Respironics Omnilab advanced - 2cm pulses - is it normal?

[DreamDiver]

I had a titration last night. I was a little put out by the flow generator they used. Every time I was about to drift off to the Land of La, it would pulse a 2cm slap of extra pressure on my face for three seconds and then go back to the prescribed current titration pressure. They wanted to start me at five. I told her I couldn't breathe at 5, let's try 8. She said what about 6. I said 8. So at 8, we did the normalizing tests for the leads: (blink, shake your leg, etc.) She got the point where she asked me to hold my breath for ten seconds. That's when it first happened: two pulses, 3 seconds apart, each three seconds long. I figured she was adjusting the pressure. So I start the night.

Just as I'm drifting off, pulse... pulse... It was then I vaguely remembered something like this happening in my first titration of 2007. After the tenth time, I woke up and asked for her assistance. She came in the room and I took off my mask. I told her the machine was pulsing and that it is a sleep arousal factor for me. This is not going to be a very useful study if it keeps waking me up. She said the prescribed pressure at the desk hadn't jumped. The pressure hadn't changed - she was watching. I said, "let's get a manometer out and check." At first she said she didn't have one. I raised an eyebrow and said, "A sleep lab without a manometer? I don't think so." It took a good ten minutes, but she found one and together we saw the pressure jump 2 cm from 8 to 10 and then back down again, multiple times. I think she honestly didn't know, but there was the proof staring her in the face.

She got the administrator on the phone, who guided her through an attempt at retrying what we just did. Same thing. So she unplugged the machine and it stopped doing it for a while. The tech suggested that if it happened again, we'd switch machines. The administrator hung up, I masked up, and the tech plugged me in again, and I was ready to drop off again. Pulse... pulse.... I got the tech's attention again. She very kindly got an identical machine out of a room from a no-show and switched them out in front of me. Same thing. I asked her to try 7 cm instead of 8. I figured if it happened again, maybe 9cm wouldn't feel like as much of a slap. As I nodded off again, I got slapped in the face. I gave up and just tried to get to sleep.

I woke up with a headache around 1pm and this time with tinnitus - something that usually only happens when I'm not well oxygenated. Then the slapping started again. I got up and did the bathroom thing and went back to sleep, this time on my belly, in hopes of trying to ignore the slap. Not much success at first, but finally I drifted off. I got titrated up to 9, and that's where the study ended. She said my 02 was good all night, except a couple times when it dipped to 91.

She said she couldn't raise the pressure if I didn't get any apneas/hypopneas. Apparently I only had a couple of hypopneas. No centrals. So I don't know if centrals are really happening on my machine. When I use the S9, it still says all my apneas are centrals. I still felt like garbage after the titration.

I don't know if the titration was really valid. I know from looking at the flow lines on my S9 that COS and FOT are valid for each marked apnea. Only three times since I've had the machine have I seen an 'unknown' apnea, and only four times have I seen obstructive - which are obviously obstructive in the flow graph.

The tech and I both saw the 2cm jump in pressure. She said she was going to test out the machine on herself on Tuesday to feel what's really happening - she's never tried out the machines herself. I told her that if this is normal for all respironics ominlab advanced machines, they have a serious problem because a 2cm pressure change is a slap that is going to wake anyone who is used to CPAP. Imagine what it's doing to those who aren't used to it? How can you really be sure this device is giving an accurate titration if it's slapping people awake all night?

I wrote in my exit form that while the sleep personnel are excellent and friendly, I thought the titration was flawed and that they need to seriously look at the titration machines they're using.

Unfortunately for me, regardless of pressure, the first part of my nights before the bathroom break, I usually sleep through without apnea. It generally happens more frequently after the bathroom break.

