A couple of questions. I have been using my ResMed S9 VPAP in S setting with an AirFit P10 nasal pillow for about a month, with no machine prior to that. My AHI has consistently been under 5.0. But SleepyHead and the machine are also telling me I'm experiencing large leaks, often well over 24%. This also occurs with a Swift fx and a ZestQ. So I have an appointment with a respiratory tech to check it out. The SleepyHead leak graph shapes suggest I may be unknowingly mouth breathing and that a chin strap may be a fix. That's the prelude - I see the tech next week. But here are two new problems which have just emerged.
This past weekend our family went up to Wintergreen Resort up along the Blue Ridge. The altitude change wasn't enormous - we were sleeping in a home somewhere between 3500 and 4000 feet ASL. But Friday night and Saturday night both yielded AHI's of about 32! This after routinely seeing AHI's under 5. As with other readings, the large leak number was significant. I've read that elevation can trigger central apneas - but at 3500 feet??
Question 2. I'm back home now - around 500 feet ASL. I used the machine last night, but my AHI had not returned to NL - I ended up with an AHI of 17, in the moderate range. This is on a 5.5 hour recording, with the usual leaks issue. But here's what was strange. I also used my CMS 50H recording pulse oximeter in parallel with the Bilevel. The CMS has been very reliable and accurate. The SpO2 reading was as good as I've seen for me during sleep. Basal SpO2 was 95.2, Average low was 92.2 and minimum SpO2 was 91 - and it didn't drop to that level often. The adjusted SpO2 index per hour was 4.8. The graph, with a few dips, is relatively flat! Before starting the BiPAP a month ago, the pulse oximeter showed excursions below 88%, including some drops to 84% - and a lot of variation in pulse and SpO2. So if it weren't for the AHI of17, I'd be really delighted with the pulse ox data. What's going on here? Thanks for any help and input.
I recently got a copy of the clinician's manual for my CPAP machine. It mentions an altitude setting. I have a Phillips Respironics machine. The altitude setting is supposed to be set to 1 for elevations under 2500 ft., 2 for elevations 2500-5000 ft., and 3 for elevations of 5001-7500 ft.
I don't know if your ResMed machine has a similar setting, or how much the altitude would affect the pressure supplied by the machine.
What was the make-up of your AHI at higher elevation? What was the make-up when you got 17 back closer to sea level? What I am asking is how much of your AHI was OAs, CAs, and Hypopneas?
I go from my normal home at less than 100' above sea level to a residence that is almost 6,000 feet above sea level. I make no adjustments. Sometimes my AHI goes up, and sometimes down, and sometimes about the same. I personally feel that for me, any changes are due to external factors other than elevation. That is probably just me.
I think that I am using the same machine as you.