respironics autoSV & new software - why AHI so high?

[kolchak]

Hi,
I've had an autoSV for ~ 7 months due to complex SA and finally bought encore viewer and a card reader. I'd been feeling much improved since getting machine late last year, so never bother to get software (I know big mistake) but many days of feeling tired inspired me to take the plunge. After reading the reports, I know why I'm still feeling bad, but I'm not exactly sure which numbers from the report are most important to determine the overall effectiveness of my therapy. This is not due to lack of trying but the more threads I read about interrupting these numbers, the more confused I become . It seems one almost needs a medical degree to really understand more then basic definitions & concepts.
My hope is some nice, knowledgeable person could take a look at my numbers & make some suggestions on possible setting tweaks to improve my numbers. I know this is asking a lot, and since I'll be meeting with my Dr. next month I'll understand if not wanting to invest time interrupting everything.

My settings are max IPAP @ 30, min IPAP @ 10 and EPAP @ 5.

The reports show the averages for the last month as -
Avg peak IPAP @ 15.3
Avg apnea index 19
Avg Hypo 1
Avg AHI 20
Avg breath rate 12 (auto back - up)
Avg tidal volume 644
Avg breaths per min - 13
Peak flow - 37.7
Avg max leak 131.1
Avg 90% - 41.4
Avg leak 32.9
Avg large - 3 min.
Avg Patient triggered breaths 36 (today’s # was 94 using swift 2 with silicone seal around the pillows)

Most of these numbers were generated using HP 431 before getting the software, but a recent switch back to the swift 2 has lowered AHI a bit the past few days - my avg AHI was ~ 14. I'm sure the averages will improve as I continue using the swift but the mask alone will obviously not make numbers good enough. Am I missing anything?

I was about to purchase an HP 432 but since the 431 numbers were so bad and the swift 2 numbers (with mouth taped) were better, I'm thinking I should look for another pillow or pronge type mask and just keep taping to handle the mouth breathing issue.

Lastly, my “sleep flags” get much worse the last couple hours of sleep, when sleep is the deepest. I guess this is to be expected?

Thanks for any advice!

[-SWS]

My settings are max IPAP @ 30, min IPAP @ 10 and EPAP @ 5

Avg apnea index 19
Avg Hypo 1

Those excessive residual apneas could be obstructive. If that were the case then you might expect your doctor or sleep clinic to raise that EPAP. A higher EPAP will usually address frank obstructive apneas. However, if residual obstructive apneas turn into residual hypopneas after increasing EPAP, the clinician will presumably raise min IPAP to address those "apneas turned hypopneas" (as if they were under-addressed obstructive apneas, absent of central hypopnea thoracic-effort identifiers).

However, those excessive residual apneas could be central instead of obstructive. In that case you might expect IPAP parameters to be adjusted instead. Unfortunately this machine does not differentiate obstructive apneas from central apneas. So the objective of a PSG titration for SV would be to address obstructive events with EPAP and min IPAP (w/some central events affected along the way), and to address remaining central events primarily with IPAP parameters and backup rate.

Lastly, my “sleep flags” get much worse the last couple hours of sleep, when sleep is the deepest.

Obstructive events tend to get worse in REM, whereas complex central events tend to be worse in NREM.

My highly unqualified hunch is that you just may have obstructive apneas inadequately addressed by that low EPAP=5---and that your obstructive trend manifests more heavily during those last couple hours of sleep, presumably in REM. Then again guesses never stack up to hard measurements, let alone comparative measurements across a compSA/CSDB patient population.

We presently don't have any genuine SV expertise on this message board IMO. Plenty of guesses and opinions, though. Grain of salt advisory issued...

[ww]

Why don't you get a copy of your sleep test summary data before and after titration as well as the Full Scored Data Summary Report with condensed graphs from both sleep studies. Then post the information here or summarize it and maybe someone can understand your background and offer some suggestions. I am only familiar with a CPAP, but maybe someone can jump in and offer a better explanation. Since you have the software, you can see if there is any improvement from sleeping on your side or in a recliner while you investigate further.

[Snoredog]

My guess:

I would increase EPAP Minimum from 5 to 7. I would want to see the AutoDaily report before any other suggestions.

HI is so low because IPAP is so high, as SWS suggested those AI's can be central and included in the count. If you increase EPAP minimum and that number doesn't drop or gets worse you have your answer.

Your highest IPAP seen was 15.3, that would indicate the events that drove it up there were FL, Hypopnea or snore. But with EPAP down at 5, it cannot do much in the way of addressing apnea.

after you make that change, you may see IPAP remain much lower. Of course if AI gets worse you want to drop EPAP back down.

