Keeping hospital department in Orient running (9)
I believe the answer is:
retention
'keeping' is the definition.
('retention' can be a synonym of 'keeping')
'hospital department in orient running' is the wordplay.
'hospital department' becomes 'ent'.
'in' means one lot of letters goes inside another.
'running' is an anagram indicator.
'orient' is an anagram of 'retion'.
'ent' placed inside 'retion' is 'RETENTION'.
(Other definitions for retention that I've seen before include "Saving" , "Keeping hold (of something)" , "Enter into custody" , "Failure to eliminate a substance from the body" , "memory" .)