14 ms·

> AEDs don't actually bring you back to consciousness. They just make CPR more effective. (much more!) Perhaps a trained medical professional will correct me,

> AEDs don't actually bring you back to consciousness. They just make CPR more effective. (much more!) Perhaps a trained medical professional will correct me, but I've worked closely with the technology for years and I don't believe this is accurate. An AED can indeed bring someone back to consciousness if the shock is successful. If it isn't successful, then it wouldn't affect the efficacy of CPR one way or the other. The rest of your comment seems spot on.

pygy_ 14y ago
This is correct. The only point of defibrillation (automatic or not) is to stop ventricular tachycardia or ventricular fibrillation (electric rhythms that don't cause effective heart contractions), and kick-start a sinusal (normal) rhythm. If the cardiac arrest is the result of another mechanism, defibrillation is ineffective.
- jcheng 14y ago
  If the cardiac arrest is the result of something else, does defibrillation hurt anything? Or does it have no effect either way?
  - kevinskii 14y ago
    AEDs are smart enough not to shock unless they detect VF. This is important because defibrillating a normally beating heart could actually cause VF. Would-be rescuers may not always be trained well enough to tell the difference between cardiac arrest and something else, such as a seizure or fainting. But to your specific question: If a patient is in cardiac arrest but not in VF, then this means his heart has completely stopped. Forcing defibrillation won't likely improve the situation, but nor can it make it much worse.
graeham 14y ago
Finished a 2-day first aid+CPR course today, the stat was that ~0.2% (or was it 0.02%) or people getting CPR have their heart start without a defib (AED or at the hospital) (also am a biomed engg researcher working on arteries but not the heart directly). CPR is bascially to keep the person somewhat oxygenated until they can get a defib (such as from an AED). A study found a 39% boost in likelyhood in surviving to being discharged from the hospital if AED+CPR was used compared to CPR alone [3] An AED disrupts the fibrillation of the heart - often an outcome of a heart attack. Fibrillation is basically different parts of the heart firing randomly, with the effect that not much blood gets pumped. A defib (from AED or otherwise) is like a hard reboot of the heart, to try to reset the heart so it all contracts together again. Consciousness is more to due with a neuro-state, which is affected by blood flow so its a symptom of the heart problem rather than the problem itself. Also, as someone else mentioned, heart stopping /= death anymore, it is determined by brain activity [2] [1] http://intensivecare.hsnet.nsw.gov.au/cardiac-arrest http://intensivecare.hsnet.nsw.gov.au/cardiac-arrest [2] http://en.wikipedia.org/wiki/Death#Diagnosis http://en.wikipedia.org/wiki/Death#Diagnosis [3] http://depts.washington.edu/chru/May-20-A-Wicks-2_JC.pdf http://depts.washington.edu/chru/May-20-A-Wicks-2_JC.pdf

pygy_ 14y ago

This is correct. The only point of defibrillation (automatic or not) is to stop ventricular tachycardia or ventricular fibrillation (electric rhythms that don't cause effective heart contractions), and kick-start a sinusal (normal) rhythm. If the cardiac arrest is the result of another mechanism, defibrillation is ineffective.

jcheng 14y ago
If the cardiac arrest is the result of something else, does defibrillation hurt anything? Or does it have no effect either way?
- kevinskii 14y ago
  AEDs are smart enough not to shock unless they detect VF. This is important because defibrillating a normally beating heart could actually cause VF. Would-be rescuers may not always be trained well enough to tell the difference between cardiac arrest and something else, such as a seizure or fainting. But to your specific question: If a patient is in cardiac arrest but not in VF, then this means his heart has completely stopped. Forcing defibrillation won't likely improve the situation, but nor can it make it much worse.

graeham 14y ago

Finished a 2-day first aid+CPR course today, the stat was that ~0.2% (or was it 0.02%) or people getting CPR have their heart start without a defib (AED or at the hospital) (also am a biomed engg researcher working on arteries but not the heart directly). CPR is bascially to keep the person somewhat oxygenated until they can get a defib (such as from an AED). A study found a 39% boost in likelyhood in surviving to being discharged from the hospital if AED+CPR was used compared to CPR alone [3] An AED disrupts the fibrillation of the heart - often an outcome of a heart attack. Fibrillation is basically different parts of the heart firing randomly, with the effect that not much blood gets pumped. A defib (from AED or otherwise) is like a hard reboot of the heart, to try to reset the heart so it all contracts together again. Consciousness is more to due with a neuro-state, which is affected by blood flow so its a symptom of the heart problem rather than the problem itself. Also, as someone else mentioned, heart stopping /= death anymore, it is determined by brain activity [2] [1] http://intensivecare.hsnet.nsw.gov.au/cardiac-arrest http://intensivecare.hsnet.nsw.gov.au/cardiac-arrest [2] http://en.wikipedia.org/wiki/Death#Diagnosis http://en.wikipedia.org/wiki/Death#Diagnosis [3] http://depts.washington.edu/chru/May-20-A-Wicks-2_JC.pdf http://depts.washington.edu/chru/May-20-A-Wicks-2_JC.pdf