19-10-2012, 05:03 PM
Cardiac Defibrillators
203 MDE defibrillator1 lectuers.pdf (Size: 508.54 KB / Downloads: 48)
Need For A DefibrillatorNeed Defibrillator�
Defibrillationis the definitive treatment for the life-threatening cardiac arrhythmias ventricular fibrillationand pulselessventricular tachycardia
Ventricular fibrillation results from:
Coronary occlusion
Electrical shock
Abnormalities of body chemistry
This irregular contraction of the muscle fibers
causes non effectively blood pumping and that
results in a steep fall of cardiac output
An energy storage capacitor is charged at a relatively slow
rate from:
The AC line by means of a step-up transformer and rectifier
arrangement or.
A battery and DC to DC converter arrangement
During defibrillation the energy stored in the capacitor is then
delivered (Discharged) at a relatively rapid rate (in order of
milliseconds) to the chest of subject through the patient’s
own resistance
Energy level of defibrillators is from 2 to 400 Joules (J)
(depends on the size of the patient and skin resistance)
Required voltage in the range of 1000 to 6000 V (depend on