A large 247 page handbook on software safety assembled by the US Military and Electronic Industries Association (EIA) Committee G-48 in December 1999. Appendix E provides technical information and Appendix F has a series of lessons learned from software safety incidents including the Therac radiation treatment system.
While there is a fair amount of information specific to the military contract and development process Appendix E and F provide useful information that could be relevant to medical device software design and the document overall has extensive information on management of software safety in large projects especially where outside development companies are involved.
An electronic copy (pdf) of the handbook is available at no charge at the link provided.