Here is a good explanation of PH in layman's terms.
http://www.chfpatients.com/ph.htm
In particular, look at the bottom of the page where it has acronyms and abbreviations.
And look at PH and MPAP. Those are the measurements for PH pressures. The MPAP or Mean Pulmonary Artery Pressure is actually a formula that is used to determine PH.
And also, if you want to take a look at the PHA website forum, here is the link.
http://www.phassociation.org/Message_Boards/main.asp?board=1
The site itself has good information.
http://www.phassociation.org/
Joe's MPAP was severe at 75
He took Tracleer (Bosentan) and Isosorbide which reduced it over time to the mild to moderate range, but he did have to stop taking it due to liver problems which Tracleer can cause.
Revatio (Sildenafil citrate), that Norma is on, seems to work well for many w/o the liver toxicity.
There are other drugs used and the PH specialist is the one to determine which one or combination is the right one.
It is a sad fact that most doctors know little about PH, and they don't treat it, because they don't know what to do for it.
Seeing a PH specialist is highly recommended!
They are the only ones who deal with it on a regular basis.
You should find out what all of Brian's pressure are.