(07-14-2017, 05:24 PM)fwg1947 Wrote: I continued therapy with my old machine at 9.0 cmH2O until I obtained a new machine and supplies on 5/31/17.  From that night through last night I have been on fixed CPAP pressure of 7 cmH2O for a total of 44 nights, with not so good results. AHI for the whole period is 9.93, with the lowest daily AHI being 1.75 and the highest being 56.15.  My machine shows mask fit of 99% to 100% throughout this period, which I understand to mean that large leaks are not an issue.  The highest AHI numbers occurred during a consecutive 5 day period while in Colorado and New Mexico (altitude 7,000 to 7,700 ft.):  17.39, 16.80, 22.49, 56.15, 41.96.  My home altitude is 700 ft.  My CPAP machine manual states that it adjusts automatically for altitude up to 7,500 ft.

Questions
(1)  Does my prescription of CPAP fixed pressure 7.0 make sense considering that per the 2 sleep studies, my apnea has progressed from mild to moderate, and considering that I had an acceptable (i.e., <5.0) long-term AHI of 1.9 at a pressure of 9.0 for the 7 plus years leading up to the new sleep study?

Quote:(2)  I will be returning to high altitude at least twice a year to visit family.  What can I do to prevent the extremely high AHI numbers that occurred on my recent trip?

(07-14-2017, 07:20 PM)bonjour Wrote: IMHO you need to titrate the best response at altitude then subsequently change the settings when you go to altitude and change them back when you return.
What length of time will you be at altitude each visit/per year?

Altitude will impact your AHI, and frequently we see an increase, as Robysue indicates, in CA events.

(07-14-2017, 07:12 PM)robysue Wrote:

(07-14-2017, 05:24 PM)fwg1947 Wrote: I continued therapy with my old machine at 9.0 cmH2O until I obtained a new machine and supplies on 5/31/17.  From that night through last night I have been on fixed CPAP pressure of 7 cmH2O for a total of 44 nights, with not so good results. AHI for the whole period is 9.93, with the lowest daily AHI being 1.75 and the highest being 56.15.  My machine shows mask fit of 99% to 100% throughout this period, which I understand to mean that large leaks are not an issue.  The highest AHI numbers occurred during a consecutive 5 day period while in Colorado and New Mexico (altitude 7,000 to 7,700 ft.):  17.39, 16.80, 22.49, 56.15, 41.96.  My home altitude is 700 ft.  My CPAP machine manual states that it adjusts automatically for altitude up to 7,500 ft.

Questions
(1)  Does my prescription of CPAP fixed pressure 7.0 make sense considering that per the 2 sleep studies, my apnea has progressed from mild to moderate, and considering that I had an acceptable (i.e., <5.0) long-term AHI of 1.9 at a pressure of 9.0 for the 7 plus years leading up to the new sleep study?

Sounds to me like the titration part of the split study didn't allow you enough time to get into a nice long REM cycle. Or you didn't sleep as much on your back. Or whatever.  And the result is that you were left under titrated.

If this were my data, I'd just quietly get the clinical manual for the new machine and change the settings to CPAP @9cm and see if the numbers go back to what they were on the old machine.

Quote:(2)  I will be returning to high altitude at least twice a year to visit family.  What can I do to prevent the extremely high AHI numbers that occurred on my recent trip?

Not sure about this.  But I'll take a stab.

First, I'd make sure that the CPAP was set to 9cm rather than 7cm. Next, I'd evaluate the data after each night at high altitude.  If the AHI goes up substantially AND the increase is due to OAs and Hs, then I'd increase the pressure 1 or 2 cm and see if that helps.  If the AHI goes up substantially but the reason is that all of a sudden you have a whole bunch of CAs, I'm not sure there's much you can do. In that case, I'd report the problem to my sleep doc when I got back and see if s/he has any ideas on what to do on future visits.



I changed the pressure setting to 9.0 as you suggested.  Tonight will be the first data at the higher pressure.  Thanks for all the advice.

(07-14-2017, 08:42 PM)fwg1947 Wrote:

(07-14-2017, 07:20 PM)bonjour Wrote: IMHO you need to titrate the best response at altitude then subsequently change the settings when you go to altitude and change them back when you return.
What length of time will you be at altitude each visit/per year?

Altitude will impact your AHI, and frequently we see an increase, as Robysue indicates, in CA events.

My trips to Colorado and New Mexico will be no longer than a week to 10 days per visit.  Not very long to adjust to the altitude.  My AHI was 1.75 for the night I got home from the last trip, compared to AHI of 41.96 for the last night at high altitude, with no change in machine settings.

(07-14-2017, 09:08 PM)Sleeprider Wrote: [quote pid='214281' dateline='1500082936']
Are your events predominately central (CA), or obstructive (OA).  Hypopnea could go either way, but your recent sleep study results suggest you may have developed a more complex apnea problem with centrals rather than simple obstructive apnea.  The appropriate recommendation differs depending on the type of event.  Since you spent considerable time at higher altitude, it CA events are more likely, and hopefully they are lower when you are at your normal altitude.

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