Medical Just a random question about asystole and CPR

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The discussion focuses on the differences between pulse monitors and ECGs in the context of performing CPR on patients in asystole. It clarifies that a pulse oximeter, which measures blood oxygen saturation, can show pulses during effective compressions, while an ECG measures electrical activity and will not display normal cardiac cycles during asystole. When compressions are applied, the ECG may show spikes due to the electrical impulses generated by the compressions. The conversation also touches on defibrillation, noting that it temporarily causes asystole before potentially restoring a normal rhythm, as it allows the heart's sinoatrial node to synchronize the beats. Overall, the thread emphasizes the importance of understanding these devices and their functions during cardiac emergencies.
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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?
 
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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).
 
Thanks for your post, DaleSpam.
True that I got both of the machines mixed up, I forgot what I learned about those last year.
 
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:
Tsu said:
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.

opps. sorry. that would be 'effectivness'. :redface:
 
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
 
Invictious said:
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

Yes, it does measure the electrical impulse. However, when you are giving compressions you are actually causing electrical impulses with each downward stroke.
 
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?
 
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!
 
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GoldShadow said:
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!

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