My husband has a pro-bed that turns him on a set time schedule. We have it at the optimal 20 minutes at 20 degrees on right side and then the same on his left side. We have chosen not to have him on his back as he is in his chair all day, but it can be programmed in as well. It can turn him while the head of the bed is elevated and the knees up. It is an extremely expensive bed but the VA pays for it. Check it out, we are extremely happy with it, and they have 24/7 support if there is any problems. We have not had any, but they really mean it when they say they are there for you. It increases circulation, and decreases the chances of secretion sitting and consolidating in the lungs. His skin never gets even the slightest pressure spots, and there is a special bolster that holds his legs so that they don't flop on turns. It also allows a roho insert for the "bum" if there are a pressure sores already.
Paulette