Question for APAP users

Dale92 · Post by **Dale92** » Sat Jun 24, 2006 9:38 am

I am still holding on to the APAP unit my doctor OK'd me to use for a two week trial since I am waiting to hear from him. I figure no sense in returning it to my DME and going back to my regular CPAP unit if the doctor is going to tell my insurance it is medically necessary for me to switch to the APAP.

Anyway to my question: What is the purpose of reducing the operating range of the APAPs from wide open 4 - 20 cm/w to a narrower range of say 9 - 14 cm/w?

I can understand going up from the lower level to something that is easier to start breathing at say a setting of 8 cm/w because I have a hard time breathing at a very low pressure. I have to take a lot of rapid breaths for about a half a minute before putting my mask on to get enough oxygen in my lungs so that if the setting is low like a 4 I do not struggle for 5 to 10 minutes trying to pull air in faster to satisfy my lungs. After I relax then either the unit moves the pressure up a bit because I suck air in so fast or I am adjusting to the low setting I am not sure which it is. But the reason I ask why some of you report fine tuning your APAP settings is I thought the whole idea of an APAP was to let the machine decide what you need for pressure. I was just wondering why the need to manually adjust the pressure range when the APAP should be doing that by itself?

I am hoping my doctor does OK my need for an APAP. If he does OK this it will save me some money because I will most likely order one from CPAP.com if my insurance will not cover it. I have been feeling a lot better since I have been on this trial now about 2 1/2 weeks. My AHI has been around 3 for the last couple of days and has been consistently under 5 for the test period compared to between 6.5 - 10 AHI before using the APAP. Even though I am still taking my Provigil to wake me up during the day prior to the apap it made little difference. Now I am more awake and eager to get things accomplished. Big improvement in my opinion.

Dale

Linda3032 · Post by **Linda3032** » Sat Jun 24, 2006 9:55 am

Hi Dale, glad you are doing better with the Apap.

You got the low pressure figured out. If you aren't already, after you get your mask on, you might manually turn your machine on. The automatic on doesn't kick in until you have taken several breaths - which is a struggle sometimes. By manually turning the machine on as soon as you get your mask on, then you get air right away.

High pressure. If you have a bad leak, the pressure can keep bumping itself up to a high pressure you don't need. Plus, it screws up your data and can make you have apneas or centrals (I think on the centrals).

I recently narrowed my range down even more because I found I feel better with a high of 8 rather than a high of 10.

Hope that answered your question. Good luck in getting your Auto.

Goofproof · Post by **Goofproof** » Sat Jun 24, 2006 10:05 am

By changing the pressures to 2 cm below and 2 cm above your sleep lab pressure, the machine can respond to your needs faster and will not be prone to runaway pressure increases. After a 4 day test you can see your 90% pressure levels and readjust 2CM up and down from that. I would die at 4 cm, the Dr should be forced to use one set to 4 cm for a night.

Your numbers are good, but by narrowing the setting to the correct range they can get even better

Take it, that I don't have APAP, but mines, in the mail, as soon as I get it, I will reset it to 12 cm to 16 cm, because I already know at 16 cm my AHI starts up higher again due to centrals. Jim

Dale92 · Post by **Dale92** » Sat Jun 24, 2006 10:26 am

Thanks Jim and Linda
I just read the another thread recently started today and I did not know that there was a problem with run away pressures on some APAPs. It makes sense then to set a range if that is the case. I just figured the machine would stay in the proper range - interesting.

Linda, if I understand what you are telling me I think you misunderstood what I was saying about hyper-ventilating. I was taking rapid breaths prior to putting my mask on and then manually turning it on. I needed the extra oxygen in my lungs because when the machine started up I could not get enough air into my lungs at the 4 cm/w setting which my doctor insisted I put it at. I had started out at a range of 10 - 18 because that was what my first and last sleep study settings were set at. The first study set it at 18 and the second with my new oral appliance set it at 10. So I figured 10 -18 was a good way to go but no the doctor said put it back to 4 -20 and like a good little soldier I did. It just seems so difficult to breath when it is at 4. Now that I have printed off my daily data reports for the last 2 weeks I have sent them off to my doctor I have moved my pressure to a much more wonderful setting of 8 - 20, so much easier to breathe. If it gets too low I feel suffocated.

