Replies to This Discussion

Permalink Reply by Chris on May 10, 2009 at 7:48pm

Judy said:

Rock Hinkle, Rock Connor, Daniel Levy!!!!!! Help me out here! I'm outta my league trying to explain the relationship between IPAP, EPAP and pressure support and the reported 95th percentile pressure!

*sigh* CPAP and APAP were so easy to unnerstand.

Thanks for the help Judy. Ill hang back and see if any one jumps in. And yea, just trying to sort this stuff out will give you a headache. LOL

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Permalink Reply by Judy on May 10, 2009 at 11:00pm

(((((hugs)))), jnk!!! And bless you for coming to our rescue!!! Even "I" could understand your explanation. Youse a keeper!!!!

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Permalink Reply by Judy on May 10, 2009 at 11:16pm

And now, jnk, would you please also check out JoshCoop's thread, "I Am New Here ... (Intro)"?? He needs help too.

Or Rock Hinkle, Rock Connor or Daniel Levy?? Josh could use the help.

Now all this doggone chat about headaches, me, who almost never gets one, has one!! I'm re-reading Taylor Caldwell's "Captains and The Kings" for about the 5th time thru the years. One of my favorite 3 books of all times - and the only book by Taylor Caldwell I ever liked!!! My daughter got me the DVD for my birthday but I haven't figured out how to switch from satellite to DVD yet. *sigh* I lost the instructions. Ah well, the movie is never as good as the book.

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Permalink Reply by Mike on May 11, 2009 at 12:26am

j n k, i didn't follow the part about adding and subtracting 2. if you wouldn't mind explaining that another way, i'd certainly appreciate it.

j n k said:

The reported pressure of 12.8 is a number given you to figure out your 95 centile IPAP and EPAP. If your pressure support is at 4, you add 2 to the 12.8 to get your 95 centile IPAP, and you subtract 2 to get your 95 centile EPAP. That math works out to 14.8/10.8 for your 95 centile IPAP/EPAP. That isn't important to grasp right now, but I explain it in case you are the kind of guy that likes to know. :-)

If your doc doesn't mind you tweaking the numbers a bit, you can slightly adjust them in an attempt to get your AI consistently below one. I would start by seeing what happened if I raised my Min EPAP. The Min EPAP of 5 is pretty low. In fact, many find it hard to breathe when the pressure is that low. That machine is so comfortable to use that you should have no problem at all starting out the night at a higher pressure during settling. You could raise your Min EPAP to 6 for a week or two and see if that gets your AI below one. If it doesn't, you can try raising it to 7 for a week or two after that, and so on. (Do not, however, raise Min EPAP over 11. You need a distance of at least 4 between Min EPAP and Max IPAP, since your pressure support is set to 4. There is no reason to even think about getting the Min EPAP that high any time soon. I think you would see that AI drop below one long before that.) Any adjustment should be tried for a week or two before trying another one. That is the slow, methodical, scientific approach to minor self-titrating.

If your AI is still above one after playing with your Min EPAP setting, you may want to ask your doc about permission to raise your Max IPAP. I would not do that without the doc's permission, myself, since that would be actually affecting the delivered pressure, not just the range (which is all that changing Min EPAP is, changing how low you start out). Your titration study may have shown a reason to keep your IPAP below 15 at all times.

Nevertheless, all that being said, I very much doubt any of that is the reason for the headaches. The humidity would be where I would start for that, along with giving your body time to adjust to PAP therapy, if you are relatively new to it.

jeff

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Permalink Reply by Kristina Zabala on May 11, 2009 at 1:03am

What kind of headache? Are your straps too tight?

JoshCoop said:

I have a headache almost every single day and I was wondering if I get them *because* I have sleep apnea......

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Permalink Reply by Judy on May 11, 2009 at 1:10am

Good question, Kristina, and a distinct possibility.

