Air in IV flush syringe??

jjjoy, LPN · Nov 4, 2011

Sure would be nice if more instructors could/would explain things so thoroughly... we had "critical thinking" pushed down our throats. Then they'd give a never-break rule of nursing such as "NO AIR IN THE LINE. EVER. IT CAN KILL" We'd see nurses we're supposed to be learning from not getting every last little bubble out and wonder at their competency, maybe even put them on the defensive when explaining "my instructor said 'no air ever'". I've heard the rationalization that it's better to be safe than sorry, so to just tell students "never"... but that is the direct opposite of critical thinking, is it not? Ugh. Another justification is that there just isn't time to go into the details of why in general no air is best but a teeny bit of air usually poses no problem. But what is nursing school for if not to teach to that depth?

I'm venting because I see this question again and again... and had it myself. If instructors can't trust students to tell the difference in risk between 0.01 ml of air and 10.00 ml of air - and instead continue to teach "ANY AIR IN LINE = LIFE THREATENING EVENT"... then it would seem that they don't have very high expectations of the students' critical thinking potential.

Rant over!

jesskidding, LPN · Nov 4, 2011

You are going to have to push at least 60 cc of air to cause death.

I know of an RN who was suffering from depression and was in treatment. She committed suicide by getting a 60 cc syringe and pushing it while in the hospital for a psych eval.

She died almost instantly. I don't even know if she got all 60 cc's of air in her IV by the time she died.

I wouldn't worry about that small of an amount. It's going to take a lot to do any damage.

*60 cc's does sound like a lot though. Does anyone know the exact amount that could actually kill someone? Or cause problems?

whichone'spink, BSN, RN · Nov 4, 2011

I get the bubble out before I flush lines. Peripheral and central alike. I end up squirting myself a lot of the time, but it's best to be safe.

merlee · Nov 4, 2011

I was an IV nurse and a dialysis nurse for many years. It takes a substantial amount of air to do any damage, at least 20 cc. The tiny bubbles that may form along the walls of tubing, or that tiny dot of air in a pre-filled flush syringe will not do harm. Although we should take care to not inject air, we waste a lot of time AND ENERGY attempting to eradicate every tiny bubble.

Does anyone remember that scene in 'One Flew Over the Cuckoo's Nest' where the young man committed suicide by injecting air with a very large syringe? It can't be easy to do that.

We are sometimes our own worst enemies, making each other crazy about stuff like this.

nerdtonurse?, BSN, RN · Nov 4, 2011

You are going to have to push at least 60 cc of air to cause death.
I know of an RN who was suffering from depression and was in treatment. She committed suicide by getting a 60 cc syringe and pushing it while in the hospital for a psych eval.
She died almost instantly. I don't even know if she got all 60 cc's of air in her IV by the time she died.
I wouldn't worry about that small of an amount. It's going to take a lot to do any damage.
*60 cc's does sound like a lot though. Does anyone know the exact amount that could actually kill someone? Or cause problems?

It's whatever it would take to cause a "vapor lock" in the heart or have the heart "pump dry" from my understanding -- just like the old hand crank kitchen pump, if there's not at least some blood in the chamber to hold it open, the chamber collapses and never pumps again. The average size of a R atrium in an adult is 30ml, plus or minus 15 (size of body habitus, heart failure, cardiomegaly, etc., could change that number upward). So I think 60 would definitely do it for most folks, but a person with an enlarged heart might require more to cause them to pump dry.

I also think it would probably hurt like xxxx because the heart would do a hard stop, and it would probably feel like the mother of all PVCs. The heart would "deflate" and put a lot of torque on the 'cavas and the aortas, and we all know how painful an MI feels to a patient -- the heart would go hypoxic and start hurting horribly. You'd be conscious until your brain went hypoxic, so you'd probably have 3 minutes or so of sheer pain and misery to wish you could change your mind, and there wouldn't be any way to unless somebody literally "primed the pump" with an needle into the atrium and the ventricle to replace the volume in the chambers and then shocked you, even if you fell backwards onto an OR table at a cardiac center when it happened.

Seems like a pretty horrible way to go.

DixieRedHead, ASN, RN · Nov 4, 2011

I believe it takes 20ml of air to do damage.

I heard 6 ml somewhere, still that's a lot of air.

AgentBeast, BSN, RN · Nov 4, 2011

*60 cc's does sound like a lot though. Does anyone know the exact amount that could actually kill someone? Or cause problems?

Generally for peripheral IV's it 5ml per kg of weight. It's a lot less for central lines. All this is highly variable though. It's a rather pointless discussion as I'm certain most people aren't going to volunteer to try and find out how much air injected into a venous access device it takes to kill them.

psu_213, BSN, RN · Nov 4, 2011

First, I always push the bubble out of my flush. However, radiology never seems to do this....when I have a pt return from a CT scan where contrast was invovled, the J-loop has mostly air in it, which means they are not pushing air out of the flush syringe before they flush the line after giving contrast.

Interesting story...I once had a very experienced cardiologist tell me, "I had to clamp his IV because there was an air bubble in the tubing." Well, the 'bubble' was a VERY small bubble in the J-loop and he felt the need to clamp it. I could not believe that this well respected cardiologist believed that a 0.05 mL air bubble was going to cause serious harm to his pt.

Anyway, to the OP, don't worry about it.

NYLiz · Nov 5, 2011

little are bubles wont do any damage just try not to make it a habbit. its always best to not have any.

khotso mayelane · Nov 5, 2011

injecting bubbles is medico legal harzad proper expeling of air should be done before you flush ,another thing is flushing of IV line allowed?

klone, MSN, RN · Nov 5, 2011

Generally for peripheral IV's it 5ml per kg of weight. It's a lot less for central lines. All this is highly variable though. It's a rather pointless discussion as I'm certain most people aren't going to volunteer to try and find out how much air injected into a venous access device it takes to kill them.

They did studies on this at Nazi concentration camps.

applewhitern, BSN, RN · Nov 5, 2011

I have always heard it takes about 20 ml of air, also, MomRN. But I don't want to be the nurse who finds out it isn't true!