Changing settings for High Altitude?

[Tberrytpt]

Hi,

I am vacationing in a high altitude and getting AHI of 5 and 6. ( Normally under 2)
Is there a setting I should change while here (at 6500 ft) I normally am at sea level....
I also tried to read how to send a snapshot of the Sleepyhead data but the pictures on how to set up screen were not available.

Thanks!

T
Resmed S9 w/humidifier
Opus nasal

[Pugsy]

ResMed S9 machines will automatically make altitude adjustments up to 8500 ft.

[LSAT]

Hi,

I am vacationing in a high altitude and getting AHI of 5 and 6. ( Normally under 2)
Is there a setting I should change while here (at 6500 ft) I normally am at sea level....
I also tried to read how to send a snapshot of the Sleepyhead data but the pictures on how to set up screen were not available.

Thanks!

T
Resmed S9 w/humidifier
Opus nasal

If your S9 is an autoset, just make sure the max pressure is set high enough and the machine should adjust as necessary

[Tberrytpt]

This may be a stupid question, but how do I tell if it's high or low enough?

T

Resmed S9 w/humidifier
Opus nasal

[ajack]

high alt can also bring on some CA and more pressure won't fix that, you need to look at your sd card and see what the AHI are. oa/h/ca

[D.H.]

Apparently, your machine does adjust automatically for the altitude, at least as high as you report being.

Note that some older machines have manual altitude adjustment or none at all. However, assuming that your machine is functioning properly, that's not your issue.

[CapnLoki]

This has piqued my curiosity - not that I often travel to high altitude. While modern cpaps can correct for the pressure, do they actually make up completely for the deficit of oxygen? People who live at altitude develop increased lung capacity; does the cpap do this? I'm guessing that the pressure adjustment only partially compensates.

[Pugsy]

While modern cpaps can correct for the pressure, do they actually make up completely for the deficit of oxygen?

I don't see how they could because the machines don't have a clue what the oxygen levels are because there's nothing in them to measure oxygen either on the patient or in the air.

I did find this with a quick search.
http://www.sleep-apnea-guide.com/cpap-t ... itude.html
and there were other hits as well.

The machine compensates by changing how it works to maintain the desired pressure settings. It won't change the pressure and someone using apap mode will likely see the same results in terms of where the pressure goes. It just changes how it ends up delivering that pressure is how I understand it.

[CapnLoki]

While modern cpaps can correct for the pressure, do they actually make up completely for the deficit of oxygen?

I don't see how they could because the machines don't have a clue what the oxygen levels are because there's nothing in them to measure oxygen either on the patient or in the air.

I did find this with a quick search.
http://www.sleep-apnea-guide.com/cpap-t ... itude.html
and there were other hits as well.

The machine compensates by changing how it works to maintain the desired pressure settings. It won't change the pressure and someone using apap mode will likely see the same results in terms of where the pressure goes. It just changes how it ends up delivering that pressure is how I understand it.

The link seems to say that the pressure compensation is to provide equivalent "opening pressure" to prevent apnea, which makes sense. We can only guess whether this also provides enough oxygen to fully replicate the sea level experience (I doubt it).

It does make the rather laughable mistake that the pressure difference is because of reduced gravity at altitude. By my napkin calculation its only reduced 0.06% at 6500 feet. The pressure is caused by the weight of the air above, which obviously goes down with altitude because there's less of it.

[Pugsy]

The link seems to say that the pressure compensation is to provide equivalent "opening pressure" to prevent apnea, which makes sense. We can only guess whether this also provides enough oxygen to fully replicate the sea level experience (I doubt it).

I doubt it also. Cpap primary job is hold the airway open and adequate oxygenation is a secondary byproduct due to the open airway and not because the machine is working harder or whatever. At thinner air the oxygen is less and it's going to be even harder to maintain adequate oxygenation for some people.
Plus there is the little added tidbit that higher altitudes and cpap can cause the unstable breathing patter where centrals pop up in rather large numbers for some people and that opens a whole other can of worms. The machine can compensate for the altitude in terms of mechanically but it still doesn't prevent the unstable breathing.
The machine can only do so much.

