If AirSense10 EPR 3 feels good, might BIPAP be even better?

[justMongo]

I think the OP lives in the land down under, so not sure what their "federal law" is.

You are correct, the OP is in Oz. I should read the profiles more carefully. The OP may very well be able to by a bilevel in Oz without an Rx.

Doesn't hurt to remind our US audience that Apneaboard must not advocate nor facilitate the transfer of items requiring an Rx. In a recent discussion with our Moderator in Perth, I was told that we have consistently applied that policy to people outside the US too.

[robysue]

then the presumption was that he'd have the minps set lower than he might have the fixed ps of the resmed,

Why? Why would you assume that he would automatically set his min PS lower than the fixed PS on a resmed machine? That's certainly NOT the way that I'd set my PR machine if I had a Series 60 BiPAP or a DreamStation BiPAP.

A DreamStation BiPAP Auto user is probably more likely to set the min PS on a PR = the fixed PS on a Resmed.

The choices that PR and Resmed have made in their bilevel algorithms are all about whether you want to allow the IPAP to increase without increasing the EPAP or whether you want to force the EPAP to increase with the IPAP.

To make it very concrete: Let's look at a Resmed VPAP with the following settings:

• Min EPAP = 4
  Max IPAP = 10
  PS = 4

The EPAP varies from 4-6 and the IPAP varies from 8-10. But the various pressure combinations are limited to IPAP = EPAP + 4 at all times. In other words, if we look at the various possible IPAPs for "nice" EPAP values we see that on the Resmed VPAP you have:

• EPAP = 4, IPAP = 8
  EPAP = 5, IPAP = 9
  EPAP = 6, IPAP = 10

The settings that many (probably most) PR Series 60 or DreamStation BiPAP users would use to "match" the above Resmed settings on their PR machine would be:

• Min EPAP = 4
  Max IPAP = 10
  Min PS = 4
  Max PS = 6

Again, EPAP varies from 4-6 and IPAP varies from 8-10 with these settings. But because IPAP - EPAP can vary from 4 to 6, you wind up with these possible pressures:

• EPAP = 4, IPAP = 8
  EPAP = 4, IPAP = 9
  EPAP = 4, IPAP = 10
  EPAP = 5, IPAP = 9
  EPAP = 5, IPAP = 10
  EPAP = 6, IPAP = 10
  

That variable PS allows you to let the machine raise IPAP to max IPAP without forcing the machine to raise EPAP to max EPAP. In my own data, my IPAP is often running at max IPAP (due to flow limitations) while my EPAP is sitting at min EPAP since there hasn't been any snoring or OAs to warrant an increase in EPAP. And keeping that EPAP as low as possible is one thing that can be very important if aerophagia is an issue.

[Carbon]

Thanks for the detailed explanations everyone.

And keeping that EPAP as low as possible is one thing that can be very important if aerophagia is an issue.

I'll gradually take my APAP to 10 with EPR 3 and see how that goes. My flow limitations drop to 95% 0.02 at 10 which seemed to give me deeper sleep, that seems disturbed mainly some aerophagy with the EPR at 2. If 10/3 doesn't work, then I'll ask my Resp Physician for a Bilevel script. The DreamStation BiPAP Auto looks to have more options and flexibility than the ResMed.

I'm sure it is price anchoring on my part, but having paid about the same in AUD for an APAP as a US sourced bilevel costs, getting one of those would feel a bargain!

[palerider]

the resmed bilevels are more configurable, except with the varying ps.

you can change a lot in how they respond to breathing with the trigger, cycle, TiMin and TiMax settings, which aren't available on the respironics.

as long as you're fine with the defaults, then it's a non-issue.

[robysue]

the resmed bilevels are more configurable, except with the varying ps.

But for some of us the varying ps IS the critical thing that we want to be able to configure. And you just can't do that on a VPAP.

you can change a lot in how they respond to breathing with the trigger, cycle, TiMin and TiMax settings, which aren't available on the respironics.

All of this is true. But for most of us, the default trigger, cycle, TiMin and TiMax values that the Resmed and PR machines use work just fine in terms of letting the machine correctly identify our inhalations and exhalations.

