Electrophysiology 2003; 14: 868-72.

[7]

Stothert JC, et al. 2004. "Rectilinear biphasic waveform defibrillation of out-of-hospital cardiac arrest." Prehospital Emergency Care 8 (4): 388-92.