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sptrout wrote: ↑

Sat Mar 18, 2023 1:43 pm

If you look at the ResMed graphs on page 5 you will see a very disturbing pattern. (BTW - - All machines in the Study were set "wide-open" 4-20). Both patterns look like the blade from your favorite saw; sharp vertical rises followed by a rather fast decline. The levels are far above what was necessary to correctly respond to any detected breathing change and could easily cause sleep disruption from either the sharp rise in pressure in the user's face, or the increased likelihood of leak problems.

Anybody who has looked at a Resmed's pressure curve in either ResScan (going back to the S8's and S9's) or SleepyHead/Oscar (S9's, AirSense 10's & 11's) knows all about that saw toothed curve. It's not a surprise at all: Resmed has not significantly changed much about their Auto algorithm since the introduction of the S9 with its FOT algorithm to determine whether the airway is open or obstructed. If I recall correctly, before FOT was introduced, Resmed machines did not increase pressure for clusters of OAs if the pressure was already above 10 cm. Resmed also redefined how hypopneas were scored with the introduction of the S9s; I remember a lot of talk back in 2010 about how much more aggressive the S8s were in scoring Hs than the S9s.

Some of us have argued in the past that Resmed's auto mode is too aggressive in responding to events and that those sudden pressure increases can cause problems with either sleep disruption or increased leaks. Others have praised Resmed's aggressive algorithm as being responsive enough to really break up clusters of events before they get started. It's a point that's been argued about before and no-one's opinion is "better" than anyone else's opinion.

Also worth pointing out: We continuously recommend against running a machine wide open---i.e. with a pressure range from 4--20. Most people do much better when their minimum pressure is set to something close to what an in-lab titration study showed they need or something pretty close to their 95% pressure level if they don't have an actual titration study. And some of us also regularly recommend that setting a maximum pressure that is less than 20 can be a good idea if you have reason to believe that sharp pressure increases may be causing you to wake AND you've already got your min pressure set up where it needs to be set.

Note that the "for Her" model was better than the standard model, but still poor, or really just plain bad. The other brands of APAPs had their own problems, but 2 or 3 did fairly well.

You need to define what you mean by "fairly well." Because not everyone here will agree with your definition of "fairly well" regardless of how you define it.

One other item that I found interesting was the APAPs reaction to the first 50 minutes of each test. The first fifty minutes simulates the user being awake and breathing normally, therefore, the APAP machines should just sit at 4ccH2O waiting for the user to fall asleep and start having breathing problems.

Three comments:

1) In some people, real wake breathing is notoriously irregular compared to sleep breathing; in others? Not so much. We have no idea what the "simulated wake breathing" looked like in this study. But if it didn't look like yours, then there's no way to guarantee that a machine will respond to your particular wake breathing the way these machines responded to the simulated wake breathing.

2) A simulated sleep latency time of 50 minutes is way, way, way too long. Anybody who is regularly taking 50 minutes to get to sleep after turning the light out has a problem with sleep onset insomnia. Yes, some people are likely to slap the machine on their face and read for an hour in bed or (shivers) watch tv or (more shivers) spend time looking at their phone. But if you're not even trying to get to sleep and the pressure does wind up increasing, that's not really a problem unless you are uncomfortable. If you are uncomfortable, you can always turn the machine off and back on to reset the pressure while you are reading in bed. Once you turn the light out? Ideally you should be drifting off to sleep within 15-20 minutes at most.

3) Many, many, many people do not feel comfortable breathing at 4cm. And when you're not comfortable, your wake breathing is even less likely to match whatever was used as "simulated" wake breathing in this study.

On the 10 graphs this 50 minute "awake" time is easily seen on the left side of each plot; a straight line at pressure level 4. If a machine is responding correctly it should be doing nothing except providing a level 4 pressure.

