General Question

antimatter's avatar

Can an air bubble kill you and how?

Asked by antimatter (4261 points ) May 8th, 2013

Someone at my work got a friend who tried to commit suicide by trying to inject himself with an injection. Fortunately he pushed the injection needle past the main artery and injected air. I was told if he had the needle in the artery the air bubble would have killed him. I found it a bit strange that an air bubble can kill somebody.

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20 Answers

Lightlyseared's avatar

If the air bubble is big enough when it gets to the heart it would cause problems. The heart works by contracting ie making itself smaller. Because blood is a liquid it is very hard to compress it so the contraction has the effect of squeezing the blood in the heart out one side and then drawing more blood in to fill the gap. Air on the other hand is compressible so when the heart contracts when its full of air the air just contracts with it so there would be no blood circulation.

Realistically you need quite a large amount of air for it to be fatal. It’s debatable whether or not the volume of air in a small syringe would be enough to kill.

Seek's avatar

An air embolism can cause a stroke or worse. They’re not f*king around.

KNOWITALL's avatar

Oh yeah, that’s a well-known fact here in Meth-ville. Either that or a Hot Shot, which is an intentional overdose.

Jeruba's avatar

“here in Meth-ville”?

KNOWITALL's avatar

@Jeruba Missouri is the meth capital of the US.

nofurbelowsbatgirl's avatar

As far as I know its like a blip that you don’t want to occur in your heart. I’ve always heard it can kill you also. It makes sense to me.

gasman's avatar

Under ordinary circumstances an air bubble injected into a vein is harmless. It travels through larger & larger vessels until it reaches the right side of the heart, then gets pumped to the lungs where the small volume of oxygen and nitrogen are released in the process of gas exchange and exit the body.

A large volume of air, as @Lightlyseared noted, can be fatal because the heart just squeezes the air with no forward ejection of blood. It probably takes at least 30–50 ml in an average size person. Not your average air bubble.

A bubble in the arterial system, on the other hand, is a way bigger problem because it will travel through smaller and smaller vessels until it lodges in an arteriole where it can obstruct the flow of blood, causing the tissue served by the vessel to be deprived of oxygen. If, by chance, this occurs in the brain it causes a stroke; in the heart, a heart attack, etc. If it’s not in a critical organ (for instance, if you accidentally inject into the brachial artery instead of an antecubital vein in your arm) a single arterial bubble is still probably harmless.

The real problem is when there’s a pathway between venous and arterial circulations. About 10% of the population has a patent foramen ovale—a potential passageway between right & left atrium of the heart—that could act as a conduit to shunt a venous bubble to the arterial circulation. Normally, however, pressure gradients keep this from happening. With heart failure or other abnormal conditions, that might not be true.

Bottom line: Venous bubbles are probably harmless, but it’s best to avoid them.

Mariah's avatar

Air bubbles in your IV/injected drug being harmful is a total myth. I had to manage an IV at home for two months when I was 17 and I called the nurse freaking out when I had air bubbles. She told me to calm down and that it was harmless unless it was a ridiculous amount. As I recall I was told that it would take about 40 mL, which would be the entire length of tubing in my IV five times, before I’d be in danger.

JLeslie's avatar

An air bubblein your blood stream will kill you if it is big enough. Smallish ones just get absorbed by the body. If you think of an IV line, an air bubble say that is 3 inches long might scare you, but it isn’t enough to do any damage in an adult, it needs to be bigger. A typical syringe of air would not be likely to kill you either, so the addicts are probably worrying unnecessarily. LOL. I don’t know how many cc’s of air you would need for it to be very dangerous that it might cause a heart attack or death.

Blueroses's avatar

great answer @nofurbelowsbatgirl

In my field, we make IV drips and injections for patients and we’re always extremely careful to get all the air bubbles out, but it would indeed, take a very large amount of air 40cc’s or more as mentioned in your reference to be lethal.

Dr_Lawrence's avatar

What terrific and informative answers! We jellies can learn so much here!

Rarebear's avatar

I’ve personally seen two deaths from air emboli.

JLeslie's avatar

@Rarebear Were they accidental?

TulsaOkie1's avatar

It takes quite a large bubble to cause the heart to lose suction. I’ve seen them inject bubbles in an IV I had in the hospital. I got all upset seeing the bubbles going towards my arm. The nurse said it would take a large syringe full of air not just a small bubble to cause death.

mattbrowne's avatar

Subcutaneous insulin injections with air bubbles don’t.

antimatter's avatar

Thanks @gasman and every body who replied this should clear up a few things.

Rarebear's avatar

Oh, didn’t see the second half of the question. Death occurs from right ventricular outflow obstruction from air, and ultimate bilateral pulmonary artery air occlusion. It acts like a pulmonary embolism, with circulatory collapse because of inability to fill the left ventricle. There is a subsequent precipitous drop in cardiac output.

If suspected, the treatment is to place people in the Trendelenberg position with the right side down, in the attempt to pull the air out of the right ventiricular outflow. But the symptoms are so sudden and catastrophic that this rarely if ever works.

You can not get this from a regular IV as the air required to cause an air embolism is far more than this.

Raubhautz's avatar

Not being a doctor or nurse, I am not professing to be doctrine, but from various (3-rd) parties, I think it has to be an enormous amount of air (say 35+ ml). In addition, it would matter more so in an artery than a vein. So, it does not seem likely that somebody could do that very easily (not an accident).

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