The variable PS on the PR machines is a godsend to those of us with aerophagia problems because the allowing the IPAP to increase without dragging the EPAP up can make PAP therapy much more comfortable.

On the other hand the Resmed machines can be a godsend to folks who need to tweak the trigger, cycle, TiMin or TiMax settings in order for the machine to properly detect their inhalations and exhalations.

[Carbon]

Carbon, I am pretty sure you are looking for the same thing I was. My Doctor changed me from APAP to VPAP so I could have "an EPR of 4" and set up the settings to provide the BiLevel equivalent. Yes it help me sleep better, and I also discovered that there are several additional settings that have made a dramatic impact on my sleeping: Timin, Timax, trigger and cycle sensitivities.

Thanks PoolQ - I'll have a look at your previous threads to get my head around all those additional settings, and have a talk to my respiratory guy if any of it might be relevant to me.

the resmed bilevels are more configurable, except with the varying ps.

you can change a lot in how they respond to breathing with the trigger, cycle, TiMin and TiMax settings, which aren't available on the respironics.

as long as you're fine with the defaults, then it's a non-issue.

Thanks pale rider. I think I am in the group that is pretty sensitive to flow limitations and RERA's. I have never snored, and had only one apnoea (but loads of hypopneas) on my diagnostic sleep study. Flow limits weren't assessed. My fatigue only really started to improve once I pushed pressures well over the 7 IPAP suggested by titration. It's a bit annoying my box doesn't report RERA's which might give a bit more granular information than current usual AHI <1.

I'm still not sure what is good or bad with flow-limitation graph on sleepyhead, but it seems the fewer little blips I see on that dataset, the better I feel. If 95% FL is 0.05 I feel pretty ordinary, if its 0.02, not too bad My waveforms look flat-top a lot of the time unless pressures are 10+

As a caveat - I am still taking my impressions cautiously as I have had improvement in fatigue since recently adding Sifrol to address periodic leg movement disorder, so misattribution of what is helping my fatigue is quite possible, and I will take a while longer to form more certain opinions about how important higher pressures are to me.

My impression to date (having yet to really look into all the ResMed T's) is that the DreamStation bilevel's varying pressure support makes it more suitable for this scenario, whereas the ResMed bilevel's cycle timing configurability is more focused on more complex and complicating issues like COPD?

[palerider]

I'm still not sure what is good or bad with flow-limitation graph on sleepyhead,

the higher the peak, the more flow limited your breathing was at that point.

[robysue]

Thanks pale rider. I think I am in the group that is pretty sensitive to flow limitations and RERA's. I have never snored, and had only one apnoea (but loads of hypopneas) on my diagnostic sleep study. Flow limits weren't assessed. My fatigue only really started to improve once I pushed pressures well over the 7 IPAP suggested by titration. It's a bit annoying my box doesn't report RERA's which might give a bit more granular information than current usual AHI <1.

The PR machines all attempt to report RERAs. The AirSense 10 AutoSet for Her machines also attempt to report RERAs. How accurate the RERA detection algorithms are for both platforms is not well known since high quality information about the detection algorithms is proprietary information.

I'm still not sure what is good or bad with flow-limitation graph on sleepyhead, but it seems the fewer little blips I see on that dataset, the better I feel. If 95% FL is 0.05 I feel pretty ordinary, if its 0.02, not too bad My waveforms look flat-top a lot of the time unless pressures are 10+

Sounds to me like you understand the FL graph for a Resmed machine quite well. It also sounds like you understand the connection between the FL graph and the wave form graph.

My impression to date (having yet to really look into all the ResMed T's) is that the DreamStation bilevel's varying pressure support makes it more suitable for this scenario, whereas the ResMed bilevel's cycle timing configurability is more focused on more complex and complicating issues like COPD?

I would agree with your impressions. I say that as user of a PR Series 50 BiPAP Auto, so I may be a bit prejudiced in my opinions. The DreamStation can respond to the FL without increasing the EPAP and that can be much more comfortable for some folks.

