Why is it bad to have air in your blood vessels?
Does it cause your heart to stop beating?
To add to the question, how bad is it? It seems to have become common knowledge - based on TV shows - that a tiny air bubble in your blood vessels will kill you, but I’ve also been told that it’s only a problem if it’s in one of the major central blood vessels. Is that true?
It’s more a problem in the capilliaries. The bubble can be too small to pass through them, thus blocking blood flow. The danger is dependent on where the bubble gets stuck.
An air bubble can block the blood from getting through the vessel, causing something on the other side to not get the nutrients and oxygen it needs. This is usually not immediately fatal, of course. When it is fatal, it’s because the bubble, or embolism stops blood from flowing into the right ventricle of the heart. This causes a heart attack, and often death.
It has to be a pretty big bubble, though. That little bubble you see in your IV lines or the injection your nurse gives to isn’t going to hurt anythiing. Big bubbles can get in through surgery (usually brain surgery, or surgery up above the heart, where the blood pressure is lower) and through trauma to the lungs, like a ventilator on the wrong setting pushing air into the vessels around the lungs.
“The Bends” is another type of gas embolism caused by surfacing too quickly from a dive.
Just to add a bit to what WhyNot said (and with whom I generally agree) -
As noted, the air bubble has to be big to harm you. Those little ones you see in IV tubes are harmless.
Basically, a big air bubble takes up space in the blood that should be filled with blood (duh). So, when the bubble hits the lungs, there’s gonna be a portion of the lungs that receives air and not blood. Further, the air bubble will act as a stopper or plug within the vessels of the lung. So, no more blood can get to that part of the lung. The affected part of the lungs may die. If a large enough portion dies, so do you.
Another possibility is that the air bubble will travel directly across the wall (septum) of the heart from the right side (from which blood normally flows to the lungs) to the left side (from which blood flows to the rest of body including the brain and the heart itself). This can only happen, though, if there’s a hole in the heart (which is actually NOT rare - a “potential” hole is present in 20 percent of us). In any case, if the bubble does cross from the right side to left side of the heart, and then goes to the brain you’ll have a stroke. If it goes to the heart, you’ll have a heart attack.
I had an IV drip in me a few months back, and was getting a tad concerned by the little bubbles I could see making their way towards my vein. The nurse reassured me that it takes a big bubble to kill, and I seem to have survived thus far.
I had a similar experience many years ago when I was in the hospital. I saw that bubble in my IV line and freaked, until I was better informed.
In his memoir Junky, William S. Burroughs quotes another junky as saying that “If bubbles in the blood always killed, there’d be a lot more dead junkies out there.” Since I suspect there are already a lot of dead-before-their-time junkies out there from other causes already, and i don’t know how many deaths are added by embolisms, this isn’t terribly reassuring, but there’s probably truth to it.
I hope it’s OK to resurrect this recently deceased thread.
In today’s issue of the New England Journal of Medicine, there’s a free “article”, actually an image with accompanying text, that nicely shows the presence of quite a lot of air (60 cc) within the heart and the major blood vessels. As you can read, the patient, an old fellow at that, recovered quickly.
I suggest clicking on the three stacked images on the left. That will lead to a bigger image, and then clicking on the image again which will show the biggest magnification (minus the text).
The three panels represent images taken parallel to the ground at three different levels through the patients chest - the top one around the level of the clavicles (collar bones) and the other two through the middle of the chest. The two large dark bean-shaped areas on the left and right of each image are the lungs (the darkness being air). The heart and “great vessels” are in the centre and should appear whitish (blood looks white on x-rays). In fact, you’ll see dark areas (air!) in the heart and the vessels (you’ll even see how the dark air is floating on top of the blood in the heart in the middle picture).
Here is the link: Air embolism.
I should have said that the patient is lying on his back for this scan. So, the front of his body faces up.
60cc is roughly 2 ounces, or a quarter of a cup, for those still worried about tiny bubbles.
The forensic literature says it takes 200 cc on the venous side to kill you. That’s a heck of a lot of air.
I hate to disagree with Whynot, whom I both like and respect, but it’s not usually air in the right ventricle that kills you. Air will foam in the right ventricle - I’ve seen the bubbles in a dead person - but, like the much commoner pulmonary embolus, it’s when it gets into the mainstem pulmonary artery branches that it kills you.
I am the proud possessor of a photograph (not from an autopsy I did, alas) of a guy with fatal air embolism in his coronary arteries. That takes smaller bubbles, but on the other hand, getting air into the coronary arteries is really difficult, and is so extremely rare you should never worry about it.
I do not recall the number for the arterial side (since air so rarely gets into arteries) but does 30 cc sound right? Less, but still a LOT.
shrugs
Dude! (Dudette!) I get my information from introductory Anatomy textbooks and second level pathology courses. You’re a friggin’ forensic pathologist! I think we know who has the more reliable, real-life information here. 
Even worse, I think I used Wikipedia to make sure I remembered what I was talking about. Lemme see…yep . “When death occurs, it is usually the result of a large bubble of gas stopping blood from flowing from the right ventricle to the lungs.” We all know how reliable they can be. :smack:
Thanks for clearing up my muddied waters!
If the air bubble is large enough, the heart will lose it’s prime, too.
Or so I’ve heard. Could’ve heard wrong though…
Gal, if I can be as gracious as you when someone disagrees with me, I think I’ll be well on the way to sainthood. Instead of curmudgeonliness which is where most people agree I’m currently headed.
Just to prove that: Some people would disagree with applying the words “real life” to my experience…
Diggleblop - not sure what “prime” means in this answer. The heart will lose its prime what?
Confused, gabriela
I assume he means “prime” as in priming a pump - filling it with liquid and expelling air in order to get a seal. Not sure if that could apply to the heart though…
I don’t see how it could. The ‘prime’ on a well pump is applicable where a vacuum is needed to pull fluids up against gravity to a higher elevation.
The heart drives the blood thru a closed system. And will push whatever contents it has in its chambers thru that closed system, whether it be blood, air, or maple syrup.
IIRC- one time when someone may be more vulnerable to air embolism than at other times is pregnancy, due to the changes in blood volume, pressure and capillary dilation.
Air embolism was a possible cause of death in the days of the back street abortionist. One method of causing an abortion was to force large quantities of soapy water into the uterus in order to strip the amniotic sac away from the wall of the womb. This was usually achieve with large bore tubing, a bucket or jug of water, and gravity. If a large enough air bubble entered the tubing, it could easily pass into the circulation via the very vascular bed of the placenta.
It was judged to be the cause of death in one very famous Irish murder (the name of the case escapes me and my google fu is weak).
This person claims to have seen one case of murder by air embolism.
Having worked in dialysis for several years, I’ve seen the effects of air embolus on living people. And saved them to do something else stupid and life threatening to themselves. :rolleyes:
The emergency treatment for a venous air embolus is to place the patient on their left side in, trendelenberg (head down, feet up) to trap the air in the right ventricle.
As long as the volume of air is less than 200 ccs, this position will prevent the air from travelling to the brain or lungs.
A large amount, (over 100 ccs) can be drawn out with a long needle, by a physician trained in the procedure.
Less than 100 ccs will eventually be absorbed, over several hours, making it important that the patient stay in the position. Serial chest xrays are taken to follow the progress.