So we are talking about "patient records". In my experience, doctors "hate" research that includes patient records and 20 patient records is a lot. But that is another topic.
I assume that you have the doctor's email as you seem to use a token based survey.
So you could use that email and one of the admin notifications to send them an email after they completed a patient record.
So far, so good. Now we need to find a solution on how to count the patient records one doctor did.
I am thinking aloud here and throw a few thoughts out:
You could use the statistics module and count the numbers of responses in the database. Not sure if the statistics module can do this over the token, but if not, you could always save the token into a hidden question and do statistics based on that I guess.
My other idea is to create a custom attribute in the token table where you store the count. You probably would need to install a plugin (I think it is called something like "updateTokentable" or something).
There you could start off with zero and add 1 each time a doctor responds.
It would be perfect if one could access the "uses left" for the token, but I don't think this is possible.
One issue that I see with such an automated approach: We all know how doctors are. Many of them are "technically challenged" and they often fill in forms wrong (not sure if on purpose or if they just don't pay attention or if they are just not capable of doing so). But the automatic approach suggests that everything is allright. So I would still check from time to time if they patient records are filled in correctly.
Let's see if Joffm has a good solution for this.