'Centrals' - Clear Airway Apneas - 1 year anniversary

[DreamDiver]

The anniversary of my first night using the S9 was on the 3rd of March. I have gone from an AHI of 1.1 for the month of March 2010 to an AHI of 0.6 for the month of February 2011. My AHI rarely goes over 2 these days. I certainly feel better than I did last year this time, but as many of us are, I'm still trying to find ways to get more truly restorative sleep.

The question I'm putting to forum members is this: of the people who are currently using S9's, System Ones, Intellipaps or other machines capable of making the distinction, I'm curious how many of us are predominantly seeing "central", "clear-airway" or "non-obstructive" apneas in our AHI?

EDIT: As avi123 points out: please feel free to post your numbers... Mine are below.

[avi123]

Dream, b/c you have not posted a Statistic of your ResScan results I can't evaluate your AHI number.

Here are my numbers after 3 months of CPAPing:

Statistics


Product: S9 Elite
3/6/2011 - 3/6/2011
Device Settings
Therapy Mode: CPAP Set Pressure: 7.6 cmH2O EPR: Off
EPR Level: 2.0 cmH2O
Leak - L/min
Median: 0.0 95th Percentile: 63.6 Maximum: 105.6

AHI & AI - Events/hr

Apnea index: 11.5 AHI: 13.5 Obstructive: 3.2
Central: 3.3 Unknown: 4.9 Hypopnea index: 2.0


********************************************

About a month ago:


Statistics
2/2/2011 - 2/13/2011
Device Settings
Therapy Mode: CPAP Set Pressure: 7.0 cmH2O EPR: Full_Time
EPR Level: 2.0 cmH2O
Leak - L/min
Median: 3.6 95th Percentile: 25.2 Maximum: 51.6

AHI & AI - Events/hr

Apnea index: 16.3 AHI: 17.9 Obstructive: 10.8
Central: 3.2 Unknown: 1.1 Hypopnea index: 1.7

Note: I took RG suggestion to raise pressure b/c of the Obsturctive.
So I raised it from 7.0 CM to 7.6 CM, and the Obstructive fell from 10.8 to 3.2.

Good Job!

[DreamDiver]

Dream, b/c you have not posted a Statistic of your ResScan results I can't evaluate your AHI number.

Here are my numbers:

3/3/2010 - 4/3/2010
Obstructive: 0.0
Central: 0.9
Unknown: 0.0
Hypopnea: 0.2
AHI: 1.1
Median Leak: 0.0
95th Percentile Leak: 1.2
Maximum Leak: 12.0

2/3/2011 - 3/3/2011
Obstructive: 0.0
Central: 0.6
Unknown: 0.0
Hypopnea: 0.0
AHI: 0.6
Median Leak: 0.0
95th Percentile Leak: 0.0
Maximum Leak: 22.8

[JohnBFisher]

Whirled Peas came in as a close second for me.

My machine does show centrals. Fortunately, I'm down to an AHI less than 1 with centrals being what is left to conquer. Of course, that's with an ASV machine. It's much worse without it. I have a lot of LONG centrals during sleep/wake transition, which can make getting to sleep "interesting". So, bad nights can be rough. But once asleep, the machine does its job.

[chrisp]

Something about centrals. In a nutshell " Independent research has documented that cardiac oscillations on the airflow signal accompany only 60% of all central apnea events during manual PSG." So, what does that mean? The machine probably does even worse at scoring and classifying central apneas.

And if misdiagnosed and pressure is added more centrals may be caused. Thats why the unit can't rush to treat. Slow and steady makes a good apap.

Read the piece about the intellipap.

[Slartybartfast]

I have both an S9 Autoset and an iPAP. AHI is usually less than 1, so I seldom see "Centrals" anymore. Usually a hypop or two and maybe an Obstructive, and that's it for the night. Sometimes a "Central" shows up. But nothing exciting.

