[Diagnosis] Reasons to BPAP, over CPAP

[robysue]

What I'm really curious about (BPAP users, please weigh-in) why wouldn't one want the IPAP/EPAP spread to be GREATER, therefore causing as much exhaust air to get out of the body???

Like so many things in PAP therapy, there's an individual sweet spot for the difference between IPAP and EPAP. Note that IPAP-EPAP is called pressure support (PS) for short.

If PS is too small, there's not much difference between BiPAP and CPAP and between Auto BiPAP and APAP. When PS is small, the EPAP needs to be set pretty close to the pressure needed to prevent Hs, RERAs, and FL from occurring and that may not provide much relief in terms of aeropagia. And there's also not much of a difference between BiPAP and CPAP in the effort needed to exhale fully.

If PS is too large, then the constant change in pressure from EPAP to IPAP and back can be disturbing to some people's sleep. It also can make it much harder to get and maintain a good seal on the mask. In other words, as PS increases, the tendency for the mask to have some leaks on every inhalation increases. And while it's much easier to exhale with the PS is large, for some people, that decrease in pressure can lead to the feeling of "not enough air coming through the mask."

I'm not sure how the PS setting and the connection between BiPAP/Auto BiPAP and the tendency to develop CompSA works.

CompSA tends to develop when a PAPer starts to have trouble consistently blowing off the right amount of CO2 with each exhalation. For a while, the PAPer will blow off too much CO2 (the overshoot part of the cycle), and this will lead to a decrease in respiratory drive, which leads to a decrease in breath sizes and a decrease in how much CO2 is blown off in each breath (the undershoot part of the cycle). The respiratory cycle bottoms out in a CA,. At that point, an increase in the respiratory drive kicks in, but this once again allows the person to blow off too much CO2, which starts the cycle over again. It's this overshoot/undershoot cycle for blowing off CO2 that leads to CompSA and addressing this cycle is what the ASV algorithm in ASV machines is designed to address.

I suppose it's possible that a large PS can somehow lead to a tendency to blow off too much CO2 during the exhalations ...

I.e. What is the downside of a much lower EPAP (exhaust air) number?

The EPAP has to be high enough to prevent the OAs and snoring. If it's too low to do that, then BiPAP won't effectively treat the OSA.

The IPAP has to be high enough to prevent the Hs, RERAs, and FLs. If it's too low to do that, then BiPAP won't effectively treat the OSA.

The advantage of BiPAP is that the required EPAP is usually several cm H2O lower than the required IPAP (as determined on a BiPAP titration study). At high pressures, this leads to more comfort and a more natural feeling when breathing with the machine. For folks with serious aerophagia, the mean pressure needed to control the OSA is typically less with BiPAP because the EPAP pressure can be set several CM less than a therapeutic pressure setting for straight CPAP.

[robysue]

I guess what I'm trying to determine is if min EPAP settings actually impact aerophagia.

I'm trying to get a picture here, and I think you're saying that increasing IPAP will likely increase likelihood on more stomach air. But does a change in min EPAP make any difference?

It seems to me that higher IPAP is more likely to push air into the mouth and subsequently into my stomach. Does a higher EPAP add to that problem? I'm just trying to understand the pressures at play here.

Or how about this: will an otherwise "normal" or "Safe" IPAP result in aerophagia if the EPAP is too high?

Phil

Aerophagia is related to the mean pressure you're using over the course of the night. EPAP lowers the mean pressure needed to effectively treat the OSA.

If the EPAP is too high, then the mean pressure will be high enough to continue triggering the aerophagia.

if the IPAP is too high, but the EPAP is low enough, that too can increase the mean pressure and lead to aerophagia problems.

If the EPAP is low enough, but IPAP is too high, that can also lead to a host of other problems including additional leaks and sleep disruption from the constant (large) change in pressure from EPAP to IPAP and back.

Figuring out the appropriate PS really is tantamount to finding the appropriate EPAP and IPAP pressures.

EPAP has to be high enough to prevent (most) of the OAs.

IPAP has to be high enough to prevent (most) of the Hs.

[pdeli]

Robysue,

Very helpful information here, and again I have no idea how you ever unraveled all of this and in such detail.

Thanks.

[WakeUpTime]

The EPAP has to be high enough to prevent the OAs and snoring. If it's too low to do that, then BiPAP won't effectively treat the OSA.

The IPAP has to be high enough to prevent the Hs, RERAs, and FLs. If it's too low to do that, then BiPAP won't effectively treat the OSA.

The advantage of BiPAP is that the required EPAP is usually several cm H2O lower than the required IPAP (as determined on a BiPAP titration study). At high pressures, this leads to more comfort and a more natural feeling when breathing with the machine. For folks with serious aerophagia, the mean pressure needed to control the OSA is typically less with BiPAP because the EPAP pressure can be set several CM less than a therapeutic pressure setting for straight CPAP.

I've got to decide which machine to finally purchase in the next few days. My loaner of a standard CPAP is over. If the PS is only a few degrees apart, Philips has their "C-Flex+" (Resmed has an equiv) for CPAP models which gives a 1-3 cm PS in the settings, mimicking a BPAP machine (supposingly).

From what I've read elsewhere, the difference between that max-of-3 and a-little-bit-more-than-3 can be huge in comfort! I've also read that there might be a little more to it than that. A BPAP machine has better timing between inhales and exhales. Those tiny little differences (amounting to a 50-60% higher cost of the machine) is still significant.

[robysue]

From what I've read elsewhere, the difference between that max-of-3 and a-little-bit-more-than-3 can be huge in comfort! I've also read that there might be a little more to it than that. A BPAP machine has better timing between inhales and exhales. Those tiny little differences (amounting to a 50-60% higher cost of the machine) is still significant.

