The CBC recently ran an interesting article (with equally interesting comments) on hospital noise.
As part of a study by researchers from Harvard and the Cambridge Health Alliance, subjects spent three nights sleeping in a lab as recorded hospital sounds played from nearby speakers. The researchers found that not only were the subjects woken up by things like people talking, machines beeping and toilets flushing, but their heart-rates jumped as much as 10 bpm when they were disturbed.
This doesn't surprise me at all, and I think noise-induced stress is probably even worse for hospital patients who are actually ill or recovering from something, unlike the healthy subjects of the study.
One of the biggest problems highlighted in the comments is the noise made by other people - especially patients and their guests. When I had my lead extraction and defib replacement last summer, my student health coverage didn't extend to a semi-private or private room. I knew I'd be sore and stressed after the surgery, so I decided to suck it up and pay for a semi-private room for myself. I shouldn't have bothered - I wound up sharing a room with a woman with dementia so severe she had a 24-hour watch stationed at the foot of her bed. She was up all night, hallucinating, screaming, threatening people, throwing things, slapping nurses... not her fault, of course, and it must have been horrible for her (and those who were caring for her), but I was utterly miserable. While she thrashed in her bed through the night and shouted "I'm going to fucking kill all of you!", I lay there crying in frustration and bleeding into my sheets. Not cool (and not worth $350). I didn't sleep for a minute.
I'm normally not a complainer, and of course I'm grateful for the care I received - and I know the nurses and hospital staff were doing the best they possible could in a difficult situation. But I think it's important that this is being looked at. There might be various solutions - dedicated space for patients who need extra attention, quieter machines, designated quiet hours (a new ward at Johns Hopkins even has sound-absorbing materials in the ceiling!).
More sleep-friendly hospitals would benefit everyone.