Jeff, here is some data for future calculations. I have one of those VED pumps with a pressure gauge attached. I got it online from an adult shop, so I'm skeptical if the instructions are medically accurate.
The gauge measures in inches of mercury from -1 to -30. I assume anything even close to -14.7 is unatainable, since that's atmospheric pressure at sea level, meaning a perfect vaccum, right? The instructions that came with it say to pump to -10 but never exceed -12. No problem! It starts feeling very uncomfortable at around -5.
I looked at the instructions for pumps at medical sites and they say that 3-5 is about
right. I find that even at -2 the blood starts flowing into the penis, and if I just have patience, within 5 minutes or so it's about
as full as it's going to get, about
the same as pre-surgery, so I keep it between -2 and -3, with an occasional pump to -5 just to see what happens. The pump has a quick release valve, and when I
open it the penis goes flaccid very quickly, in about
five seconds. Not as flaccid as before I pumped it, but I can tell that the bulk of the blood has leaked out. That's pretty darned fast, so that might tell you how much of a leakage there is in the veins.
What I don't understand is why it takes 5 minutes for the penis to become fully erect and about
5 seconds for it to drain back. Maybe it's just me, and when you start pumping you might get different results. In either case this is not good enough for intercourse, not even with those bands that come with it (when one of those snap while putting it on, ouch!). So I just use the VED to exercise blood flow in and out, you know, use or lose it.
Anyway, hope this data helps for your next science fair project
Age 64 yrs
8 out of 12 cores positive
Gleason Score 3+4=7
Da Vinci Surgery 08/07/2009
Upgrade Gleanson Score 4+3=7
Neg Margins and Nodes
Extracapsular extension noted but neg Extraprostatic Extention
First PSA 11/3/09 <0.1