I'll try radials multiple times, and if I can't get it, I will consider femorals. If the femoral is not feasible, or if it is just too much trouble to take the patient's blankets off and get to the legs (private practice), I will do a brachial if it is easily justified for the case.
You may ask then why am I doing radials in the first place if the indication is not justified? Sometimes, you just have to make an executive decision, and sometimes the indication for a radial is soft. Doing a AAA repair on a guy with CAD, CHF, etc., I will do a brachial. Doing a multi-level spine fusion with a deft surgeon on a guy with CAD s/p MI but good functional status? Soft call, but to me it is not as clear cut as the carotid, so I would just ditch the line alltogether if I had trouble with the radial.
So basically I prefer radials, and if I have trouble, only the strong indications get brachials. I do think brachials are not as safe, but I can't find compelling data to back me up. The vascular surgeons I work with don't like them either and would prefer radials or femorals.