We’ve all seen it. Patients looking wide eyed and worried at a small bubble of air as it travels down the IV line and off into the mystery of their arm. “Don’t worry”, we assure them… “its far too small to cause any problems”.
So exactly how dangerous are those little air bubbles? And how much air would be needed to cause an adverse event?
Or to put it simply: would 10mls of air injected into the IV line by the evil ninja assassin disguised as Dr Singer (who has been tied up and thrown in a linen skip), be enough to kill our sleeping hero and stop him getting the girl?

Once a volume of air is introduced into a peripheral vein, it can potentially make its way through to the Right Atrium and Ventricle, and then on into the pulmonary vasculature. Here air may occlude the microvasculature increasing dead space and damaging the vessels endothelial lining. This in turn, may trigger an inflammatory response resulting in noncardiogenic pulmonary oedema and bronchoconstriction. In animal studies, the ability of the lung to filter air micro-bubbles fails when air enters the circulatory system at a rate greater than 0.30 mL/kg per minute

A large, rapidly-entrained bolus of air can fill the right atrium with air and cause an air lock, which leads to obstruction of the right ventricular outflow tract, decreased venous return, and decreased cardiac output. Myocardial and cerebral ischaemia soon follow.

Small amounts of air are probably absorbed by the plasma and haemoglobin, but larger amounts have been associated with interfering with pulmonary gas exchange, and causing cardiac arrhythmias.
Air bubbles may also occlude the micro circulation of other organs such as the brain, spinal cord and the skin.

OK. So now you’ve really scared me. But how much is safe?

Emedicine quotes that more than 5mls per kg is needed to cause significant complications. Although it states that as little as 20 mls (around the amount of air in an unprimed IV line) has been reported to cause some problems.
Large amounts (of between 100 to 300 mls) have allegedly been fatal.
So those pesky little bubbles travelling down the tubing are probably not going to do any damage. But never-the-less, it would be wise to take steps to minimize the risk of larger amounts of air entering the system.

  • Dont forget to prime the IV line! Sounds stupid, but it happens more often than you think.
  • When hanging a new bag on an existing line, check to make sure the previous fluid hasn’t run down the line leaving a large airspace.
  • Do not place IV fluids down on the bed when transferring patients etc. Laying the drip chamber down on its side only encourages air to enter the tubing.
  • Expel any air from syringes of IV antibiotics, analgesia etc that you are about to administer.
  • And of course always check to make sure any drugs or fluids being injected into the line are compatible with the fluid. Incompatible fluids may crystallize or form a sediment that will cause similar problems.

priming tip:

Heres a quick tip.
When priming a new IV line, first invert the bag of fluids so you are spiking it from above.
Once you have inserted the giving set into bag of fluids open the roller clamp and gently squeeze the bag expelling all the air from the top of the IV bag into the giving set. Keep squeezing until the fluid from the bag is pushed up into the drip chamber.
Invert the bag back into its normal position and continue to prime the IV line.

Now, when your patients IV fluids are finished they will stop at the level of the bottom of the flask. There will be no air in the bag to run down into the giving set necessitating a re-priming of your line.

and another thing:

Never pull the cap off the spike with your teeth like they do on TV. It looks cool, but you run the risk of contaminating the IV fluids with your oral flora (and, no doubt, fauna).
Do not let the patient end of the IV tubing drag around on the ground while you are spiking the bag. It may be a hospital, but its still pretty dirty down there.
Do not let fluid squirt out onto the floor as you prime your line . Someone carrying a brimming bedpan is sure to slip arse over nipples on your mess.

[ Read on: Venous Air Embolism - emedicine.
Venous Air Embolism - Rashad Net University
Air Embolism - Liza C O'Dowd, MD]

47 Responses to “air bubbles of death.”

  1. Wow…some heated discussion about nurses being a “know it all” and “patients being ignorant”. First of all, nurses, like doctors, surgeons, auto mechanics, US presidents, are all human. And guess what, ALL humans make mistakes. A nurse that thinks they have no more to learn shouldn’t be in that profession. A nurse that has major problems with a patient concerned about their treatment shouldn’t be in that profession. I’ve always had a ton of respect for the nursing profession, but holy kow are there some real bad ones out there. And to call a patient ignorant for not knowing a lot about the nursing profession is misuse of the word. The nurse choosing to dismiss a patients concern is being ignorant. Patients aren’t choosing to not listen or learn, nurses choose to ignore patients. I’ve seen it, I’ve dealt with it. A person working a twelve hour shift has a huge chance of making a mistake as the odds of that happening increase ten fold after the eight hour mark. Training or no, it’s a fact. I think too many get into a rhythm and end up going through the motions, forgetting that each patient is different, and cannot be dealt with exactly like the last one.

