CANopenBed

CAN has been around for some time, not as long as the Medical Information Buss (MIB) now known as IEEE 1073. CAN was developed to provide communications and control between safety-critical devices in a variety of industries. From the CAN website's page on medical devices:

As far back
as the early 1990s, the flexibility, robustness, reliability and
reasonable costs made the standardized Controller Area Network (CAN)
serial bus (ISO 11898) interesting for use in the field of medical
technology. Initially, due to the lack of an industrial standard
protocol, numerous proprietary communication profiles with a focus on
individual application requirements were developed. The standardized
CANopen application layer and communication profile (EN 50325-4) filled
this void, enabling the simple integration of devices from various
vendors and providing the basis for the re-use of CAN devices in
several applications. By the end of the 1990s, CANopen had become the
common industrial standard for system control in medical imaging
devices. In such devices several CANopen networks are implemented.

CANopen supports a variety of message types one would expect for real time systems. Functions like scheduling, configuration, and diagnostic data are supported by confirmed services (which means that the receiver responds to a message so you confirm communications). Additionally, there is a Heartbeat protocol, a communications state machine, Emergency protocol and Time protocol.

Besides the generic device
profiles for sensors, electrical drives, and I/O modules, there are
specific profiles for medical sub-systems. One example thereof is the
device profile for automatic X-ray collimators targeting the OEM
market. General Electric Healthcare, Philips Medical Systems, and
Siemens Medical Solutions have developed this profile jointly. Other
CANopen profiles for dose-meters, stands and tables as well as X-ray
generators are under development.

Currently the standardization of
a new class of device profiles for medical diagnostic add-on modules,
such as contrast media injectors and electro-cardiograms (ECG) are in
work. The contrast media injector profile covers devices to be used
with AG (angiography), CT (computer tomography), MR (magnet resonance),
and US (ultrasonic) scanners. The profile supports also multi-piston
injectors. The communication and application is defined. The scanner
provides CANopen manager functionality, and the injector functions as
CANopen NMT slave device. In order to avoid the assignment of
node-identifiers, a geographical addressing scheme is recommended.

CANopen networks are used in many other medical applications, e.g. in
patient beds [pictured], and in laboratory analysis equipment. The standardized
network is also considered for the plug-and-play operating room of the
future (PnP ORF). Currently there is a research project running in the
United States of the non-profit CIMIT organization.

You can see examples of medical devices that have implemented CANopen here. There is also a general information article here on the Medical Device Link website.