IV air bubble compensation

[JL123]

Hello, I hope someone can help me with this question. I am a nursing student and it's been bothering me for a long time. What happens to air that enters the blood stream through a peripheral IV? I understand how the air can become an embolism, but my question is related to the scientific or physiologic mechanism that happens in the body that prevents complications. I have seen many air bubbles enter through PIVs and the people are fine. I just wonder, what really happens to the bubbles once in the body?

*Does the air bubble get absorbed somehow in the body? If so, how? Or, how does the body get rid of the small bubbles?

I've read in other forums that the lungs filter the bubbles but I don't understand exactly how, since I thought the blood stays separate from actual air in the alveoli. And also, the bubble would have to pass the right heart before getting to the lungs.

I would appreciate any explanation! Thank you!

[noggin_wise]

It takes about 60cc of air to do any harm unless the patient has a patent foramen ovale and then a little air could do it.

[Elvish, BSN, DNP, RN, NP]

If you gave me a penny for every time I've had somebody flip out over a tee-tiny air bubble in their PIV, I'd be a rich rich lady.

[withasmilelpn]

I was nationally certified in IV therapy at one time. I've always been a kind of nurse geek seeking out answers to questions like this. I just happened to know the answer to this one because I had thought of it before myself. It used to bother me to watch nurses nonchalantly let all kinds of air bubbles run into people's veins without a second thought. I would hang around a room waiting for these patient's to have strokes or heart attacks. Well, it never happened and I was determined to find out why, not that I wasn't thrilled for the patients and that they survived a major cataclysm! I can't remember the total amount it takes to cause a vessel to occlude and cause infarct of the surrounding tissue. I do remember that it took more than a full 1 milliliter bolus. That's a full bubble of 1-milliliter. IV tubing holds about 3-5 milliliters, so that's a lot of air. Most pumps will detect even the tiniest amount of air. Occassionally, a miniscule and undetectable bubble of air in the plastic of the IV tubing for IV pumps will set off the air detector in an IV pump. This is due to a defect in the manufacture of that one IV tubing that you just can't see with your eye. If you have an IV pump whose air detector keeps going off and you can't find an air bubble, just change the tubing.

The easiest way to get air out of IV tubing is still to use a needle, or the equivalent needleless substitute. I used to carry a few needles in my pocket for these emergencies. Uncap the needle, swab off a Y-port between the patient and the air bubble, take the tubing out of the IV pump (if it's on a pump), insert the needle, open the clamp on the IV tubing and atmospheric air will do the rest. It will pull all the IV fluid including any air bubbles down and out through the hub of the needle, so you need to have a trash can, a towel or something to shoot the works into unless you want a mess to clean up. D5W is very sticky when it dries. When the air is out, pull out the needle, readjust the IV flow clamp and/or put the tubing back into the IV pump and the IV will resume infusing--air bubbles will be gone.

Nurse geeks are cool!

[netgeek]

I am a nursing student and I was shadowing an RN for my first day on our surgical unit. We needed to saline lock a pt's IV so they could go for shower. I asked the nurse if I could flush it and she said yes. She was the one who drew up the saline (approx. 2.5 ccs) , so I just assumed that she had ensured all the air was out of the syringe. So I went disconnected the IV Tubing and inserted the blunted syringe into the IV site in patients arm and as I was injecting the last little bit I noticed a small air bubble in the syringe (maybe 1/5th of a CC in size) and before I realize I had injected it. I got so scared! I immediatley told the nurse and she said not to worry about it. When I left shift 8hrs later the client was alright. Vitals were all stable, a little bit of tachypnea but this seemed to have started the day before and was slowly progessing.

Should I worry??

Thanks

[netgeek]

One other thing.

Someone in a previous post brought up something about Patent Foramen Ovale. This is something new to me, but I understand that its a hole in the heart connecting the left and ride sides. Most sources say approx. 20% of adults have this. If air is injected into the vein and then goes to the heart can the air then go through the Foramen Ovale into arterial circulation?

Most sources are saying that small amounts of air (under 10cc's) isnt really going to cause much harm and judging all the posts it seems to be agreeable.... but now im worried that what if the patient i mentioned in the above post maybe by some chance had some sort of foramen ovale. If the air went into the artery it would be fairly evident right away right?

I am sure that this is nothing... but I worry about these things.

Thanks

[LilPeanut, MSN, RN, NP]

HOWEVER, I have always had a problem with being told that a central or picc line could receive zero air as it was very very dangerous to get even a tiny amount of air in. This NEVER has made sense to me. The Central or PICC is going into the left venterical for heaven sake. To me it should be less of a risk because of this for the reasons already cited. (large chamber means nothing to block and turbulance breaks up the bubble.

PICCs and other central lines do NOT rest in the left ventricle. They are going up through the vena cava and resting right at the entrance to the right atrium.

If your PICC is resting in the left ventricle, you're in huge trouble because it's then come up through an artery!!

[Mommy TeleRN, RN]

We have pretty cool IV pumps - you press a combo of buttons and it back primes all the air and fluid back into the bag. Nifty for air above the cassette.

[netgeek]

anyone know anything about my above post about foramen ovales???

Thanks, I appreciate it :)

[Little Panda RN, ASN, RN]

What about IV bags hung to gravity. If the bag was to run dry before it is stopped is there any consequences to the patient. I have seen this happen and the patient was okay. I did notice that the bag was completely collapsed. A new bag was hung with new tubing. But it made me wonder if the patient got any air into their circulation.

[UM Review RN, ASN, RN]

What about IV bags hung to gravity. If the bag was to run dry before it is stopped is there any consequences to the patient. I have seen this happen and the patient was okay. I did notice that the bag was completely collapsed. A new bag was hung with new tubing. But it made me wonder if the patient got any air into their circulation.

If you had looked carefully, you might have seen that there was still liquid in the tubing of the IV and that no air had gotten into the patient. The reason that the fluids are not completely empty and the veins are not sucking air when IVFs are hung to gravity is that the blood pressure is higher than the pressure of the IVFs when the bag is empty.

[Daytonite, BSN, RN]

i had started to compose an answer to this for you, nd mom, when my internet connection dumped me off line and i lost it all. angie o'plasty, rn explained it. this is the same reason why you never put an iv bag below the level of the patient's heart--the pressure in the person's vein will begin to push blood back into the iv tubing. you'll also get some blood backing up into an iv line with an empty iv bag from the patient moving their limb around a bit once all the downward actions stops. that aggravates the problem since this blood will get trapped in the iv cannula. if it sits there a while, it firms up (clots) and you have to restart the iv as well. these were common problems back in the days before iv pumps were required on all ivs (yes! there was a time when we counted drops and had to make hourly rounds on our ivs!)

[BonesGilmore, LPN, LVN]

sadly, not all hospitals here in our country uses IV pumps...

what about antibiotic or amino acid sidedrips that are infusing only for 30 minutes? what if it run dry? Does a small amount of fluid still remain on their bottles?