- There is some residual oxygen in your blood when you die;
- There is some residual air in your lungs when you finish exhaling;
- Some air will move in and out of the lungs when you perform chest compressions, particularly if you can get the victim's head into the "sniffing position." [Sniff to see if you can smell something. Freeze. That's the sniffing position.]
Saturday, July 31, 2010
The easiest way to remember this is to think about what CPR accomplishes: it causes the oxygen-caring blood to circulate.
...and where does that oxygen come from?
So what about the person who drowned? That person used up every shred of residual air in the lungs and nearly every shred of residual oxygen in their blood. They will get a little bit of air in-and-out of the lungs as you perform chest compressions, but not a lot. They could really use a little help in the oxygen department.
And what about the child who arrested, whether or not they drowned? The residual air in the lungs doesn't help a lot, because their lungs are so small. The amount of air that is going to go in and out with chest compressions is very small compared to their need. And children "compensate" very well - they won't have much residual oxygen in their blood stream when they arrest. They also could really use a little help in the oxygen department.
Personally, I don't have a problem doing mouth-to-mouth CPR on any young child I've just pulled out of a pool. You're blowing in, not sucking out, after all. What you really want to watch out for is doing mouth-to-mouth without a barrier device on someone who perhaps bit his tongue when he fell down in cardiac arrest and has blood flowing out of his mouth. That's when - as a bystander - the "If it's not safe, don't do it!" rule ought to occur to you. On the ambulance, we have a duty to respond. When you have a duty to respond, you don't have the protection of a Good Samaritan law, and you don't have a choice regarding whether the victim is going to get mouth-to-mouth or not.
One last point: if you position a toddler on his or her back on the floor, the disproportionately large back of the head will cause the head to tilt "chin-down" and thus effectively pinch off the air path to the lungs. You may have to improvise, but to maintain a viable airway in those victims, a phone book under the shoulder blades will really help, unless you are from a really small town, in which case two phone books might be needed. The nice thing about phone books is that they are not compressible.