Can I give blood and not pass out?

April 14, 2015 6:00 PM

There is a blood drive coming up at my workplace and I have always wanted to give blood. I am hesitating, though, because when my blood pressure drops, I tend to faint. Is there any correlation between donating blood and low blood pressure? Or do people who faint tend to do so due to dehydration or low blood sugar?

I really, really do not want to faint at work. I also don't want to be lightheaded or incapacitated and have to try to commute [a long way, driving] home.

I know you are not my doctor, phlebotomist, etc. etc. and I have read to drink water and snack beforehand. Also, I am not talking about squeamishness. I do not get faint at the sight of blood, just when something affects my blood pressure.

Any tricks, tips or warnings to skip it are greatly appreciated.

posted by Ink-stained wretch to Health & Fitness (22 answers total)

Best answer: I have low-normal blood pressure, and I cannot donate blood. The last couple times I've tried, I've fainted. When blood is removed from the body, it lowers blood pressure even more (less volume=lower pressure), and if it's too low, you'll faint. I would strongly suggest you forgo it.
posted by Yellow Silver Maple at 6:06 PM on April 14, 2015 [4 favorites]

Best answer: There is actually a low range to blood pressure that is listed on the Red Cross' website. I would say if you've experienced fainting from low blood pressure, it may be a good idea not to participate.
posted by xingcat at 6:08 PM on April 14, 2015

Best answer: I have low blood pressure. I don't faint while giving blood (though sometimes it is too low for me to donate). The big deal is staying fed and hydrated and making sure you've been up and around for a while (literally one time they told me to go out and run down the hall for a bit, this was for medical not Red Cross donation, but still!). The big thing is though that I am a small person and blood donation makes me tired. So I don't know if it makes sense for your first time to be at work if you don't have a plan B for getting home if you do pass out or otherwise feel badly.
posted by jessamyn at 6:28 PM on April 14, 2015 [1 favorite]

Best answer: I have naturally low blood pressure, and gave blood once (for myself, a few days before I was going into surgery) without fainting. But, I've never actually fainted so far in my life, just felt on the verge of it a couple of times when I've had a vasovagal syncope (triggered by being overheated+dehydrate+standing with my arm too high in a train), so, my low may be in the safe range still. If you were going to donate at a hospital where they could give you IV fluids afterwards until your pressure normalized, or you were going home right after with someone else to drive you, it might be worth trying. But donating in the office and having to go back to work and then drive seems like it could go disastrously wrong. Like multiple-car pile-up wrong.
posted by oh yeah! at 6:30 PM on April 14, 2015

I have low blood pressure and have donated blood without ill effect. If you decide to do it, making sure you're well hydrated before you go is one safeguard you can take. And of course they will give you a little glass of tang or that peach-flavoured faux-tang when you're done. And a cookie.
posted by If only I had a penguin... at 6:45 PM on April 14, 2015

Best answer: Don't do it. I also faint from low blood pressure (and am always careful about staying hydrated/keeping snacks on hand as a result) and haven't made it past having one medical test-sized vial of blood drawn without fainting. I wouldn't risk it at work with a long drive home.
posted by snaw at 7:04 PM on April 14, 2015

I also suspect I faint when my blood volume drops during blood donation and I got some good advice when I asked a similar question. After reading the responses, I realized that I tended to faint during/after larger draws and not after blood tests, so I can confirm that this is definitely a real thing that happens, and might not be exactly the same as a vasovagal response, at least in my case.
posted by pullayup at 7:34 PM on April 14, 2015

You can try, be hydrated, maybe a cup of coffee and something salty to really get the pressure up. It's a safe place to try next to a professional phlebotomist and good to donate. I once passed out after donating blood and it only hurt my pride, they just sat me down, had me drink more fluids, and watched me for 15 minutes before letting me go. Since then I've had no problem multiple times.

They'll ask you multiple times if you want to go ahead, and if you don't feel like it, no problem.
posted by nickggully at 7:46 PM on April 14, 2015 [1 favorite]

Best answer: I have low blood pressure and cannot donate without fainting, or at the very least being woozy and not capable of driving safely. There are other ways to help, and I wouldn't do it.
posted by peanut_mcgillicuty at 7:51 PM on April 14, 2015

I all but completely faint when giving vials of blood for normal, routine bloodwork. Paleness, fuzzy hearing, tunnel vision, the works; it is an involuntary reaction like shock. I have never attempted to give blood because of this.
posted by ArgentCorvid at 7:52 PM on April 14, 2015

I've been nearly turned away from donating blood due to low blood pressure as well. They took my blood pressure shortly before I was going to donate and had to make a bunch of calls to other nurses and stuff to see if I was okay to donate. They only let me after they reviewed my medical record and saw that my normal blood pressure really was as low as it was. They also made me drink two water bottles first and preemptively laid me down before the draw and got me extra snacks.

In the end, it didn't work out. My blood pressure was so low that the blood coagulated mid-draw (15 or 20 minutes in...) and they couldn't get the full unit. They gave me a number so that I could follow up to see what the blood was used for (they said "possibly research"), but I was so disheartened and didn't want to even try and check, lest I find out that they couldn't use my blood for anything at all-- not even research purposes. I don't know if I'll try again unless I can somehow drastically raise my blood pressure between now and the next time. I didn't faint or even get lightheaded, though-- the issue in my case was only with the blood flow.

For reference, I don't remember what my blood pressure was when I tried to donate, but it normally is around 80/50 or 75/50, if that helps. 90/60 is fine to donate, I think. Stay hydrated and make a tight fist and have juice nearby.
posted by gemutlichkeit at 7:55 PM on April 14, 2015

I have gotten lightheaded from donating whole blood, but I find that drinking a lot of water completely prevents it. I drink a half-liter just before the appointment, another half-liter while they're doing the anemia check and paperwork, and a final half-liter in the canteen afterwards. Anecdata, but I found it helped with both the lightheadedness and the possibility of clotting, which is, as gemutlichkeit says, just about the most disappointing thing ever.