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Permalink Reply by RockRpsgt on May 11, 2009 at 8:19am

sJudy push the input button on your tv remote. This should switch you to DVD.
Judy said:

And now, jnk, would you please also check out JoshCoop's thread, "I Am New Here ... (Intro)"?? He needs help too.

Or Rock Hinkle, Rock Connor or Daniel Levy?? Josh could use the help.

Now all this doggone chat about headaches, me, who almost never gets one, has one!! I'm re-reading Taylor Caldwell's "Captains and The Kings" for about the 5th time thru the years. One of my favorite 3 books of all times - and the only book by Taylor Caldwell I ever liked!!! My daughter got me the DVD for my birthday but I haven't figured out how to switch from satellite to DVD yet. *sigh* I lost the instructions. Ah well, the movie is never as good as the book.

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Permalink Reply by RockRpsgt on May 11, 2009 at 8:39am

I appreciate the vote of confidence Judy, But in all honesty I am just beginning to understand the whole BiPaP,ASV thing. There are many people on this site that have way more knowledge than I do on this subject. Last night was the first time I had an actual RPSGT breakdown the whole BiPAP protocal. Tonight will be my first actual educational BiPaP titration. I am really excited. My knowledge of the basics, and luck have gotten me through a few BiPaPs up to this point. Up to now I have never had a patient fail CPAP. One of the many reasons I switched labs was so that I could get the more difficult studies and experience. I want to be a titration artist!

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Permalink Reply by RockRpsgt on May 11, 2009 at 8:45am

Me again, I donn't believe anyone has mentioned yet. Chris have you had problems with allergies in the past? Sometinimes when you are new to Pap therapy it can and irritate your sinuses and or allergies. It does not always have to be a technical issue. Headaches can be caused by many things as the others have mentioned.

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Permalink Reply by Mike on May 11, 2009 at 5:06pm

ok, thanks j n k, i get it now. my next question is why do they make us do the math? in other words, why do they make it so difficult for the lay person? i have my theories, but before I give my cynical response, i'd like to hear out whether, putting them in the best possible light, there's a way for ResMed to justify not reporting this data in a more straightforward way?

j n k said:

No problem, Mike.
Here is how ResMed explains it in their words:
"AutoSet pressure is a conceptual value. The patient is delivered an auto-titrated
inspiratory and expiratory pressure based on the AutoSet algorithm, which has
the AutoSet pressure as its midpoint. The AutoSet pressure is reported in data
management and efficacy results information."

In other words, the machine does not tell you your 95 centile IPAP and EPAP, it leaves it to the clinician to figure it out from the reported midpoint between IPAP and EPAP. (That is because the autobilevel uses the same algorithm, A10, that was written for an auto-CPAP.) Instead of reporting two numbers, the machine reports one number. IPAP is one-half of pressure support above the reported number, and EPAP is one-half of pressure support below the reported number. As long as you have the AutoSet pressure number and the pressure support number, you can always do the math to get your IPAP and EPAP.

To review, for a ResMed autobilevel user to find out 95 centile IPAP and EPAP, the user must read the AutoSet number from the screen then add one-half of pressure support to get IPAP and subtract one-half of pressure support to get EPAP.

This chart may help . . .

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Permalink Reply by Mike on May 11, 2009 at 5:12pm

j n k's explanation was good, but i disagree that it's something that makes it super simple to understand. i'm an ivy-league educated corporate lawyer, and i still had trouble making heads or tails of this. i get it now, but it took too much work for me to get there. my view is that the manufacturers have to break this down and be more transparent to end users.

Judy said:

(((((hugs)))), jnk!!! And bless you for coming to our rescue!!! Even "I" could understand your explanation. Youse a keeper!!!!

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Permalink Reply by Chris on May 11, 2009 at 5:25pm

j n k said:

That AI is a little high for a ResMed. Generally it is good for AI to consistently be below one, whenever that is attainable. If you are just starting out, I wouldn't worry about it right now. But if you have been using your machine over a month, it is my opinion some tweaking of your pressures should be done to see if that AI can get below one. I would ignore the AHI number until AI is below one.