  2. Hi, I went to ve some blood test today for thyroid check.the nurse injected a syringe and pulled it out to take blood, the syringe was half full and so she pressed it again half way and pulled out again.she did this 3 times.I ‘ve paininmy hand now. Is this ok?

    • it seems that she didn’t hit the vein correctly so she adjusted placement of the syringe. the pain probably came from the blood which came out of the pierced vein. it’s entirely normal. just put a warm compress for 15 minutes and it will subside eventually in a few days.

  3. I work in diving medicine. Those air bubbles when treating someone with hyperbaric pressure really will cause death and damage. Even the small ones!

  4. I’m in the hospital right now and actually earlier today I had potassium cloride and ciprofloxacin and the antibiotics had run out and for somereason (even though its run through a pump (alaris pc)) it began to draw air. I have no clue how long it was happening before I caught it but everytime it switched to pumping the the empty bag it put bubbles in (about half liquid half air) that was some scary stuff so ATM I’m getting phenergan and even though it makes me tired I’m staying awake till its done to make sure it doesn’t happen again and before I go to sleep ima make sure the nurse stops that one cuz that scared the shit outta me… if I didn’t see it then who knows what coulda happened??

  5. I see tiny bubbles or tiny air sacs in venous locks all the time. I try to aspirate them out but instead blood comes out of the vein. Any suggestions how to flush venous/saline/heparin locks in a proper way that there is no air in there and how to remove those tiny sacs of air that are already there?

  6. these patients freak me out!!! the day we have patients showing us how to do our job is the day i resign for good. air in the line through a pump cannot cause harm, the pump will stop and the nurse will get it out before any harm occurs. that is the good thing about pumps. relax and let us do our job

    • I wish I could relax. but just the other day while my husband was a patient in the ICU, I had to stop his nurse from putting his disposable thermometer which was marked with an R for rectal in his mouth!!

    • Excuse me !!!patience have right to feel safe. And some peace of mind lying on that hospital bed. As I write I have an IV and endless bubbles kept flowing I kept thinking they wil stop until I had to stop it my self and called. The nurse to drain the bubles. I wasn’t trying to show the nurse how to do her job I just want to feel safe. Better to be safe than sorry

    • Hi Deb –

      I have a lot of respect for your position and for your profession. However, the only information that I have received (as a patient) was from the nurses at a hospital that I was previously admitted to. I was told that the micro-bubbles were not an issue and that they would naturally be absorbed by my body. However, I was told that larger bubbles (an inch or so in length) in the IV line could pose a problem. As a result, when a nurse from a different hospital didn’t prime the line very well an caused a three inch long bubble in the line – I got a bit nervous.

      From there, the nurse became upset and began to argue with me. Pardon me for being nervous… but if I am reacting to a situation based on information that I obtained from someone that is considered educated in that field of study then I don’t see where starting an argument is the proper thing to do.

      I’ve never been to medical school so I may be wrong in this line of thinking. But I feel that making the patient feel comfortable and confident in the abilities of the nurse/doctor is a key role in regards to patient care. If a three-inch-long bubble in an IV line scares the stew out of a patient and it only takes a couple more minutes of your time in order to draw it out with a syringe or to bleed it out using the pump – what’s the big deal? If you aren’t in the nursing field to make the patient feel better… should you really be in that profession? Please don’t take that as a snide remark, because it’s not meant to be one. It’s just an observation from the patient’s perspective.

      • Hi Michael,

        I think you’re spot on there – it’s about making people feel better (although if it costs more) then I don’t know but it doesn’t sound like it would to me. As a pre-nurse and an avid watcher of Murder She Wrote, I would freak out if I saw that.

        I’m looking forward to having all myths busted for myself – a great post!

      • I’m about to graduate from Nursing School this August and I understand how frustrating it will be to have patients question you and your knowledge. However, I also believe that patients SHOULD know as much as they can about their health. Isn’t that our job as nurses? To educate our patients on prevention and maintenance involved with their health? Personally, I’m sure I will be slightly bugged if one of my patients keeps hitting the call light for trivial things that aren’t a problem, but at the same time I will be so glad to have another set of eyes on the lookout. With nurses being so busy, it’s easy to overlook things or forget things. I mean, we’re human too, right? So why not have another set of eyes to keep a check on things. I would certainly appreciate a patient making sure I’m doing my job right. Does it put me under pressure and stress me out a bit? You better believe it. But that’s what keeps me double checking things to make sure I don’t make a mistake. I believe in being a team with the patient. They are the extra set of eyes that says, “I usually only take one of those pills. Not two.” And that’s what makes you check the MAR and you notice you accidentally pulled two instead of one. If we don’t empower our patients, what’s the point of us nurses?