An APAP cannot tell (for sure) whether you are awake or asleep, and the vast majority of them have been programmed to assume the patient is asleep if they're using the machine. Yes, some of them now have so-called "smart ramps" that attempt to detect the onset of real sleep breathing by looking for something like 2 or 3 minutes of very regular breathing that has the characteristics of sleep breathing. But if a patient has a serious problem with apneas occurring just as real sleep is established, then that person's breathing might never settle down enough due to repeated OAs, CAs, Hs, FLs and RERAs that start just as soon as the person is asleep. This is a very serious potential problem if the minimum pressure is left at 4cm and the patient needs at least 8 or 9cm to control the apnea. Do we really want a machine refusing to respond to something that might be significant FL breathing, along with Hs and OAs when you've dropped off to sleep just a few minutes after turning the machine on just because the machine is now programmed to assume that you are still awake until a real, regular normal sleep breathing pattern has been detected for at least two or three minutes?

However, look at the various machines, some go straight to a very high pressure and others climb but not as high. Most of the machines try to start correcting a non-problem; a couple remained at or near 4. As Nick mentions in his video if using one of the machines with fast rising pressure you may want to use the "ramp" feature to help control these rockets.

Three comments:

1) There was a similar bench test done even earlier than this one with much the same results, but with only 5 machines: Some machines seem to be overly aggressive; others barely reacted to the simulated events that should have triggered pressure increases. But in the earlier study, no-one had the crazy idea of trying to see if the machines would be "tricked" by simulated wake breathing over a 50 minute period. (See Auto-Adjusting Positive Airway Pressure from 2009.)

2) If the minimum pressure is 4cm, the ramp is disabled on many (most) machines: You can't "ramp" up to 4cm. So in order to use the ramp, you can't be running at 4-20.

3) If you do have a minimum pressure set, ramping up from 4cm may or may not be a good idea in the first place: Many people feel like they're suffocating at 4cm because too little air is coming into the mask. Next, if the ramp is a traditional ramp, it starts increasing the pressure almost as soon as you turn the machine on because the machine is programmed to steadily increase the pressure in a linear fashion until the minimum pressure is reached at the end of the ramp time. If pressure increases while awake are "troublesome" to you, then you might just notice the constant increase in pressure if you're lying awake while the ramp clock is ticking down. (I know I always did and that made it doubly hard for me to relax enough to get to sleep during my rough early days.)

I have two main takeaways from this Study.
1. Make sure that you control the "awake" pressure since this could be reoccurring each night and even maybe multiple times per night if you wake for one reason or another and have to restart your machine.

What do you mean by "control the 'awake' pressure"? Most of us turn the machine on, turn the light off, and go to sleep. If you're asleep within 10 minutes of turning the machine on, pressure increases before you get to sleep should not be a big issue. If you are reading in bed or otherwise using the machine while not actively attempting to go to sleep AND you are bothered by the pressure increasing while you are awake, you can always turn the machine off and back on.

2. Do Not leave your APAP machine pressure set to "wide-open" unless you absolutely have to due to severe SA issues.

If you have severe SA issues, you should NEVER run the machine wide open: You absolutely need that minimum pressure set up high enough prevent your airway from collapsing in the first place. While you might need to run the machine at 4-20 for a week or so at home if your insurance won't pay for an in-lab titration study, once you've got a weeks worth of data, you need to use it to set your min pressure setting no more than a couple of cm less than your 90% or 95% pressure level. Anything less than that and you're inviting lots of events to happen before the machine can respond by increasing the pressure to a more appropriate level. Moreover, anytime the pressure drops below the level needed to prop your airway open, you're likely to see additional events piling up before the machine has a chance to respond by increasing the pressure to an appropriate level.

If you do leave it wide-open you can see what happens with your machine. I have 4 ResMed 10 machines and I have seen the sawtooth pattern many times before I reduced the maximum pressure considerably. I now have my machine set for a low of 6 (could be lower I expect) with a high of 9. My AHI is nearly always less than 1, mostly between 0 - .5. each night (from OSCAR; my 30 day AHI average as of this morning is .32). Before I reduced the maximum pressure from I believe it was 15, I was having several CAs each night; almost certainly caused by excessive pressure. I seldom have CAs at the reduced pressure.

