If the iPad indeed has iOS 7 and the employee set up Find My iPad on it, then it has Activation Lock on it which will prevent it from being restored. You will need the former employee's Apple ID to remove the lock. If you can't get that information, then you may well have to pay to have the iPad replaced, though it's possible that Apple Support or an Apple Store could on proof of ownership have a way to remove the lock. I've not seen anyone report that as being the case, but you can ask.
Contact Apple's Enterprise Support. You will need to provide proof of purchase (like a PO number and serial number of the device) to prove that you as a business or enterprise own the device. If you can prove that the device was purchased and is owned by your hospital, they can clear the lock for you.
Hope this answers your question!