    • I hate to tell you this but you are a dangerous know-it-all. It is very possible that many of your patients know more than you and the rest need reassurance. Sounds like you have problems with humility and bedside manner. Not a good look for a “professional”.

      • Oh my God…. what can I say …. but YES I do agree ….. and experienced it too I got admitted and when I refused what did the nurse did she called security oh and many more bad experience… this is ABUSE … now I am traumatized… because of reality of negligence…

    • Those patients aren’t telling you how to do their job; they are protecting their own lives. Research has shown that errors are prevented when patients speak up and voice their concerns. Get over yourself – you are not infallible, and neither is anyone in the medical profession. If a patient tells me of a potential error that I would have otherwise made, I will say a prayer of thanks.

      • Dead on Carole and might I add I have a picc line in and the nurses couldn’t agree on how much air is safe (much less than a port in a vein). I’ve caught enough errors to respect my own judgement and desire to know what is being done.
        Deb, get over yourself…you’re not perfect….time to “resign for good”.

    • Deb,

      I agree with so many who have responded to your comments.

      As an initial matter, you seem to rely on machines always working properly. They don’t always work correctly. They can and have failed. An Alaris pump failed just now, allowing more than 3 inches of air to pass without complaint. That is what caused me to search and find this thread. Is 3 inches enough to worry about? There Is disagreement on how much is too much. But the point is a nurse should not put patient safety in jeopardy by assuming machines always work correctly.

      As for a patient knowing more than a nurse, you do have a lot to learn. Nurses do not know it all and many patients know considerably more about their specific condition, especially when the condition is rare.

      Your comments also suggest arrogance in a field where arrogance can kill. Please get over your pride and start focusing on good patient care — or find a new line of work better suited to your temperament.


  7. Thanks for the info ….me and my boyfriend are in the hospital and the stupid nurse put air in the iv I got mad and spoke with other nurse she said in order to have problems with air in the iv it has to be alot of air im not buying it im pist so if ne thing happens I researched about air bubbles..im so upset with the nurses ughhh do I need to show them how to do there job

    • Hannah – there will almost always be a tiny amount of air. You are still alive, nurses aren’t stupid it is ignorant people like you that are.

      • I have seen nurses do stupid things. Don’t be so naive.

      • Victoria, you’re really rude. I would also venture to say, stupid. If someone is expressing anger or frustration, it’s often due to fear. People who are not in the medical profession are at the mercy of those who are when they are in need of medical attention. MERCY. I certainly hope you are not in the medical profession. If you are, you are definite exhibiting your own ignorance. Regardless of how ignorant those of us that are not medically trained are, when it comes to medical operating procedures, we are not supposed to be well versed in the medical field. That’s the job of those who are helping us. To react the way you did here, with someone who is afraid of the consequences of something they may or may not understand, is nothing short of childish. A medical professional of any rank or title should know that dealing with people is what you are doing and one needs to remain merciful and gracious while doing so. If one can’t manage that consistently, one shouldn’t work in the field.

    • Sweet heart you have more chance of falling out your bed and hitting your head causing injury than you would dying from an air bubble in your IV line. And with an attitude like yours, I would hate for you to be my nurse. That’s If you had enough brains to be one.

    • And before you start posting comments about “stupid nurses”, you should learn how to spell correctly.

  8. Well I was a nurse back in the stone age(late 70′s). We did not have luer locks on tubing and used glass bottles with airways to administer TPN. We had to tape the tubing together and be very vigilant that the tubing didn’t come apart because if it did the central line was a needle clipped with the catheter wide open so any air just flew into the pts and they would crash rather immediately and we’d have to code them. I had an ambulatory pt trip in the kitchen and break his TPN bottle and besides dodging the shards of glass I had to get to the fluid control clamp so he didn’t get an embolism. Phew,he was fine.The popular notion was that if you came upon a pt who had a large amount of air introduced that you were to put your pt in reverse trendelenberg on his left side so any bubble would rise out of the heart(hopefully)into his feet rather than into more important areas. I saw a young doctor do that with a patient and he turned out ok,we never lost anyone directly to air embolisms but they were a big threat back then and we all breathed a deep sigh of relief when we got luer lock tubing and they started putting TPN in the airless bags. Phew. And triple lumens were such a big improvement. Oh well Tales from the wild west,I don’t miss them.