And you are right: The Resemd TiMin, TiMax, trigger, and cycle settings are all there to tweak how the machine detects the beginning and end of the inhalations and how it responds to the inhalations, and that is particularly important for people who have other respiratory problems like COPD since the standard "auto" settings may not follow their breathing very well. And if the machine can't tell when you first start inhaling or exhaling, the pressure transitions between IPAP and EPAP can get out of sync with the patient's actual breathing. And that is as uncomfortable as it sounds.

My understanding is that both TiMin and TiMax can be set to "auto" or they can be set to "timed values". If TiMin is set to a timed value then there is a minimum amount of time that IPAP will be maintained during the breath cycle, even if your inhalation is shorter than the TiMin time. Likewise if TiMax is set to a timed value, there is a maximum amount of time that the IPAP pressure will be maintained during the breath cycle. If the TiMax is set too short, the pressure may drop to EPAP while you are still inhaling on your longest inhalations. Trigger and cycle settings control how sensitive the machine is in detecting the change between inhalations and exhalations, and that can affect how the switches between IPAP and EPAP feel. One of them controls the EPAP-to-IPAP transition and the other controls the IPAP-to-EPAP transition.

[Carbon]

Very detailed and helpful robysue

I'm still not sure what is good or bad with flow-limitation graph on sleepyhead, but it seems the fewer little blips I see on that dataset, the better I feel. If 95% FL is 0.05 I feel pretty ordinary, if its 0.02, not too bad My waveforms look flat-top a lot of the time unless pressures are 10+

Sounds to me like you understand the FL graph for a Resmed machine quite well. It also sounds like you understand the connection between the FL graph and the wave form graph.

It would be handy to get a feel for what FL numbers are significant.
Are my FL 95% numbers 0.02-0.05 better than/ worse than/ average for those feeling good on their CPAP?
Is there a better FL metric to look at than 95% number? Maybe just eyeball graphs for lots of flat-top waveforms?
Maybe it only matters for a subset of people at the symptomatic Upper Airway Resistance end of the OSA spectrum?

[robysue]

Very detailed and helpful robysue

I'm still not sure what is good or bad with flow-limitation graph on sleepyhead, but it seems the fewer little blips I see on that dataset, the better I feel. If 95% FL is 0.05 I feel pretty ordinary, if its 0.02, not too bad My waveforms look flat-top a lot of the time unless pressures are 10+

Sounds to me like you understand the FL graph for a Resmed machine quite well. It also sounds like you understand the connection between the FL graph and the wave form graph.

It would be handy to get a feel for what FL numbers are significant.
Are my FL 95% numbers 0.02-0.05 better than/ worse than/ average for those feeling good on their CPAP?

There is no known information about the significance of those numbers. ResScan does not even use numbers on their FL grap. They have three icons: Top icon is a flat line indicating a "apnea" level flow limitation. Middle icon is a "table shaped" inhalation. Bottom one is a nice rounded hump indicating an inhalation with no flow limitation at all.

Flow limitations are not routinely scored in sleep studies and it's not completely clear how much significance they have. Moreover, a CPAP-scored flow limitation is technically nothing more than a misshaped set of inhalations. And things other than a partially collapsed airway or an airway in danger of collapsing can cause them.

Is there a better FL metric to look at than 95% number?

Nobody know the significance of the 95% FL metric on a Resmed machine. Likewise nobody knows the real significance of the "Flow Limitation Index" on a PR machine. What we do know is that both machines respond to the FLs scored by their machines by raising the pressure. The Resmeds are quite aggressive about increasing the pressure in response to FLs; the PR machines are less aggressive. But PR machines are less aggressive about pressure increases in the first place.

Maybe just eyeball graphs for lots of flat-top waveforms?

This is probably as good as anything. But keep in mind that if the FL is very small, you might not see anything. When I look at flow limitation "events" in my own data, I often am scratching my head saying, "Why is that marked as a FL?"

Maybe it only matters for a subset of people at the symptomatic Upper Airway Resistance end of the OSA spectrum?

There is a lot of anecdotal evidence to support this idea. UARS is not as well understood as OSA, and, at least here in the states, not all sleep labs routinely measure RERAs on in-lab PSGs.