55
9.
Tec
hnical Specifications
Published Clinical Data
The published clinical data is mainly derived from an out-of-hospital clinical study from a prospective, multicenter, out-
of-hospital clinical study published by Schneider et al.
1
for adult defibrillation. Pediatric defibrillation was supported
by an animal study performed on swine for defibrillation success and safety
2
and by a clinical study published by
Atkins et al.
3
Adult Waveform
The objective of the Schneider et al.
1
study was to compare AEDs that delivered 150J biphasic shocks with AEDs
that delivered high-energy (200 to 360J) monophasic shocks. AEDs were prospectively randomized according to
defibrillation waveform on a daily basis in four (4) EMS systems. First responders used either the 150J biphasic
waveform delivered by the Philips AEDs or 200 to 360J monophasic waveform AEDs on victims where defibrillation
was indicated. As noted above, the data provided by Defibtech demonstrates that the waveforms from Philips and
Defibtech are almost identical. Therefore, the clinical data for adult defibrillation included in the Schneider publication
was leveraged to support the safety and effectiveness of the Defibtech waveform.
A sequence of up to three (3) defibrillation shocks was delivered: 150J-150J-150J for the biphasic units and 200J-200J-
360J for the monophasic units. Defibrillation was defined as termination of VF for five (5) seconds without regard to
hemodynamic factors. Of 338 patients with an out-of-hospital cardiac arrest, 115 had a cardiac etiology, presented
with VF, and were shocked with one of the randomized AEDs. There were no statistical differences between the
monophasic and biphasic groups in terms of age, sex, weight, primary structural heart diseases, cause or location
of arrest, bystanders who witnessed the arrest, or type of responder. A summary of the results is presented in the
following table.
Biphasic vs. Monophasic Waveform
Biphasic Patients
Number (%)
Monophasic Patients
Number (%)
P Value
Defibrillation Efficacy
1 shock
< 2 shocks
< 3 shocks
52/54 (96%)
52/54 (96%)
53/54 (98%)
36/61 (59%)
39/61 (64%)
42/61 (69%)
< 0.0001
< 0.0001
< 0.0001
Patients defibrillated
54/54 (100%)
49/58 (84%)
0.003
ROSC
41/54 (76%)
33/61 (54%)
0.01
Survival to Hospital Admission
33/54 (61%)
31/61 (51%)
0.27
Survival to Hospital Discharge
15/54 (28%)
19/61 (31%)
0.69
More patients were defibrillated with an initial biphasic shock than monophasic shock and ultimately the biphasic
waveform defibrillated at higher rates than the monophasic waveform. A higher percentage of patients achieved return
of spontaneous circulation (ROSC) after biphasic shocks. Rates of survival to hospital admission and discharge did not
statistically differ between the two (2) waveforms.
The Schneider study was performed exclusively in Europe, and the following summarizes why that study is applicable
to the US population. The American Heart Association (AHA)
12
and European Resuscitation Council (ERC) guidelines
5,6,7
published when the studies were conducted recommended similar basic life support (BLS) and advanced life support
(ALS) steps for treating sudden cardiac arrest. The sudden cardiac arrest chain of survival is consistent between the
AHA and ERC, recommending delivering a shock as quickly as possible for VF and pulseless ventricular tachycardia,
performing CPR and ensuring access to advanced medical care for post resuscitation care. In addition, these
recommendations by AHA and ERC are still applicable to today’s resuscitation procedures and practices.
8,9,10
Therefore,
the study applies to the US population since the most significant factors influencing sudden cardiac arrest outcomes
are based on the specifics of the victim and the circumstances around the event,
11
none of which are dependent on a
US or European designation.
Defibtech DDU-2000 Series AED (continued)
DAC-U2510EN-BF rev H
55
