question about privacy laws and family members

Hi there....I just graduated from nursing school (woohoo!) and work as an aide on a floor in a hospital. I see the nurses all the time in the icu giving out information (like the patient is heading to CT, etc) to whatever family members/friends are sitting there. When I take vitals, I say them outloud to the patient no matter who is in the room.

I am wondering how this works. I mean, we learned about the whole "next of kin" thing but it's not as if we are looking at people's ids?
Anyone?

If I am unsure who the people in the room with the patient are, I ask the patient if they are okay if the people in the room know what's going on or get information. If the patient is not able to respond, I simply ask the people who they are and look at the chart to see if they are noted on the chart as someone allowed to receive information. If they are not allowed to receive information (per the chart), I simply tell them that I cannot give them more information. Many hospitals use "passwords" for people that are allowed to receive information. If the person doesn't know the "password", then they don't get any information.