Distinguishing OA from CA

[MarcoSil]

Can anyone explain to me how the Respironics and Resmed machines tell the difference between an Obstructive Apnea and a Central Apnea?

[jnk...]

Can anyone explain to me how the Respironics and Resmed machines tell the difference between an Obstructive Apnea and a Central Apnea?

They assess whether or not your airway is open during the apnea. It isn't perfect, but it gets you in the ballpark:

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

[palerider]

Can anyone explain to me how the Respironics and Resmed machines tell the difference between an Obstructive Apnea and a Central Apnea?

Resmed video: https://www.youtube.com/watch?v=4GW97Xk06N8

Respironics uses a single pressure pulse instead of the FOT, since (I believe) their fan can't vary it's pressure as rapidly as the Resmed can.

[MarcoSil]

Thank You

[jnk...]

A little more info for reading:

Since responding to central apneas can lead to over titration, testing for airway patency allows for differentiation of central from obstructive apneas. Two methods used to test for airway patency include cardiogenic pulsation testing and device-generated pressure oscillations. The first method looks for cardiogenic pulse artifact in the flow, which is only present if the airway is open. In the second method, the device provides single pressure pulse or small oscillation in the flow (eg, 1 cm, 4–5 Hz or forced oscillation technique), which is only reflected back to the flow sensors if the airway is closed. Respironics uses pressure pulses and also defines an obstructive apnea if there is a larger than expected breath after apnea termination. A mixed apnea can be determined if the airway is open for only part of the flow. ResMed from >9 onward uses force oscillation technique to define central apneas and defines central apneas if leak is >30 L/min. DeVilbiss Autoadjust 2 uses a modulating micro-oscillation to determine airway patency during apneas. -- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629962/

A table from above article that compares three methods from ResMed, Respironics, and DeVilbiss (Just look at line that starts with Non-OA detection): https://www.ncbi.nlm.nih.gov/pmc/articl ... der-8-425/

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, 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. . . . DeVilbiss is not unique in defining or reporting non-obstructive apneas but the AutoAdjust has had this ability as early 1996. In a clinical study comparing DeVilbiss AutoAdjust to sleep lab equipment, Martin Scharf et al found that the AutoAdjust device’s definition of non-obstructive apneas had an 85% correlation to the lab’s definition of central apneas. The AutoAdjust is NOT attempting to diagnose central apneas; it is, however, able to recognize therapy-induced non-obstructive apneas and, following common lab procedures, stop all pressure increases while these events are present. (Increasing pressure during central apneas can cause further reduction of carbon dioxide levels along with further increases in central and non-obstructive apnea densities.) By defining and reporting non-obstructive apneas, the AutoAdjust offers clinicians a view of non-obstructive apnea density so that they can determine if clinical intervention is appropriate.-- http://www.devilbisshealthcare.com/file ... 14_Web.pdf