HealthSupervisor 12+

HealthSupervisor – app for remote monitoring condition of the health, namely lungs and heart.

Monitor remotely the condition of other people's health or entrust the control of your health to professionals.

You can create groups and review people that asked you to supervise their health state.
And of course, that is possible to observe your personal data independently.

Connect Garmin devices or any other Bluetooth devices that measure oxygen saturation, heart rate or respiration and can send data to Apple Health. 
You should remember that the accuracy of the measurements depends on the device you choose and it's used according to the manufacturer documentation. We do not take responsibility for the measurements accuracy.

Read about Garmin devices accuracy of measurement:
https://www.garmin.com/en-US/legal/atdisclaimer/

DISCLAIMER
We are not developing any measuring devices, we are only using devices that are on the market and have an Apple HealthKit interface.
HealthSupervisor application does not make any changes to the data that is transferred to the user from the devices. That means that data is not distorted and fully corresponds to the information received from the devices.
Data collected by this app from external devices is for informational purposes only. You must not rely only on information provided in the app, it is recommended to always check your health state with a doctor.
We are not responsible for measurement accuracy, you should check your device documentation to define how to get the most accurate results.