[kolchak]

Thanks for the advice. My biggest issue is the centrals. My initial sleep test showed that CPAP helped the OSA but made the centrals far worse thus the "complex apnea" tag. Prior to my next apt I will try raising my EPAP & IPAP slightly and monitor the results. I wasn't sure how or if tweaking those setting would make a difference given the advanced nature of the machine.
I initially set up my machine based on advice from the forum, because my Apria branch had/has no clue how to set it up. The machine was new, the tech hadn't been trained. He had the max & min IPAP both set at 19 for some reason, which obviously wasn't going to work. They wouldn't show me how to adjust the settings or gove me the manual so thank God for this forum and all the caring people willing to help.

[-SWS]

Your highest IPAP seen was 15.3, that would indicate the events that drove it up there were FL, Hypopnea or snore.

That machine doesn't increase pressure in response to snore. Unfortunately it doesn't measure or report FL or snore either.

Rather that SV model works with peak flow comparisons, pressure delivery measurements, and frequency/time based measurements only. No wave shape or snore detection, though.

[-SWS]

My initial sleep test showed that CPAP helped the OSA but made the centrals far worse thus the "complex apnea" tag.

Your two SDB components are diametrically opposed with respect to pressure requirements. So raising min IPAP may or may not be the way to go:

http://doctor.medscape.com/viewarticle/515202_8

Avoiding Pressure Toxicity

Patients with complex disease are sensitive to positive airway pressure, and usually flow limitation cannot be eliminated without worsening periodic breathing or inducing central apneas. An immediate worsening with bilevel ventilation may be seen, consistent with an effect of induced hypocapnia on the peripheral chemoreceptors. One approach is 'permissive flow limitation' - allowing some obstruction to persist and thus avoiding the worsening of control dysfunction.

Unfortunately pressure related trial-and-error becomes much more complicated for any complexSA/CSDB patient compared to typical OSA pressure tweaks.

[kolchak]

FL = ?

thanks again - I'm trying to keep up with everyone, and it sounds like general consensus is to raise EPAP to 7 & go from there?

I would have posted the encore report summary but the program won't allow a left click / copy /paste. Is their an easier way (for a person of limited computer skills mind you) to post these & the sleep studies other then scaning & emailing them to myself, save the docs to file and then copy & pasting?

[Snoredog]

Your highest IPAP seen was 15.3, that would indicate the events that drove it up there were FL, Hypopnea or snore.

That machine doesn't increase pressure in response to snore. Unfortunately it doesn't measure or report FL or snore either.

Rather that SV model works with peak flow comparisons, pressure delivery measurements, and frequency/time based measurements only. No wave shape or snore detection, though.

[Snoredog]

FL = ?

thanks again - I'm trying to keep up with everyone, and it sounds like general consensus is to raise EPAP to 7 & go from there?

I would have posted the encore report summary but the program won't allow a left click / copy /paste. Is their an easier way (for a person of limited computer skills mind you) to post these & the sleep studies other then scaning & emailing them to myself, save the docs to file and then copy & pasting?

it means you should use caution with increasing pressure as that can make things worse. The machine will change IPAP to manipulate your ventilation rate/volume. FL=Flow Limitation. Flow limitation can also look like a central, so can shallow breathing, as SWS's abstract indicated you may have to let Flow Limitation go as trying to eliminate them turns your sleep into a train wreck.

The number of concern is the AHI (and leak). It is 20 while this is probably a great improvement over no therapy it sure would be nice to see that go lower. If you could cut that in half that would be great.

Understand that the machine cannot tell the difference between a 40 second obstructive event and a 40 second central event, to the machine they both look identical like 40-second periods of no breathing.

If pressure is applied and that is a obstructive event and it goes away things are fine, but if that 40 second event is a central applying that same pressure can make it worse as you can be sensitive to pressure changes or increases. That pressure for the most part (of which you may be sensitive to) comes from the EPAP pressure. Sensitivity to pressure and having mixed events (obstructive apnea combined with central) is what makes your disorder complex.

So any change you make you have to make carefully, for the most part the machine should automatically control ventilation rates to keep central under control. The change suggested would be to only address the obstructive portion of the AHI=20. If you increased EPAP slightly (try 1 cm first) and it eliminated more obstructive events, that AHI may drop to 15. If it made things worse, that AHI would rise above 20. Keep in mind that AHI=20 may be made up of both obstructive and central events (as it cannot tell the difference). Since it is to your benefit to have fewer of both events, seeing your AHI go down would be a good thing.

