The first device I heard of was an HP (now Philips) Criticare heart monitor. Philips/HP Criticare equipment is common in our area but I don't know if I have actually ever seen one of these.
I assisted in the development of a BSP for what was going to be a blood analyser for Roche. I recall it be m683xx-based but do not know exactly it tested for.
The AMV Technic I is a certified syringe pump for sale in a number of European countries. It uses RTEMS on an ARM CPU and we have information in the RTEMS Wiki. It uses Microwindows to provide the graphical user interface.
There are also RTEMS based intercom systems which are used by patients to summon or talk to a floor nurse. This product is ARM based and is on its second generation of hardware using RTEMS. Seeing a user build multiple product generations on RTEMS is personally very satisfying. It makes me know they are pleased with RTEMS.
There may well be other medical devices out there, but I don't know about them. Unfortunately, many people do not tell us about their application. I don't know how to change this but will continue to beg for marketing literature from RTEMS based products. Please save me from begging! Just send me the information.