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Philips Medical Systems
APPENDICES
Defibrillation waveform
category nominal specifications
waveform parameters Biphasic truncated exponential. Waveform parameters are automatically
adjusted as a function of patient defi brillation impedance. In the diagram at lef t,
D is the duration of phase 1 and E is the duration of phase 2 of the waveform, F
is the interphase delay (500 µs), and Ip is the peak current.
The HeartStart FRx delivers shocks to load impedances from 25 to 180 ohms.
The duration of each phase of the waveform is dynamically adjusted based on
delivered charge, in order to compensate for patient impedance variations, as
shown below:
adult defibrillation
load phase 1 phase 2 peak delivered
resistance (Ω) duration (ms) duration (ms) current (A) energy (J)
25 2.8 2.8 65 128
50 4.5 4.5 40 150
75 6.25 5.0 30 155
100 8.0 5.3 24 157
125 9.65 6.4 21 159
150 11.5 7.7 18 160
175 12.0 8.0 16 158
pediatric defibrillation
(using Infant/Child Key 989803139311)
load phase 1 phase 2 peak delivered
resistance (Ω) duration (ms) duration (ms) current (A) energy (J)
25 2.8 2.8 35 43.4
50 4.5 4.5 22 50.2
75 6.3 5.0 16 51.8
100 8.0 5.3 13 52.4
125 9.0 6.0 11 52.3
150 9.0 6.0 10 50.2
175 9.0 6.0 9 48.1