When I first learned CPR (way back in the Dark Ages), the rhythm that was taught was 5 chest compressions, then one breath.
A bit later on, when I re-certified CPR in the process of certifying as a lifeguard, it was changed to 15 compressions and 2 breaths.
Now it’s changed again, though I don’t know exactly when – 30 compressions and 2 breaths.
I get that our understanding of how these things work marches forward, I’m just curious as to what the advantage is to the current pattern over the previous one, or the one before that?
Oh, oh! I just finished renewing my CPR/First Aid training on Thursday night, so I know this one. Our teacher said that people were worrying too much about how many compressions and breaths to do and not concerned enough about technique, so they’ve made it 30-2 across the board and have started emphasizing technique more with the thought that any blood circulating through the body is good. There’s also a new thing about not doing any breaths and just doing compressions with the thought that the lungs are inherently going to expand and contract during compressions, so some air will be received by the patient regardless of if you are giving breaths or not. It isn’t as effective, but if for some reason you are unable to administer breaths, don’t fret too much because some oxygenated blood will still get circulated through the body.
I, of course, have absolutely no useful sources to cite, but I imagine that someone will come along soon enough with more specifics.
My CPR instructor said the same thing as MissMossie’s. As an amusing tangent to this thread, an easy way to keep the rhythm is to sing Staying Alive. No joke. I’m pretty sure the falsetto is optional.
Actually, unless the person was choking or almost drowned (primary respiratory issues), it is better to NOT interrupt chest compressions AT ALL. You can have someone else do rescue breathing, but don’t stop chest compressions. If they just keel over and collapse, the most important thing is to keep blood pumping and maximize perfusion of the brain and heart. There is still some oxygen in your lungs that will get exchanged with blood, and your hemoglobin does not release all of the oxygen in your tissues at normal tissue oxygen levels (i.e., when there is constant delivery/circulation), and properly done chest compressions may cause some air exchange due to compressing and relaxing the thorax. Thus, your chest compressions are doing more to oxygenate the tissues than you might think. The ideal rhythm is 80 compressions/min, IIRC, which is rapid and tiring; with the ribs, sternum, and muscles in the way, it takes a lot of force to actually compress the chest enough to pump blood.
Hopefully St. Urho or one of our other CPR experts will come along and elaborate on or correct what I’ve written, since I am far from an expert.
Actually, if you witness them just keel over and collapse, the most important thing is defibrillation. If they’ve been down for a few minutes, then perform chest compressions first (at least two minutes worth, at a rate of 100 per minute), then begin defibrillation.
The logic is this – if you witness them go into cardiac arrest, the cells are still adequately perfused, since they were breathing just before they arrested, thus, no need for compressions. Additionally, if they just went into arrest, their heart is most likely still in a shockable rhythm - either ventricular fibrillation or pulseless ventricular tachycardia. The patient’s heart can quickly be “shocked” out of those non-perfusing rhythms into perfusing rhythms.
On the other hand, if they’ve been down for awhile, the cells need to be adequately perfused before defibrillation happens, otherwise, all you’re doing is electrocuting dead muscle. After ventricular fibrillation or pulseless ventricular tachycardia, the heart will inevitably go into asystole (flatline). An asystolic rhythm is not a shockable rhythm, in which case, chest compressions need to performed to get the cells perfused.
The change came about for a variety of reasons. The biggest were: everybody that was doing CPR wasn’t doing it well (including healthcare providers) and research that shows effective compressions are significantly more important than ventilations/rescue breathing for almost all types of cardiac arrest. Drowning is the exception to this.
The studies found that patients in arrest were being ventilated too often. This is bad because it increases the intrathoracic pressure, which means there is more pressure resisting blood flow out of the heart. They also found that compressions were interrupted too often. This is bad, because the coronary perfusion pressure drops below the level needed to perfuse the heart when CPR is stopped and it takes about 30 seconds of GOOD compressions to get it back to the level needed to perfuse the heart.
Vandal is absolutely right, as well. For a witnessed arrest, if a defibrillator is available immediate defibrillation has about an 80% success rate. For unwitnessed arrests, outcomes are much better when 2 minutes of CPR is done to perfuse the heart prior to defibrillation. We also now do another 2 minutes of CPR after defibrillation before rechecking for a pulse. The rationale is that it takes time to regain a perfusing rhythm, and we need to maintain coronary perfusion in the meantime.
That was kind of long, I hope it answered your question. For more information, look here.
Another One Bites The Dust by Queen works as well
For those of you that are interested, the latest change in cardiac arrest treatment is therapeutic induced hypothermia. We start cooling any patient who is successfully resuscitated with ice packs and/or iced saline with a goal of them maintaining a core temp of 32 C for 12-24 hours. This reduces metabolism and prevents neurological damage that occurs after reperfusion. I can’t remember the numbers of the top of my head, but substantially more patients survive to 6 months with good neurological function.
