11-15-2015, 12:50 PM
(This post was last modified: 11-15-2015, 12:52 PM by OMyMyOHellYes.)
ow much pressure does a CPAP put out?
Occasionally I see some threads from folks worried about a CPAP/APAP/BPAP/VPAP "blowing out their lungs". I was curious and farted around on the world wide internets for a while this morning. I found a converter tool and plugged in some various pressures in cm H20 and converted them to psi (pounds per square inch for the more metrically orientated):
06 cm H2O - 0.0853 psi
09 cm H2O - 0.1280 psi
12 cm H2O - 0.1707 psi
15 cm H2O - 0.2134 psi
18 cm H2O - 0.2560 psi
21 cm H2O - 0.2986 psi
24 cm H2O - 0.3414 psi
I also found a yootoob of a high school science class trying to determine the pressure at which a standard dime store latex balloon would inflate/explode. Their results showed that the balloon inflated at 810 mm Hg. It popped between 830-840 mm Hg - let's call it 835 mm Hg - more a measure of its upper stretchiness limit before the very thin latex would rupture.
810 mm Hg - 15.6628 psi
835 mm Hg - 16.1462 psi
So my lungs, when blowing up a balloon, would be subject to a pressure around 15 2/3 psi relative to the surrounding ambient atmospheric pressure.
So my APAP, at its maximum pressure setting of 15 cm H2O is pushing out roughly 1.36% of the pressure required to inflate a kid's balloon.
Note that most commercial jetliners have a pressure differential of around 7.5 - 8.5 psi to maintain around an 8,000 foot cabin pressure altitude cruising at say 35,000 feet MSL.
OMMOHY
06 cm H2O - 0.0853 psi
09 cm H2O - 0.1280 psi
12 cm H2O - 0.1707 psi
15 cm H2O - 0.2134 psi
18 cm H2O - 0.2560 psi
21 cm H2O - 0.2986 psi
24 cm H2O - 0.3414 psi
I also found a yootoob of a high school science class trying to determine the pressure at which a standard dime store latex balloon would inflate/explode. Their results showed that the balloon inflated at 810 mm Hg. It popped between 830-840 mm Hg - let's call it 835 mm Hg - more a measure of its upper stretchiness limit before the very thin latex would rupture.
810 mm Hg - 15.6628 psi
835 mm Hg - 16.1462 psi
So my lungs, when blowing up a balloon, would be subject to a pressure around 15 2/3 psi relative to the surrounding ambient atmospheric pressure.
So my APAP, at its maximum pressure setting of 15 cm H2O is pushing out roughly 1.36% of the pressure required to inflate a kid's balloon.
Note that most commercial jetliners have a pressure differential of around 7.5 - 8.5 psi to maintain around an 8,000 foot cabin pressure altitude cruising at say 35,000 feet MSL.
OMMOHY
