Im confused when you inject air into the vials

Nurses Medications


Im reading nursing skills by potter its a very good book. They say to inject air into vials before drawing up meds

yet for ampules you dont have to inject any air. So I'm confused why we even inject air in the first place and why we dont inject it into ampules? Im guessing the pressure is greater INSIDE the bottle hence we inject the air. What would happen if you dont inject the air? Would the bottle blow up?

Thank you

The reason that you inject air is because the vial is basically a vaccum sealed space, so you need to replace the liquid with air. (And, no, it won't blow up.)

The reason that you don't inject air into an ampule is because you break the glass by snapping the "neck." (You would, of course, you a filter needle to draw up from an ampule.)

Specializes in Med-Swing/Rehab.

When I was in nursing school, a fellow student told me she blew up a vial of Diluadid because he injected air into it.

Specializes in Emergency Room, Nursing Education.

ok, to clarify- "blowing up" is a little graphic, lol. :) When you inject air into a vial, the extra pressure helps when you draw the fluid out. Before drawing fluid out of an ampule, you break the tip off and there is now an unsealed opening- if you inject air into it, it will force the fluid out of the ampule and you will lose your medication. I think your friend who "blew up" the dilaudid vial was probably using a single dose tube. Those have a little rubber end on them, and if you inject air into them, it will cause that little rubber end to shoot off the end of the tube. Oops, again, you might lose your medication. Did that clear things up for you? Good luck in school!

There are certain vials that we don't inject air into. One of these is morphine and I think the other is protonix (powder that gets reconstituted with NS)...and I was told that these bottles are already pressurized, so we don't inject air. This might also be the case with the dilaudid....

So, there are some vials that you do inject (and a few that you don't)...Can anyone think of any others?

Specializes in Med/Surg.

The dilaudid and morphine single dose tubex you do not need to put air into, otherwise you will over-pressurize the container and yes the bottom and all the medication will go outwards, hopefully it was not aimed at anyone. Protonix and other powders that come in vials you re-constitute with NS/SW so you will add the specified fluids rather than air. You do not need to add air to a vial, if you do though, the medication pretty much vaccuums itself into your syringe whereas otherwise you have to manually withdraw it.

As another poster said, with an ampule you are not working with a vacuum system and adding air would likely be like blowing air through a straw into a full cup of liquid, the liquid will evacuate the cup to make room for the air.

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