Well this information is not part of your "record" as people usually think about it. information regarding a 72 hour hold is considered mental health data and is therefore private. That means that it can only be accessed by you and necessary government agencies.
Expungement of records makes them not viewable by the public. Your data is already not viewable by the public. So an expungement of the data wouldn't do anything.
Also, there really isn't a mechanism for expunging mental health data in the first place.