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[CPAP] Understanding charts - Printable Version

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Understanding charts - csl1 - 03-05-2020

Hello.  Am new to this forum and to using Oscar.  Have been on CPAP for around 2 months now but still struggling to feel better as very tired still and don't feel my sleep is of good quality although I am considered compliant and average AHI is generally below 5.  Was diagnosed as moderate OSA (AHI= 18) but with significant desats. Although it is improved with CPAP I still feel my sleep is very interrupted with frequent arousals, lots of vivid dreams throughout the night and at least 2-3 toilet breaks every night. 

I had first sleep technician appointment on Monday and she told me that if I was still tired then it was nothing to do with OSA as if it was OSA I would just be sleepy.  She also said that any AHI up to 8 wont affect you and pressures less than 8cm/h20 don't do anything. I'm inclined to think this is nonsense - tiredness and sleepiness are closely connected in my view but it has made me a bit uncertain. I now want to make sure that the therapy is as effective as possible and 10 minutes with a sleep technician every 3 months is not going to help me do that, hence now using Oscar and joining this forum.

Despite her comments, the technician set machine to CPAP check mode at 6cm/h20 with a ramp from 4 (she didn't ask me, or explain why) and it made me feel rubbish fr the next two nights so I downloaded Oscar and saw I was getting AHI spikes up to 12 and so changed my settings back to APAP with min/max of 6/12.  Last night was much better but would be good to get some feedback and tips so have posted last nights charts.

One thing I have noticed is that it almost feels like there is not enough air in the mask.  When I pull it away I can feel the whooshing but with it on I can't feel anything. I previously was using an Amara View which was giving me some trouble with leaks at higher pressures but did feel like it was helping me breathe. The clinic gave me an Airfit F20 this week and also added a humidifier but breathing seems harder. I am wondering if this means I need a higher min. pressure. I am also wondering if it would be a good idea to have some overnight pulse oximetry.  Tidal volumes seem low for my size (93kg, 5'9) at around 440 and I am guessing they are connected to saturation levels.

Lots of questions, sorry! Any thoughts/tips welcome.


RE: Understanding charts - jaswilliams - 03-05-2020

Welcome to Apneaboard. It looks to me like you need more minimum pressure if you want to change your own pressures look here https://www.apneaboard.com/adjust-cpap-pressure/change-cpap-pressure-settings-adjusting-your-machine-with-a-clinician-setup-manual how to get the clinical manual for your machine. I am in the UK as well and I took charge of my own settings to get the lowest nightly AHI I could


RE: Understanding charts - csl1 - 03-05-2020

Thanks.  I've worked out how to get in to change settings so was able to switch it back to APAP but wasn't sure about what pressures to use and set it to min 6/max 12.  Perhaps I will move it to 8/14.  Will be interested to see how clinic reacts to self adjustment


RE: Understanding charts - SarcasticDave94 - 03-05-2020

Welcome to Apnea Board and it looks like you've been given some contradictory technician advice, of which I'm not at all surprised.

I can see here at AB, some need minimal pressure even 4 and be OK. Somewhat rare but it does happen. Most need at least actual 6 where no other aspect diminishes that number. Ramp up diminishes the settings and in most cases makes therapy ineffective until ramp time expires.

As for tiredness and sleepiness, aren't they the same thing? There are many medical reasons for being tired or sleepy. It can be apnea related or it could be something else. It can also be caused by apnea and something else.

AHI up to 8 is of no consequence? BOGUS! At least here in the US, your CPAP isn't treating unless AHI goes down to 5. Why set the goal to 5 if up to 8 does not matter? Duck/quack alert. The person that said that knows not how to treat you. FLEE! Tell this technician you'll disturb her sleep 8 times per hour. Betcha 8 matters now.


RE: Understanding charts - jaswilliams - 03-05-2020

If they were my charts I would set the min pressure to 6 to start with but we will likely go higher over the next few nights to 7 maybe even 8 but lets take it a step at a time rather than big jumps. For the max pressure set it to 20 and forget about it the Dreamstation wont go there unless it needs to and it did not go over 10 in the last graph even though it was set to 12.


Don't bother using the Ramp there is no need with the pressures your using. A start pressure of 4 for the ramp often make users feel air starved


RE: Understanding charts - Sleeprider - 03-05-2020

Looks like JasW and I are on the same page in regard to needing more minimum pressure. At 5-12, your events were obstructive in nature with hypopnea and flow limits. Higher minimum pressure will help to clean that up. The Philips Auto is a good therapy device, but a bit slow to increase pressure, so you will need to increse to 7 or 8 before everything is cleared up. It appears you will resolve events at relatively low pressure.


RE: Understanding charts - Gideon - 03-05-2020

Yes there are those rare individuals that need pressures lower than 6. even 4. But . . . . A good starting pressure on PR machines is 6 and with a Flex of 1 or 2, I think yours is set on two but I could be wrong.
You are seeing Flow Limits and RERAs, RERAs are a series of flow limits ending in arousal. flow limits are a restriction of less than 50%/flow rate of between 50 and higher. Sort of like a small hypopnea. These are best treated with pressure support so we need to add pressure in a slow and controlled manner, until we get your RDI below 2.5. RDI = AHI + RERAs.

Also with your numbers, at least when they hit that 2.5 number how you feel is important. This represents your symptoms. So a typical "I feel fine" is not a good response. If that is the case it means we have done a fine job of optimizing your therapy and keep an eye on it and see is it makes a significant change. It also means if you don't provide that how you feel response the assumption is that you are feeling fine. . .


RE: Understanding charts - csl1 - 03-05-2020

Thanks everyone for your help. It is much appreciated. I will set min pressure to 6 and max to 20 as suggested and see how it goes tonight.


RE: Understanding charts - Sleeprider - 03-05-2020

I just want to emphasize that it is not the maximum pressure, but the minimum pressure that needs adjusted. You never came close to your current maximum pressure of 12 cm, and it's unlikely you ever will. Our concern is entirely with minimum pressure. I think you will ultimately be increasing that to 8.0 or so.


Mask suggestions - csl1 - 04-04-2020

Hello all.  Thanks for your previous help and, following the suggestions I am often achieving AHI plus RERA of 3 or less with some blips but generally feeling like I am sleeping better than I was.

I would now like to ask for some help with choosing a different mask.  So far I've tried 3:

Amara view:  Most comfortable of the 3 but I find it really difficult to achieve a consistent seal and my AHI is higher with this mask. Have to wear an eye mask as it is always blowing in eyes. I sleep less well with this mask.
Dreamwear nasal cushion:  Non-starter.  Found it really noisy and couldn't even succeed in getting to sleep.  Gave up after a few nights trying. I'm also more of a mouth breather than I realised so think full face is for me
Airfit F20:  Most successful in terms of sleep and AHI but have occasional large leaks and find it often very uncomfortable. It makes the bridge of my nose sore leaving red marks that last all day and are getting worse.  Also the headgear digs into the back of my neck. If I loosen it the mask leaks badly when I am asleep.  I think the problem may partly be that I have some age related degeneration in the cervical spine which has affected the curvature a little.  This means my chin tends to come forward sometimes depending how I am lying which can pull the straps very tight at the back of the neck but then if I move they become loose again.  Something a little more springy might help as the straps don't feel very stretchy on the F20

I have followed the wiki and know I need to persist. I only get 1 per year from NHS so don't have the option of trying different ones through my healthcare provider but I would like to try one more mask. It would be good to know any suggestions for what to try taking into account my issues above eg something with a forehead stay or gel cushions perhaps.



Thanks