If your doctor won't write the script with the generic name (or indication that this substitution is acceptable), without justifying the name brand to *you*, find another doctor. It really is that simple.
Financial interest aside, it is usually done out-patient. My Carotid angioplasty (except that they didn't do the "plasty" part - false positive on the CTA) was outpatient. My first ablation was an overnight but my next is planned as an outpatient procedure. They try to keep people out of the hospital these days. Not only is it expensive but it's a dangerous place. There are all sorts of sick people there.