I'm still not convinced calling them "Centrals" is appropriate since the scoring is being inferred from other measurable parameters, rather than from EEG or effort bands. Sure, they've shown correlation in the 90 percentile in a study they commissioned, but for me it's still an inference, not a determination. It seems to me that DeVilbiss is being more intellectually honest in referring to them as "non-obstructive apneas."

[KatieW]

Jan 1 -31: AHI .4, AI .3, CAI .1, OAI .2, HI .1

Feb 1-28: AHI .5, AI .3, CAI .1, OAI .2, HI .2

[DreamDiver]

Whirled Peas came in as a close second for me.

My machine does show centrals. Fortunately, I'm down to an AHI less than 1 with centrals being what is left to conquer. Of course, that's with an ASV machine. It's much worse without it. I have a lot of LONG centrals during sleep/wake transition, which can make getting to sleep "interesting". So, bad nights can be rough. But once asleep, the machine does its job.

Thanks, JohnBFisher. In your case, if I'm not mistaken, you actually have been diagnosed as actually having central apnea, yes? I hope at some point the long centrals during transition will resolve for you.

Something about centrals. In a nutshell " Independent research has documented that cardiac oscillations on the airflow signal accompany only 60% of all central apnea events during manual PSG....

I'm still not convinced calling them "Centrals" is appropriate since the scoring is being inferred from other measurable parameters, rather than from EEG or effort bands.

chrisp, Slartybartfast,
No worries, I'm aware of the differences between what's measured on the XPAP machines we use at home and the sleep lab equipment. It's good to have brought it up though for those who are not familiar. I'm more curious about the numbers of our members who don't have obstructive apneas but rather the kind our machines generally mark as not obstructive. Airway patency through something like FOT is not part of what's incorporated in current sleep lab tests. I'm wondering if it should be. I wonder if the population of people with Patent Sleep Apnea that doesn't resolve as central on lab equipment might merit study, if it's not already happening.

[avi123]

Dream wrote:"Airway patency through something like FOT is not part of what's incorporated in current sleep lab tests. I'm wondering if it should be. I wonder if the population of people with Patent Sleep Apnea that doesn't resolve as central on lab equipment might merit study, if it's not already happening."


I wonder if FOT will ever be incorporated in PSG tests b/c of this:

The ability to detect central apneas is a useful addition
to an automatic algorithm used in the treatment of OSA.
Automatic algorithms respond to the presence of apneas
(assumed to be obstructive) by raising delivered pressure
because, although this does not treat the apnea that is
detected, the pressure increase reduces the likelihood of
further obstructive events occurring.
If the apnea, however, is central an increase in pressure is inappropriate
and may increase the chance of further central apneas.
This may potentially lead to the device “running away”
with progressive increases in pressure causing increasing
numbers of central apneas. To prevent this from occurring
the previous AutoSet algorithm would not increase pressure
in response to apneas beyond 10 cm H2O. While this
prevents the device from “running away” it is not ideal as
obstructive apneas above 10 cm H2O are not responded to
and central apneas occurring at pressures less than 10 cm
H2O cause inappropriate increases in pressure. It is for this
reason that APAP devices are generally not recommended
for patients known to have conditions, such as congestive
heart failure, that predispose to central apneas.

Source: http://www.resmed.com/us/assets/documen ... -paper.pdf



In the meantime see this article about the causes for Central Apneas:


http://health.nytimes.com/health/guides ... rview.html

[DreamDiver]

It is for this
reason that APAP devices are generally not recommended
for patients known to have conditions, such as congestive
heart failure, that predispose to central apneas.
...
Source: http://www.resmed.com/us/assets/documen ... -paper.pdf

Excellent resources! Once again, I'm more interested in finding out exactly what is going on with patients that have non-obstructive apneas, if they aren't ostensibly central. If we knew that different treatment would work better for non-obstructive apneas, it might change both the method by which we test and the types of machines we are given.

The current generation of machines is apparently safe enough that if patent apneas are detected, the pressure is not raised, since it's 'like' a central, while if obstructive apneas are detected (no patency), the pressure is raised. What's the deal with that?