I do know that I once took my machine to the mountains in Utah for the weekend. Actually never even gave the altitude much thought until after the fact and I slept at a little below 12,000 ft I think it was. Well above Respironics stated "up to so and so elevation" & I know it got down to freezing and it was mid July. I really didn't notice anything different in terms of pressures used shown on the report or the events that popped up and I certainly didn't have any more than a random central.
I think we just have to trust the machine to do its job and try not to over think things because there's not a lot we can do about it anyway.
I know that I certainly wouldn't go changing my pressures upwards just because I was going to a higher altitude. The last thing I would do if I was on a little vacation or trip to the mountains would be changing my pressures upwards willy nilly and risking having those changes mess up my sleep and thus mess up my vacation.

[zoocrewphoto]

I do know that I once took my machine to the mountains in Utah for the weekend. Actually never even gave the altitude much thought until after the fact and I slept at a little below 12,000 ft I think it was. Well above Respironics stated "up to so and so elevation" & I know it got down to freezing and it was mid July. I really didn't notice anything different in terms of pressures used shown on the report or the events that popped up and I certainly didn't have any more than a random central.
I think we just have to trust the machine to do its job and try not to over think things because there's not a lot we can do about it anyway.
I know that I certainly wouldn't go changing my pressures upwards just because I was going to a higher altitude. The last thing I would do if I was on a little vacation or trip to the mountains would be changing my pressures upwards willy nilly and risking having those changes mess up my sleep and thus mess up my vacation.

I have done a few trips at elevation, and never changed anything. My machine is set 11-17 and usually only does short spikes to 15 or 17. I wasn't aware of any differences while traveling. I slept fine. My numbers were good. I may have been a bit more tired, but I also did a lot of hiking on some of those trips.

[D.H.]

This has piqued my curiosity - not that I often travel to high altitude. While modern cpaps can correct for the pressure, do they actually make up completely for the deficit of oxygen? People who live at altitude develop increased lung capacity; does the cpap do this? I'm guessing that the pressure adjustment only partially compensates.

CPAP is based on the premise that there's enough oxygen in the air, it's just that the patient isn't able to inhale and exhale it properly during sleep. If a patient has an additional respiratory deficiency, supplemental oxygen might be prescribed; either at night or perhaps around the clock. I guess for some, there might be a need for supplemental oxygen at higher altitudes; either at night or all the time there.

BTW, let's just say that your CPAP would compensate at night. What would happen during the daytime?

Also, please note that I traveled to Quito, Ecuador (elev 9,350 ft.), Putre, Chile (elev 11,647 ft.), and Shangri-La, China (elev 11,089 ft; yes, that's really a place), and did not have any serious issues. The one problem I had in all those places was that the heated humidifier on the Everest 3 CPAP that I had at that time did not heat up at those altitudes (although the pre-heat worked). I have yet to travel to such altitudes with my current machine, but I expect this won't happen.

[chunkyfrog]

Some people with pre-existing respiratory problems (other than OSA) should speak to their doctor before going to a very high altitude.
In some cases, a pulse-ox monitor may be recommended. If you run into trouble, THEN you should go to a local ER.
Taking oxygen along might be advisable, but less likely to be done.

[zoocrewphoto]

I would also add that the first time my sister and I traveled to a high altitude location, she was the one who got a headache and felt sick. I have allergies, asthma, and that year, untreated sleep apnea. I had some ear popping, but no other issues.

I got my cpap two years later, and the only time I need to change pressure settings is when I have a bad cough. I raise my minimum so that I can have a coughing fit without the need to rip off my mask (same feeling that most people have at a pressure of 4).

[ChicagoGranny]

By my napkin calculation its only reduced 0.06% at 6500 feet.

It's reduced by around 20%. You can check your calculations here - https://www.mide.com/pages/air-pressure ... calculator

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It does make the rather laughable mistake that the pressure difference is because of reduced gravity at altitude.

Actually, that is part of the reason for lower pressure at higher altitude:

1. The gravitational attraction(*) between the earth and air molecules is greater for those molecules nearer to earth than those further away - they have more weight - dragging them closer together and increasing the pressure (force per unit area) between them.

2. Molecules further away from the earth have less weight (because gravitational attraction is less) but they are also 'standing' on the molecules below them, causing compression. Those lower down have to support more molecules above them and are further compressed (pressurised) in the process.

http://www.npl.co.uk/reference/faqs/why ... -pressure)