The Physics Factbook
Edited by Glenn Elert -- Written by his students
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|Glencoe Health. 2nd ed. Glencoe-Mcgraw Hill. California, 1989: 555.||"As it senses an abnormal pattern, it sends out a 700- volt shock that can be repeated three times."||700 V|
|Sobel, Rachel K. "A Shocking Story: Handy Defibrillators." US News & World Report. 28 September 1998.||"A button was pushed on the unit, made by Heartstream, now a unit of Hewlitt-Packard, sending a 1,700 volt electric shock cursing through Adam's body."||1,700 V|
|University Hospital of Brooklyn. Telephone Interview.||"I was told 200 volts are needed."||200 V|
The human heart is a delicate muscle and must be taken care of. Sometimes disease can cause malfunction to occur and the heart to stop beating. When this happens, it is necessary to resuscitate the person to bring him/her back to life. This is done by sending electric shocks to the heart muscle until it starts beating again. This shock is administered by a device called a defibrillator. These defibrillators range in the amount of shocks they can administer.
From the discrepancies in the research, there does not seem to be an universal amount that will revive a heart. The voltages can range from 200 to 1,700 volts. The shocks can be repeated up to three times. Since it may take more than one shock to resuscitate the heart, the doctors administering the three shocks will start off with a small voltage and increase the amount of voltage with each shock.
|Powerheart: Fully Automatic External Cardioverter Defibrillator-Monitor. Cardiac Science.||"The maximum energy that can be delivered by the device is 360 joules, which is the maximum limit
recommended by the American Heart Association (AHA)."
|Spear, Dave. Electronic Mail.||"We dose current to the chest in units called joules (watts/sec) and use 200 to 360 joules per shock."||200–360 J|
The shock to the chest is also measured in joules. This quantity is a measurement of energy and is different from the voltage. My research shows the energy can start off as low as 40–60 J but can not be greater than 360–400 J. Anything over that amount would not result in saving the person's life.
Medical physics has benefited society by allowing for new technology to emerge. These devices have helped make the doctor's job a little easier and have provided new ways to save patient's lives. Thousands of people each year are saved because doctors and emergency medical technicians can give an electrical shock to the heart to resuscitate the person and bring him/her back to life. Regardless of the actual number needed to save the person's life, we should all be grateful that the technology exists to allow such miracles to occur.
Cindy Ann Romanowich -- 1999
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