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Medical Just a random question about asystole and CPR

  1. Jan 3, 2008 #1
    Many of use have watched medical drama (the Great White Tower, House, Gray's Anatomy [bad bad bad medicine] etc).

    Obviously here are patients who go into asystole, then people perform CPR.
    (ignoring the fact that most in most TV movies or series, people can regain consciousness ALL the time)

    When performing CPR on a patient in asystole, will it show on the Pulse Monitor (or whatever is it, that shows your heart pumping (ECG??)?
    Like when you compress, will the ECG show a spike, or will it still keep a flatline?
    My first thought is that it won't show any 'spikes' because the ECG measures electronic signals?
  2. jcsd
  3. Jan 3, 2008 #2


    Staff: Mentor

    There are actually two completely different devices that you mention in your post. One is the pulse monitor. Typically this is attached to a fingertip and it shines a light through the finger to determine when the finger fills with blood. This measures an optical effect and not an electrical effect. It will show pulses with cardiac compressions if you can get good enough compressions.

    The other device is the ECG. This is attached to three or more electrodes placed on the chest. This device measures an electrical effect. Since there is no electrical activity (or uncoordinated electrical activity) it will not measure the normal cardiac cycle. If it does start measuring electrical activity you better stop compressions right away because you don't want to squeeze a beating heart (Unless you are a witch-doctor in Indiana Jone's: Temple of Doom).
  4. Jan 7, 2008 #3
    Thanks for your post, DaleSpam.
    True that I got both of the machines mixed up, I forgot what I learned about those last year.
  5. Jan 20, 2008 #4


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    Actually, I believe the device on the finger is called a pulse oximeter and it measures the percentage of oxygen saturation in the blood. The ECG (EKG) will spike during external cardiac compression. Watching the monitor during CPR shows us the effectives of our compressions.
    Last edited: Jan 20, 2008
  6. Jan 20, 2008 #5


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    opps. sorry. that would be 'effectivness'. :redface:
  7. Jan 22, 2008 #6
    Doesn't the ECG measure the electrical impulse? Maybe I should do some research on it. it's just a curious question in life I want to know
  8. Jan 22, 2008 #7


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    Yes, it does measure the electrical impulse. However, when you are giving compressions you are actually causing electrical impulses with each downward stroke.
  9. Jan 25, 2008 #8
    I've always thought it measured the electric impulses from your brain, telling your heart bo beat?
    Wow, I guess we all learn something new everyday.

    What about defillibration? What will happen to the reading, both the pulse oximeter or the ECG?
  10. Jan 26, 2008 #9
    Pressing on any muscle will discharge some of its electricity, so compressions would cause a spike on an EKG.

    Heart muscle is myogenic, which means it produces its own electrical impulses and rhythmic contractions, not the brain, though the brain certainly can and does regulate the rhythm.

    As for defibrillation, since it essentially "restarts" the heart, I think you would see momentary asystole ("flat line") followed by a normal sinus rhythm if everything goes right!
  11. Jan 26, 2008 #10


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    Yes, defibrillation actually stops the heart, allowing the sinoatrial node to sync all the heart cells' beats.
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