Good for you for finding a pressure range that works for you in terms of your data. The important question, however, is: How do you feel when you get up in the morning? If the answer is something like Pretty Good, more power to you---you've optimized your APAP therapy.

But there are people who do have problems with RERAs, FLs, and snoring continuing to make them feel bad even though they have a near perfect AHI each night. And one giveaway that they may have the max pressure set too low is if the machine is constantly bumping up against that max pressure when there is something obviously wrong with the breathing pattern---i.e. you're hitting max pressure while there is are severe flow limitations or snoring that is present. For these people, they may need to do some additional dial wingin' to find the best pressure range for them to use.

I hate to say this: But, according to Nick's recommendation the maximum pressure does not need to be much more than the "95% Pressure" as shown on the OSCAR Statistics page. I use the "7 day 95% Pressure" reading of 8.94 to set my max pressure to 9.0. As I mentioned already, the results are great. Low AHI, no sleep interruptions from unnecessary high pressure, and no leaks.

By using a pressure range of 6-9cm, you pretty much doing what we usually tell people:

• Set min pressure 1-3 cm less than the 95% pressure if you're comfortable breathing at that pressure.
• Set max pressure 1-3 cm above the 95% pressure; if you set it just above the 95% and you don't have too many events and you are feeling fine when you wake up, then that's also ok.

sptrout wrote: ↑

Sat Mar 18, 2023 1:57 pm

Not true. He has never mentioned this Board or even referred to this Board or any other SA Board.

Incorrect. He referenced this board and specific members of this board in one of his YouTube videos.

sptrout wrote: ↑

Sat Mar 18, 2023 2:19 pm

I have seen mention somewhere in the past that it was okay, even recommended, that the APAP pressure be left at factory default 4-20.

Any time any poster advocates leaving an APAP at the factory default of 4-10 on this board, there will be a whole lot of folks jumping in to counter that so-called recommendation with what you already do: Set the min pressure a bit lower than your 95% pressure level and your max pressure (if you want one) to a bit higher than your 95% pressure level.

I am sure that poor folks that get their machines from a dumb DME with and even dumber sleep doctor (I have one of those, dumb as a stump) have their machines set at default and never know that they are setting themselves up to fail and want to trash CPAP/APAP therapy because of hating the high pressures.

Yep. A lot of folks come here with machines that have been left wide open. We typically first ask whether the person has had a titration study or whether the machine itself is being used to titrate the person. If the person has had a titration study (rarer these days than when I started), we immediately jump to "reset the pressures". If the person hasn't had a titration study, we'll typically tell them to use the first week's worth of data to set the pressures. And we'll tell them that if they feel like there is not enough air coming in through the mask to inhale comfortably at 4cm, then bump the min pressure up to 6 or 8 and see if that's more comfortable for inhaling.

And yes, a whole lot of people are set up to fail by dumb DMEs (and insensitive sleep docs). But the problem is not always "hating high pressures". Sometimes the problem is not being able to breathe because the pressure is too low. Many times the problem is the newbie was taught to overtighten the headgear, sometimes to the point of pain, in order to "eliminate leaks". Sometimes a DME tells a newbie, they absolutely must use a full face mask when the person will do just fine with a nasal mask or nasal pillows. Sometimes a DME tells a newbie that no-one needs a full face mask, but that person actually is more comfortable with a full face. mask.

There are lots of ways to set a new xPAPer up to fail, and, unfortunately, the average DME finds multiple ways to do it for far too many of their new patients/customers.

sptrout wrote: ↑

Sat Mar 18, 2023 1:57 pm

"Actually, it's him that don't like us:"

Not true. He has never mentioned this Board or even referred to this Board or any other SA Board. He was just pointing out that some scumbag (my words not his) was posting false information and using new IDs each time to avoid detection.

Listen kid. I am the aforementioned dickhead. The image in Nick's post is from one of my characters. They kept throwing me out because I kept pointing out errors and he REALLY don't like that. There were not "hundreds of annoying comments". Since the free period only lasts 2 weeks I had to keep creating characters cause I had no intention of paying them to do their work.