Jim, I understand about moving my lower pressure up I think because then the machine doesn't have to move through lower pressures to determine where I need to be which might take time. What I don't understand is why would we want to move the higher range down? You mentioned the run away pressures - does that happen while sleeping or just while people are awake, as another member mentioned in another thread happened while he was awake. Would the machine not normally lower the pressure after awhile if it does not need to be in the higher range? I admit I don't understand anything about the logarithms or really anything the machines do to determine pressure needs.

Dale

Linda3032 · Post by **Linda3032** » Sat Jun 24, 2006 11:03 am

Dale, here is a link to some postings as to why some of us lower our maximum pressure. It should help explain why "wide open" isn't good.

viewtopic.php?t=10245&highlight=puffy

Dale92 · Post by **Dale92** » Sat Jun 24, 2006 12:10 pm

Thanks Linda

Dale

Guest · Post by **Guest** » Sat Jun 24, 2006 12:35 pm

With a lower pressure at 7 my obstructive apneas were averaging 1-3 per night. My hypopneas, however. were quite high, 12-15. By raising the lower pressure to 8 I was able to lower the hypopneas to 4-8 per night and keeping the obstructives low. I have the upper pressure set at 15 and occasionally need it. I have experimented for 3 weeks at 8 and now am going to raise it to 9 and see if I experiene more changes. Waking up feeling rested and being able to function daily is much more of what I base my success at.

Bonnie · Post by **Bonnie** » Sat Jun 24, 2006 12:37 pm

opps, above post was me....power outage last night, login cleared out and I forgot to sign back in.

Dale92 · Post by **Dale92** » Sat Jun 24, 2006 1:22 pm

Hi Bonnie
I see you are using the same CPAP machine as I was before I started this trial with the APAP. I tried adjusting my pressure on straight CPAP from my prescribed level of 10 up a little at a time each setting for about a week and my numbers never improved. I think I went from 10 to maybe it was 14 over 4 weeks. Nothing improved. I have noticed with the APAP that the first few days of my trial it went from the 90% mark of 13 for the night to 20 for the next night. Then a few days into it the 90% mark stayed between 9 and 16 usually.

I had my oral appliance adjusted forward a little during this trial and I think it helped a bit but it is unscientific after all it could just be coincidence. However when I was using CPAP I did notice that the pressure setting did affect my snore rate quite a bit.

Dale

Goofproof · Post by **Goofproof** » Sat Jun 24, 2006 1:31 pm

[quote="Dale92"]Hi Bonnie
I see you are using the same CPAP machine as I was before I started this trial with the APAP. I tried adjusting my pressure on straight CPAP from my prescribed level of 10 up a little at a time each setting for about a week and my numbers never improved. I think I went from 10 to maybe it was 14 over 4 weeks. Nothing improved.
Dale

Snoredog · Post by **Snoredog** » Sat Jun 24, 2006 2:36 pm

Low Pressure setting: The low pressure setting should be as high as you can tolerate yet not high enough to hinder you from falling asleep. The reason you would increase the bottom pressure from a previous set value is to pre-treat or eliminate any flow limitations or hypoapneas. This usually results in a lower HI score. If you study your reports and you are having higher HI scores then increasing the bottom pressure may help. If you are looking at a AHI score (sum of both AI + HI), then you need to determine from that score what the HI score is alone. You also have to look at the frequency of these events occur. If they are runs close together you may want to increase the bottom pressure to reduce the frequency or eliminate them altogether.

High Pressure setting: If you lower the default 20cm ceiling on the high pressure side you can reduce the chance of the machine from triggering pressure induced central apneas. With some apaps this is not a problem (like with the Remstars) but with other machines it can be a real problem. I'm always Leary of a mechanical device that continues with pressure increases as long as the event is seen. The Remstars have a limiting factor built into their algorithm where if the event is not reduced or eliminated after a period of time the pressure is reduced back down.

Together these pressure(s) become your apap's range. Your 90-95% pressure should land within the established range. Normally, you want to allow 2cm pressure above any 90-95% pressure found to allow the apap to increase if needed and yet prevent flat-lining but within a limit that you control.

