Passing out while taking blood?

I am 18 and have high blood pressure. I am on 2 medicines now and it is under control. The next step for me is to find out why I’ve high blood pressure and so I’m having my kidneys checked for problems. While getting blood drawn today (5 vials) on the 3rd vial I noticed my heart beating very slowly than my vision began to gray out and i started to have heart palpitations. The nurse taking my blood stopped drawing the blood as I got a bit worse. It was not very serious as I didn't actually pass out from low blood pressure, but it was very scary as I had never had it happen before. I soon got back to normall. I have to go tomorrow to get the other two vials drawn, but this time they’ll have me lay down instead of sitting up in a chair. My question is, when laying down and reducing the amount of blood taken from three vials to two will I almost pass out again? I know each situation is one-of-a-kind, but what was your experience. Thanks for the help.

I was surprised to learn that this happens to many people while getting their blood drawn. The nurses were very helpful and kept me calm through it.

It's important to remember that it is NOT the amount of blood being drawn that causes the problem. Though it seems like a LOT of blood is taken, in reality those little tubes hold about 3-5 mls each. Even 5 tubes full would be less than a tablespoon!

What happens is called a vaso-vagal reaction. The very act of getting stuck with a needle can stimulate your vagus nerve. This can happen even if you don't feel nervous or anxious about getting stuck.

When the vagal nerve is stimulated, your blood pressure drops a bit and your heart rate slows down (you were even able to feel that your heart was beating slowly). Low blood pressure + low heart rate = less blood/oxygen to the brain. Less oxygen to the brain = you feel faint, your vision greys out, and you may even feel nauseous, dizzy, or get sweaty. This is basically god's way of saying “LAY DOWN, YOU NEED MORE OXYGEN TO YOUR BRAIN!”

Usually these symptoms pass after a few moments of laying down.

I'm very glad the nurses were helpful. Most are, once they've experienced this a few times! As an experienced nurse, I very much like to have people laying down when I draw their blood.

You might never have this happen to you again - it's just something that happens sometimes. But you may wish to simply request that you lie down during any future blood draws. Any nurse or phlebotomist should be happy to do this - they'd rather have you lie down than have to catch you!

Hope this helps - good luck to you!

I’ve a very serious case of passing out, and being a Junior in High school I have passed out probably close to 20 times.

It happens to me with shots, but also talking about certain topics that make me queezy (usually blood topics).

I know when I am about to pass out, and normally leading up to it I feel restless, dizzy, headach. Usually also I hear this loud sound right before I pass out. Not a fun thing, has caused some head injuries from falling

Anyway.. I have found some things to help. Make sure you tell whoever is drawing the blood from you what happened before. Try to get something to eat and drink before, as that will help you not pass out. Also, don't focus on it. If you can listen to music to divert your attention, and not look at it that might also help.

A lot of passing out, at least for me, is in the head. I’ve a very imaginative mind and can almost feel what is being talked about. Hopefully you can find something to think about and completely ignore what’s happening around you.

Good luck my friend