Shortcomings in the DeVilbiss IntelliPAP??

[timbalionguy]

I have had a problem since day 1 of APAP in late April, with an inability to find a pressure that works for me. Yes, I have had some good therapy, but I feel it is suboptimal. I am a 49 year old male, who is about 100 pounds overweight, but with no other major health issues. I am working on the weight issues, which so far have not made a big improvement. But I can just see now where things are starting to improve.

I chose the DeVilbiss IntelliPAP based on a lot of good reviews, and an up-to-date computer interface. I skipped the whole DME thing and bought the machine online. In general, it is a good machine, and has been reliable. But no matter what I do, I can not get my long term average AHI to go below about 7.

My original split night sleep study had to be terminated at 13 cm because of the emergence of centrals, something common on a first try at CPAP. The technicians had a hard time trying to find a pressure that provided optimum therapy. Both the sleep technician and my doctor called me 'hard to titrate'. The recommendation on the PSG report was to try another titration with a more advanced machine, and be ready to try an 'adapt servo ventilator' (The ResMed ASV unit) should centrals continue to be an issue. In any case, my doctor, knowing up front that I would self-titrate, prescribed an APAP machine. I think her thinking was like mine: the centrals would go away after getting used to therapy, which they mostly did. The initial pressure range was 10-13 cm. This range effectively prevented most apneas. So the majority of my events are hypopnas, as is the case with many here.

I experimented all summer and fall, slowly raising pressure, and eliminating other variables. Therapy was improving, but only stubbornly. In early September, based on a recommendation from a different sleep doctor in the same clinic, I started working towards a pressure range of 14-18, where I am at currently.

I found over the course of the last 9 months that one very noticeable flaw in the IntelliPAP was a tendency towards 'runaway pressure'. This problem decreased as I approached a more reasonable pressure range.

Recently, an article came out in 'Sleep review', that compared some common autoadjsting CPAP machines. I was quite surprised to see that the IntelliPAP seemed to be a very 'conservative' machine, and had the slowest response to events of all the machines tested. Although DeVilbiss claims that this is an advanced algorithm, based on years of research, I am wondering what they were thinking or who they were targeting. As I deal with my inability to get thoroughly effective therapy (I am sleepier than I should be, but much better than pre-therapy), I am beginning to wonder if the IntelliPAP, while a fine machine, is not the machine for me due to it's 'slow' algorithm. I may actually need a faster responding machine, like the Autoset II. Or maybe even one of the more advanced machines like the BiPAP ASV. (BTW, no peirodic breathing noted on my PSG, nor is there any reason why I should be experiencing that.)

Oddly, my AHI seemed to take a jump about 10 days ago for no reason that I can deduce. Went from an long term average of about 7 to an average of about 10. This was after a 1 week period where the average had worked its way down to near 5. Little difference noted on the machine data, other than a return to 'runaway pressure' on some nights. Two nights ago, I changed my pressure range from 13-18 to 14-18. So far, not enough data collected to tell if there is an improvement. Previous experiments moving 13-18 to 14-18 tended to make things ever so slightly worse. Straight CPAP at 14 at first seemed effective, but left me very tired. Only tried that 3 days.

Here are my current thoughts: I am planning to see my sleep doctor in March (February is too cash-tight). At this time, I am going to lay this all out before him, and suggest maybe it is time for a new PSG, possibly with a more advanced machine.

What are your thoughts?

[JohnBFisher]

You've clearly done your homework. Just a caution ... your sleep doctor might want to do another couple sleep studies ... one on BiPAP and then one on ASV. Ask your sleep doctor if you continue to have problems with centrals (so at least one more will be needed) then won't a BiPAP (especially an auto adjusting BiPAP) have the same problem.

Due to the price of an ASV unit, doctors like to demonstrate that they tried less expensive systems first.

You might also ask if a split night on one unit then on the ASV could be done. That might get the answers to both at the same time.

[Muse-Inc]

Can you rent an AutoSet for a wk or so and see what results you get? As reported here, there is quite a difference in 'feel' between the response algorithms of the ResMed and Respironics xPAPs, so you might need to trial both before buying.

