Welch Allyn AED 10 User Manual page 84

User Manual
Results
The study consisted of 82 total fibrillation/defibrillation episodes. ID50 peak currents and
ED50 delivered energies are shown below for each group. The mean impedance for these
animals was 62
significantly different. The significance of difference (p-value) was calculated by the Wald
test in each case, and is shown below. The mean ED50 peak current for the biphasic
waveform was 39 percent of that required with the MDS waveform.
Summary Table - ED50 & ID50
Mean
ID50 Peak Current (Amps)
Significance of difference (p-value)
ED50 Delivered Energy (Joules)
Significance of difference (p-value)
Conclusion
The MRL Orbital Biphasic waveform is capable of converting fibrillation episodes using
less energy than the MDS waveform, and requires lower peak currents than MDS
waveform defibrillators.
Study 2
Objective
Comparison of the defibrillation effectiveness of the MRL Orbital Biphasic waveform
defibrillator, with a commercially available Biphasic 2kV defibrillator capable of 360 J and a
monophasic truncated exponential defibrillator.
Methods
A canine model (n=6, 61.6 ± 5.5 lbs) was used in a study that was approved by the
Institutional Animal Care and Use Committee. The animals were anesthetized with an
intravenous injection of 20 mg/kg sodium pentothal. They were then intubated with a
cuffed endotracheal tube, and maintained on isoflurane gaseous anesthetic. The femoral
artery was cannulated and an intra-arterial line was placed for continuous measurement of
arterial blood pressure, and for acquiring samples for arterial blood gas and electrolyte
monitoring. The chest was shaved and adhesive defibrillating electrode pads were placed
on the left and right chest walls.
Fibrillation was induced by delivering 60 Hz current to the external electrodes. The ED50
energy (that required to defibrillate with 50% probability) was determined by a protocol
modeled after that of Dixon. An initial shock strength of 30 joules was used, which was
applied after 15 seconds of ventricular fibrillation (VF). If successful, VF was re-induced
after a 4-minute rest period, and the shock strength was reduced by one energy step for
the next defibrillation attempt. If the initial shock failed, a rescue shock was delivered, and
after a rest period, VF was again induced. The energy was now increased one energy step
for the next defibrillation attempt. This procedure was continued until a nominal sample
size of six episodes was achieved (both sides of the first reversal in result, plus 4
Ω
. The mean ED50 energies were compared and were found to be
Welch Allyn
AED 10
6.4
26.3
Monophasic
Damped Sine
16.6
<0.001
35.3
0.014
Specifications 75