DeVilbiss Missing CA Data or Left Out on purpose?

[Thunnar]

The following excerpt is from the Devilbiss AutoAdjust Clinical Overview on their website.

"Determining central and non-obstructive apneas is a controversial subject among manufacturers
of Autotitrating devices. Some Autotitrating units are limited to flow signals. Due to this
limitation, some manufacturers do not attempt to define non-obstructive apneas. Others use
questionable definitions such as – any apnea occurring at pressures greater than 10 cmH2O. (Lab
reports sub- stantiate the presence of REM- or position-induced obstructive apneas at 10+ cmH2O.
Obstructive apneas require a therapy response.) Others, using a clinically unsubstantiated echo
concept, pulse pressure into the patient’s airway. If the pulse is not returned, the apnea is
considered central based on the assumption that ‘no echo’ indicates an open airway. (This method
entirely ignores CSDB or non-obstructive apneas caused by a PAP-induced reduction of carbon
dioxide.)"

Being a new DeVilbiss user as prescribed by my Sleep Doctor, I wondered why the machine supplied all the data with the exception of Central Apneas (whether I experience them or not). It would appear that their data sets do not display CA's on purpose while other AutoAdjust CPAP's do? Like ResMed S9? Am I wrong about that? Is the Devilbiss definition of Non-Obstructive Apneas essentially correct here or self-serving? I am not versed enough in the subject to know, but I know that many of you are.

[49er]

Hi,

This is the company's explanation of how centrals are handled with the NRI index:

Non-Obstructive Apneas (NOA)
Non-obstructive apneas, including complex sleep disordered breathing (CSDB), may occur during OSA therapy. These non-obstructive apnea events occur if the PAP’s pressure reduces carbon dioxide levels in the patient’s system. Without the proper CO2 stimulus, the brain will fail to trigger breathing and a non-obstructive apnea will occur. Most Autotitrating manufacturers do not increase pressure in response to non-obstructive apneas because higher pressures will reduce CO2 levels
further; however, it is important to report non-obstructive apneas for two reasons: clinically, if the NOA incidence is high, clinicians may want to investigate central apneas in a lab setting; and mechanically, if pressures are not rising as expected, checking the non-responding event index (NRI) may eliminate returning the unit for repair when it is operating normally. Non-obstructive apneas mimic central apneas. Central apneas occur when the autonomic nervous system fails to trigger breathing as a response to the CO2 stimulus. Sleep labs are able to properly identify central apneas using muscular effort, EEG readings and pulse oximetry in combination with
the defined lack of breathing.

NOTE— Primary central apneas follow the waxing and waning pattern defined as Cheyne-Stokes breathing. Clinical consensus today indicates primary central apneas are best treated using bilevel PAPs with timed backup. Determining central and non-obstructive apneas is a controversial subject among manufacturers
of Autotitrating devices. Some Autotitrating units are limited to flow signals. Due to this limitation, some manufacturers do not attempt to define non-obstructive apneas. Others use questionable definitions such as – any apnea occurring at pressures greater than 10 cmH2O. (Lab reports substantiate the presence of REM- or position-induced obstructive apneas at 10+ cmH2O. Obstructive apneas require a therapy response.) Others, using a clinically unsubstantiated echo concept, pulse
pressure into the patient’s airway. If the pulse is not returned, the apnea is considered central based on the assumption that ‘no echo’ indicates an open airway. (This method entirely ignores CSDB or non-obstructive apneas caused by a PAP-induced reduction of carbon dioxide.)

http://www.devilbisshealthcare.com/file ... erview.pdf

When opening with Adobe Acrobat Program, the information will be on page 4.

49er

The following excerpt is from the Devilbiss AutoAdjust Clinical Overview on their website.

"Determining central and non-obstructive apneas is a controversial subject among manufacturers
of Autotitrating devices. Some Autotitrating units are limited to flow signals. Due to this
limitation, some manufacturers do not attempt to define non-obstructive apneas. Others use
questionable definitions such as – any apnea occurring at pressures greater than 10 cmH2O. (Lab
reports sub- stantiate the presence of REM- or position-induced obstructive apneas at 10+ cmH2O.
Obstructive apneas require a therapy response.) Others, using a clinically unsubstantiated echo
concept, pulse pressure into the patient’s airway. If the pulse is not returned, the apnea is
considered central based on the assumption that ‘no echo’ indicates an open airway. (This method
entirely ignores CSDB or non-obstructive apneas caused by a PAP-induced reduction of carbon
dioxide.)"

Being a new DeVilbiss user as prescribed by my Sleep Doctor, I wondered why the machine supplied all the data with the exception of Central Apneas (whether I experience them or not). It would appear that their data sets do not display CA's on purpose while other AutoAdjust CPAP's do? Like ResMed S9? Am I wrong about that? Is the Devilbiss definition of Non-Obstructive Apneas essentially correct here or self-serving? I am not versed enough in the subject to know, but I know that many of you are.

[Thunnar]

So......... No NRI's = No Central Apneas? According to the definition by DeVilbiss?

[49er]

So......... No NRI's = No Central Apneas? According to the definition by DeVilbiss?

Usually, I would say yes. However, I am curious, did you show any centrals on your sleep study?

49er

[Thunnar]

No. I didn't show any CA's on my sleep study, but occasionally show NRI's on the DeVilbiss data.

[49er]

No. I didn't show any CA's on my sleep study, but occasionally show NRI's on the DeVilbiss data.

Good to hear. It sounds like you have nothing to worry about.

A few centrals on the odd occasion is quite normal. And even if you were to get a cluster, that is nothing to worry about as long as it didn't happen on a daily basis. It is when you average 5 or greater centrals and they are a certain percentage of your AHI (can't remember exact statistic) that you would need to alert your sleep doctor.

49er