air bubbles of death.
By impactEDnurse • Apr 24th, 2007 • Category: clinical skills, the nurses desk:, tips and tricks
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]
impactEDnurse is also known as Ian Miller, a nurse with over 26 years experience working in a busy emergency department in, Australia. This site in no way reflects the opinions of that hospital.
All stories (although based on actual experiences) have been changed to protect patient confidentiality.
Email this author | All posts by impactEDnurse
Thanks for the priming tips. it helped.
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?
Good to know, can’t wait to try the new spiking tech. Thanks for taking the time to inform the curious.
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.
Have nursed for 25 yrs and didn’t know that. How cool.
cheers
Fiona
I’v had a iv before in my hand,arm and my neck but thanks for the tips!
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I am currently a patient. Your page was very reassuring, thank you.
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.
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?
Im sitting arhere in the hospital bed watching air bubbles flow into my arm. Scariest shit in life after reading this
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!
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.
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.
Thanks for the tip – very helpful. This is why we love your blog =D