You would also have to compare leak rates when looking for the changing AHI (leak for comparison period should be similar), you had some periods there where leak could be improved on. I could be wrong, but I don't think the mask interface you choose is ideal for your disorder.

Printing Encore Reports:
I don't have Viewer, I have EncorePro, it has the option under File to save as html or to PDF or print it.

If you cannot change the way Viewer saves reports, if it will let you print it, you can install a PDF writer and save the report to PDF format, Then you can open that and print any single page to a printer or to another PDF file.

Cute PDF writer is freeware, installs just like a printer, instead of printing to your physical printer you select Cute PDF printer and it creates the file.

http://www.cutepdf.com/Products/CutePDF/writer.asp

Then if you want to post the PDF you post it using the Img tags just like a picture. But the pdf file must reside on a server or photo storage space that you can link to.

[kolchak]

Thanks for the detailed explanations snoredog.
One last question before I need to sign off for now - I just tried changing the settings as I've done before on this respironics BiPAP auto SV. According to the manual, I press left & right arrow keys simultaneously while device is in standby however nothing beeps and the display doesn't change. I can actually changr the light, the rise time, and the ramp by pressing the right arrow key alone and cycling through them. No matter what I press it's not giving me acess to change EPAP, IPAP, alarms, etc.
I have done this before, however it's been six months since I last attempted to monkey with those settings. I've tried every combo of buttoms to access the providers or clinicians mode and get to the EPAP but no luck.
Any idea what I'm doing wrong?

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, bipap, auto

[ww]

Load a utility called cute pdf (free) and then when you print your page, the file will be saved as a pdf file assuming you can find a way to use that format.

Oops...Snoredog posted the same thing.

[dsm]

EncorePro outputs reports in pdf format as a standard feature.

If you can get me one of your reports I'd like to have a look at it.

Just off the top of my head the epap of 5 seems very low by any standards even if you have no OSA component at all.

My 1st question though is this . Does your PSG say you had any OSA in the sleep study ? if yes then someone may well have set your machine up incorrectly. But that PSG data is important to determine these matters.

My 2nd Question is are you overweight ? - if yes then the 30CMs suggest the doc thinks you are quite overweight. If you aren't then I would be interested in why the RT set IpapMAX so very high.

Cheers & good luck

DSM

[Snoredog]

EncorePro outputs reports in pdf format as a standard feature.

If you can get me one of your reports I'd like to have a look at it.

Just off the top of my head the epap of 5 seems very low by any standards even if you have no OSA component at all.

My 1st question though is this . Does your PSG say you had any OSA in the sleep study ? if yes then someone may well have set your machine up incorrectly. But that PSG data is important to determine these matters.

My 2nd Question is are you overweight ? - if yes then the 30CMs suggest the doc thinks you are quite overweight. If you aren't then I would be interested in why the RT set IpapMAX so very high.

Cheers & good luck

DSM

The AdaptSV doesn't respond with increased EPAP in the presence of obstructive events does it?

As I understood it, it was static from where you set it and only IPAP and other parameters adjusted automatically to SDB events.

[dsm]

EncorePro outputs reports in pdf format as a standard feature.

If you can get me one of your reports I'd like to have a look at it.

Just off the top of my head the epap of 5 seems very low by any standards even if you have no OSA component at all.

My 1st question though is this . Does your PSG say you had any OSA in the sleep study ? if yes then someone may well have set your machine up incorrectly. But that PSG data is important to determine these matters.

My 2nd Question is are you overweight ? - if yes then the 30CMs suggest the doc thinks you are quite overweight. If you aren't then I would be interested in why the RT set IpapMAX so very high.

Cheers & good luck

DSM

The AdaptSV doesn't respond with increased EPAP in the presence of obstructive events does it?

As I understood it, it was static from where you set it and only IPAP and other parameters adjusted automatically to SDB events.

Snoredog,

Yup the BipapSV requires the RT to tune for OSA as the 1st as part of the titration. If OSA is detected it is ironed out 1st with Epap pretty much as you described. The IpapMAX is used to apply rapid pressure (can increase my several CMs in one single breath).

The machine tracks Peak Flow & seeks to maintain that withing a tracked value plus tracks breathing rate & seeks to maintain that (as SWS described).

This presentation covers the aspects pretty well (see chart 15)
http://www.internetage.com/cpapdata/dsm ... -preso.pdf


Cheers

DSM