release management

I am doing a little research on standard practice for software release
management in an agile environment. Does anyone out there have a
process you'd like to share?

We would especially love to hear from other teams that produce
software for operating rooms, or in other chaotic fast paced
environments. I imagine ever changing requirements and users needing
it done last month but asking for it now are pretty common.

My new team is currently defining our process for release management.
Any input/best practices/references/war stories would be appreciated.

Thanks.