Which is the best serial protocol for medical devices?

[bomba]

I'm working in a medical device that has three boards interconnected with a serial protocol, in which one must be at 20 mts far to others. I was thinking to use CAN protocol, or maybe exits a specific protocol to medical PCB devices communication.
What do you think about CAN Protocol? And there is another protocol available to use in medical PCB devices communication?

Thanks in advance