Urgent - Altitude adjustment for travel??

guest27 · Post by **guest27** » Sat Feb 16, 2008 5:23 pm

Hello,

I am traveling to Denver (~5000ft) from the midwest (~600ft.) with my CPAP for a few days. Do I need to concern myself with having the machine recalibrated? How essential is it for that altitude difference?

There's no time to arrange a visit to the DME who sold the device - is this something I can do myself? It's a Resmed S6 lightweight.

Any help is greatly appreciated.

Thanks.

Vonon · Post by **Vonon** » Sat Feb 16, 2008 5:37 pm

Hi Guest,
I live in Colorado at 7,300 ft and have my altitude adjustment set at 3. I recently spent time at 1,000 ft and set the machine at 1. I think I noticed that it felt like less pressure at the lower altitude setting. I have an M series Respironics so I'm not sure how the settings compare to your machine. If you can fugure that out, I suggest you try to make the adjustment. My manual has suggested settings for various altitude ranges.

Good luck

billbolton · Post by **billbolton** » Sat Feb 16, 2008 7:28 pm

guest27 wrote:I am traveling to Denver (~5000ft) from the midwest (~600ft.) with my CPAP for a few days. Do I need to concern myself with having the machine recalibrated? How essential is it for that altitude difference?

Since that atltude change will reduce your effective flow rate settings by at least 4cm H20 if you don't do something about it, it is definitley essential!

guest27 wrote:It's a Resmed S6 lightweight.

If its a S6 Lightweight II it has automatic altitude adjustment. If its a S6 Lightweight you will need to do a manual adjustment setting which should be covered in the user manual (the S6 is before my time as a CPAP user so I can't tell you how to do it).

Cheers,

Bill

guest27 · Post by **guest27** » Sun Feb 17, 2008 12:29 pm

Thanks for the replies....

OK, so now I'm a little worried. 4cm is significant. I'm now thinking I need to get this adjusted somehow. I found the user manual and altitude isn't even mentioned.

Can anyone point me toward an online version of the appropriate manual, or walk me through the procedure? It's not the lightweight II, just the Resmed Sullivan S6 Lightweight. It's about 5 years old.

Does anyone have a copy of this manual?

As a side-note - it appears from the responces that this is perhaps considered an older machine. How long do folks typically keep their CPAP machines before replacement?

Wulfman · Post by **Wulfman** » Sun Feb 17, 2008 1:33 pm

You could try reading the following thread as it contains the instructions to get into the Setup for at least one of the models of the S6:

viewtopic.php?p=243714&sid=8ba84b5bc023 ... 8d0254a535

Yes, it's an older machine. The S8 machines are the current generation. The S7 machines were on the market when I started 3 years ago.....so they go back for some period beyond that.

Den

guest27 · Post by **guest27** » Sun Feb 17, 2008 2:09 pm

Thanks so much, I'll give it a try.

I'm not sure how I missed that...thanks for reposting it.

So, can anyone tell me - do i just increase my pressure by 4cm for the duration of my trip, or is there some other adjustment needed?

Thanks again.

guest27 · Post by **guest27** » Sun Feb 17, 2008 2:24 pm

OK, i got into the setup (thanks Wulfman) and the number displayed is essentially equal to my current prescribed pressure.

If someone knows whether there is any adjustment on this machine directly for altitude that would be great, otherwise I assume that I just increase my pressurefor the duration of the trip?

Thanks so much.

Wulfman · Post by **Wulfman** » Sun Feb 17, 2008 2:28 pm

I don't know about the S6 and I doubt that there are many here who may have that advice to offer, but many of the CPAPs had/have separate altitude settings that would make the compensation internally, so you would just change the "altitude" and it would take care of whatever pressure you'd need and wouldn't have to actually change the pressure itself. I would assume that it will become apparent once you get into the configuration. I would highly suggest that you try to use those instructions and familiarize yourself with them. You would also want to write down on paper the existing options and settings so you'll have them handy in the event you need to refer to them in the future.

Den

billbolton · Post by **billbolton** » Sun Feb 17, 2008 5:54 pm

guest27 wrote:So, can anyone tell me - do i just increase my pressure by 4cm for the duration of my trip, or is there some other adjustment needed?

As far as I'm aware, there should be a manual altitude adjustment setting on your S6.

If it is like the S7 and S8 flow generators, it will be in 600 metre bands, that is 0-600, 601-1200, 1201-1800, 1801-2400.

If that is the case, you just needs to pick the right band for your needs, which for ~5000' would be the 1200-1800 metre band.

Once you have made that altitude adjustment, you don't need to make any other adjustment on the indicated flow rate.

Cheers,

Bill

GumbyCT · Post by **GumbyCT** » Sun Feb 17, 2008 6:49 pm

Doesn't the M series have auto adj. for altitude? I don't see any adj. on mine.