The other option that helps is the double red donation, aka Alyx. There, they return all the fluid to you, minus the red blood cells, and the needle is smaller, so it's overall a gentler procedure, physically. Also, they use an anti-clotting factor, so that's not an issue, either. It takes longer (figure 90 minutes after walking in the door, instead of an hour) and some people are squicked out by having part of their blood returned to them, but I love it. Plus it's equivalent to two donations at once.

I also used to get faint while doing bloodwork, but blood donation has cured me of that, and I'm now a three gallon donor. I think you can do it.
posted by wnissen at 8:33 PM on April 14, 2015

Best answer: If it were me, I'd find a lower-stakes drive for my first time, and bring a friend if possible (in fact, this is exactly what I did given similar concerns). Maybe you'll be fine, but why take that chance in the middle of a workday far from home?
posted by teremala at 8:35 PM on April 14, 2015 [1 favorite]

Best answer: I have low blood pressure and the two times I have attempted to give blood, I was very dizzy and blacked out for a couple seconds after. So I no longer do it.
posted by celtalitha at 9:50 PM on April 14, 2015

Best answer: I've fainted after giving blood one a few occasions, I've donated blood perhaps 15 times to date. I found that I only faint when it is warm and/or humid with temperatures from 70s up. When I did faint I felt fine half an hr later so this does not necessarily ruin the rest of the day. But as others have said perhaps start with a donation nearer your home at the end of the day so you can just go home, eat, rest and not worry about having to get back to work or the commute. If that works you can then take part in the next blood drive at work.
posted by koahiatamadl at 10:28 PM on April 14, 2015

Best answer: Blood donation of a pint (470mL) is a loss of about 8-12% of the average person's blood volume, and is below a Class I hemorrhage, which doesn't change vital signs (heart rate, blood pressure, respiratory rate, temperature). The fluid lost can be replaced in a matter of hours. If your tendency to faint is postural - if you pass out when you stand up - the mechanism isn't about total blood volume as such, it's about pooling of large volumes in the limbs, which is detected by pressure receptors in the chest. According to this large study, only about 1 in a thousand donors loses consciousness completely. Still, bodies are funny, and I agree with what's been said in the thread so far - consider trying donation near home, make sure you're well-hydrated starting the night before, and tell the staff so they can put the head of the bed down. You can also help protect yourself against a postural response by tensing your leg muscles for 5 seconds every 1-2 minutes, and of course by getting up from the bed slowly.
posted by gingerest at 12:35 AM on April 15, 2015 [3 favorites]

Low blood pressure here, gave blood regularly for years, no problem. Woman in one of our groups did faint once, or perhaps only came close, we all had to wait an extra 15 minutes or so to give her time to fully recover, which she did, and she was perfectly normal on the bus and at work for the rest of the day.
posted by GeeEmm at 3:02 AM on April 15, 2015

I am a frequent blood and platelet donor, and have volunteered at blood drives. There will likely be a comprehensive screening, so if your body weight, hemoglobin or blood pressure are too low for you donate safely, rest assured you will not be allowed. The staff should also be trained in looking for warning signs, and will feed you juice or encourage you to take it easy before returning to work if you show any difficulty. (I've seen physically active and fit people faint while others one might expect to be a risk have no trouble whatever -- personally I never have.)

Will your work situation be cool with you remaining in the canteen resting and having some extra juice and cookies for a few minutes more than average? If so, bearing in mind the excellent advice above about staying hydrated and fed, I say go for it.
posted by Gelatin at 5:43 AM on April 15, 2015 [1 favorite]

I used to get horribly lightheaded and woozy from donating blood and quit donating for a while. Then one of the nurses told my husband that I should ask them to lay me down completely from the start, rather that starting in a sitting position and then laying down once I started to feel bad. Evidently once you start to get woozy, the laying down, feet elevated thing helps keep it from getting worse, but doesn't really fix it. She said if you are in that position from the beginning, it can prevent it altogether.

I've donated 3 times since then with no problems. So ask them to lay you down from the beginning. Also, drink lots of fluids before and after.
posted by thejanna at 7:49 AM on April 15, 2015

The first time I donated blood, I was a total idiot about it, eating a very light snack before heading upstairs to donate. I got about two steps away from the chair (not even out of the room), before I vomited. Lesson duly learned.

The second time, I ate a big, protein-heavy meal beforehand. I was ready for this! I could do it. I got all the way down the stairs and outside the building before I almost passed out in the parking lot. Some nice bystander went upstairs to get a nurse for me and I dragged myself to bed for the rest of the afternoon.

The nurse told me that if this was my second awful reaction, then maybe I shouldn't donate blood anymore. I haven't donated since, but I keep thinking if I try again, I'll probably have someone else drive me (instead of walking like I did previously), and probably budget the rest of the day for lazy times.
posted by PearlRose at 9:10 AM on April 15, 2015

I gave blood a few times, and every time was very woozy afterwards. My blood type is apparently very common, so the nurse advised me not to bother again. If my blood type had been rarer I think they'd have asked me to continue giving.
posted by TristanPK at 1:19 PM on April 15, 2015

I have high blood pressure, and have passed out once when giving blood (and almost done so once or twice).

Just tell the people that you are at risk for passing out, and they will set you up accordingly; elevate feet, watch carefully, etc.
posted by ObscureReferenceMan at 1:32 PM on April 16, 2015