If you have NFI what you're talking about, then don't.

TIA.

If I recall correctly, before FOT was introduced, Resmed machines did not increase pressure for clusters of OAs if the pressure was already above 10 cm.

Point of clarification only.
FOT was new with the S9 model.
Prior to the S9 we had the S8 model line and the auto adjusting algorithm had some limitations when the pressures got up to 10 cm. Sometimes it wouldn't go higher and a lot of people thought that if someone needed greater than 10 cm pressure then apap mode on the S8 wasn't a good choice but that's because they didn't understand the entire auto algorithm.

S8 auto models wouldn't go above 10 cm UNLESS it had a good reason and the good reason wasn't so much OAs as it was flow limitations and snores.
While it wouldn't be impossible to have clusters of OAs without FLs or snores.....lets face it most of the time there is something else going on besides OAs all by themselves.

As for the "wide open" thing. It works sometimes for some people but the level of success is going to depend on what level of pressure is needed to hold the airway open. Some people might only need 6 or 7 or 8 or 9 cm to hold the airway open and going from 4(assuming the person is okay with that low of a pressure) to 7 or 9 is doable in a timely manner and get the job done.
Now if someone needs say 15 cm to hold the airway open then having the minimum at 4 means more time at sub optimal pressures until the machine works its way up to the 15.

And don't forget...often with a more optimal/higher minimum the need for really higher pressures gets reduced and sometimes significantly.
I remember one woman who came here with the 4 to 20 range and she was hitting 18 quite often and for long periods of time. Everyone was talking "you need a bilevel" but that was easier said than done.
Anyway it took not quite 2 weeks and we had her moved up to a 12 cm minimum and added in a bit of EPR for comfort and we left the max at 20 but it was a moot point.....On a very rare occasion she might see the pressure go to 15...never went to 18 again. Just because a machine CAN go to 20 doesn't mean it WILL go to 20....but if people sleep better limiting the max to something it never reaches anyway...more power to them.

Limiting the max....we do that if going higher causes some sort of problem and then it's usually a trade off or compromise.
Nothing wrong with doing it though. If it doesn't go higher then it becomes a moot point. My machine can go to 25 IPAP but the highest it went to in past 2 weeks was 14 and that happened only twice. Some nights 11 might be my max IPAP and another night it might be 12 or 13. I could limit my max IPAP but changing the max IPAP to say 15 really wouldn't accomplish anything for me since I probably wouldn't ever reach it and I don't have any problems caused by the 14 it might go to.

Now if I had bad aerophagia above 12 cm IPAP....for sure I would limit the max but then I would have a good reason and I would have to accept the trade off or compromise if there was one.

Bench tests are mostly about comparing differences in algorithms by using a standard. Some read waaay too much more into them.

Treatment efficacy, on the other hand, is about real-world results across populations of actual human beings.

No matter how good the bench tests become, I believe that the above distinction will always exist, much as how animal testing in other aspects of medicine will never replace actual human results.

ResMed stands behind the effectiveness of the design of its products, including the algorithms. I consider ResMed's algorithm approach(es) to be brilliant and its machines to be top notch. I do have a personal distaste for their business practices, but I still prefer their machines. Especially these days.

Nick the Clown, on the other hand, has not impressed me with his recent methods. He does not seem to me to be particularly insightful or knowledgeable on sleep, from where I sit. I think he's in over his head. And now that he appears to be all about getting hits and subscribers by means of contrived controversy instead of trying to talk sense, I choose to avoid his channel completely, on principle.

I might agree to have a pint with him, as long as he promised not to talk about sleep medicine. But that's about it.

Hey, just me.

Yes... Uncle Nicko can be annoying, but I watched the video.
There were some interesting take-aways.

1. Some providers have provided machines with the settings at 4-20. The study and Nick point out that in some cases having the 20 top end is detrimental, because the machines may respond to an event with more pressure and longer than it's actually needed. One of the reasons that people don't tolerate therapy is due to the discomfort of too much pressure, or too much pressure before falling asleep.

