What are the risks if a patient loses consciousness during a blood draw?

My SO often faints during blood draws. It’s less of a problem when they’re lying down, but it still happens sometimes. Whenever it does people seem to appear out of thin air to shout and generally carry on as if they were trying to wrest a soul from the icy grip of death. I tend to stand there, bemused, and try to remember all the details so I can tell my SO about all the fun they missed.

Is there an actual risk of injury of some sort? Or is this simply a reflex of medical personnel when a patient shows signs of drifting off? I’ve tried asking once everyone has cooled off and never received much of an answer–the best is a claim that it’s against the law to draw blood from an unconscious person without some sort of signed document. That doesn’t seem likely to me, but I speak from ignorance.

So, what’s the big deal?

Not a complete answer by any means, but what I heard from a Red Cross technician at my last donation was that they were worried about the needle placement going awry if something like that happened.

When someone becomes suddenly unresponsive, the concern is to ascertain if they’re a pulseless non-breather, which is the chief worry.

After it’s ascertained that they both have a pulse and respirations, then generally other dangerous conditions like low blood sugar, low oxygen levels, or low blood pressure need to be considered, as if those are left uncorrected, damage may be severe.

Once those are ruled out, and everyone’s comfortable with the idea that the sudden change in status was due to a vaso-vagal phenomenon, and the person is getting over it, then folks tend to relax and the crisis ends up resolved.

But just because someone passed out during a blood draw doesn’t mean that others can assume that it wasn’t a life-threatening situation, even if the odds favor such a benign outcome.

Thank you for your response. We do try to always warn phlebotomists before the draw, but it seems to have little effect on their actions.

As a former phlebotomist who had a large man faint on her at least once, I can tell you the concerns from this end. In one hand I’ve got an extremely sharp metal needle (or in your husband’s arm) which might already be contaminated with blood; in the other I might have a fragile tube of possibly infectious material. Now I need both my hands for catching the falling large man. Movement while getting blood drawn is strongly discouraged; in my relatively-short lab tech career, I was stuck in the hand with a dirty needle once and had a patient bend a needle 90 degrees on the bone in his arm - both happened because the patient jerked away.

If you tell phlebotomists and they don’t take it seriously, they’re fools. If anyone told me they were a fainter, they immediately went to lie down for the draw. That was standard operating procedure everywhere I worked, for the safety of the phlebotomist and the patient.

There must be more fools than I thought. I’ve had the same thing happen. Repeatedly.
I’m a fainter. I ALWAYS warn the tech. At least half the time I’m told “Nobody ever faints on me”. The last thing I remember is the tech slapping my arm trying to get blood flow as my BP drops into the toilet. I don’t even remember how many times…