When I was working for a hospital we used AS400 for records. This is
a very old type system and does not integrate well. However, as far
as security of the network it is top notch. They also used an
internet procument database. For email they used Lotus notes. Again
Lotus was used instead of Outlook,for security measures since Lotus is
less prone to viruses.
As far as the IT structure. It changed during my employment there
from Novell to NT, I think.
Hope this helps.