When I had my back surgery in March, I had a vasovagal syncope (extremely low blood pressure), passed out, and bashed my head on the way down. When the aide found me, I not only had very low blood pressure (something like 30/58) but was bleeding a lot from a wound on my head.
Within a few minutes - as soon as they determined my blood pressure was on the way back up - they sent me for a MRI of my head to make sure I did not have (yet another) concussion (nope, but I bled all over their equipment). Once that was ruled out, they had to test my heart to make sure my replacement aortic valve was not failing.
This was the second vasovagal syncope I'd had following a surgery. I have put it on my list of conditions and things to watch for, because I do not want to pass out again from it.
At least this one was not as dramatic as having a vasovagal syncope after the valve replacement - my heart monitor sent out a code blue to the entire hospital and a few dozen people showed up in the hospital room in response!
The funniest part was when they tried to wrap my head. I have a very round head so their first attempt just slipped right off. Then they tried to wrap it around my head and under my chin, which didn't last much longer. They finally gave up and put an absorbent pad on the pillow and let me bleed into that until the place clotted.