From the feel of the response and the feedback on other machines I've heard about on this forum, I'd guess it's using a CPAP pressure regime overlayed with some kind of spontaneous/timed algorithm. Whatever it is, it doesn't work for me -- and it is not CPAP. Half the time, I was breathing in when it wanted me to breathe out. You may imagine I was fairly steamed. I imagine, if I had a machine like this in my home, I could probably get used to being slapped in the face on a spontaneous/timed interval -- but we don't get those at home. We get straight CPAP. This is comparing apples to oranges. They have no idea how that pulse is changing the effect of what I'm experiencing in the lab as compared to what I experience at home. It's just wrong-headed and illogical.

So - those of you in the know - is it normal for the omnilab advanced to slap some of their patients awake all night like that? Just curious as to whether I just wasted a couple thousand of my insurance dime for nothing.

[echo]

You must be so frustrated! I'm sorry I can't help you out on the specifics of that machine, but I -- well -- dunno what words to say! I'm so sorry about the titration!

[DreamDiver]

If I look at it objectively, it could be interpreted that I'm having centrals because my pressure is set too high - not having yet seen the report, but reading between the lines of what the tech said. But previous self-titrations at 9cm showed really crummy results as compared to 10, or better yet, 10.4. Using my machine, I get one result. Using their machines I get another. The machine they use for titration is so drastically different from what I use at home, I cannot see how they can tell me what I need to use pressure-wise for anything other than the respironics omnilab advanced. Even my M-Series never slapped me like that.

[dsm]

I am not certain by any means, but think I read somewhere where some Respironics machines use pulsing to try to determine if closed airway apneas ore occurring.

Doing a hypothetical, if the machine detects a hypopnea taking place, it may do the pulse cycle as a way of trying to determine if the airway is open or closed. This of course is different to FOT which IIRC adds a 1 CM pressure pulse at 4 cycles per second.

What model machine was it, I can try to do some research on its algorithms.

Cheers

DSM

PS found these links thus far ...

http://omnilab.respironics.com/

http://www.rtmagazine.com/respiratoryre ... -10_12.asp

[echo]

Maybe you never got into REM sleep if your sleeping was so fractured from the wake-ups, and thus no severe apnea's? Just conjecture, the full report will be useful to peruse. Yep, if they're centrals they're only coming out > 10 or 10.4 in your case.

I couldn't find anything major on the Omnilab, it's seems to be a newer titration device that can also be used in Cpap & Bipap modes (http://omnilab.respironics.com/)... I couldn't find info on how it works though I didn't search very hard, I also trolled a bit through the binarysleep.com site and didn't see anything noteworthy there.

I find a 2cm slap in the face quite severe, it doesn't sound like the 'puff of air' to check what's going on...

[dsm]

It seems the device is a multi-mode (software controlled) and thus the lab would most likely have set it in one of the modes.

Can you find out which mode they were using ?

>>
Six modes - with multiple technologies - including
- Respironics BiPAP autoSV Advanced and
- Respironics BiPAP AVAPS - are accessible directly from your PC, so you can titrate more types of patients than ever before.
<<

Pressure Ranges
==============
CPAP 4 - 20 cm H2O
BiPAP S EPAP 4 - 25 cm H2O
........ IPAP 4 - 25 cm H2O
BiPAP S/T, T, PC EPAP 4 - 25 cm H2O
........ IPAP 4 - 30 cm H2O
BiPAP autoSV EPAP 4 - 25 cm H2O
........ IPAP min 4 - 30 cm H2O
........ IPAP max 4 - 30 cm H2O

Device Setup PC Direct and onboard keypad

“The OmniLab contains two of our most advanced technologies, BiPAP autoSV® for patients with various forms of central apneas (such as complex and mixed apneas and Cheynes-Stokes respiration) and BiPAP AVAPS™ for patients with underlying, progressive respiratory conditions that require frequent changes over time (such as restrictive thoracic, neuromuscular, and obesity hypoventilation disorders),” says Kevin Dorcak, Respironics product marketing manager.

[unadog]

Responding to sleep onset central apneas?

I'm not familiar with the Omnilab. If it's not in auto mode or ASV, it must be trying to collect it's OA/CA/FLOW, etc. statistics?

