Does ResScan Software show centrals?

I was just reading another post about compliance and someone remarked that it's easy (with software) to see if the pressure is causing centrals.

Does the ResScan software show OA vs. CA events?

tattooyu wrote:I was just reading another post about compliance and someone remarked that it's easy (with software) to see if the pressure is causing centrals.

No, that is not "easy with software" to see at all. Not if the person was talking about the regular treatment machines (cpap, autopap, bilevel) most of us use.

There are two exceptions among the "regular" machines: the Puritan Bennett autopap, and the Covidien Sandman Auto (based on the 420E's technology.) Those two machines are are designed to sense cardiac oscillations (heartbeats) which indicate the airway is open. If there's no airflow from the person, and cardiac oscillations are sensed, those two machines will mark the event on the software as a central apnea.

Studies comparing the PB machine's "this is a central" with simultaneous PSG reading during the development of that feature, came up with:
Central Apnea Specificity=100%
Central Apnea Sensitivity= 62%

If a 420E's Silverlining software, or a Sandman Auto's Sandman software marks an event as having cardiac oscillations, the machine is saying "this is a central." It really was a central. That's 100% "specificity."

There were times when PSG equipment showed people to be having a central, but the 420E was missing it -- machine didn't sense any cardiac oscillations, so couldn't know for sure that the airway was indeed open and that a central apnea was happening. The PSG showed it, but the treatment machine couldn't see it.
Thus, PB's statement that the machine's "sensitivity" to recognizing every central apnea that could be happening is only 62%. That means the machine could be "not noticing" 38% (edited to correct my error with simple math! ) of the central apneas that could be happening.

Still, that is more identification of some centrals than other "regular" machines (Respironics, ResMed, DeVilbiss, Fisher & Paykel, for example) are designed to do. They don't attempt to identify centrals at all.

Then there's a whole other ballgame -- specialized machines. Machines that are designed specifically to treat central apneas are the "adaptive servo ventilator" machines. Not the kind of machine you have, Kenny, or even should have. Trust me on this...LOL!!...you almost surely would find treatment with an ASV machine annoying, or worse, unless you have a type of sleep disordered breathing that really needs ASV treatment. Nothing in your sleep study, or in the data from your present machine, or in how you've been getting along with treatment, or in your health history has given any indication whatsoever that you need an ASV machine.

The software used by ASV machines (ResScan for the VPAP SV, Encore Pro 1.8.49 or higher for the BiPAP Auto SV) would, I suppose (don't know that for sure) mark centrals, since that's what those machines are designed to treat, each in its own way.

So, I think (could be wrong) the answer to this....

tattooyu wrote:Does the ResScan software show OA vs. CA events?

.... is a qualified "no." Definitely "no" if you're talking about using the ResScan software with a regular ResMed machine. By "regular" ResMed machines, I mean all their cpap, autoset, and vpap machines that DON'T have "SV" (those two specific letters togther) tacked onto the end of their names.

Kenny, you really don't need to worry about centrals, ya know? Not even if you raise the pressure several cms.

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my edit -- I can't add or subtract worth a darn! Thanks to a PM from a nice person who can, I've corrected my original "48%" to 38%.

Rested Gal has done a very good answer. I was about to chime in with "a cpap basically can't tell anyone for certain they just had a central - at best they can guess about it". RG put it far better

But there have been technologies built into some cpaps (e.g. Weinmann from Germany- who call their machines "Somno-something") who added techniques such as "FOT" http://ajrccm.atsjournals.org/cgi/conte ... 160/5/1550 + http://www.ncbi.nlm.nih.gov/pubmed/9603133 ) that send an oscillating (e.g. 5000 cycles per sec) pulse of air down the airhose & use the response to determine if the airway is open or closed. Also - Puritan Bennett who use acoustic heartbeat sampling as a way of trying to determine if the airway is open or closed.

Those machines are quite fancy but still aren't considered accurate enough to say for certain someone is having a central. That really requires sampling thoracic effort & airflow as a bare minimum.

So, it is considered that some cpaps can do a best guess, but none are regarded as capable of reporting accurately that a central has taken place.

DSM

If a oximeter shows no desaturation events all night does it meant there were no centrals that night. Can centrals occur with no negative effect on one's ability to breath normal or are they clearly a problem that will result in a drop in saturation level? Centrals I take it is a problem due to brain damage/malfunction and not physical blockage of air ways?

Gale Hawkins wrote:If a oximeter shows no desaturation events all night does it meant there were no centrals that night. Can centrals occur with no negative effect on one's ability to breath normal or are they clearly a problem that will result in a drop in saturation level? Centrals I take it is a problem due to brain damage/malfunction and not physical blockage of air ways?

Centrals are more likely to be driven by CO2 levels being too low. The SpO2 result is more of a side effect. So a nights good SpO2 data isn't the best indicator of centrals but naturally a prolonged central should show a dip in SpO2.

Rolling over in the night can cause the sleeper to take a couple of deep breaths after which a 'central' can be detected but is totally benign because the deep breaths elevated the O2 level. The deep breaths may have (and can) cause the Co2 level to drop (Co2 washout) & that then triggers a slowing in respiration. If that shows as a desat, depends on the timing of the Co2 adjustment vs the prior SpO2 level. SpO2 tends to show a lag in what appears on a probe - this is due to the time between the gas-exchange in the lungs & the time the blood reaches the finger where the SpO2 probe is.

DSM

Now---Let me ask the question in a different way.
If central apneas are occuring, will they be detected and shown by the ResMed software even though they are not identified as centrals?
Or-- will they not be detected and not displayed?

I may be wrong, but I think any (not just ResMed and its Autoscan software) "regular" (non ASV) machine that records data about events can mistake some centrals for obstructives, and mark them as obstructives.

rested gal wrote:I may be wrong, but I think any (not just ResMed and its Autoscan software) "regular" (non ASV) machine that records data about events can mistake some centrals for obstructives, and mark them as obstructives.

I think so too - so I may be wrong as well...
O.

Most modern cpaps can detect a 'no flow' situation so yes they can 'technically' detect a central but as already replied to by the others, can't say with any certainty wether the no flow was a central or an obstruction. They can flag an event as 'non-responsive' but again that doesn't say if it was a central.

So, when you look at your Resmed data, you can try to guess if a 'no-flow' event (recorded as an AI) was obstructive or central. The guess can be improved by any observation of a partner or spouse "you simply slowed then stopped breathing dear"

DSM

Bottomline: NO! a cpap doesn't know if a no-flow was a CA or an AI event.

Thanks for all your responses. I am just amazed at rested gal's and DSM's (don't know your real names!) wealth of knowledge and resources!

I'm just concerned that since my titrated pressure is on the high side (16.0), that when I eventually work up to that pressure, it may cause pressure-induced centrals.

I decided to bite the bullet and stop flying blind. I'm getting my ResScan 3.7 and card reader!

tattooyu wrote:I decided to bite the bullet and stop flying blind. I'm getting my ResScan 3.7 and card reader!

Goodluck - it is absolutely worth it.

DSM