What does your pulse ox read when you stop breathing? when doctor said my dad was gone the pulse ox showed a ox of 40 and heart rate of 0

Pulse ox: The pulse ox reads the percentage of oxygen in the blood. A normal healthy person should have a pulse ox reading in the high 90's, like 98 or 99. It also provides a heart rate which can range from 60-100 normally but can go a bit lower or a bit higher. A pulse ox reading in the 80s is usually worrisome. So a pulse ox of 40 and a pulse of 0 could be found in someone who just past away.