Take a look at Medical Device Regulation, which sets out standards for medical devices - software included (in fact, any medical software is automatically considered an active medical device).
The demand for supervision is so high, there are now third party companies (Notified Bodies) taking care of the approvals. They are appointed by their respective Certification Authorities (which are governmental organisations).
The approval usually works in the way where the manufacturer classifies the device and performs all the necessary tests and submits the documentation to the Notified Bodies where they verify that the device is correctly classified and all the necessary tests for the given class of the device have been performed and that the documentation checks out.
MDR: https://www.ema.europa.eu/en/human-regulatory/overview/medic...
In 2019, the PE software exam was discontinued: https://ncees.org/ncees-discontinuing-pe-software-engineerin...
If our API that accepts readings from devices goes down, real people's health could be at risk.
We have multiple levels of redundancy, including at the device level, but it is the point of highest stress.