Originally Posted by
TranscriptionFactor
No, no, no....
The correct answer for an adult is at least 20cc injected intra-VENOUSly for a significant air embolism. The lung can and will clear smaller bubbles without difficulty. That's rare that even that amt would cause a problem, usually takes about 100cc or more - probably depends on one's underlying Lung function.
Also, between 9-27% of people have a "Patent Foramen Ovale" which is a hole present from birth between the left and right atrium for fetal circulation, which in these people never closes over. If someone has a PFO, a venous air embolism could go into the left atrium and become ARTERIAL which is much much worse.
Injecting air Intra-ARTERIALly is another story, a very small amount, 1-3cc could cause an embolism and prevent blood flow distal to the embolism, which could possibly result in tissue death of the tissue supplied, unless there is adequate collateral circulation.
Take home lessons:
1. Don't inject Arteries under any circumstances. The way to avoid this is ALWAYS draw back after you get into the muscle before you inject to see if your in a vein or an artery. If some blood comes back - A vein has darker, free flowing blood, an artery has brighter red, pulsatile flowing blood. In either case, come out with needle and hold some pressure.
2. Don't inject Veins either for any AAS or other compounds - they are all either Intra muscular or Sub cutaneous.
3. Try not to inject air anyway, but unless your in an artery, which is pretty hard to do if you're injecting in one of the approved injection sites, you will be OK
Signs of a significant venous air embolism are hyptotension (causing dizziness or fainting) and possibly arrythmias.