Backed by over 40 studies, SMART Biphasic was the first biphasic therapy with sufficient evidence to receive a Class IIa recommendation from the American Heart Association: “Standard of care”, “Intervention of choice”.1 No other biphasic defibrillation therapy is backed by more evidence. In contrast, there are some biphasic therapies on the market today with no published out-of-hospital clinical data.
SMART Biphasic: A Track Record of Outstanding Effectiveness
The SMART Biphasic waveform is highly effective at terminating ventricular fibrillation (VF). A multi-centered, pre-hospital clinical trial with long-downtime VF patients showed an impressive 96% first shock efficacy (with 76% return of circulation and good brain function in 87% of the surviving patients).2 Another study showed 100% first shock efficacy.3
SMART Biphasic is effective across the broad spectrum of patients, even the “difficult” ones (e.g. obese, high or low body resistance (impedance), recurring fibrillation, and myocardial infarction). Other manufacturers claim that being able to escalate to higher energy levels on successive shocks is important, in case you are treating a “difficult patient”. Studies show that if you start with the right therapy, there is no need to escalate. 4,5,6 They conclude that Philips’ therapy is highly effective with these difficult patients. In other words, if you assume every patient is a difficult patient, and gear your initial therapy accordingly, there is no need to escalate on successive shocks.
Current is the Correct Measure of Shock Strength, Not Energy.
It is now widely accepted that current is the right measure of shock strength. Not energy.7,8,9,10,11
“Because it is accepted that defibrillation is accomplished by passage of sufficient current through the heart, the concept of current-based defibrillation is appealing. Energy is a non-physiologic descriptor of defibrillation despite its entrenchment in traditional jargon…Transition to current-based description is timely and should be encouraged.”
American Heart Association Guidelines 2005.
Circulation 2005; 112.
“Although energy levels are selected for defibrillation, it is the transmyocardial current flow that achieves defibrillation. Current correlates well with successful defibrillation and cardioversion. Future technology may enable defibrillators to discharge according to transthoracic current: a strategy that may lead to greater consistency in shock success. Manufacturers are encouraged to explore further this move from energy-based to current-based defibrillation.”
European Resuscitation Council Guidelines 2005.
Resuscitation 2005; Vol 67 Supplement 1 Page S31
SMART Biphasic: Leads in First-Shock Current
Philips’ patented capacitor implementation packs more high-potency defibrillation current at any given energy level than conventional, escalating high-energy waveforms. Philips leads in first-shock current, delivering more defibrillation therapy right to the heart.9 In fact, some manufacturers’ waveforms need twice the energy to deliver current at a level equal to SMART Biphasic at 150J.9,12
The Downside to High Energy: Potentially Fatal Side Effects
There is more to the biphasic story than just efficiently delivering potent shocks. The rest of the story centers on minimizing cardiac dysfunction. Defibrillation is electric medicine with potential side effects like any kind of medication. The downside to high energy is the potentially fatal side effects.
One study found that while high current was associated with defibrillation success and survival, high energy was associated with harmful myocardial stunning detrimental to an already-fragile heart.10 The study concluded that a defibrillation waveform that combines high current with low energy is optimal, maximizing effectiveness while minimizing cardiac dysfunction. Several additional studies have linked myocardial stunning with early death after initially successful resuscitations.10,13,14,15,16
SMART Biphasic: Best Shock From the Start
Philips SMART Biphasic therapy assumes every patient is a “difficult” patient and needs the most potent shock right from the start. Philips SMART Biphasic combines high current for shock strength with low energy to minimize potentially fatal heart-stunning side effects of cardiac dysfunction. By minimizing side effects, there is no reason to hold back on shock strength. The patient benefits from our strongest, most potent shock right from the start. There is no reason to escalate and delay life-saving treatment.
SMART Biphasic provides the best of both worlds – maximized shock strength with minimized side effect risk.
Manufacturers using escalating, high-energy waveforms, hold back their most potent shock until the second or third shock, presumably to avoid the cardiac dysfunction accompanying their highest energy settings. Under a Guidelines 2005 protocol, it can take up to 6 minutes to reach their most potent shock. With cardiac arrest, time is the enemy.1,4,5,7,8 Those “difficult patients” are left waiting, making them even more difficult.
The Bottom Line on Philips SMART Biphasic
• Set the industry standard is now the most proven waveform on the market.
• Packs more high-potency defibrillation current at any given energy level than conventional, escalating high-energy waveforms.
• Leads in first-shock current, delivering more defibrillation therapy right to the heart.
• Combines high current to maximize shock strength with low energy to minimize potentially fatal heart-stunning side effects of cardiac dysfunction.
• No reason to hold back on shock strength. No reason to escalate and delay life-saving treatment.
1. American Heart Association Guidelines 2000. Circulation 2000; 102 No 8.
2. Schneider et al, Circulation. Vol 102 No 15 Oct 2000.
3. Page RL et al. New England Journal of Medicine 2000;343:1210-1216.
4. White et al. Critical Care Medicine. 2004; Vol 32 No 9
5. White et al. Resuscitation 64 (2005) 63–69.
6. Hess et al. Resuscitation (2008) 79, 28-33.
7. American Heart Association Guidelines 2005. Circulation 2005; 112.
8. European Resuscitation Council Guidelines 2005. Resuscitation 2005; Vol 67 Supplement 1 Page S31
9. Niemann et al. Academic Emergency Medicine; 2005: Vol 12 No 2
10. Tang et al. Journal of the American College of Cardiology 2004; Vol 43 No 7:1228-35
11. Lerman, B. B. et al. J Clin Invest. 1987 Sep; 80(3):797-803.
12. HeartStart FR2 Series Defibrillator Technical Reference Manual, Edition 3. P3-10.
13. Neumar et al. A Consensus Statement from the International Liaison Committee on Resuscitation. Circulation. 2008 Oct 23.
14. Laver, S.et al. Intensive Care Med. 2004 Nov; 30(11):2126-8.
15. Herlitz, J. et al. Resuscitation. 1995 Feb; 29(1):11-21.
16. Laurent, I. et al. Journal of American College of Cardiology. 2002 Dec 18; 40(12):2110-6.