2. More pressure than needed can cause other issues, like mask leak, waking the user up, etc.

This was a computer based simulation, so it may not apply to every situation in the real world, but it was interesting nonetheless.

zonker wrote: ↑

Sat Mar 18, 2023 11:43 am

do people NOT read the whole thread before replying?

Of course not, gotta get them delicious posting points...Oh, wait, there aren't any points.

sptrout wrote: ↑

Sat Mar 18, 2023 1:43 pm

I find Uncle Nick's videos both entertaining and very informative. For example, one recent video he compared the recommended parts (air filters, hoses, etc.) replacement schedule for the exact same device, but one from the USA Manual the other from the Aussie Manual.

I bet he made the video *AFTER* that subject was posted here.

viewtopic/t185894/CPAP-Supplies-Last-Up ... erent.html

I'm sorry you have such low standards for 'entertainment'.

But, hey, as long as he got the views, he's happy.

sptrout wrote: ↑

Sat Mar 18, 2023 1:57 pm

"Actually, it's him that don't like us:"

Not true. He has never mentioned this Board

Where has your head been? it must be dark up there.

Since you love that loser so much, watch this: https://www.youtube.com/watch?v=oMpTyG1m8oo

In other words, you're as wrong about that as you are about the OTHER things you posted.

sptrout wrote: ↑

Sat Mar 18, 2023 1:57 pm

The SleepHQ Board is growing rapidly

most cults do.

Wouldn't you be happier over there?

PS, I've never been on his little money making forum, his rant was because he was *OVER HERE*.

sptrout wrote: ↑

Sat Mar 18, 2023 2:19 pm

The pressure each machine went upto never reached 20, 15 I believe was the highest.

It's not about the Max pressure, it almost never is, what's important is the MINIMUM pressure.

For the majority of actual human beings, leaving the max at 20 is fine. It is the min needing to be within one or two cmH2O of what is needed to prevent apneas that is crucial for some. Not all. But I believe it to be very rare for someone to have a breathing pattern that makes a ResMed run away with unnecessarily high pressures. Limiting max is generally more a matter of sacrificing some treatment effectiveness for an individual in order to prevent some side-effects, such as swallowing air, as has been mentioned.

My opinion is that he is now more than annoying. I believe he may have moved solidly into the misleading and detrimental category with some of his statements.

Then again, he would probably put me in that category.

So researcher beware.

sptrout wrote: ↑

Sat Mar 18, 2023 2:19 pm

I have seen mention somewhere in the past that it was okay, even recommended, that the APAP pressure be left at factory default 4-20.

Not recommended by anybody that knows even the slightest bit about how the machines work, no.

jsmit86 wrote: ↑

Sat Mar 18, 2023 6:10 pm

Yes... Uncle Nicko can be annoying, but I watched the video.
There were some interesting take-aways.

1. Some providers have provided machines with the settings at 4-20. The study and Nick point out that in some cases having the 20 top end is detrimental, because the machines may respond to an event with more pressure and longer than it's actually needed.

Creepy "uncle" dicko knows so very little.

If the machine has the MINIMUM pressure set properly, then it won't *NEED* to ever come close to the max pressure.

All you do by lowering the max pressure, for MOST people, is prevent the machine from being able to respond if you need more pressure for some reason, like REM after rolling onto your back.

jsmit86 wrote: ↑

Sat Mar 18, 2023 6:10 pm

One of the reasons that people don't tolerate therapy is due to the discomfort of too much pressure, or too much pressure before falling asleep.

2. More pressure than needed can cause other issues, like mask leak, waking the user up, etc.

If only you knew a tenth as much as you think you do.

lazarus wrote: ↑

Sat Mar 18, 2023 6:26 pm

My opinion is that he is now more than annoying. I believe he may have moved solidly into the misleading and detrimental category with some of his statements.

All 'he' cares about is conning people out of their money in his cult.

Otherwise, he'd WELCOME the corrections to his garbage posts by whatever username Rubicon is using at the moment.