A few month ago while we were taking a break from failing to kill hogs, Ambulance Driver mentioned that a lot of what we think we know about first aid is completely wrong. He specifically mentioned CPR and mouth to mouth resuscitation as something in that category. I filed it away as interesting and mostly forgot about it until I stumbled across this video:
It reminded me of what AD had been saying so I asked him if this was legit.
There are a few reasons why artifical breathing isn’t all that effective in cardiac arrest. First, most adults go into cardiac arrest because of an arrhythmia. They already have enough oxygen stores to last their brain and organs for 4-6 minutes without damage. Second, chest compressions are only about 30% as effective as a an actual heartbeat, so there is very little blood flow to the lungs to actually pick up what little oxygen you may be delivering to the patient when you give those artificial breaths.
Third, and probably most important, is that the likelihood of resuscitation depends almost entirely on how much blood flow reaches the coronary arteries. It takes roughly 10 compressions to get a measurable increase in the pressure needed to push blood into those arteries, and every time we stop to breathe for the patient, the pressure falls to zero and you have to build it back up again. So when we’re doing CPR with artificial ventilations, roughly half our compressions are not resulting in measurable blood flow to those critical arteries.The other part of that equation is, every time you take a normal breath, the pressure within our chest cavity falls to less than that of ambient pressure, and air rushes into your chest. This *negative* pressure is also responsible for dilating the great vessels in our chest, and results in most of the venous blood return to our heart. When we start breathing artificially, we are *forcing* air in, resulting in *positive* intrathoracic pressure. The end result is impaired blood return to the heart.
Blood no reach heart, blood no reach coronary arteries. Blood no reach coronary arteries, patient much more likely to assume room temperature and eat his salads from the roots up from then on, capische?
Probably more than you wanted to know…
Time to go unlearn all that stuff you think you know.