Sounds like a bad night. Sorry!! Wow, sucks, waiting still....

Michael

[park_ridge_dave]

For what it's worth, I have the Respironics REMStar Pro Cflex+ (System one) and if I don't breath for about 10 seconds it gives me a short "Pressure Pulse". I see them in my detailed reports.

I was trying to do a pressure check using the "bubbler" technique and the pulses were driving me crazy(short trip ). I was told by one of the members here and subsequently confirmed that on my unit the pulse is indeed used to check to see if it is a clear way apnea or an obstruction event. To do the test for pressure (without an expensive pressure meter) I had to go to provider setup mode and run it from there (no pulse then). Anyway, that probably doesn't help you much, though

Cheers,

Dave

[dsm]

Some more info I have found.

The Omnilab has been in use since about 2008 around various labs in the US.

There is now an 'Advanced' version & this implies to me it has added algorithms for doing the open/closed airway test
(IIRC, this algorithm was added to the Bipap Auto SV either last year or early this year, so by deduction the 'Adavanced' Omnilab probably came out in the same time frame especially since it emulates the Advanced Bipap Auto SV).

If it has the open closed airway sensing then it does 'pulse' the sleeper. I don't know enough about that sampling & exactly how it works to say more. SWS may well be able to comment though.

Cheers

DSM

[DreamDiver]

Thanks everyone for your replies and help. It is the Respironics omnilab advanced, as dsm suggests. I confirmed that they set it to straight CPAP with no C-Flex. It was only when I showed the tech the flaw that she believed me. The weird thing is - I seem to remember something like this from my lab in 2007, but it was not anything this obnoxious. park_ridge_dave, how anyone could sleep through that is beyond me. Were you seeing the 2cm abrupt rise and fall in pressure too, or was it more subtle? To me, the force of it was too obvious - a posterized discreet step between 8 cm and 10, then back down to 8 -- no smooth transition. I will never buy a system one if that's its 'answer' to FOT or any Respironics 'advanced' machine. That is utterly ridiculous.

The sad thing is, the techs - even the manager did not know it existed. Consequently, they didn't know how to turn it off.

So what does Respironics call this alleged... 'feature'?

I hope perhaps someone who is completely familiar with the omnilab advanced will comment.

[-SWS]

So what does Respironics call this alleged... 'feature'?

"Clear airway" apnea detection. Apparently that new detection feature went into the PR System One Series and the Omnilab sequel called Omnilab Advanced. Well, so far we know that very few PR System One users on this message board report their machine's "clear airway" detection pulse to be objectionable.

DD, do you happen to remember my recent fishing expedition about your possible hypersensitivity?
viewtopic.php?f=1&t=51219&st=0&sk=t&sd= ... li#p471855

S9 FOT is definitely your better bet between those two central-apnea detection methods IMHO.

[dsm]

DD
I agree with SWS that perhaps you have a notable sensitivity to particular pressure rises (fast ones).

The FOT 1 CM pressure on the S9 is shaped (shark fin wave form) which makes it easier to take anyway. The extra FOT 1 CM is delivered within the sharkfin wave form already being delivered (being part of what Resmed calls EasyBreathe). On the Respironics machines the shape of the sampling pulse is (from my educated guess) more squared (but not purely square - i.e. steep slope up then level then steep slope down). From what I know, that shape wave form is more easily sensed by users. The normal bipap epap to ipap pressure jump is similar but that slope can be adjusted with variable rise time settings. It seems the open airway sampling pulse risetime isn't settable. Being 2 CMs shouldn't be too big a deal as a Bipap Auto SV will whack up pressure by 3 CMs within a single breath (but adjustable by normal risetime settings).

I also agree with SWS that not too many people have indicated much discomfort from the Respironics open airway sampling pulse.

