Looks like rbury found an old thread via search, and the topic is getting a second life. Good idea.
After a dx of OSA with AHI 55, I started CPAP ... but am fighting cumulative nasal congestion, even without a cold. To the point of not being able to use CPAP beyond 2-3 hours per night. My post is intended as a logical thinker's comments, not expert advice.
- I agree with Rycharde that one should NOT force CPAP to blow against a plugged nasal passage; my doctor said if you wake up and can't fall asleep for 1/2 hour, give up trying. I read about the mucus and tissue in the nose forming a very delicate filtering system, which also processes the external air's velocity, humidity, and temperature before letting it into the lungs
- one needs to look at the entire flow system: what the room air contains, the HEPA filter at the flow generator inlet, whatever the CPAP machine does to this air before it gets into the mask (temperature, humidity, possibly irritating plastic smells, velocity and turbulence) ... like trying to drive my fuel-injected and carefully tuned car engine through a dust storm in Death Valley
- the pressure and flow velocity are measured by a sensor at the mask entrance; which is not the same thing as the pressure and flow velocity in the nasal passage; it depends on mask type, leakage, etc.
- like Rycharde, I have experienced a doubling in AHI (10 to 20) when going from nasal pillows to full face mask ... for the same constant CPAP pressure setting of 9 cmH2O, for breathing only through my nose, sleeping on my back, etc... repeatable several nights in a row. The differences: the smaller nasal orifice through pillows, the more turbulent flow irritating the nasal tissue, the different sleep quality. If the CPAP objective is to keep the "pipe" open, and once the nasal passage is no longer a problem, then I still suspect that a full face mask would require a different pressure setting for the same AHI count
- who said that the total A+H events should be assumed to be evenly space through the night, so that a nightly AHI is a good measure? on the ResScan graphs I see event bunching up as I go to sleep, then as the nasal congestion builds up, peaking to wake me up
In my case nasal sprays, saline washes, warm and humid airflow, HEPA filters haven't helped yet. I've raised the mattress head 8 inches ... no effect; may have to try Janknitz' trick of sleeping in an easy chair... doesn't work for me on an airplane flight. When CPAP sleep shuts the nose, I remove it and have to get up for a while; feels like my sinuses drain and the nasal passage opens up more, then I have no trouble falling asleep without CPAP. So I have to assume that the CPAP's airflow does it to me: content, speed. I could lower the pressure, but it wouldn't help me to raise it.
I am currently trying out various masks, concerned that pressure on the sinuses or on the nose may be a cause for flow restriction.
This has been going on for a month now ... doesn't look like forcing or habituation are the solution.
Moderate / Severe OSA (2 tests offCPAP).
CPAP ResMed S9 AutoSet EPR, Hi5 Humidifier.
ResMed Masks tried: nasal pillows Swift FX, nasal mask Mirage Activa LT, FF mask Mirage Quattro or FX.
Home CPAP data analysis: ResScan 3.16 sw, oximeter, pulsemeter