It may be your doc is going to check your numbers later and adjust your range. So work with the doc on that if that is the game plan.

Here is what the settings mean, if that hasn't been explained sufficiently to you. Your Min EPAP is the lowest your exhale pressure can go. Your Max IPAP is the highest your breathe-in pressure can go. Your pressure support is the difference between the experienced breathe-in pressure and experienced breathe-out pressure with any given breath, and that difference between inhale and exhale is a constant on a ResMed autobilevel.

So, in practice, with the settings you have now, you start out the night with 9cm pressure for inhale and 5cm pressure for exhale. It stays there until your "settling" time is up. Then the machine algorithm kicks in to try to prevent events and raises your pressure. With your Max IPAP at 15, your pressures never gets above 15cm for inhale and 11cm for exhale, since the difference between inhale and exhale stays at 4 all night. Does that make sense? If not, let me know.

The reported 95 centile autoset pressure number of 12.8 shows that your machine is giving you pressures of 14.8 on inhale and 10.8 on exhale, or below that, for 95% of the night. So your pressures are likely hitting the 15cm ceiling on that machine momentarily, as it is set now. The reported pressure of 12.8 is a number given you to figure out your 95 centile IPAP and EPAP. If your pressure support is at 4, you add 2 to the 12.8 to get your 95 centile IPAP, and you subtract 2 to get your 95 centile EPAP. That math works out to 14.8/10.8 for your 95 centile IPAP/EPAP. That isn't important to grasp right now, but I explain it in case you are the kind of guy that likes to know. :-)

If your doc doesn't mind you tweaking the numbers a bit, you can slightly adjust them in an attempt to get your AI consistently below one. I would start by seeing what happened if I raised my Min EPAP. The Min EPAP of 5 is pretty low. In fact, many find it hard to breathe when the pressure is that low. That machine is so comfortable to use that you should have no problem at all starting out the night at a higher pressure during settling. You could raise your Min EPAP to 6 for a week or two and see if that gets your AI below one. If it doesn't, you can try raising it to 7 for a week or two after that, and so on. (Do not, however, raise Min EPAP over 11. You need a distance of at least 4 between Min EPAP and Max IPAP, since your pressure support is set to 4. There is no reason to even think about getting the Min EPAP that high any time soon. I think you would see that AI drop below one long before that.) Any adjustment should be tried for a week or two before trying another one. That is the slow, methodical, scientific approach to minor self-titrating.

If your AI is still above one after playing with your Min EPAP setting, you may want to ask your doc about permission to raise your Max IPAP. I would not do that without the doc's permission, myself, since that would be actually affecting the delivered pressure, not just the range (which is all that changing Min EPAP is, changing how low you start out). Your titration study may have shown a reason to keep your IPAP below 15 at all times.

Nevertheless, all that being said, I very much doubt any of that is the reason for the headaches. The humidity would be where I would start for that, along with giving your body time to adjust to PAP therapy, if you are relatively new to it.

jeff

I never had a sleep study to set the pressure. My doc went with the bi level machine because it sets the pressure to what you need. When I went to my first study to find out what the pressure should be I had such a bad case of congestion the nasal mask was useless. Not sure why they did not try a full mask but any way you said they may of had a good reson to set my machine up the way they did but it looks to me like they are doing some gueesing so what I am going to do is get the tech to download the info and send it to the doctor and take it from there. I might try to tweek things a bit while I wait for my appointment.

And yes, I am the kind of person who wants to know everything about my treatment so thanks for taking the time to explain all the math involved with how the Vpap Auto comes up with the results. As for the headaches I just found some warnings in the manual that say If you get SERVERE headaches to cal a doc immediately. The headachs are not that bad so I just might mess with the settings including the humidifier.

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