depends. At 14000 feet 80% is fine... The real issue is there are 2 components to respiration. — Oxygenation and ventilation. You can die from respiratory failure with a perfectly normal O2 saturation if you are not getting rid of CO2. A pulse oximetry does not measure CO2. there are conditions such as emphysema where we want the pulse ox lower than normal to prevent the build up of CO2. it it takes a blood measurement and experienced physician to determine if you are at risk. For those that retain CO2 too much oxygen is deadly
I’ve never used a pulse ox. The only experiences I have heard about with these things has been anecdotal. Bad anecdotes.
By the way, everyone seems to know that you don’t want to put someone who has “become O2 dependent” for Respiratory drive on a high FIO2. Can you remember ever encountering anybody who was actually dependent on O2 for Respiratory drive? Anybody who actually quit breathing because they wee put on Supplemental Oxygen? Is this one of those things “everybody knows” that may not be true?