Interestingly, 4 and 9 are not used as room numbers at hospitals where the most advanced medical devices are used to treat (their) patients.
Is this acceptable? Also, should I include their?
"their" is not required. The sentence is correct English, but a potential problem is that it can be read as implying: Interestingly, 4 and 9 are not used as room numbers at hospitals where the most advanced medical devices are used to treat patients (but they may be used at hospitals which don't use advanced medical devices). I believe this is probably not what you intend.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
"their" is not required.
The sentence is correct English, but a potential problem is that it can be read as implying:
Interestingly, 4 and 9 are not used as room numbers at hospitals where the most advanced medical devices are used to treat patients (but they may be used at hospitals which don't use advanced medical devices).
I believe this is probably not what you int