Modern apaps can increase the pressure very rapidly in response to events seen. But they reduce that same pressure very slowly over a 10-30 minute period. You can similarly test this yourself by creating a large mask leak, you'll hear the machine rev up very fast to compensate for the leak then rev down much slower when the leak is suddenly stopped. They do this because sudden changes in pressure can interrupt your sleep or even awaken you, you can see this more clearly on the reports if you have them.

Bonnie · Post by **Bonnie** » Sat Jun 24, 2006 4:06 pm

Dale, I have an auto, I never realized my profile said cpap....I changed it!
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GoofyUT · Post by **GoofyUT** » Sat Jun 24, 2006 4:59 pm

[quote="Snoredog"]Low Pressure setting: The low pressure setting should be as high as you can tolerate yet not high enough to hinder you from falling asleep. The reason you would increase the bottom pressure from a previous set value is to pre-treat or eliminate any flow limitations or hypoapneas. This usually results in a lower HI score. If you study your reports and you are having higher HI scores then increasing the bottom pressure may help. If you are looking at a AHI score (sum of both AI + HI), then you need to determine from that score what the HI score is alone. You also have to look at the frequency of these events occur. If they are runs close together you may want to increase the bottom pressure to reduce the frequency or eliminate them altogether.

High Pressure setting: If you lower the default 20cm ceiling on the high pressure side you can reduce the chance of the machine from triggering pressure induced central apneas. With some apaps this is not a problem (like with the Remstars) but with other machines it can be a real problem. I'm always Leary of a mechanical device that continues with pressure increases as long as the event is seen. The Remstars have a limiting factor built into their algorithm where if the event is not reduced or eliminated after a period of time the pressure is reduced back down.

Together these pressure(s) become your apap's range. Your 90-95% pressure should land within the established range. Normally, you want to allow 2cm pressure above any 90-95% pressure found to allow the apap to increase if needed and yet prevent flat-lining but within a limit that you control.

Modern apaps can increase the pressure very rapidly in response to events seen. But they reduce that same pressure very slowly over a 10-30 minute period. You can similarly test this yourself by creating a large mask leak, you'll hear the machine rev up very fast to compensate for the leak then rev down much slower when the leak is suddenly stopped. They do this because sudden changes in pressure can interrupt your sleep or even awaken you, you can see this more clearly on the reports if you have them.

Dale92 · Post by **Dale92** » Sat Jun 24, 2006 7:12 pm

Chuck Snoredog and Jim thanks for the info, lots to chew on.

I am going to go back and look at my numbers the last couple of weeks on APAP and then decide how I want to set it up. I know for sure that I can not drop the floor down to 4 cm/w it is way to low for me to breathe adequately. I need at least 6 to 8 to not feel like I am suffocating as I try to draw breaths and wait for the unit to bring up the pressure to where I can breathe easier, usually at least 5 minutes.

As far as the high range I will look at the data like I said. The second week was a better week for me which happed to be the when my oral appliance was moved. Before that I had several days where I spent a lot of time at the high pressure of 20. After adjustment it didn't make it past 16 or 17 and was there only for a short while.

All I can say is I am feeling better and if I can keep this unit I hope to improve it even more.

Thanks again.

Dale

GoofyUT · Post by **GoofyUT** » Sat Jun 24, 2006 11:15 pm

Dale-

I couldn't agree more that many of us need pressures greater than 4cmH2O in order to breath comfortably and not feel air-starved, or like we're rebreathing. I found the low pressure so unpleasant that I discontinued using the ramp on my first CPAP, a Fisher&Paykel HC608, and went straight to my PSG-titrated pressure of 10 cmH2O.

Since I switched to APAP, I still have a floor above the 4 cm. All that I'm suggesting though, is that titrating to the maximum "tolerable" floor pressure may be a mistake for many people, and I'd be loathe to recommend it. It certainly had an adverse effect for me, and others. And, it may not be necessary or useful to "pre-empt" SDB-related events. But I certainly would recommend titrating to comfort at the floor.

Hope this helps.

Chuck

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