Which Res? Urgent!

[diamaunt]

...and Resmed has Pacewave which monitors your breathing and adjusts the machine to support your unique breathing pattern. The Respironics takes a "machine knows best" approach and forces you to conform to the machine's breathing pattern. I found a huge difference between the two machines, in being able to sleep in the first place, less arousals and much much lower AHI using the Resmed. See the Resmed Pacewave page here: http://www.resmed.com/au/products/s9_vpa...nc=dealers

The Resmed has both autoadjusting EPAP and PS.

I think pacewave and the auto adjusting ps are only on the asv.

ps is set and doesn't vary on the vpap auto.

I'm with you on how easy the vpap auto is to breath, I don't even notice the pressure changes.

[robysue]

When it comes to bilevel machines, Respironics BiPAP wins hands down.

why?

In my opinion the PR BiPAP Auto wins over the Resmed VPAP Auto for the following reason that is significant to me:

The BiPAP's Auto algorithm allows it to independently increase just the IPAP or just the EPAP. The VPAP's Auto algorithm does not.

In my case that allows my BiPAP to increase my IPAP for flow limitations without increasing my EPAP. This leads to less problems with aerophagia.

[robysue]

...and Resmed has Pacewave which monitors your breathing and adjusts the machine to support your unique breathing pattern. The Respironics takes a "machine knows best" approach and forces you to conform to the machine's breathing pattern. I found a huge difference between the two machines, in being able to sleep in the first place, less arousals and much much lower AHI using the Resmed. See the Resmed Pacewave page here: http://www.resmed.com/au/products/s9_vpa...nc=dealers

The Resmed has both autoadjusting EPAP and PS.

I think pacewave and the auto adjusting ps are only on the asv.

ps is set and doesn't vary on the vpap auto.

This is indeed true. The VPAP Auto has a fixed ps setting.

I'm with you on how easy the vpap auto is to breath, I don't even notice the pressure changes.

Actually this is something that would bother me on the VPAP. I *like* the fact that I can feel the pressure DECREASING immediately when I exhale on my PR BiPAP.

And I *disliked* the EPR and Easy Breathe technology on my S9 AutoSet back in 2010 intensely: With EPR = 2 or 3, I constantly felt as though that machine was trying to force me to inhale before I was ready to.

I also found the S9's aggressive pressure increases to be a constant source of agony for my stomach and they did wake up up more than the gentler increases on my PR BiPAP.

But as I said earlier: I'm in a bit of a minority here. Still it's important to realize that not everybody finds the S9's Easy Breathe way of transitioning the pressures "natural" feeling.

[Sleepster]

only, that's not how biflex works. it's documented as giving a *maximum* of 1.5cm reduction (given the prohibition of posting links, just google 'biflex pressure reduction',

The maximum setting is 3, although the units are not given.

Your first google hit takes me to the Provider Guide. I don't see it there.

The 2nd hit takes me to Supplier #1's website where the product information says

"The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort."

Is that the only place you found it? I've never seen that anywhere in the primary literature and I don't recall ever having heard it before. It might be true, but I suspect it's a typo. Also note that they don't have the units right, which further raises my suspicions that it's a typo.

For example, when I go to Supplier #3's description I don't see any mention of 1.5 there.

and as our very own robysue said on "another forum"™:

I can say what happens with BiFlex when using a PR System One BiPaP. If the pressures are set at IPAP =14 and EPAP=10 and BiFlex is turned on, when you first start exhaling, the pressure does drop below 10cm*. And about halfway through the exhalation, the pressure is brought back up to 10cm. And when you start inhaling the pressure is increased to 14 cm. The time it takes to reach 14 cm is also determined by the flex setting. The higher the flex is set to, the longer it takes the machine to increase the pressure from 10 to 14cm.

* NOTE: How much below 10cm the pressure drops at the start of the exhalation is determined both by what BiFlex setting is used AND how deep the exhalation is. Unlike EPR, the Flex systems do not decrease the pressure by a fixed amount on all exhalations. You can read more about BiFlex by clicking here

So, could it be that when Bi-Flex is set to 3 it gives you a maximum pressure drop of approximately 3 cm H2O?

[Sleepster]

The BiPAP's Auto algorithm allows it to independently increase just the IPAP or just the EPAP. The VPAP's Auto algorithm does not.