  9. My son has had a PICC line in for one month and recently the alarm goes off, red light comes on and it reads: air in line air in line air in line. He is in a top notch cancer only hospital and I am afraid air bubles have caused his left arm to really be in pain; sonograms, blood culture, etc. have been done…but this should NEVER happen in this particular hospital. Why can’t a new PICC line be put in…he is running a temp and feeling terrible plus now has a cough. Diagnosis: myelofibrosis. Has had his stem cell TRANSPLANT…I am very angry at the staff!!!.

    • Zelma – rest assured if the imed (the machine that gives the fluid/drug over a set time) alarms it is saying that there is air in the line as it has a sensor – the air wouldn’t have reached your son :)

  10. Was lyin in bed just now half asleep when i woke up saw nurse changed my bag and was busy injecting some solution. Only problem was ther was air in the injection and the tube near my arm after injecting i could feel how the air rushed in my vein. One qeustion. How long bfor i coul notice an reaction cause i gt pain in my chest and right shoulder could this be from angst or is it some type of symtom?

  11. Thanks for the tip – very helpful. This is why we love your blog =D

  12. Thank you for the article, you have dealt with it very skilfully as to not introduce panic and also to exercise caution. I read it just because one of my relatives had an iv drip and i watched a small bubble (about 5mm. in diameter) trickle down into her, I was too worried, but your article has put all the ghosts to rest. Thank you so much.

  13. So what does it mean when you got the infusion stopped and blood is flowing back into the line? Does that mean air has entered the cannula or that the infusion has stopped and the blood flow is greater than having no running fluid?

    Coz that scared me a bit tonight when I was in the ER after work up on one of the wards, and i didnt see the bag finish, and then i got up to look, saw the bag was empty and then saw blood come down the line.

    How quickly does an air embolism kill? Coz on tv you see like they die pretty quick right? I think thats what scares people. Coz the nurse i had who gave me the IVT the line had a few bubbles in it and i was worried. When I get to a patients bedside i always double check the line and let a little bit of fluid run out…more careful when its a PICC coz thats more of a chance of harm since it goes to the heart than a vein.

  14. is it ok to have small amount of air to enter the veins? I was in the er when I got an iv. I seen small pockets of air, not that big enter I paniced!!!!!! the dr says it is ok and I was let go at 2pm and it is 6pm now. will I be ok? I have chest pain from panic attacks thinking I am going to die!

  15. Im sitting arhere in the hospital bed watching air bubbles flow into my arm. Scariest shit in life after reading this

    • Me too I read this and I stopped the drip then called the nurse to drain the bubbles. She says its ok but she doesn’t realise I watched a lot of bubbles go in my arm. And that’s why I googled and found this site

  16. I had an outpatient procedure this morning and when the IV was put in three fairly sized airs bubbled raced inside me. It SCARED me to death. I questioned it and the Nurse told me not to worry. She responded that they should “really try to prep better to avoid this happening”. I’m angry, and a bit scared. Do I face any danger?

  17. Came here because I am a patient with a PICC line, administering my own IV antibioitcs daily for two weeks. I am completely freaked out by air bubbles. It seemed like we only had to flick a few when the home health nurse showed me the ropes but today, on my own, I feel like I spent 30 minutes flicking bubbles before starting my drip. I was sure I was going to kill myself with an air bubble. I think I’ve been hanging the bag and priming the line in the wrong order, so I will try as you suggest above.

  18. I am currently a patient. Your page was very reassuring, thank you.

  19. [...] much air is it safe to have in your IV line? And what about those bubbles? Check out: air bubbles of death. Link love: These icons link to social bookmarking sites where readers can share and discover new [...]

  20. I’v had a iv before in my hand,arm and my neck but thanks for the tips!

  21. Have nursed for 25 yrs and didn’t know that. How cool.

  22. Thank you, you are such an inspiration to learn from, since I am only a new grad… my five days at Medical Ward. The Priming tip came at a very opportune time…

    Thank you for sharing your knowledge.. and keep on writing.

  23. Good to know, can’t wait to try the new spiking tech. Thanks for taking the time to inform the curious.

  24. I love it when you give tips like that. :) Any suggestions on good ways to find veins on people who are hard to start IV’s on?

    • warm the pts hands with a wet towel , use a venous torniquet , not and arterial one and be patient

    • I was admitted to hospital overnight with abscessed appendix. Admitting nurse put the line in the bend of my arm. When time to go to surgery they tried to put a line in back of my hand. Very painful. I asked if they could use existing line instead. They did. I had that line in for five days with no discomfort. Back of hand where they had tried to inset the line was lumpy and sore for weeks. Worse than my incision! Why do they insist on back of hand? Saw old people on my ward with deeply bruised and painful hands.

  25. Thanks for the priming tips. it helped.

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