Resmed vs. Respironics - Help

[StillAnotherGuest]

There's a rumor circulating that Rapoport sold patent 6299581 to Volvo for use in the S80. Sir, do you have any clue just how that rumor got started?

LOL! Wasn't that one great?

I got another one for you...

A priest, a rabbi, and a ballistocardiographer walk into a bar...

Speaking of that thread, I never did find out how expiratory instability can be sucessfully addressed with lowering EPAP. This is going to be a great segue.

Then...same 4 questions if the obstructive apnea were a full occlusion -- no air, not even a thread, being breathed.

For that one, with only 1-2 cmH2O, I'm going to go with "nothing".

Out of all the factors involved, the one that would have the most effect would be increase in lung volume, which wouldn't occur until the ensuing period of spontaneous breathing.

SAG

Thank you.

De nada.

However, invoking the 4W Principle (Wishy-Washy Waxing and Waning), I also believe that increasing pressure mid-apnea might effect a change depending on the severity of the 100% occlusion (are you occluded, or REALLY occluded) and the duration of the apnea.

The negative forces at work are largely intermittant. Depending on the respiratory rate and duration of apnea, there will be a number of "tweeners" - periods of no negative inspiratory effort. Although one could continue to exhale, but not inhale (the "one-way valve" philosophy) and continue to lower lung volume (FRC) and make the occlusion worse, there probably is some pressure that would overcome the occlusion with the splinting effect and/or "Arnold IPAP" (assuming you could somehow synchronize that).

During periods of effort, however, even though pharyngeal dilator activity increases, the negative inspiratory forces increase faster, and the occlusion persists.

(Holding finger on checker) And all this may/will change once stable sleep is attained.

SAG

[split_city]

Rightio, here is a snapshot from a patient showing three obstructive events. It should be pretty obvious that collapse occurs towards the end of expiration and not during inspiration.

[split_city]

Thanks for coming to our cocktail party, split_city!

Velbor's also trying to understand why his dental device seems to work better for him than CPAP. I took some purely speculative attempts at answering that question. If you had thoughts toward that question, we would love to hear those as well.

Hmmm, I'm no expert in this field

A few questions for Velbor:

1) What's your AHI under baseline conditions?
2) Do you have posture-dependent OSA?
3) What type of events i.e. hypopneas, apneas do you predominantly have?
4) Are you CPAP compliant?
5) Leaks an issue?

Perhaps the OSA is caused by a craniofacial abnormality which is "fixed" more effectively by a mandibular splint. There are likely to be a number of potential reasons though.

[NightHawkeye]

However, invoking the 4W Principle (Wishy-Washy Waxing and Waning), I also believe that increasing pressure mid-apnea might effect a change depending on the severity of the 100% occlusion (are you occluded, or REALLY occluded) and the duration of the apnea.

The negative forces at work are largely intermittant. Depending on the respiratory rate and duration of apnea, there will be a number of "tweeners" - periods of no negative inspiratory effort. Although one could continue to exhale, but not inhale (the "one-way valve" philosophy) and continue to lower lung volume (FRC) and make the occlusion worse, there probably is some pressure that would overcome the occlusion with the splinting effect and/or "Arnold IPAP" (assuming you could somehow synchronize that).

ROTFL. Amazing, SAG!

You have encapsulated all 23 pages of this thread in 2 concise paragraphs. Excellent work!

[Needsdecaf]

By the way, what kind of prize do I get for having my first ever thread on the forum go to 23 pages?

[NightHawkeye]

By the way, what kind of prize do I get for having my first ever thread on the forum go to 23 pages?

Uh, oh ..., might not should have asked that question. .

[Wulfman]

Then...same 4 questions if the obstructive apnea were a full occlusion -- no air, not even a thread, being breathed.

For that one, with only 1-2 cmH2O, I'm going to go with "nothing".

Out of all the factors involved, the one that would have the most effect would be increase in lung volume, which wouldn't occur until the ensuing period of spontaneous breathing.

SAG

Thank you.

De nada.