[avi123]

Dream wrote: If we knew that different treatment would work better for non-obstructive apneas, it might change both the method by which we test and the types of machines we are given.


Dream, I am not sure if this will answer your question about which way to go about Central Apneas:


Source:

Sleep Apnea and Heart Disease
N Engl J Med 2006; 354:1086-1089 March 9, 2006

Central sleep apnea is a consequence
of heart failure in some but not all patients.
1 A key question is whether eliminating this
sleep disorder is beneficial. In the study by Bradley
et al., CPAP had no effect on survival or freedom
from transplantation after three months, as
compared with untreated controls. CPAP therapy,
which was used by 85 percent of treated subjects,
reduced the number of episodes of central apnea
by 50 percent and was used for approximately four
hours per night. Thus, CPAP reduced the sleepbreathing
disorder by roughly 25 percent — a substantial
undertreatment effect and a potential
confounder of the study conclusions.

The initial approach to central sleep apnea in
heart failure should be the optimal treatment of
heart failure, including pharmacologic and devicebased
therapies.2,3

There are a variety of approaches
to suppressing residual central sleep apnea: the
administration of oxygen, fixed-pressure CPAP,
and such newer approaches as nasal ventilation4
and adaptive servo-ventilation5 (“breathing resynchronization”),
which may eliminate central sleep
apnea in heart failure more effectively than does
fixed-pressure CPAP.


Ian Wilcox, Ph.D., F.R.A.C.P.
University of Sydney
Sydney, NSW 2006, Australia
iw@mail.med.usyd.edu.au

Dr. Wilcox reports serving as a consultant to Resmed and holding
a minor equity interest in the company.

p.s. I am surprised that a Resmed advisor is belittling CPAP treatment for Central Ap.

[Slartybartfast]

Not wishing to pick nits RE: the definition of what we observe as being "central-like." For our purposes, if it looks like a duck, quacks like a duck, we can call it a duck. Some of the professionals (my pneumo-Doc among them) become righteously indignant with such imprecision, so I mentioned it in case you should ever run across him. Would save you a tongue lashing and a 15 minute lecture on the differences.

There's a feedback loop between stretch receptors in the bronchi and bronchioles and the CNS through the vagus nerve that controls maximum lung inflation under normal breathing. Maintaining positive pressure in the respiratory tract via CPAP can stimulate the Hering-Breuer reflex, which mimics a Central, but is actually a response by the CNS to an external stimulus. So even the true Centrals occurring when most patients are being treated by CPAP aren't really Centrals, such as would occur to an individual not being treated by CPAP. [Ok: Nit-Picking Mode - DESELECT]

It might be that what you're describing is that reflex.

http://medical-dictionary.thefreedictio ... r+reflexes

It seems successful xPAP therapy balances the risks associated with allowing obstructive apneic events vs. provoking the H-R reflex.

[avi123]

More on Central Apnea by RG:

viewtopic.php?p=22702

[john.michael]

Whirled Peas came in as a close second for me.

My machine does show centrals. Fortunately, I'm down to an AHI less than 1 with centrals being what is left to conquer. Of course, that's with an ASV machine. It's much worse without it. I have a lot of LONG centrals during sleep/wake transition, which can make getting to sleep "interesting". So, bad nights can be rough. But once asleep, the machine does its job.

Hello John,

I am just going to sleep for night 9 with the resmed VPAP auto sv enhanced. I just got the rescan software setup a few days ago. I see "apneas" in the event section, but no distinction as to type of apnea. Am I doing something wrong or looking in the wrong place? Unfortunately, I am still getting ahi > 8 and AI >3 most nights as far as I can tell.

I have had little time to write these past few days, but will try to update with my actual numbers soon.

Thanks in advance for any help/comments.

John

[idamtnboy]

Here's my numbers for the three month period from 12/6/2010 to 3/6/2011.
AI = 0.7
OAI = 0.2
CAI = 0.2
Unk = 0
HI = 0.1
AHI = 0.8

Obviously, some of these numbers are off a bit from averaging rounded numbers since OAI + CAI <> AI.