I work in hospice in a major hospital. The only use of heat we can order is the facility heating pads (also called K-mods). We are not allowed to use wet towels heated in the microwave, as I've seen some do. There was a pt who sustained 2nd degree burns as a result of someone doing this and not watching the time heated.
We use heat with caution in our very debilitated patients...they are too easily burned. Sometimes our more alert and mobile patients may use a heating pad or similar device to help with pain, but we would rarely recommend that use in a bedridden or totally dependent patient.