ARDS criteria formula

cardiacRN2006, ADN, RN · Jul 31, 2008

https://allnurses.com/forums/showthread.php?t=302075&referrerid=62980

Here is a short thread on it. In addition, simply typing PaO2/FiO2 into google shows 13,000 results.

MBCRNA · Jul 31, 2008

First, paO2 is not a % it is mmhg. So this is what is messing u up.

60/1.0= 60 (way below 200)

Another good tidbit of info:

Expected PaO2 based on Fio2

(Fio2 % x 6) -PaCO2

So, if you would like to know what this patient's PaO2 is SUPPOSED to be....

Hope this helps!

joeyzstj, LPN · Aug 1, 2008

hi everyone,
does anyone know how the ards formula works in real life?
[color=#9999ff]pao2/fio2

so, if a patient has a pao2 of 60%, or 0.6, and is on fio2 of 100%, or 1.0:

0.6 / 1.0 = 0.6

the formula says less than 200 mmhg, is there a conversion you have to do to make it make sense?

thanks in advance for any replies

loveicu gave a very good explanation. basically, the p/f ratio is an oxygenation index. we dont really use it that often honestly, at least for the places i have been. there are books full of indexes and equations you can figure that most respiratory therapist have to learn. pick up a good old egans respirtory care book and they are full of them. in reality, you can simply tell by looking at gases and the oxygen requiremts that a p/f ratio is low. ards can get very, very complicated to treat and there are some newer modes of ventilation geared specifically toward ards and similar types of lung injuries.