you might be underestimating modern med devices which even have wireless access (beats a port or invasive surgery to read a log).
example for the issues in this area: https://spqr.eecs.umich.edu/papers/49SS2-3_burleson.pdf
example for the issues in this area: https://spqr.eecs.umich.edu/papers/49SS2-3_burleson.pdf
For what it's worth, devices I work on have a few wireless interfaces while guaranteeing 20-year life time: one interface is long-range (on the order of 10km), two are short range (on the order of a few mm). There is no way we can get to 20-year life time with doing WiFi (maintaining current battery size/capacity) for long'ish range and maybe not even BT for shorter range.
and just like any other IoT, using generic chips and stacks is cheaper.
run QNX or Linux on it and walk away.
there are DYI insulin pump monitors out there already that use Linux on RaspberryPi - see here: https://openaps.org/
A RasPi has no chance of running for 20 years off a single A-size non-rechargeable non-serviceable battery.