S9 Settings

[halu]

I recently upgraded from a S8 resmed, which i believe is refered to as the brick, to S9 auto. i have lost my original settings from the S8 and was wondering if it will be ok to use the S9 on its default settings, of 4 to 20 and trust the machine to manage my sleep. by the way thanks you guys for a great forum

[RandyJ]

Do you remember what your S8 settings were?

If not , you may want to check what your 95% pressure number is after using the S9 Autoset for a few days, and bump up your minimum pressure accordingly to 1-2 cm below your 95% pressure number. (If 4 cm is way below where you need to be, the machine has to work for too long to get to your required pressure.)

I would check the 95% number every few days and adjust minimum accordingly until you are in the right zone.

Consider turning EPR off if you don't need it, as this will lower your pressure automatically on the exhale.

[halu]

Thanks randy3. That explains why i feel like i am suffercating when i start treatment. I can't remember what my lowest pressure settings were on the S8, But i think my upper pressure was 14 cm. On the auto it can be anywhere between 14 and 19. forgive my ignorance but i am fairly new to all this. I should also mention that i have lung disease from asbestos exposure, which comlicates things even more. i also have a service provider who treats me like a mushroom.

[Otter]

It sounds like 4 cm is too low, and 20 cm is obnoxiously high for most people.

Try 8-16 cm h2o as a new starting point. Be sure "Sleep Quality" is set to "On" so that your new machine logs detailed data. Then after a few days you can look at it in SleepyHead or ResScan and see if you need to make changes.

[-tim]

My CPAP script said 11. My APAP was set for 4->11 but I bumped it to 6 recently and I'm ok with that but my AHI is almost always less than 2 and often less than 1 wit a 95% of around 9.

[Otter]

My CPAP script said 11. My APAP was set for 4->11 but I bumped it to 6 recently and I'm ok with that but my AHI is almost always less than 2 and often less than 1 wit a 95% of around 9.

The rule of thumb for APAP is 2 cm under CPAP and 3 cm over. 6-11 means you only get up to your therapeutic pressure when you're already in trouble, and as soon as you're out of trouble, an S9 will start lowering the pressure again. You might want to try 9-14 for a few nights.

[FizzyWater]

My CPAP script said 11. My APAP was set for 4->11 but I bumped it to 6 recently and I'm ok with that but my AHI is almost always less than 2 and often less than 1 wit a 95% of around 9.

The rule of thumb for APAP is 2 cm under CPAP and 3 cm over. 6-11 means you only get up to your therapeutic pressure when you're already in trouble, and as soon as you're out of trouble, an S9 will start lowering the pressure again. You might want to try 9-14 for a few nights.

Out of curiosity, if the APAP only goes higher if you need it higher, what's the harm in leaving the top end wide open (20, for example)? Wouldn't it only go that high if you needed it to be?

[Otter]

Out of curiosity, if the APAP only goes higher if you need it higher, what's the harm in leaving the top end wide open (20, for example)? Wouldn't it only go that high if you needed it to be?

That works for some people. Others find that the machine goes higher than it really needs to, and that the large pressure changes and leaks disturb their sleep. And though most people don't have to worry about pressure induced central apnea, a few people will have clusters of CAs if the pressure goes too high.

Generally, you're more likely to get away with leaving the top wide open if the bottom is close to your titrated pressure. When the minimum is too low, you can get a springboard effect that launches you to the top end, whereas if the minimum was high enough to keep your airway open, the machine wouldn't need to raise the pressure at all.

[Bluecat]

From my own experience, I can confirm that if the lower pressure is adequately set (i.e. close to what would be the titrated CPAP pressure), there is no problem leaving the higher pressure at 20.
My initial range was 6-18 (I didn't have a titration sleep study so I was autotitrated with the APAP) and the pressure did go up to 18 sometimes with a 90% average around 13/14. With the range at 10-18, I think the machine never has gone above 13... (90% is 11).


With access to the software, I think it is interesting to bump up the lower pressure slowly (small increments with a few nights at each value) until the variation during the night is "reasonnable".

[Pugsy]

From my own experience, I can confirm that if the lower pressure is adequately set (i.e. close to what would be the titrated CPAP pressure), there is no problem leaving the higher pressure at 20.

Same here when I used APAP 10 min and 20 maximum except that on occasion I still saw pressures to 18 cm but not every night. Some nights I had reports that looked like yours with 10 cm minimum and some nights I had a few excursions to 18 cm. I just figured some of the events were on steroids and needed a little more pressure. AHI didn't increase particularly during to times at 18 cm so I assume that the machine did its job. If I lowered the minimum then I could see that the machine couldn't get there quickly enough and AHI increased rather dramatically.

The pressure changes to 18 never bothered me. I slept right through them and never knew they occurred until I looked at the reports.

My CPAP script said 11. My APAP was set for 4->11 but I bumped it to 6 recently and I'm ok with that but my AHI is almost always less than 2 and often less than 1 wit a 95% of around 9.

AHI low and 95% pressure around 9 cm? Then your 6 to 11 cm setting is probably doing a great job. CPAP RX at 11 might have been a worse case scenario pressure. My step sister used 14 cm straight cpap for 7 years (old brick straight cpap machine) and when we recently got her a S9 Autoset I set it at 10 minimum and 16 maximum mainly to see where things need to be and it rarely goes above 12 cm. Her AHI is under 2 now and able to use less pressure to get great results.
If you are sleeping well, minimal events with 6 to 11...there is no great need to change anything. I sure don't see the need to raise the minimum to 9 cm. Now if you aren't sleeping well...different story.

