Hospitals know the necessity for beds to be adjustable. After all, patients need to be treated in these hospitals for all kinds of things. It can be some manner of trauma, such as an injury or something of that nature, or it may be recuperation from a surgical treatment. At times its simply a matter of trying to keep the individual as secure as you possibly can.
The point being that lying down on your back, flat and out, is sometimes not the best thing for you. Adjustable beds are the answer in these cases.