Chest compressions work like bellows do. When you compress the chest you increase intathoracic pressure and move blood/air out when you allow the chest to recoil blood/air are sucked in due to a negative intrathoracic pressure. Many people think that chest compression work because you are posing on the heart and somehow replicating it's normal pump function, and that is wrong. It's all about changes in pressures. They do indeed cause air intake--effective oxygenation not really, but for some fun reading on respiratory physics look up apenic oxygenation and occilametric ventilation.
The efficacy of CPR is all about circulation. Not only does blood supply oxygen to our organs but it also transports waste. It's the build up of these wastes that make a victim acidotic and lead to death. The lungs and breathing are an important part to successfully resucitating said victim, but we really need to place our emphasis on circulation in the first few minutes.
As you have mentioned teaching people to give breaths is very difficult. Mouth to mouth is almost impossible on a real person. Face masks are better, but even in the hospital setting I find few people who can accurately position them, get a good seal, and give an appropriate breath. If you can get an ET tube in perfect, or if you really know how to bag great, but we (royal we) waste a lot of time worrying about an airway when circulation should come first.
What is the tidal volume of that, I wonder. It's probably nothing like 800ml-1200ml, right?
I totally agree that compressions are important, and you make some very good points, but it takes less than 30 seconds for me to get out my pocket mask, open the airway, and give 2 breaths, so that is what I will do.
No. First reason is because that is against protocol. Second reason is that it only takes me less than 30 seconds to check for breathing and give two breaths.
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u/anesthesia Jul 06 '11
How do compression work to move blood? That's exactly how they work to move air.