Effects of Pressure Too High… Part 2

[70sSanO]

This goes against conventional wisdom, and probably not typical so don’t lower your settings…

Some background… Last March I got a S9 data machine and discovered that my 10+ year old titration of 10cm was too low. So I kicked it up a bit to the 12/13cm range and my numbers, except for centrals, were pretty good. One thing that bothered me was getting a few 30/40 second obstructive apneas.

In July I posed a question about the effects of pressure set too high based on some unusual data. It has been about 2 months since I last posted... didn't have much to say when I was in the middle of it.

Conventional wisdom says that more pressure will keep the airway passage open and, except for the possibility increased central apneas, there will be a point at where the therapy will be maximized. I just needed to find that point. So I would bump it a little, get used to it and bump it again, and sometimes added some EPR. Over about 3 months, I got as high as 17cm, but I needed 1cm EPR. I have a newfound respect for those who have to adapt to higher pressures.

What I discovered, at least for me, was the increased pressure was not reducing the length of my apneas. They were getting longer and more clustered together. My worst was 84 seconds long. It was not uncommon to have 5-10 obstructive apneas one right after the other in a 10 to 15 minute period. It was just a sea of red lines streaking upward right on top of each other, with basically a breath in between each event. These were typically in REM sleep and occurred 2-3 times a night. My AHI was over 7.5 during this span. My leaks were generally good; and although there were some at 16-17cm. There is no correlation between leaks and these clusters. I use a Quattro FX. I check my detail data everyday.

These clusters were so bad that I wasn’t breathing 2/3rds of the time. As an example, I had 11 obstructive apneas in 14 minutes… consisting of one 73 second, one 65 second, five over 40seconds and a few more thrown in for good measure totaling 8 minutes of obstructive apneas.

Over the past 10 days, at 13cm, my AHI is getting closer to 5; I still have 3-4 of centrals. Over those 10 days, I have had one 60 second apnea and three apneas over 40 seconds… obviously not stellar, but no massive clustering, and so much better than it was.

I don’t know what to make of it. It sure appears as though too much pressure was triggering some reaction. I always regretted not getting an Autoset, but that may have just pushed the pressure even higher and, as odd as it may sound, made things worse. There is another thread (viewtopic/t68516/Obstructive-apneas-per ... 16-cm.html) that really intrigues me because I am wondering if my jaw is part of the problem and getting it out of the way may improve my CPAP therapy.

John

[JohnBFisher]

... Over the past 10 days, at 13cm, my AHI is getting closer to 5; I still have 3-4 of centrals. Over those 10 days, I have had one 60 second apnea and three apneas over 40 seconds… obviously not stellar, but no massive clustering, and so much better than it was. ...

John, good for you for taking a scientific approach and measuring this. As you appear to recognize a few central apneas is not at all that unusual and is normally acceptable. Since the machine only measures if you are breathing and if it appears to be obstructive or not, you can not be certain if the central is "expected" or not. Since almost all of us have central apneas during the transition to and from sleep, our units are quite liable to record some obstructive apneas.

Also, remember that the most important thing is "How do you feel?". Even if your AHI is a bit higher than 5, if you feel better (more alert, less likely to fall asleep if you sit still for a few minutes, more likely to take on projects at work and around the home), then the therapy is a success. This is especially true if most of the AHI score is hypopneas.

Of course, as you note, you need to keep an eye on the apneas you still do have. If they continue to persist especially if you continue to feel poorly, then do discuss what you have done with your doctor. He might have some additional suggestions. They almost always have some extra tricks in their bag of tricks.

But most importantly, congratulation on doing such a good job of monitoring and managing your therapy. Hope it continues to lead to many happy hours of sleep.

[70sSanO]

John,

Thank you for your kind words.

I do have to admit that even though I have been at this a long time, the whole process was getting me down a little because it seemed that everything just suddenly fell apart. There were times when I thought things would never get any better. It never occurred to me that maybe I needed to just go back to a lower pressure. And then when I started to lower it back down there was this fear that it would get even worse.

I am feeling pretty good and I still need to monitor my numbers.
John

[agbagb0]

Absolutely right. I use S9 VPAP Auto. My EPAP pressure is 7.6 and I saw my median pressure was 8. So, I increased the EPAP pressure - just +0.2 -to 7.8. For the first time, I got an apnea that was 40 seconds and many 30 seconds. My AHI went from 1.2 to 4.5 - there were more events and are clustered together. I think I need to dial it down.

Before
AHI 1.2
EPAP : 7.4

After
AHI 4.5
EPAP : 7.6

I wish I can add a screenshot of the graph..
Edit : I figured out how! Sign up at photobucket.com website, upload the picture, get the link and click img tag, paste the line from photobucket

[copygirl]

This is very relevant to me right now, as I've posted in the thread I've started. For me, raising the epap but keeping the ipap the same seems to be working. AHI went from 10 the first night to 6 the next night and down to 2 last night! So I'm going to keep this route and see how it goes.

I really want to learn more about how epap affects apneas vs the affect of ipap.

[rested gal]

About the EPAP setting on a bilevel machine:

December 2007 - my understanding of how a bipap titration is done.
viewtopic.php?p=231786#p231786

[rested gal]

copygirl, the next two links were about a bilevel auto, not just a bilevel like you have (your VPAP machine), but what I wrote about EPAP's job being primarily one thing... to prevent apneas... would apply to a straight bilevel machine just as well. To Respironics "BiPAP" and to ResMed's "VPAP."

November 2007 - EPAP is for more than just comfort exhaling.
viewtopic.php?p=227068#p227068

May 2008 - discussion with RonS about importance of EPAP setting.
viewtopic.php?p=265020#p265020