Pulse Form; Functioning Principle - CardiAid CT0207RS Manuel D'utilisateur

12.2 Pulse Form

The delivered shock is a biphasic current-based shock. Two different energy levels are implemented in
the device, a low energy shock and a high energy shock. The current-based shock has the advantage
that the delivered energy depends on the patient impedance. Myocardium damage caused by high
electrical current applied to patient with low impedance is reduced considerably with this pulse form.
Pulse form / shock energy can only be configured by factory.
Factory setting is as follows:
1st Shock: Low, 2nd Shock: Low, 3rd and Subsequent Shocks: High
Delivered Energy:
High-energy adult-impulse at 50 Ohm: 270 J ± 15%
Low-energy adult-impulse at 50 Ohm: 170 J ± 15%
High-energy paediatric-impulse at 50 Ohm: 75 J ± 15%
Low-energy paediatric-impulse at 50 Ohm: 50 J ± 15%
Current characteristics of high-energy adult-impulses
for different patient impedances
pulse. Proportion of supplied electrical current (integral of current in time) between 2nd (negative) and
1st (positive) phases is 0,38 on average. This value is determined as optimal in clinical studies.
Impedance Dependence
For safety reasons, a current of maximum 2000 Volt is used. Resulting current as a function of patient
impedance is shown in the graph.
Energy Flow in High Patient Impedance
Supplying a fixed current has a determining effect on the energy applied to the patient. Ohm's law
requires higher voltage with increasing impedance. Because the voltage enters the supplied energy
quadratic; with increasing resistance, applied energy also rises considerably. This, in turn, provides a
better treatment for patients with high impedance and has a positive effect on decreasing death rate
in this patient group.
12. Technical Information

Functioning Principle

If the current exceeds the
specified value, current
transmission is interrupted.
Current continues to flow to
the patient with inductivity in
connection path. However, the
current falls gradually. If the
specified current value exceeds
1 Amp, current transmission
re-starts. In this way, current
supplied to the patient rises
again. This creates a saw tooth
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