That's why I want to try one and that's what I meant when I said that it has auto-adjusting pressure support.

Like you, aerophagia bothers me. I also have fragmented sleep. I'd like to improve in both those categories and that's why I'm experimenting with the S9 VPAP Auto and the BiPAP Pro. I just need to add the BiPAP Auto to the laboratory that is my bedroom.

[vsheline]

So, could it be that when Bi-Flex is set to 3 it gives you a maximum pressure drop of approximately 3 cm H2O?

Yes, it could be, if you are exhaling hard enough. With Flex, the larger the magnitude of the Flow ("Flow" is the rate of airflow being exhaled or inhaled) the larger the pressure relief.

Respironics has stated that the "Flex" maximum pressure reduction is roughly 1 cm H2O per step. But for many it would be lower, depending on the individual characteristics of the user's Flow.

The BiPAP's Auto algorithm allows it to independently increase just the IPAP or just the EPAP. The VPAP's Auto algorithm does not.

That's why I want to try one and that's what I meant when I said that it has auto-adjusting pressure support.

The PRS1 BiPAP Auto adjusts both EPAP and Pressure Support independently and VERY SLOWLY, and not necessarily during events, which may last many seconds. (The ResMed S9 VPAP Auto does not adjust EPAP until an event has ended, and I think the PRS1 BiPAP Auto is the same in this regard.)

ASV models adjust the Pressure Support VERY QUICKLY, during pauses or reductions in breathing, to prevent apneas and hypopneas right away, within a couple seconds or so, starting long before a potential event has lasted 10 seconds.

[diamaunt]

The maximum setting is 3, although the units are not given.
Your first google hit takes me to the Provider Guide. I don't see it there.
The 2nd hit takes me to Supplier #1's website where the product information says
"The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort."

the maximum *setting* is 3, the maximum *pressure reduction* is 1.5, and that, as robysue says, depends on how you're breathing, you don't get that max all the time.

[robysue]

only, that's not how biflex works. it's documented as giving a *maximum* of 1.5cm reduction (given the prohibition of posting links, just google 'biflex pressure reduction',

Uhhh ... Without posting a link could you be a bit more specific? I get 246,000 hits when I googled that.

The first hit takes me to the Provider Guide. I don't see it there.

The 2nd hit takes me to Supplier #1's website where the product information does say that. Is that the only place you found it? I've never seen that anywhere in the primary literature and I don't recall ever having heard it before. It might be true, but I suspect it's a typo.

All of the recent stuff from PR seems silent as to the maximum amount of pressure relief. All of the academic papers I can find describe Flex as providing a "small" amount of variable pressure relief that is based on the patient's airflow: the stronger the exhalation, the more the relief. But none of the academic papers seem to include information about the maximum amount of pressure relief for each Flex setting. So a good question is: Can a 3cm drop in pressure be considered a "small amount" of pressure relief?

So I don't have what I consider a reliable primary source for the maximum possible drop under all of the Flex systems. The material from PR on Bi-Flex clearly states and shows that the amount of pressure relief is "flow based" and varies from breath to breath. In contrast, all of Resmed's materials make it clear that EPR represents a fixed drop in pressure equal to the EPR setting.

I have found a very, very old Resprionics advertising flyer aimed at clinicians called C-Flex: You simply have to experience it. There is a chart that seems to imply that that under certain circumstances, a flex setting of "3" may result in a pressure reduction of 3cm, but it is also clear that most of the time, the pressure relief will be less than 3cm even if Flex is set to "3". The written description of Flex does NOT say that the pressure might drop by as much as 3cm, however.

Nonetheless the chart in C-Flex: You simply have to experience it that indicates the pressure might drop by as much as 3cm is news to me since everything I've previously read has hinted at, but not confirmed that the maximum drop in pressure under Flex is not that great even with Flex set to 3. Notably I've not seen another chart or figure describing Flex that has any scale on it so that the reader has a chance of determining the maximum potential pressure drop.

and as our very own robysue said on "another forum"™:

I can say what happens with BiFlex when using a PR System One BiPaP. If the pressures are set at IPAP =14 and EPAP=10 and BiFlex is turned on, when you first start exhaling, the pressure does drop below 10cm*. And about halfway through the exhalation, the pressure is brought back up to 10cm. And when you start inhaling the pressure is increased to 14 cm. The time it takes to reach 14 cm is also determined by the flex setting. The higher the flex is set to, the longer it takes the machine to increase the pressure from 10 to 14cm.