Here's info you might check out: http://www.resmed.com/us/products/devic ... clinicians

[ozij]

My original split night sleep study had to be terminated at 13 cm because of the emergence of centrals, something common on a first try at CPAP.

Do you have any idea how may appeared? One of the problems with a split night study, in any case, is that you have less time to get used to pressures.

The initial pressure range was 10-13 cm. This range effectively prevented most apneas. So the majority of my events are hypopnas, as is the case with many here.

Everybody on the DeVilbiss/Respironics challenge found they had less apneas and more hypopneas on the DeVilbiss -- a direct result of the DeVilbiss's default setup, which defines many events as hypopneas, that others would have defined as apneas. It has nothing to do with the machine's therapy, and everything to do with formality. The only events the DeVilbiss recognizes as apneas in its default configuration are those that have a drop in flow of 90% to 95%. An 87% drop in flow, on DeVilbiss's default is already a hyoponea. It's still an apnea on ResMed, Respironincs and PB (Sandman). DeVilbiss is the only machine on which you can move the apnea/hypopnea cutoff from one point to the other -- in order to fullfil the preferred definition of the doctor or the insurance company. Pure formality.

I was quite surprised to see that the IntelliPAP seemed to be a very 'conservative' machine, and had the slowest response to events of all the machines tested.

The machines in that study were faced with stimuli take from real life PSG's. Ironically, the obstructive apnea in the stimuli was of the type DeVilbiss defines as central - but their definition (see below) is very rough, and misses many obstructive apnea because of that - as happened in that study.

Things worth knowing about the DeVilbiss:

• It only responds to three types of events: hypopneas apneas and snores. It doesn't take flow limitations into account at all - no analysis of the shape of the wave.
• Furthermore, it has the exact same response to apneas as it does to hypopneas - both in speed of response and in amount of pressure added viewtopic.php?p=355874#p355874 - a very slam bang way of going about things IMO. Other machines distinguish hypopneas and apneas and respond differently.

I suggest the above points have something to do with runaway pressure, since residual hypopneas are treated with same raise in pressure as are residual apneas - something which may be entirely unnecessary.

• Its way of avoiding central apneas is by defining any apnea with 95% to 100% drop in flow as a central apnea -- but they have 80% sensitivity and specificity on that compared to hand scoring. If you have obstructive apneas within that category, the DeVilbiss will not respond to them.
• It has no other way of avoiding central apneas - neither a pressure cap for "response for apnea" nor other algorithmic protections. All other machines do:a rigid cap at 10 in ResMed machines, user adjustable cap in Sandman and Fisher&Paykel and a "Non responsive" test with pressure drop in Respironics -- meaning that each of these algorithm's will respond to the type of apneas ignored by DeVilbiss.

We had a discussion of the study on the forum back in November -- when DoriC linked to the article in Sleepreview magazine --http://www.sleepreviewmag.com/issues/ar ... 09_02.asp/

I agree with Muse-Inc -- a trial of an Autoset II is worth while. It may teach you a lot. If I were you, I'd set it at a minimum of 13, and see how it handles my breathing. Curiosity might later make my try it with a lower minimum -- ResMed will not respond directly to apneas above 10, but it will definitely respond -- and fast - to snores and flow limitations.

If it responds like that for you in good time, you may find yourself getting better therapy. A trial on another type of auto will give you more info for the doctor as well. And you may appreciate the autoset expiratory pressure relief -- even though at this point you don't feel a need for it. If I could, I would try a Respironics APAP too.

You're reaching pressures that border on the level that justifies a BIPAP for insurance -- and on BIPAP, you may find the lower pressure on exhale beneficial too.

The bottom line: if it were me, I would like to know more about my response to other APAP algorithms before I returned to the doctor.

http://www.devilbissclinicaleducation.com/ (I haven't checked it since about 6 months ago)

Although DeVilbiss claims that this is an advanced algorithm, based on years of research, I am wondering what they were thinking or who they were targeting

The creation of the DeVilbiss IntelliPAP AutoAdjust algorithm was initiated in the early 1990s. The algorithm was first born based on several clinical resources and references, then grew through the utilization of a computer-assisted diagnostic algorithm to accurately define respiratory events. Finally, the AutoAdjust and its algorithm furthered evolved as a result of fine-tuning based on extensive real-world clinical testing

.

