A job interview follow-up or notification of non-acceptance is not required/mandatory. Such notification is certainly a courtesy when it occurs, but across many and most industries, it is usually not practiced. In general, an applicant should leave the interview with an understanding, or firm, time-frame for an acceptance response from the potential employer. Not receiving a phone-call or letter within the expected time-frame (usually) is the understood result that an applicant was not accepted.
The whole process can definitely be frustrating and the degree of that frustration can be variable depending on an applicant's specific situation, but as a professional technician and workforce member, I would encourage any applicant to not jump to negative conclusions or let one negative result deter from a positive and engaging perspective for the future. There are literally hundreds of reasons why a perfectly good applicant would not be hired; usually due to a sudden financial budget cut or another applicant having more developed skills/qualifications or more experience. Often times in hospitals, their departments (supervisors/managers) are not the final decision makers for an applicant to be hired; the job submission goes through a number of hands such as H.R. and financial committees for example.
Here are a couple helpful links; communicating the right way could gain an applicant some valuable feedback and potentially increase their chances of employment in the future. Don't be discouraged, keep at it.