Early in my training, I was doing an ICU clinical rotation. I was also a raging ("righteous") dope fiend at the time and was the only one with a long sleeve white T shirt pulled up about halfway up my arms, but I digress. Anyway there was a very sick patient who needed an IV. They were trying all the usual spots on the mainline, the hands, etc. and were getting absolutely nowhere. Now basically I'm here to observe and learn, but I pipe up from the back, "can I try?" And I guess they are just like, OK, why not, so I step up, snap on the tourniquet, turn the hand to the side, give the cephalic where it rounds the base of the thumb a good smack and angle the thumb out and slightly downward - all you junkies know the hand position that I'm talking about - and WHAM instant blood flash and a patent line. People were impressed. :D
Edit to add: there's a reason, though, that this site isn't commonly used for hospital i.v.'s, it is easy to dislodge, not a concern in this patient as they weren't going anywhere (sadly in a more expansive sense of the term, too, if I recall correctly), but it was good enough to push some fluids and some drugs. Most medical people might tell you that you can't get a lot of volume in there, but we (junkies) know that vein can take a considerable amount of abuse. Just we (medical people) would probably do well to keep the infusion a little slower.
Just the other day our phlebotomist was having a really hard time on a patient (an IVDU as the case would be), the patient was catatonic so the usual process of asking the IVDU what their best vein was was out of the question, so I suggested to her this same site. She, a phlebotomist of 20 years, said she'd never used it or thought to, again, good results.