However, invoking the 4W Principle (Wishy-Washy Waxing and Waning), I also believe that increasing pressure mid-apnea might effect a change depending on the severity of the 100% occlusion (are you occluded, or REALLY occluded) and the duration of the apnea.

The negative forces at work are largely intermittant. Depending on the respiratory rate and duration of apnea, there will be a number of "tweeners" - periods of no negative inspiratory effort. Although one could continue to exhale, but not inhale (the "one-way valve" philosophy) and continue to lower lung volume (FRC) and make the occlusion worse, there probably is some pressure that would overcome the occlusion with the splinting effect and/or "Arnold IPAP" (assuming you could somehow synchronize that).

During periods of effort, however, even though pharyngeal dilator activity increases, the negative inspiratory forces increase faster, and the occlusion persists.

(Holding finger on checker) And all this may/will change once stable sleep is attained.

SAG

SAG,

Some of this brought up some questions in my little pea-brain. Relating back to my first few weeks on therapy, I had one 72 second apnea and a 60 second apnea recorded by Encore Pro.........so..........
Assuming that there was a well-qualified tech doing the sleep study.......what kind of time frame would they have to decide what to do? (like increase pressure or leave it alone) What are some of the longer/longest apneas that the sleep techs observe? At what point might the "pharyngeal dilator activity" (gag reflex) take over.......or maybe in a "worst-case scenario" like RG brought up......when would they start CPR?

Just wondering what some of the thought processes of the tech might be during these lengthy apnea situations.

Muchas gracias.

Den

[StillAnotherGuest]

Some of this brought up some questions in my little pea-brain. Relating back to my first few weeks on therapy, I had one 72 second apnea and a 60 second apnea recorded by Encore Pro...

Using Encore Pro (and therefore being on CPAP), the first thing one might ask is if that measurement is truly accurate (artifact, 2 or 3 respiratory events running together, etc.)

Assuming that there was a well-qualified tech doing the sleep study.......what kind of time frame would they have to decide what to do? (like increase pressure or leave it alone)

I don't know of anyone that adjusts pressures in mid-event. Pressure changes are generally made according to RDI, usually allowing about 15 minutes to allow each pressure to equilibrate.

Consideration is also given to snoring, flow limitations, desaturations and unexplained arousals.

What are some of the longer/longest apneas that the sleep techs observe?

Personally? 119 seconds.

At what point might the "pharyngeal dilator activity" (gag reflex) take over...

In adults, usually when an "arousal" gives it a boost (although that particular moment is debatable, termination of event <> arousal).

....or maybe in a "worst-case scenario" like RG brought up......when would they start CPR?

Intervention is usually based on the appearance of a major cardiac event (asystole, sustained bradycardia, VT/VF, etc.). Everybody should (make that "must") have a "panic list" of pre-defined criteria for intervention.

Just wondering what some of the thought processes of the tech might be during these lengthy apnea situations.

Personally? Breasts.

SAG

[Wulfman]

Just wondering what some of the thought processes of the tech might be during these lengthy apnea situations.

Personally? Breasts.

SAG

I really appreciated ALL that information.

REALLY......Thanks!

119 seconds, huh?

Den

[StillAnotherGuest]

Just wondering what some of the thought processes of the tech might be during these lengthy apnea situations.

Personally? Breasts.

No wait, I mean APNEA!! Yeah, apnea, thinking about apnea. Nice, long apneas. Soft apneas. Fully-formed apneas. Nothing like beautiful...

No wait, AROUSALS! Thinking about...

Whoops! Better not go down that road...

SAG

[Wulfman]

Just wondering what some of the thought processes of the tech might be during these lengthy apnea situations.

Personally? Breasts.

No wait, I mean APNEA!! Yeah, apnea, thinking about apnea. Nice, long apneas. Soft apneas. Fully-formed apneas. Nothing like beautiful...

No wait, AROUSALS! Thinking about...

Whoops! Better not go down that road...

SAG

I'll try to take you off the hook by pointing out that you ALREADY went down that road......and covered that quite well.