* NOTE: How much below 10cm the pressure drops at the start of the exhalation is determined both by what BiFlex setting is used AND how deep the exhalation is. Unlike EPR, the Flex systems do not decrease the pressure by a fixed amount on all exhalations. You can read more about BiFlex by clicking here

So, could it be that when Bi-Flex is set to 3 it gives you a maximum pressure drop of approximately 3 cm H2O?

What do you mean by a maximum pressure drop?

On a BiPAP the pressure will ALWAYS drop by the PS = IPAP - EPAP. The drop caused by Bi-Flex is ADDED to the drop from IPAP to EPAP. So if IPAP - EPAP > 3, then the pressure drop is already greater than 3cm.

Bi-Flex provides an additional pressure drop on top of the standard drop from IPAP to EPAP.

Let's suppose that the BiPAP is set with IPAP = 14, EPAP = 10, and Bi-Flex = 3. At the beginning of each exhalation, the pressure will drop below 10cm and then increase back up to 10cm midway through the exhalation. How far the pressure will actually drop depends on the Bi-Flex setting. With Bi-Flex set to 3 on a typical exhalation, there is likely to be an additional drop in pressure of around 1 to 2 cm (and perhaps more). In other words, with Bi-Flex = 3, IPAP = 14, and EPAP = 10, on a typical exhalation the drop in pressure at the start of the exhalation will be from 14cm to something in the neighborhood of 8 or 9 cm. And the pressure will then increase back up to 10cm about halfway through the exhalation and stay at 10cm until the beginning of the inhalation. So with Bi-Flex = 3, a typical drop in pressure will be about 5 to 6 cm at the beginning of the exhalation. Now, is it possible that Bi-Flex = 3 might give an additional 3cm of pressure relief and cause the pressure to go from IPAP = 14 to 7cm? I confess I don't know. I've always doubted that the pressure would drop that much with Bi-Flex; but that chart in C-Flex: You simply have to experience it seems to indicate that it might just happen on occasion.

---

The maximum setting is 3, although the units are not given.
Your first google hit takes me to the Provider Guide. I don't see it there.
The 2nd hit takes me to Supplier #1's website where the product information says
"The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort."

the maximum *setting* is 3, the maximum *pressure reduction* is 1.5, and that, as robysue says, depends on how you're breathing, you don't get that max all the time.

as to googling:

*The Bi-Flex setting can be adjusted up to 1.5cm of water pressure for maximum comfort.
* The Bi-Flex setting can be adjusted by up to 1.5 cm of water pressure.

* Pressure is reduced by half centimeter increments during the transition from exhalation to inhalation, inhalation to exhalation and during exhalation.The Bi-Flex setting can be adjusted up to 1.5cm of water pressure for maximum comfort.

* Pressure is reduced by .5 increments at a time. The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort.

* Pressure is reduced by half centimeter increments during the transition from exhalation to inhalation, inhalation to exhalation and during exhalation.The Bi-Flex setting can be adjusted up to 1.5cm of water pressure for maximum comfort.

* Pressure is reduced by .5 increments during the transition from exhalation to inhalation, inhalation to exhalation and during exhalation.The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort.

* Pressure is reduced by .5 increments during the transition from exhalation to inhalation, inhalation to exhalation and during exhalation.The Bi-Flex setting can be adjusted up to 1.5 H20 for maximum comfort.

and then I got tired of reading about it.

Thanks for confirming that I'm not off my rocker. I knew I had reasons to think that the maximum pressure relief was 1.5cm.

And yet, that chart I dug up earlier tonight from some very old Resprionics stuff does seem to run counter to all these descriptions about Flex.

[diamaunt]

What do you mean by a maximum pressure drop?

that was sleepster.

Thanks for confirming that I'm not off my rocker. I knew I had reasons to think that the maximum pressure relief was 1.5cm.

And yet, that chart I dug up earlier tonight from some very old Resprionics stuff does seem to run counter to all these descriptions about Flex.

well, very old, perhaps it changed...

I guess the only way to tell would be to get, or make, a manometer and breath on one for a bit and watch what the numbers are.

[Sleepster]

What do you mean by a maximum pressure drop?

Sorry. I meant the maximum pressure drop below EPAP.