Wulfman · Post by **Wulfman** » Sun Feb 17, 2008 7:15 pm

GumbyCT wrote:Doesn't the M series have auto adj. for altitude? I don't see any adj. on mine.

Yours does, however many of the low-end machines (still) do not and most of the OLDER machines did not have auto altitude adjustments. Most of the Auto-adjust machines are "good" to about 7500 ft. elevations.

Den

GeneS · Post by **GeneS** » Mon Feb 18, 2008 8:22 pm

I havent figured out why it is necessary to adjust any machine for altitude. It seems like if the machine measures pressure relative to atmospheric pressure and adjusts to the set pressure it would be correct at any altitude without touching it. I know that this assumption is wrong but I do not know why. I understand that and how pressure and density of air varies with altitude but why would that have anything to do with relative pressure. I assume that if your pressure setting is 17 at 600 feet it would actually measure something like 13 in Colorado. Is thiswhat happens? I assume I could keep my pressure gage with me and check it at any altitude and adjust the set pressure until the measured pressure was correct. I used an older cpap on top of high mountains in Europe a few years ago and do not remember having trouble but I am not sure now.

If anyone understands this I would like some help figuring it out.
GeneS

Wulfman · Post by **Wulfman** » Mon Feb 18, 2008 9:02 pm

GeneS wrote:I havent figured out why it is necessary to adjust any machine for altitude. It seems like if the machine measures pressure relative to atmospheric pressure and adjusts to the set pressure it would be correct at any altitude without touching it. I know that this assumption is wrong but I do not know why. I understand that and how pressure and density of air varies with altitude but why would that have anything to do with relative pressure. I assume that if your pressure setting is 17 at 600 feet it would actually measure something like 13 in Colorado. Is thiswhat happens? I assume I could keep my pressure gage with me and check it at any altitude and adjust the set pressure until the measured pressure was correct. I used an older cpap on top of high mountains in Europe a few years ago and do not remember having trouble but I am not sure now.

If anyone understands this I would like some help figuring it out.
GeneS

Gene,

I ran across this when I was searching the automatic and manual altitude adjustments of these machines. This one comes from the service manual of the REMstar Pro 2 and REMstar Auto:

Altitude Pressure Range 83 - 102 kPascals (Automatic Altitude Adjustment)

Since I'm not a "scientific type" person, I had to look up kPascals......and found that it's a metric term pertaining to barometric pressure. So, I presume that some of the higher-end machines have a device that determines the barometric pressure and makes the adjustment, whereas the lower end machines have to be manually adjusted.

Den

billbolton · Post by **billbolton** » Mon Feb 18, 2008 11:23 pm

GeneS wrote:I understand that and how pressure and density of air varies with altitude but why would that have anything to do with relative pressure.

You seem to be assuming a human body is somewhat like a ballon, and the pressure needed to keep an OSA obstructed airway splinted is somewhow highly dependent on the external air pressure.

This is not the case. The physiological factors which cause an airway to close during sleep in OSA are largely independent of the external air pressure.

This means that a specific air flow rate is needed to keep the airway open and that rate does not vary significantly with external air pressure..... that is, the flow rate is not relative to the external pressure, it is an absolute value. So if the external air pressure is lower than expected (due to altitude) the flow generator will need to work harder to deliver the desired flow rate.

A flow generator with an altitude sensor can automatically make the correction in terms of additional pressurisation needed to maintain the desired absolute flow for effective splinting. A flow generator without an altitude sensor will need a manual parameter change made to adjust for altitiude.

In either cae, once the flow generaor has been told (automatically or manually) what its working altitude is, it will maintain the correct absolute flow rate (as per normal settings and operational mode) for effective airway splinting.... so you don't need to carry a manometer (pressure gauge) around with you.

Cheers,

Bill

ColinP · Post by **ColinP** » Tue Feb 19, 2008 2:30 am

Thanks Bill

You've cleared the whole issue up for me - my instinctive thought was that you'd need less pressure at altitude because there is less pressure on the airways. The balloon analogy helped clear that.

There are two reasons I have an interest in the effects of altitude. I travel a bit and end up at all sorts of altitudes, but more importantly is that I was titrated at sea level, but live over 1000m up.

Am I correct in assuming that if I was titrated at 8 at sea level, and that I have auto adjustment for altitude, that I don't need to compensate?

Colin

Urgent - Altitude adjustment for travel??

Urgent - Altitude adjustment for travel??

Re: Urgent - Altitude adjustment for travel??

Anyone have the manual?

ResMed S6 Lightweight setup

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Re: ResMed S6 Lightweight setup

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Additional Comments: Airmini, Medistrom Pilot 24, CMS 60C Pulse Oximeter, ResScan 6