I spend 10-15 hours a day in a hospital setting.
Most units, particularly ICU's, prefer that you don't use your mobile phone.
There is a belief that cell phones affect the monitors, pumps, etc.
That is generally true of analog phones but in actual practice digital phones are in everyone's pocket these days, and most of the machines on an ICU's will obliterate your cell signal unless you happen to be right next to a window.
As I do dialysis at bedside in ICU's (There are 4 ICU's in the hospital I work in) I usually have signal long enough to send and recieve texts.
If a dialysis treatment goes well, it is generally 4 hours of me sitting, watching a heavily sedated ICU pt. Checking vitals every 15 minutes, and charting them. Leaves a lot of time with nothing going on.
So I reach out and touch people via text, read books, do crosswords, etc to maintain my sanity.