Bilevel Positive Airway Pressure Worsens Central Apneas During Sleep

[zonk]

Study objectives: While most patients with sleep-disordered breathing are treated with continuous positive airway pressure (CPAP), bilevel positive airway pressure (BLPAP) is often used. Having observed that BLPAP therapy increased central apneas in some of our patients undergoing sleep studies, we conducted this study to evaluate the effects of BLPAP.

Design: Retrospective analysis of all sleep studies performed in an outpatient sleep center that used BLPAP over a 2-year period. We assessed the incidence and frequency of events during rapid eye movement (REM) sleep and non-REM sleep during baseline conditions, CPAP, and BLPAP. Desaturations, hypopneas, obstructive apneas, and central events, including periodic breathing (PB), Cheyne-Stokes respiration (CSR), and non-CSR central apneas were evaluated.

Patients: Ninety-five of the 719 patients who underwent sleep studies met inclusion criteria. Eighty of the 95 patients treated with BLPAP were also treated with CPAP.

Results: BLPAP was more likely to worsen than improve CSR (p = 0.002), non-CSR central apneas (p < 0.001), and CSR or PB (p < 0.001). CSR (p = 0.03) and non-CSR central apneas (p = 0.01) were more likely to worsen with BLPAP (24% and 23%, respectively) than with CPAP (11% and 8%). Central events (p = 0.04) and CSR (p = 0.009) were more likely to worsen during BLPAP in patients with baseline CSR or PB (62% and 48%, respectively) than develop in those without baseline CSR or PB (34% and 18%). Higher BLPAP differences worsened central events in 28% of patients, while 7% improved (p = 0.02). During REM sleep, central apneas improved, while hypopneas and obstructive apneas worsened (p < 0.001).

Conclusions: BLPAP often increases the frequency of CSR and non-CSR central apneas during sleep. Since CSR has adverse effects on cardiac function and sleep, it is important to consider this possible adverse effect of BLPAP.

Full article - Chest Journal - October 2005
Bilevel Positive Airway Pressure Worsens Central Apneas During Sleep
Karin G. Johnson, MD; Douglas C. Johnson, MD
http://journal.publications.chestnet.org...id=1083869

[mjbearit]

Interesting.

[trish6hundred]

Hi zonk, Thanks for posting this article and link, it certainly is very interesting.

[johns019]

Thats just great.
I've noticed that since I started 3 weeks ago with my BiPap machine, the Sleepyhead software has shown that I started off with mostly OA and have progressed to mostly CA. Some nights show no OA and one night was all CA. At least I'm under 5.0 AHI.

[Sleepster]

Averages:
First 3 days on CPAP therapy: AHI=9.43, CA=0.19, OA=6.73, H=2.63.
Next 13 days on CPAP therapy: AHI=3.05, CA=0.13, OA=1.73, H=1.29.
Next 19 days on BiPAP therapy: AHI=9.96, CA=9.21, OA=0.42, H=0.33.

After this they lowered my BiPAP pressures and now my AHI averages 2.0.

But you can see a dramatic jump in the CA index with the onset of BiPAP therapy. This study is the first verification I've seen that this thing can happen to other people, too.

The question is, what's the cause. The conventional thinking is that when the CPAP pressure is too high your brain tells your lungs to stop breathing because there's too much oxygen in the blood. This is called CPAP-induced central apnea. Lowering the pressure fixes the problem.

But when we have bilevel (BiPAP or BLPAP) therapy there's an increase in pressure between the exhale and the inhale, and a drop in pressure between the inhale and the exhale. For some reason, this changing of the pressure also causes this effect to appear.

[mjbearit]

Averages:
First 3 days on CPAP therapy: AHI=9.43, CA=0.19, OA=6.73, H=2.63.
Next 13 days on CPAP therapy: AHI=3.05, CA=0.13, OA=1.73, H=1.29.
Next 19 days on BiPAP therapy: AHI=9.96, CA=9.21, OA=0.42, H=0.33.

After this they lowered my BiPAP pressures and now my AHI averages 2.0.

But you can see a dramatic jump in the CA index with the onset of BiPAP therapy. This study is the first verification I've seen that this thing can happen to other people, too.

The question is, what's the cause. The conventional thinking is that when the CPAP pressure is too high your brain tells your lungs to stop breathing because there's too much oxygen in the blood. This is called CPAP-induced central apnea. Lowering the pressure fixes the problem.

But when we have bilevel (BiPAP or BLPAP) therapy there's an increase in pressure between the exhale and the inhale, and a drop in pressure between the inhale and the exhale. For some reason, this changing of the pressure also causes this effect to appear.

Once upon a time the conventional thinking was that the earth was flat and the sun rotated around the earth.

Point being that sometimes conventional thinking needs to be reexamined as more evidence to the contrary is presented.

Lunacy is repeating the same action over and over, expecting a different result.

[iwant2sleep]

How do I know if I am have OA or Ca's? I Have a Resmed bilevel Stella 100.

[Sleepster]

How do I know if I am have OA or Ca's? I Have a Resmed bilevel Stella 100.

If your machine is data capable then you can install the free Rescan software (or the free SleepyHead software if it's supports your machine) on your computer and look at your data.

It may be possible to read it from the machine's on-screen menu.

[vsheline]

If your machine is data capable then you can install the free Rescan software (or the free SleepyHead software if it's supports your machine) on your computer and look at your data.

Yes, ResScan 4.2 supports the Stellar 100.

(When installing ResScan, it is usually a very bad idea to select/install any ResMed drivers. Not sure if this also applies to the Stellar 100, which uses a USB thumb drive for data storage, but I would think it is probably safest NOT to install any drivers.)

The Stellar 100 uses the H4i humidifier, not the new-generation H5i humidifier used by the S9 generation devices. I think this means the Detailed Data (which can be read using a USB thumb drive) may include apnea events but (unlike most S9 generation devices) probably would not break down apneas into Central Apnea (CA) versus Obstructive Apnea (OA) events.

I used an S8 AutoSet for a few years, and I noticed while looking at the data using ResScan that sometimes I would have apneas after which the S8 Autoset would raise the pressure slightly, but would have other apneas after which it would not respond (would not raise the pressure). When I started using an S9 AutoSet, I discovered that when the pressure was not raised the apneas involved were marked "CA" events, and when the pressure was raised after an apnea the apneas involved were marked OA events.

So even if the Stellar 100 does not show a breakdown of OA versus CA events, and although I think the S9 generation is no doubt more accurate in distinguishing OA versus CA events, the detailed data reported by the Stellar 100 may contain strong clues to how often CA events are occuring versus OA events.

Take care,
--- Vaughn

[racprops]

Is this also true with ASV machines which if I understand them are BiLevel machine with brains.

Rich