Whatever you do, don't use a ventilator tubing circuit as an improvised shower head. :twisted:
Seriously, though, my mother has just been getting bed baths. She is about to receive her power wheelchair, and then we might start to use her shower chair again. An actual overhead shower with a trach would make me nervous, unless it was an instance where the trach incision could be covered with a plug, but this isn't an option for ventilator-dependent people. Among other things, I would worry about the pressure of the water causing the tubing to pop off.
Other useful things to know: You can get pre-moistened cleansing cloths at most pharmacies. Look in the bath section with soap, etc. They come in rectangular soft plastic packages with a dispenser opening on the top. This is good for days when a full bath would be too exhausting. Also, there is a shampoo that comes in a spray can. You can wrap a plastic bag around your scalp and then massage the shampoo into the scalp. Kind of like "no water" shampoo for dogs.
While we are on the hygiene subject, zinc oxide cream is good for bedsores. Desitin baby cream is usually the easiest to find, but it has a strong smell and is hard to clean off. We use baby wipes for cleaning in sensitive areas.