Let me rephrase the above: We started our APAP development in the early 1990s. We looked for ways of diagnosing breathing events automatically - using a computer program [After all, that's what APAPs are about]. We improved the algorithm in house ("extensive real world clinical testing")[of course we did, everybody has to do that]. And we've been using the same algorithm since we first started marketing our APAP.


O.

[techno-snoreus]

I have had problems with the IntelliPAP myself. I, like timbalionguy am an overweight individual, although I have a few pounds on him.

I purchased mine last summer after I started experiencing problems with my Respironics Remstar Plus. Since it had been five years since my initial sleep study, my doctor had me undergo another one. I was titrated at 16cm, and my doctor wrote my script for the IntelliPAP at my request with an initial pressure range of 13-17.

Now you have to understand that I don't have the data component of the machine. Now criticize me all you want, but I feel that how I feel is a better indicator of how I slept, rather than what the numbers say. Not that I don't believe in using data to help better your sleep experience. Many people need to see that information to better adjust their therapy. I just don't feel the need.

I realized the first night that the range of 13-17 wasn't going to work for me because at the bottom end of the range I felt like I couldn't breathe. So I immediately adjusted the range up to 15-17cm. (Positive note about my DME here: Although I argued with the RT that she could give me the clinician manual, and it was indicated on my script that it was to be given to me, she said she could lose her job as it was company policy to not give out the manuals. She did, however, look around the room and gestured for me to watch carefully while she "turned it on" and showed me the key sequence to enter clinical mode, so props to her.)

After making the adjustment to the 15-17 range, I felt I could breathe, but felt like utter crap after sleeping all night. I was extremely bloated and felt like I had been hit by a mac truck. This went on for about a week and I then decided to set it to straight CPAP mode to see how that would work. It worked just fine. I haven't had a single problem operating it in straight CPAP mode, and aside from any of the other myriad of reasons why I don't get good sleep (a whole different issue all together), I can't blame the IntelliPAP.

I think that the problem I was experiencing was the IntelliPAP's slow reaction to an apnea and then over compensating when it finally kicked the pressure up. Like I said before, I don't have any numbers to back that up, just going by the way I felt after sleeping.

Well I've put in my two cents, take it as you will. Good luck to you Timbaliondude in your quest to get the sleep you so well deserve.

[DeVilbiss Marketing]

[quote="ozij[*]It has no other way of avoiding central apneas - neither a pressure cap for "response for apnea" nor other algorithmic protections. All other machines do:a rigid cap at 10 in ResMed machines, user adjustable cap in Sandman and Fisher&Paykel and a "Non responsive" test with pressure drop in Respironics -- meaning that each of these algorithm's will respond to the type of apneas ignored by DeVilbiss.O.[/quote]

The IntelliPAP does have a way to turn off what is scored as Central - by adjusting the setting for Apnea % = 5%, then all events below hypopnea are scored as Apnea.

[ozij]

[*]It has no other way of avoiding central apneas - neither a pressure cap for "response for apnea" nor other algorithmic protections. All other machines do:a rigid cap at 10 in ResMed machines, user adjustable cap in Sandman and Fisher&Paykel and a "Non responsive" test with pressure drop in Respironics -- meaning that each of these algorithm's will respond to the type of apneas ignored by DeVilbiss.O.

The IntelliPAP does have a way to turn off what is scored as Central - by adjusting the setting for Apnea % = 5%, then all events below hypopnea are scored as Apnea.

My point exactly: The DeVilbiss does not take present pressure level into account when attempting to decide whether an apnea is obstructive and therefore needs more pressure, or pressure induced and therefore does not need more pressure. When the scoring is changed, and all events below hypopnea are scored as Apnea, then the DeVilbiss machine will respond with raised pressure to all apneas regardless of whether they are obstructive or central in origin, and regardless of the pressure at which they appeared. Respironics, Covidien (Sandman), Fisher&Paykel and ResMed all change the machines' response patterns based on the pressure at which the event happens. DeVilbiss does not -- can not.

O.