Being in Healthcare IT myself, I know what you are saying. We have a set standard for issues to determine if they are direct patient care issues. Does the problem directly affect the patient's healthcare? (ie, delay orders being sent, delay viewing results, delay admission or discharge? Are all computers on the unit down?) Knowing that each of our units have at least 4-6 computers helps. Also, certain issues are ruled out immediately. Unless it is the medical library, ER, or pharmacy, not being able to get onto the internet is not considered a direct patient care issue. If the above mentioned departments our first question is "What site are your trying to access?" If they say the are doing medical research or trying to look up drug interactions we know this is a priority. If a printer is not working, which printer is it? What are you trying to print? Discharge papers are a priority, while email is not.
Our organization's helpdesk has also set standard response times for issues. Direct patient care issues are to be initially addressed within 15 minutes of the helpdesk ticket creation. Of course the priority of this ticket is at the sole discretion of the helpdesk dispatcher. That is why a set of standards becomes very important. For all other issues, we must try to initiate contact with the end user in 3 hours. Whether this is by phone, email, or pager. We try to give an accurate estimate of when the issue will be addressed.
Every NCM, and every Dr. is going to consider their issue to be a priority. It is up to your IT department to set standards of service, and to define exactly what is considered a Direct Patient Care issue. Once you have this, it will be much easier to evaluate incoming issues, and to deal with irate Dr.'s and nurses.
I hope this helps you in some way, and good luck.