[Otter]

Pugsy's point is valid. I suggested 9-14 cm because the original minimum setting of 4 cm shows that whoever set the machine up for you didn't know what he was doing. Hence, it might be worth starting over with the prescribed pressure and see what happens. If you really don't need that much pressure, the APAP will stay at 9 cm all the time, and you can then try lowering the range. You could also try working up from the bottom.

An AHI of 1-2 is good, but maybe it can be better. My AHI averages 0.6, and rarely goes over 1. It only goes up to 2 if I roll onto my back or confuse the machine by meditating with my mask on. OTOH, some hoseheads would be happy to get one night under 5. Everyone is different, and while your therapy appears to be adequate, you don't know that it's the best it can be unless you experiment a little.

[Pugsy]

Hence, it might be worth starting over with the prescribed pressure and see what happens. If you really don't need that much pressure, the APAP will stay at 9 cm all the time, and you can then try lowering the range. You could also try working up from the bottom.

I suggest starting at the bottom and working up with the minimum and I will explain why.
Back in my experimenting days my starting minimum of 8 cm wasn't sufficient and it was quickly determined that 10 cm for me was a better starting point. Pretty much gave me AHI between 1 and 2....I did try increasing the minimum in stages all the way up to 13 minimum...and there never was the expected further reduction in AHI. Less than 1 AHI is not always consistently available for everyone for any number of reasons and to go chasing a difference between less than 2 down to less than one may not be a goal that is realistic. Some people get AHI 0.0 often.
I have had it twice in nearly 3 years. AHI of 0.5....is not a huge monumental improvement, that is guaranteed to make us feel like Superman, over an AHI of 1.5 because we can have that much variance from night to night anyway without changing anything.

When I did use the pressures above 10 cm minimum I allowed 1 week with each 0.5 increase.
I got up to 13 cm minimum with no real reduction in overall AHI so I saw no sense in using a higher pressure so I backed the minimum down to 10 cm. I had become used to the higher pressures and going downward suddenly was very uncomfortable and it disrupted my sleep for a few nights until I got adjusted back to the lower pressure. I probably should have gone back down more slowly.

I am a firm believer in lessening any chances of having sleep disrupted for any reason. To start higher and go down...has the potential to disturb sleep just like going from lower to much higher can disrupt sleep. Unless there is a huge obvious difference for a larger increase in pressure I think it is best to go up slowly. A consistent AHI of less than 2 and often less than 1 (per the user here) doesn't warrant a huge change and we don't know if this user is having any centrals in those AHI numbers...so we don't increase pressure if the bulk of any AHI is central anyway. Another reason not to make a large jump in any pressure when "tweaking".
If this user had an AHI of 2.5 but the central index was 1.75 of that 2.5 was central component then we can't expect the AHI to reduce with a pressure increase.
We don't treat centrals on cpap machines with pressure increases.

We need to know the whole picture before suggesting an increase in pressure of any sort.

[Otter]

I started low and worked up when titrating myself, but I didn't have a sleep study to give me a starting point. You're right, of course, that increasing pressure won't help with CA and may even make it worse. OTOH, since Tim was prescribed 11cm straight CPAP and didn't adjust down from that because of centrals, I would think 11cm shouldn't cause him too much trouble. If 11 cm is really too high, then it sounds like blind luck that the RT set the lower end at 4 cm. But luck is luck, whether it's looking or not.

Either way, Tim, if you start experimenting you need to pay attention to how you feel and look at your data often. Bad things aren't going to happen unless you ignore the results.

[-tim]

The S9 says the pressure over the last 6 mo is 8.8. I'm guessing that is the 95%. I tried higher and the thing only went higher around times with leaks which woke me up. Now it rarely goes above 10 and that is always after a leak and the leak stays high got a few minutes and goes away and the pressure drops. It seems to work for me.

I was talking to my father today and he thinks his father died of sleep apnea related heart attack in the 1960s.

[DreamDiver]

... That works for some people. Others find that the machine goes higher than it really needs to, and that the large pressure changes and leaks disturb their sleep. And though most people don't have to worry about pressure induced central apnea, a few people will have clusters of CAs if the pressure goes too high.

I envy those who can get away with a ceiling of 20.

Good reasons for putting a ceiling on max pressure that I can think of:

Aerophagia (air eating).
For me, if I leave it up at 20, there are, very rarely, nights when the pressure might go up to 16. Anything above 12 shoves air down my esophagus. I wake up belching and farting and in real pain from 'gas' that I've been swallowing all night. When I get aerophagia, I tend to 'almost' wake up, but not enough to change the pressure -- Just enough to try to burp. It'll happen about as often as apnea, making it a sleep disturbance that is truly annoying. A lower pressure ceiling results in less waking up from aerophagia for me.

Flow Limitation.
I already have nothing but open-airway apneas with an occasional hypop anyway, so the only thing that increases my pressure on auto is flow limitation. There is the chance in my situation that I could get a flow limitation that ramps me up into a place where I get true centrals, if I'm not mistaken. That also would be bad. (Someone please help me out here, if I'm wrong.) In general, lots of flow limitation suggests to me the need for a tempered ceiling.