This, because of privacy. But they would leave a message to say they called.
I've called on a number of occasions. I take care of employees that have been exposed to patients' blood. I don't leave a detailed message because explaining such an incident is best done in person. But I always tell them, "it's nothing bad, [patient name or reference like, 'your mother'] is fine."
Were I calling for something else I might say something like, "call us at your convenience", which is another way of letting them know it's not urgent. Or, I'd say, "It's urgent. Ask for Mary Smith the charge nurse or Mrs B the nursing supervisor and they can explain things." That says call right away and it's best practices to give them a person to ask for.
I would have no issue leaving a more detailed message but that's because I personally get clearance from patients or the NOK, "Can I leave a confidential message about [you, your loved one, whomever] at this number?" If it is a next of kin they would have already established the legal standing to get confidential medical information (MPA or medical power of attorney) about the patient.The staff may know the family well enough they feel they have permission to leave confidential medical information.
[TMI, skip if not of interest.]
Sometimes people are only DPA or durable power of attorney and they can only make financial decisions. Once in a while there is a DPA but no MPA. In those cases there are a number of procedures you would do. Someone has to give consent. When there is no one, a guardian is assigned. I would be able to leave confidential information on voice mail on a guardian's phone. It's the same if I am calling the doctor or clinic about something.
In reality though, things are a bit less formal in a nursing home, especially with a patient with dementia. The staff often get to know the family situation and most of the time, we'll call whomever the family designates between siblings, spouses, and children. The chart will designate who to call. If daughter Jane is feuding with son John, then everyone knows the details like Jane has MPA and John is not allowed to visit. Or the chart will have a number of people to call: Call the daughter first but if you can't reach her, call the brother.
If the chart says call the wife, for example, I call the wife. I don't look for the legal assignment of MPA because I don't expect any problems. I need to get consent to draw blood and order labs that are not part of the patient's medical care. If the NOK gives me permission, I proceed.
Reasons to call (mentioned by others):
an incident— could be an injury or a potential injury. In my case, a staff member had an exposure and I need to get permission for labs. I want them to know what's going on and for a confused patient, I call the lab results to the NOK
a change in the patient's status
the heath care provider asked staff to call the family about something
the patient in a lucid moment wants staff to call a family member
Some people are confused intermittently, or they are confused to things like time and place, but not confused about other things. They may be perfectly clear headed about me drawing their blood, and then they say something very confusing to me while I am drawing the blood.