Community defibrillator query

[ByLimeAnt]

I collapsed a couple of weeks ago with no trigger and apparently went very grey and was out for 15-20 minutes.

A bystander got defibrillator and apparently a shock was not advised, but they were told to do chest compressions, which they did.

My question is, does the machine tell them to do CPR no matter what, or only if indicated? The train I ask is because I'm not entirely sure if it was necessary (not complaining, just trying to understand).

Thank you.

Yes, the machine tells you when to do chest compressions

It will tell you to do chest compressions if the patient is unconscious and not breathing normally. Anyone doing CPR should know that is when you do them anyway.

The defib will only shock if the person is in atrial fibrillation, which is where the atria (top two chambers of the heart) are not contracting in rhythm. The electric shock stops the heart, and then hopefully the brain takes over and sets up the correct rhythm again.

Ideally they'd have been doing compressions before they even turned the defib on, so yes.

Edit: "so yes" doesn't actually help when I reread your post 😂.
I meant that for them to get the defib, it is likely you were indeed ill enough for them to do CPR.
So you know now what caused the collapse?

Hope you are well now.

Anyone doing effective CPR will know when to do this, or will be adequately guided by the ambulance service after an initial assessment of the situation.

Community accessible defibrillators will only shock certain rhythms and are incredibly simple to use.

I hope you are OK!

We have them at TfL stations, depots, and offices for community use. The defib tells you exactly what to do. It's a good idea to take a course but it's not absolutely necessary.

My first aid training taught that CPR/defibrillator should be used if the patient is unconscious and not breathing - had you stopped breathing?

If you were unconscious but breathing then it would usually be ring 999, put you in recovery position (unless there's a reason not to like a potential spinal injury) and keep monitoring breathing and consciousness.

How are you now?

Oh, thank you for your kind words! Feeling very very tired! Consultant thinks that my heart stopped for several seconds leading to collapse so have monitor on for a fortnight. If it shows something they will put pacemaker or ICD in and I should be fine.

I'm upset because I saw a GP last week about overwhelming fatigue and wanted to tell him about palpitations and shortness of breath as well. He was an absolute arse and told me it was all in my head and we are finishing now because you will make my list over run (I DEFINITELY was not in there more than ten minutes, I am very mindful of the pressures they are under). When he listened to my heart he spent about 3 seconds doing so.

Luckily I wrote a letter of complaint outlining all of this before I collapsed and have just followed it up with an update.

I'm just so upset because I can't drive now. If monitor does nothing I can't drive for six months. I cannot tell you what a nightmare that will be (no public transport for ten miles).

Oh, the irony, can't even get to GP surgery or hospital!!

Sorry, in response to last question, breathing erratically and very shallow breaths, could only get pulse which was very weak on carotid

That's poor on the GPs part, I'm glad you've had the energy to follow that up.

How old are you? If you're 35 or under you may be eligible for free cardiac screening with Cardic Risk in the Young. They are a charity aiming to prevent sudden death in young people by offering free heart scans/screening. Although in my own experience with a referral to cardiology generally things move quickly. I had a holter, then and echo, then an MRI in very quick succession, mri was on a Friday afternoon and I was called in on the Monday to discuss results (which although there was something, really was not needing that level of urgency!)

Lastly, don't underestimate the toll this may take on you mentally and emotionally. Be kind to yourself and seek additional support if you need it 💜

"My question is, does the machine tell them to do CPR no matter what, or only if indicated?"

It will only administer a shock if you have no pulse.

If it detects a pulse it will recommend CPR (chest compressions/heart massage) to keep blood circulating and getting enough oxygen to your brain.

Sorry to hear all of this, it sounds like the first aiders did a great job and your GP has been rubbish.

The cardiologists know what they're doing though, you're in good hands now. Have you had a virus recently? In my experience (I'm not a medic) that can do weird things to heart rhythms.

Not being able to drive is very frustrating - do you have people around who can help until you're sorted out?

Or a budget for taxis from money you would have spent on fuel? It might be worth SORN - ing your car if no-one else can drive it and you have off-street parking.

Sending you healing wishes 💐

Also, there should be community transport for hospital appointments, ask about that - but it's often very time consuming because they pick up other patients and you will probably be hanging around at the hospital before returning.

To answer your original question, OP - no, the defib cannot advise whether CPR is actually necessary or not. If you’re using the machine at all, it assumes that the person is unresponsive with no pulse and no respiratory effort. It then assess the electrical activity in the heart, and will advise a shock if one of two rhythms is present - ventricular fibrillation or pulseless ventricular tachycardia. If anything else is happening, its default recommendation is ‘continue CPR’.

