I worked in the VA in my earlier nursing days.  They were known for momentary lapses of advanced experimental medicine mixed with third world missionary adapting style techniques.  (One nice thing about working there was that everything was considered hazardous when placed in the linen bags, so certain cleanups were made much easier.)  There is a condition called hemochromotosis where the body has an overproduction of heme or red blood cells which causes many problems including liver destruction – eventually.  Well, the treatment for excess red blood cells is simple – remove them.  This was done by inserting a catheter and draining the blood.  In some cases, this blood can be used for donation, so there is a possibility of usefulness to the loss.  I passed by a new doc doing the blood removal with a catheter inserted in the arm, and holding a beaker underneath it to catch the blood.  That was the image I remembered when noting this: