Not typically, no.  We have talked about simply shutting off the core routers (making the outage the same, but controllable by IT), but we have never done it.  I think downtime procedures really should be tested on a semi-annual basis.  The nurse teams especially need the extra reminders as the vast majority of the safety technology is computer driven and falls on the nurses shoulders.  They take the brunt of the pain when the hospital based EMR is down. 

Remember it doesn't take a tornado to knock out your EMR.  It can be anything from power outages to software issues to the latest virus.  You will want to plan for both short term outages and extended outages.  Take advantage of the disaster recovery procedures and business continuity planning of other sites and come up with a plan that best fits your organization.

Shawn