In adults, usually when an "arousal" gives it a boost (although that particular moment is debatable, termination of event <> arousal).

Consideration is also given to snoring, flow limitations, desaturations and unexplained arousals.

Den

[Snoredog]

By the way, what kind of prize do I get for having my first ever thread on the forum go to 23 pages?

Nothing! we are long winded on every topic!

[ozij]

SAG, you are a riot!

O.

[Velbor]

Have I mentioned that I dislike cocktail parties?? All the meaningless, undirected, random chatter ....

Velbor's also trying to understand why his dental device seems to work better for him than CPAP. I took some purely speculative attempts at answering that question.

Actually, my mention of my own situation on page 18, and my questions about CPAP mechanisms of action on page 21 (which I thought was the topic of most posts to that point) were not intentionally meant to be connected. Nonetheless, I don't object to linking the two, though I would word my own question (watched the debate last night) not so much in terms of why the oral appliance is better, but rather why CPAP (supposedly the "gold standard") doesn't work better for me than it does.

It's also been my general practice in this forum not to ask for personal OSA-related suggestions (I'm one of those reactionary "go back and knowledgeably talk to your doctor" advocates) but rather to collect facts and ideas and work them through myself. However, given the obvious brainpower collected here, I would be a fool not to take advantage of it. So I will respond (after a fashion) to:

A few questions for Velbor:

1) What's your AHI under baseline conditions?

Ouch. One of my least favorite questions. "I am not a number .... I am a free man!" (Patrick McGoohan, The Prisoner) Notwithstanding: my original full-night baseline PSG showed an AHI of about 28 (over 57 while in REM), with an AI of about 17 (all obstructive, no centrals), longest duration 54 seconds.

2) Do you have posture-dependent OSA?

Never well documented. I tend to sleep primarily on my side.

3) What type of events i.e. hypopneas, apneas do you predominantly have?

Overall statistics on CPAP, using ResMed auto set at 6 to 12, produce an average AHI of about 10 and an average AI of about 2. (Yes, yes, I know that's viewed as "too wide" a range. But I've run it at 9 to 12 and there's no significant change in outcome. Only rarely does the graph momentarily bump into 12 at the top.)

4) Are you CPAP compliant?
5) Leaks an issue?

Do I sound like a very compliant sort of person? I think not! But when I use CPAP (or my appliance), it's 8 to 9 hours nightly, and leak is rarely an issue. Never tried it before, but I have moved two night graphs online (I'll give links rather than take up even more room within the post), dated only a week apart, answering these questions and reflecting my variability between the best of times (AHI=8.3, AI=0.4) and the worst of times (AHI=13.5, AI=4.5)

http://links.pictures.aol.com/pic/3150p ... 3Ig=_l.jpg

http://links.pictures.aol.com/pic/3150p ... 3Ig=_l.jpg

Perhaps the OSA is caused by a craniofacial abnormality which is "fixed" more effectively by a mandibular splint. There are likely to be a number of potential reasons though.

Calling me abnormal, are you?? Well, OK. But not in terms of craniofacial structure. On the other hand, I do have a Mallampati Class 4 pharynx and a very narrow airway. Tough to intubate, but a great candidate for oral appliance therapy of my OSA.

Have I mentioned that I dislike cocktail parties?? But this one has been fun.

I particularly want to thank NightHawkeye for the diagram posted on Page 22. It portrays, more effectively than any other I've seen, how a "radial" pressure differential from CPAP can exist between the airway and the outside, which could indeed involve the movement of "craniofacial structures". So I retract my ill-advised suggestion that the airway is radially rigid. I also want to thank -SWS for his introduction of the concept of "inflation", reminding me that the "limp balloon" model in fact has a closed end. And I would thank SAG for his "thought processes" reflections, which are clearly unrelated to the "limp balloon" model.

[dsm]

SAG, you are a riot!

O.

Ditto

Without ever seeing SAG in person I am conjuring up an image of the doctor in the tv show 'House' - straight faced & entertainingly irreverent.



DSM