PO2 and aging????

[qaqueen]

I have read several articles, with opposing statements about PO2 and aging.

My understanding is that PO2 decreases with age. I have seen different formulas for calculating the PO2 reduction, that basically end up with the same value.

The simplest formula l have seen is:

Normal PaO2 (at sea level)= 100 mm Hg - the number if years over age 40.

So, my question is, if you have an 98 year old DNI patient with a pulse oximeter readings > 92% on 2 liters via nasal cannula and a PO2 of 54, would you increase the O2 flow? Would it increase the PO2?

According to the above formula, PO2 of 42 would be okay.

Thanks for your help.

[offlabel]

It isn't a linear progression. It is a function of a lot of factors, not the least of which is lung volume decreases with age, so, no, a PaO2 of 42 would not be OK. If this is for a test, I have no idea what the answer would be, but in actual practice, in this situation, I'd titrate for greater than whatever saturation you chose and ignore the PO2.

[qaqueen]

Not for a test í ½í¸€. The pt had atelectasis and infiltrates. At 2 liters, saturation was 93-98%. Colleague thought patient should be on high flow to improve PO2. I was concerned with overdoing the O2.

[qaqueen]

í ½í¸€ that was a smiley face on my phone

[offlabel]

Just check the PO2 on the x with the SaO2 on the y. At the end of the day, that'll be what you need, funky patient presentations aside...