ozij wrote:In humans, exhalation is the result of muscular relaxation, and not of muscular effort. Therefore, it's the difference between inhale pressure and exhale pressure that makes exhalation easier.
Right. The "relative difference" in two pressures (higher for breathing in, lower for breathing out) feels more comfortable and natural to me.
Right. I want a pressure that absolutely keeps my airway OPEN during exhalation....so, when I'm ready to breathe in again, my airway is open enough to allow me to get a new breath started.ozij wrote:And that's why as far as exhale relief is concerned, it does make sense to increase your pressure by your EPR.
If the CPAP titration pressure from the sleep study is the pressure a person really NEEDS to keep the airway open during breathing out, and especially during the pause before breathing in starts again, dropping that prescribed pressure with EPR may let the airway collapse shut when it's time to breathe in again. If the airway collapses at the end of exhalation, the person cannot even begin to draw in a new breath in a timely manner. EPR will suspend (stop holding the pressure down) if a person doesn't start to breathe in again after so many seconds. But I don't really want any delay if I'm trying to inhale again.
So... when using EPR, I set the pressure higher by the same number of cms as my EPR setting. I do that simply to insure that my airway will be held open nicely to allow inhaling again when I'm ready to breathe in, while still getting the comfortable feeling of a relative difference in pressures for breathing in and out.
If I'd been prescribed "CPAP @ 10 cm H2O" and I intended to use EPR for pressure relief when breathing out, I'd raise my CPAP pressure accordingly, like this:
EPR off or during ramp only: I'd leave the CPAP pressure set at 10.
EPR full time "1" (for a 1 cm drop when exhaling): I'd set the CPAP pressure at 11 (so I'm still getting "10" while breathing out.)
EPR full time "2" (for a 2 cm drop when exhaling): I'd set the CPAP pressure at 12 (so I'm still getting "10" while breathing out.)
EPR full time "3" (for a 3 cm drop when exhaling): I'd set the CPAP pressure at 13. (so I'm still getting "10" while breathing out.)
Higher-than-needed-pressure being delivered for inhaling is probably not a problem for most people on CPAP. But "same" pressure (even a fairly low steady pressure) can be unnatural feeling or difficult for some people to exhale against.
I'm not a doctor or anything in the health care field. That's just the way I always raise my CPAP pressure when I use EPR...and why I do that. Works well for me.