Leaving air in the syringe?

[Micklos]

There seem to be two schools of thought. Some people insist on removing every last tiny air bubble from the syringe, yet other people say to leave a lot of air in the syringe, so it's behind the oil and forces all of the oil out of the needle, even using the sound of air being forced into your muscle and out around the needle as a sign that you've not wasted any oil at all. What are your thoughts? Did the whole "get rid of all the air bubbles" thing just come from someone who had read about IV injections? I mean, even if you deliberately injected a full empty syringe directly into a vein, you're not guaranteed to be in any serious trouble. And a little air will surely be harmless in a muscle, and be either absorbed or expelled. I'm just wondering why all these people suggest flicking the Hell out of the syringe? I know It makes you feel like a proper doctor, but can't you just say, "Okay, you're going to feel a slight pinch" and where one of those reflective dealies over your head?
I'm pretty sure I'm not missing something, but I thought I'd ask. Just seems odd that so many people are advising that air in the syringe is something to tremble in fear at.

 

[Kazmir]

It comes down to a lot of ignorance and myth, even IV having a small bubble of air will not kill you. It actually takes a lot of air to cause great harm. Is it poor practice to remove all air for IV injection absolutely not and I recommend it. As far as IM goes its completely personal preference, the amount of gear your losing by not leaving air in the syringe is so minimal and you would never see a difference.

 

[smittiot]

Remove the air, inject and remove as normal. Then draw air back into the syringe, remove the needle and expel the remaining contents and see how much remains. Not much.
If you are concerned about waste then you can rub that last bit onto your nutsack for transdermal application.

 

[Mprtz]

In another thread, I calculated the volume of a 25 gauge 1.5" needle. I can't find the results anymore, but I'm pretty sure it was less than a cubic millimeter, on the order of 0.0007 cc.

 

[Revhenry]

For what it is worth, it takes about 3cc's of air, injected, to cause serious injury.
So I've read!!

 

[snowpatrol123]

I leave about 0.1 CC of air in the syringe, pushes the extra gear through the needle and seems to help minimize back-flow/leakage once I withdraw the pin.