What's the Difference Between a Mean and a Wood Unit?

i usually go by the mean pulmonary artery pressure, but what's this p vr, wood unit stuff? The way i think about it is when you're talking about blod ure, just systemic blood pressure. Instead of a map of like 60, which is what your organs need to profuse, you are going to talk about a min pe of like 20. So we use three awod units, just as as a number, and a cotof idoota helps.