Bariatric Bed??
I'm going to go out on a limb here are say that a bariatric bed means more about the location of where you will be put in the hospital after surgery than the actual bed it's self.
I work in a hospital and hear beds reffered to by location. Such as:
A med/surg bed
An ICU bed
An OB bed
This is so you would be put into the proper location after surgery so the people looking after you would have the correct experience.
Just my guess