Most of the time we don’t numb patients to be honest. I’ve had it done to me, we practiced on each other in Med school. It is painful, but I suspect the Novocai

Most of the time we don’t numb patients to be honest. I’ve had it done to me, we practiced on each other in Med school. It is painful, but I suspect the Novocain you got didn’t work because it’s the artery that’s painful not the skin. But it does give you different information than a pulse ox. For example, people can have respiratory failure from too low oxygen (captured on a pulse ox), but also from top high CO2 (not measured on pulse ox). It also gives a measure of acid-base status, which can be thrown off for a variety of reasons (usually renal or respiratory). It is used somewhat too much in my opinion but can be life saving in some situations.