Unnecessary CPR does sometimes happen when well-meaning bystanders panic a bit - a relative of mine sustained rib fractures in this scenario after she had a seizure in a public place.

Hope you’re doing ok now.

CPR is advised if you’re not breathing normally - this could be extremely slow, ineffective breathing or irregular snorting, gasping breaths. Google agonal breathing - many sudden cardiac arrest victims die because people assume the agonal breathing is breathing when actually it’s almost a reflex with the brain trying to force some activity as it is starved of oxygen.

An AED will only shock a ‘shockable rhythm’ - generally ventricular fibrillation which is a chaotic rhythm where the bottom 2 chambers of the heart quiver but don’t pump blood. If someone isn’t in this rhythm an AED won’t shock. Atrial fibrillation isa different beast completely and requires different treatment (either drugs/and or a specifically timed shock). If there’s no electrical activity an AED won’t shock. The shock actually stops the heart, to stop the chaos of VF and the hopefully the heart sorts itself out.

just to clarify - an Automated External Defibrillator will not shock for AF. There are four cardiac arrest rhythms the machine will recognise - two are 'shockable' (Ventricular Fibrillation and pulseless Ventricular Tachycardia) and two are not (asystole and Pulseless Electrical Activity). A person could be in cardiac arrest with a rhythm that is AF but this would be PEA and the machine would not provide a shock because it won't work. For the two 'non-shockable' rhythms the correct basic life support is CPR only. For the two 'shockable' rhythms the correct treatment is CPR and electricity. In theory you can work out which of the 4 rhythms someone is in based on whether it tells you to check for signs of life or delivers a shock.

Atrial fibrillation can be treated with electricity in an emergency or elective scenario by not by an automated defibrillator. To cardiovert rather than defibrillate it would need a synchronised shock to reduce the risk of converting the AF into a worse rhythm.

As per PPs basic life support teaches to start chest compressions if someone is unconscious and 'not breathing normally'. Keeping it this simple is to reflect that most people get in a bit of a state in this scenario (understandably!) and following complex instructions (like 'feel for a carotid pulse whilst holding the airway open') would be nigh on impossible. Chances are if someone is unconscious and isn't breathing normally then even if they've not actually had a cardiac arrest then they're probably in a very low cardiac output state and not far off arresting anyway. The risks of providing chest compressions to someone who hasn't arrested by far outweigh the risks of not providing chest compressions to someone who has arrested (IIRC the chance of getting a return of pulse reduces by something like 10% for every minute that someone isn't receiving CPR). The reason for the use of the phrase 'not breathing normally' is that agonal breathing is a pattern that has caused confusion in the past. It's an abnormal gasping pattern of 'breathing' and is a sign of a brainstem that's in profound trouble (because of cardiac arrest/low cardiac output) and if someone's only making agonal effort then chest compressions are still the right thing to do (again, IIRC, about 25% of people in cardiac arrest make agonal respiratory effort and if one used that as a 'sign of life' the outcome would be catastrophic).

@ByLimeAnt it sounds like compressions were needed. There are two main types of 'arrest' - Cardiac Arrest, and Respiratory Arrest. In the community, it really doesn't matter which it is because without correct treatment one will lead to the other.

As a PP said, the heart rarely just stops. It usually goes into a rhythm which is unsustainable beforehand. Ventricular Fibrillation (VF) is a rhythm where the bottom chambers of the heart quiver instead of contracting and relaxing rhythmically, so there isn't enough blood flow. Ventricular Tachycardia (VT) is a rhythm where the bottom chambers of the heart contract and relax so fast that there isn't time for the heart to fill with blood. Both of those are shockable rhythms because there is coordinated electrical activity and it's possible that a shock will organise it.

Pulseless Electrical Activity or Asystole can't be shocked because any electrical activity present doesn't have the ability or strength to make the heart contract.

It doesn't matter what your heart is doing if you don't have oxygen going around your body, so if you weren't breathing properly, then compressions were needed.

My partner has a genetic heart condition, his siblings both died suddenly in their 20s and 30s. He has a ICD fitted, and it saved his life about 18 months ago.
I hope you're doing well, and that the investigations provide some answers for you.

Some incredibly helpful answers here, thank you. Amylou, I'm wondering (not asking) if it is Brugada Syndrome. A lot of pieces are slotting into place - I've had intermittent tachycardia since I was a teenager and have been hospitalised twice for it with no real answers. I'm very sorry for your losses.