How does an air bubble in the blood actually kill someone? Seems like it would be harmless.
IANAD, but I did a quick search for air embolism to try to explain. (I know what it is called, because when I had my partial hysterectomy I had to wear special inflating, vibrating leg cuffs to prevent embolisms post surgery for a time in the hospital.) According to this article, it can cause heart attack or stroke.
That Wiki article isn’t too bad, it gets most of the facts pretty straight.
Here’s a recent thread on the topic of air emboli: Just how much air has to go into the vein before death? - Factual Questions - Straight Dope Message Board
FTR, (in case the OP isn’t a lurker, and for those others who also may not know) Qadgop is a doctor, so what he says holds weight.
I’ve heard of women who are very late in their pregnancy who have an air embolism while having sex, what are the chances of this happening? Are we talking like 1 in a million or what?
Basically, it blocks the blood vessel and stops blood from getting through. The blood, of course, is holding the useful oxygen and nutrients which it’s trying to get to the cells on the other side of the bubble. This air can be pushed along by the force of the blood pressure, but that means if it gets to the lungs or the brain, that portion of the lungs or brain is not getting the oxygenated blood it needs, but useless air. If it’s a big enough bubble, that lack of blood can kill you.
Those tiny bubbles in your IV line aren’t important, though. We’re talking 3/4 of a cup or more of air before we get into the fatal arena. Usually the result of a mistake in surgery or a freak accident.
Here’s a previous thread on the topic. Be sure you read it all the way through though, as I made an error in my first post which was later corrected. Don’t post to that thread, though. It’s old enough to be considered a zombie thread, and we don’t like to resurrect them unless there’s a really good reason for it. If you have more questions or comments, put them in this thread, instead.
Pretty much. The thing is, the placenta is a highly vascularized structure, so the theoretical fear is that if air is pushed up into the uterus, the air might get pushed into the blood vessels of the placenta and make their way into the mother’s (or baby’s) bloodstream. The usual warning isn’t about sex per se, but about blowing air into the vagina (apparently this is a sex kink I was unaware of.) In reality, plain ol’ sex is unlikely to pump that much air into you, unless you like having sex as if you were throwing darts. Keep the tip of the penis inside and you won’t take in extra air.
Two women did die in the UK in 1998 from embolisms during sex shortly *after *they gave birth, however. This seems more likely to me, especially if it was before they stopped bleeding - during pregnancy, after all, all of those placental vessels should be intact, and less likely to grab onto air. After birth, though, they’re wide open, and I could see air being forced into the torn ends much more easily.
So don’t have sex after pregnancy until your doctor says it’s okay - and she won’t say it’s okay before you stop bleeding.
Or the bends, aka decompression sickness.
but is that quite the same thing? isn’t the bends caused by nitrogen forming very small bubbles thoughout the boodstream, rather than a single big one? it causes muscle and joint damage - but is it likely to cause a stroke or heart failure, like a single big bubble?
The bends would theoretically be more likely to cause a stroke or a heart attack than intravenous air injection. The bubbles that form in the bends can form directly in the small arteries of the brain or heart muscle - ‘downstream’ of the left side of the heart, if you will - while air introduced into a vein first has to travel to the right side of the heart. A large bubble can stay in the right side of the heart and cause heart failure, or travel to the lungs and cause pulmonary failure. Only in rare cases will air make it from the right to left sides of the heart through a defect in the walls of the atria (or a shunt in the lungs), in which case it could move to the brain or coronary arteries. The capillary beds in the lungs serve as a very effective filter for clots and bubbles in venous blood.
Reminds me of one of my girlfriends who was a fourth year med student. After undressing each other before our 9th or 10th time having sex, she brought everything to a halt to somberly advise me against blowing into her vagina lest I kill her with an air embolism. Apparently, she thought I was the type who’d confuse cunnilingus with a blow job!