The timing between inhales and exhales and the fact that the pressure stays at EPAP all the way through the exhale were critically important in helping me get comfortable enough to actually sleep with the machine even though my PS is often only 2 or 3 cm.

But do be aware that in the US, a BiPAP requires a different prescription than a CPAP/APAP. To be very clear: A CPAP prescription is enough to buy any CPAP or APAP on the American market, but it won't let you legally buy a bi-level machine like the PR BiPAP or the Resmed VPAP.

[WakeUpTime]

The timing between inhales and exhales and the fact that the pressure stays at EPAP all the way through the exhale were critically important in helping me get comfortable enough to actually sleep with the machine even though my PS is often only 2 or 3 cm.

The rule for sleep centers is "see if they can tolerate a CPAP, if not, try BPAP". Even if one can tolerate CPAP, isn't the BPAP experience just more comfortable for everyone? Besides comfort, it seems the other benefit of BPAP might be reducing air in the stomach.

But do be aware that in the US, a BiPAP requires a different prescription than a CPAP/APAP.

Yes, of course. However, once someone has a CPAP it's extremely easy to request a BPAP instead. BPAP-SV though does seem like quite another technology as comfort actually may reduced at times because of those sudden blasts of pressure.

I overheard a distributor talking to a manufacturer's rep one time. Countries such as Russia, China, India, etc. (non-Western countries) have extremely high percentages of high-end BPAP-SV machines. Why, you may ask? They don't have the same standards/technology/availability of sleep experts so they figure "just get an Auto-Everything machine!" (Great revenues for the manufacturers!) Crazy uplifts on BPAP and BPAP-SV machines when were talking just about software algorithms.

[robysue]

The timing between inhales and exhales and the fact that the pressure stays at EPAP all the way through the exhale were critically important in helping me get comfortable enough to actually sleep with the machine even though my PS is often only 2 or 3 cm.

The rule for sleep centers is "see if th

ey can tolerate a CPAP, if not, try BPAP". Even if one can tolerate CPAP, isn't the BPAP experience just more comfortable for everyone? Besides comfort, it seems the other benefit of BPAP might be reducing air in the stomach.

Where are you? That's certainly not the rule for WNY.

As for comfort: Not everyone is more comfortable with BiPAP. Some people have a real tough time getting the machine to sync with their breathing. And if the machine has problems with consistently figuring out when you're inhaling and when you're exhaling, it can feel that the machine is trying hard to change how you're breathing. Other people don't really like the feel of the constantly changing pressure---these folks often feel as though a BiPAP is trying to tell them how to breathe, and that can be very uncomfortable.

But do b

[me50]

AASM has a guideline on their site that suggests if a patient, during a sleep study, reaches the pressure of 15 to switch them to vpap to see if that controls everything better.

EDIT: I started out on an S9 Elite and last September was switched to an S9 Auto. Then this January I was switched to an S9 VPAP auto. We didn't have any trouble with the insurance company switching and paying for the VPAP and my doctor just wrote the script and they got contacted my insurance company for authorization and they ordered the machine and I had it within a week of the script being written. My doc or the DME didn't have to jump through hoops at all. One thing I have to say is that maybe that was because I had a sleep study at the end of last year and that could be why my insurance company didn't have any issues with changing me from cpap auto to vpap auto.

[pdeli]

Robysue,

Quote: "Not everyone is more comfortable with BiPAP. Some people have a real tough time getting the machine to sync with their breathing. And if the machine has problems with consistently figuring out when you're inhaling and when you're exhaling, it can feel that the machine is trying hard to change how you're breathing."

Well that clears up a puzzling question for me.

When I was pushing for a Bi-Pap, because of aerophagia, I tested the PR and the ResMed, each for seven days. I abandoned the ResMed after one night. I reported to the Sleep Doc that, while I had no understanding of what was actually happening or what was wrong since I was either asleep or half asleep, but there was a real problem with the ResMed. I couldn't figure out why one would work well while the other was so problematic.

Your explanation above exactly describes my ResMed problem that I was unable to accurately articulate.

Another part of my so-called sleep tests was that they were at home, and so of course no one could make any adjustments during the night. Oh and plus I got minimal sleep during the test periods.

Phil

[me50]

Robysue,

Quote: "Not everyone is more comfortable with BiPAP. Some people have a real tough time getting the machine to sync with their breathing. And if the machine has problems with consistently figuring out when you're inhaling and when you're exhaling, it can feel that the machine is trying hard to change how you're breathing."

Well that clears up a puzzling question for me.

When I was pushing for a Bi-Pap, because of aerophagia, I tested the PR and the ResMed, each for seven days. I abandoned the ResMed after one night. I reported to the Sleep Doc that, while I had no understanding of what was actually happening or what was wrong since I was either asleep or half asleep, but there was a real problem with the ResMed. I couldn't figure out why one would work well while the other was so problematic.

Your explanation above exactly describes my ResMed problem that I was unable to accurately articulate.

Another part of my so-called sleep tests was that they were at home, and so of course no one could make any adjustments during the night. Oh and plus I got minimal sleep during the test periods.

Phil

It all depends on the person. I can do well with Resmed (I don't know what machine is used in the lab but I doubt it is either Resmed or Respironics) and as far as I know, I have never been hooked up to a Respironics machine. I started out with Resmed and never had issues with the brand so I have stayed with it because I didn't want to try to change brands and adjust to a different type of machine (going from Elite to s9 auto and then to vpap auto).

I have heard and/or read posts that some cannot tolerate the Respironics machine and one thing they have said is that it makes them feel as though the machine is trying to make them breath the way the machine wants them to and not the way they breath.

That is why there are several brands to choose from.