Is Embolism Something Of A Myth?

[Vern1961]

Not a medical query, just anecdotal...

I now find myself having to attend hospital on a regular basis for infusion treatment via an IV pump/drip. Yesterday I watched with a mixture of horror and morbid curiosity, after the nurse attached the line to the canula and switched on the pump, a rather substantial air bubble - 7 to 8mm of the tube - progressed immediately into the canula and presumably thence my bloodstream. I was assured by the nurse this not a problem, but have watched more than a few movies where the bad guys have "offed" someone in a hospital bed by injecting air into the bloodstream.

As I'm still here this morning typing this, guess the nurse was right. However I do find myself pondering, 1. How the air gets out of the bloodstream and, 2. What volume would actually need to be present to cause a problem.

 

[Destination]

If I recall it depends where it is.
Standard vein you'd be looking at 50mls, in the brain a few mls would do it, directly into one of the hearts arteries a ml or half a ml could do it.
But in general its about 50mls.

Gets absorbed into the blood stream where other gasses diffuse.

 

[SixTwoSix]

I went through the same "terror" in hospital years ago. Asked the nurse who said there is some kind of airlock in the canula to remove the bubble and it doesn't go to your vein.

Not sure if true but put my mind at ease and I'm still here 21 years later.

 

[FBi7]

Whilst 7-8mm in a giving set isn't going to do you any harm, it's certainly not best practice. In terms of how the air leaves the blood stream, in laymans terms, it will make its way back your lungs and you'll breath it out. As Destination mentioned, it would take somewhere in the region of 50ml of air intravenously to finish you off.

 

[Vern1961]

Thanks for the re-assurance. Still here and ticking so guess it has passed through. Normally the nurses at the clinic are very good or the pump picks up a problem - during my session on Monday it stopped during treatment because air had somehow got between the pump and canula and they ended up having to swap in a fresh IV line.

 

[Energize]

Air going into a vein is not a normally a problem, veins get larger and larger until the air bubbles reach the heart and then are pumped from the right ventricle into the lungs where they diffuse out, having some air going into a cannula is basically unavoidable.

Problems only tend to arise where a patient has a congenital heart issue like an atrial septal defect allowing the air to get into the left side of the heart and ultimately potentially blocking a blood vessel, but even then it does not necessarily cause any symptoms.

 

[Vern1961]

Appreciate the further information.

 

[tres]

Volume of air in peripheral venous cannula needed to be fatal in a human is estimated to be 200-300ml
https://anesthesiology.pubs.asahq.org/article.aspx?articleid=2026502

 

[tamzzy]

basically what everyone else said.
venous air embolism - will need a lot of air to be of any serious consequence.
arterial air embolism on the other hand. bad.

declaration of interest: intensive care doctor

 

[Chojin]

Schizoid embolisms are not a myth. They're quite common with memory implant packages.

 

[dowie]

I had a really dumb nurse try to attach a tube full of air at one local hospital, she then realised and went over to the sink, let some out and then re-attached... but tube still had air bubbles when she connected it to the machine which kept beeping... so she just removed the tube from the machine instead... I wasn't in much of a position to complain about it at the time but was left there thinking WTF???

Like I've had them before and usually they tend to wipe the connectors and flush the canals first etc.. this nurse just didn't bother with any of that stuff.

 

[Jean-F]

Interesting thread, even though it’s never affected me, (I think, and hope), but I then had to Google canula, which turns out to be cannula, I thought that it may have been the singular of cannoli, those Sicilian pastries!

 

[Luke]

During training we would fail an assessment if there was a single bubble in an IV giving set tube. In reality we could push the 11mm of air held in an unprimed tube into a patients vein and not cause an issue.

 

[WantoN]

I have regular infusions and am often in hospital. I've had alarmingly large air bubbles go in.

Generally speaking the nurses notice them and bleed them out, if they miss one I tell them. But I wouldn't worry about it; if you die you won't care anyway

EDIT: Read a couple of alarming stories above. If there's one thing I've learnt after years of hospital, it's that if you don't like something, speak up. Nurses are often exhausted, over worked, under paid and focused on too many things. Your wellbeing is no joke, and you have a right to raise a concern.