Good luck

DSM

[park_ridge_dave]

Thanks everyone for your replies and help. It is the Respironics omnilab advanced, as dsm suggests. I confirmed that they set it to straight CPAP with no C-Flex. It was only when I showed the tech the flaw that she believed me. The weird thing is - I seem to remember something like this from my lab in 2007, but it was not anything this obnoxious. park_ridge_dave, how anyone could sleep through that is beyond me. Were you seeing the 2cm abrupt rise and fall in pressure too, or was it more subtle? To me, the force of it was too obvious - a posterized discreet step between 8 cm and 10, then back down to 8 -- no smooth transition. I will never buy a system one if that's its 'answer' to FOT or any Respironics 'advanced' machine. That is utterly ridiculous.

The sad thing is, the techs - even the manager did not know it existed. Consequently, they didn't know how to turn it off.

So what does Respironics call this alleged... 'feature'?

I hope perhaps someone who is completely familiar with the omnilab advanced will comment.

DreamDiver,

I only experience the pulse if I haven't breathed in roughly 10 seconds. I am only conscious of it when I am awake. When I am asleep, I don't seem to notice it.

I must be a real heavy sleeper or something??

Anyway, I am wondering if any Respironics Representatives are "lurking" so they could shed some more light on this "feature" OBTW to my knowledge, there is no way to turn off the pulses on my machine.

I will see if I can post some "traces" later on today.

Best of luck

Dave

[echo]

Try a post on binarysleep.com if you don't find any additional info.... maybe some of the other more experience tech's on that site have more knowledge about the Omnilab.

DD, you _sure_ you don't want to try out that 420E?

By the way, stupid question: are both Resmed and Respironics now using the FOT method to do "clear airway" detection?

Some random info I found, may be interesting in light of the 'sensitivity' issue:
http://archive.ugent.be/input/download? ... OId=412650
Efficacy of Flow- vs Impedance-Guided Autoadjustable Continuous Positive Airway Pressure
This interesting article from 2004 (so a lot has probably changed since then): it compares 2 APAPs, one using FL (Resmet Autoset) and the other using FOT (OMNOsmart). They found that APAPfl was better for controlling snoring (as well as AHI but it was not statistically significant), and also resulted in higher median pressure (as 90/95% pressure) but less pressure variability.

Both the measurement of respiratory impedance based on forced oscillations applied to the upper airway, and the detection of inspiratory flow limitation have been used for monitoring of residual airway obstruction during CPAP titration. Lorino et al21 demonstrated that the former method is more sensitive than the latter. Accordingly, the responses to the detection of disturbed breathing may be different in APAPfot and APAPfl methods. Another important difference between the two methods are the reaction times (change in pressure/change in time) that determine the rate at which the pressure adjustment will be completed. The slope of adaptation is steeper in both lowering and increasing the pressure in response to certain respiratory events with the APAPfot method. While a more sensitive and faster response to respiratory changes may predispose the APAPfot method to greater variability in pressure output, the handling of unphysiologic signals by the APAPfot method is also dissimilar from the APAPfl method. The AutoSet device, in contrast to the SOMNOsmart device, has a built-in system for the continuous monitoring of bias flow. The system is able to compensate for pressure drops due to excessive air leakage up to a flow rate of 0.4 L/s.11 Since mask and/or mouth leaks often occur during sleep, this may in part explain why higher median positive pressure levels were found in the AutoSet device.

So while this doesn't address the curve of the FOT itself, the associated rise/fall of the APAP pressure seems to be more aggressive, at least with the OMNOsmart. I guess that's because they have "more confidence" in the detection algorithm.
Anyway this in no way relates to any of the device you have (at home or titration), but some food for thought, or possibly a red herring

[park_ridge_dave]

DD, as promised, here is a snippet of my results from last night. Note the pulses usually stop after I am asleep unless I have an episode of Periodic breathing or a CA event.

I am a little puzzled by some of the wave shapes (e.g. the ones that appear to be decaying envelops ) Hopefully, if and when I can see my sleep doc I can ask him.



Don't know if this helps or not, but that's what happens on my machine

Oops! Almost forgot, pressure was set at 13.5 cm and CPAP only!

Cheers,

Dave