"Consent" in passive voice to refer to subject giving consent?
To consent a patient appears to be medical jargon . . .
You can use scare quotes to signify jargon . . .
If you really don't like jargon, be sure to put an ugh after the offending term:
So there's your transitive, jargony verb.
Active: We consented the patients.
Passive: The patients were consented [by us].
It also appears that you can consent a patient to [something] and consent a patient to [do something].
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See also: When to use scare quotes in formal writing:
Use scare quotes to indicate technical jargon: Scare marks may also signal to the reader that you’re using technical jargon. But avoid jargon if you can.