I'm afraid I can't see her either - the rest of the family are at home in Tyldesley, but no Sarah....
Patients in hospitals are listed on the census like everyone else, either with their full name, or sometimes just their initials.
If she was visiting friends/family, her name, age or birthplace may have been badly mangled by the householder, or she may be wrongly listed with the same surname as the family she was visiting. Have you looked for her under her maiden name? It's worth checking on other family members (married sisters, etc) in case she's with them under the wrong name.
Not much help, I'm afraid...

Rambler