Centrals not part of sleep study

[Sleepster]

I thought that a chest belt was needed to confirm no effort to breathe.

[zonk]

The question of recording apneas when you're not asleep applies to both central and obstructive apneas.

Yes but only central apnea get us freaked out

[Kate]

Okay...what is an ASV machine if model 36006A auto sv or 36007 adapt is not? I got what supplier # 2 had in the Resmed line. I was without insurance because of the health cars act and I needed to do something.

My sleep study was on the old Resmed machine I believe that's S8. The test was done with a mask and with a something around my chest. The study was done last December 2013. My doctor then read a readout from my machine two months later and he saw the centrals. That was when he Asaid that I needed an ASV machine. My DME will not give me the ASV machine because somehow they weren't in the sleep study.

By the way, I had the adapt machine from Supplier #2 and it broke. That was in my profile. #2 sent me a replacement that was an auto. That broke and they sent me what I believe was my original machine that was broken and it "accidentally" ended up on the shelf. I am slowly starting to believe that someone doesn't want my nightime hypoxia and hypopneas to be treated with CPAP or BIPAP or any other PAP. It's too hard.

Kate

[archangle]

I thought that a chest belt was needed to confirm no effort to breathe.

The machine attempts to detect a clear airway. i.e. it tries to see if your airway is open and outside air has a path to your lungs.

If the machine correctly detects a clear airway, and you don't have any airflow, it's a pretty good assumption that you have a central apnea. If there was respiratory effort, you'd presumably have airflow. It's a matter of mechanics.

The question is, "does the machine ever think there is a clear airway when there isn't?" I tend to believe the machines are correct when they sense a clear airway.

The machine can miss a central apnea, though. If it fails to detect a clear airway, it will classify it as an obstructive. I think the CPAP machines are designed to not flag a clear airway if the data isn't clear.

The other risk is that you can have a collapsed airway and no respiratory effort. Once again, in this case, the machine will report an apnea, but not realize it's a central. I think this does happen some of the time.

There is some uncertainty, but I think the gist is that when it says it's a clear airway apnea, the odds are very high that it is. If it says obstructive, there's a possibility that it's actually a central.

Before the sophisticated pressure pulse or FOT (Forced Oscillation Technique) detection algorithms were built into the PRS1 and S9 machines, CPAP machines had no clue about whether an apnea was central or obstructive. S8 or M series machines basically had no clue. Before the PRS1/S9 era, you DID need a chest belt to measure respiratory effort.

The medical mafia is somewhat stuck in the past, and wants to do profitable $leep $tudie$. There is some validity because CPAP machines will miss some centrals, but I think you can pretty much assume that a CPAP detected CA is an actual central.

(With the caveat that no apneas count if the patient is awake and the machine can't detect that.)

[zonk]

The medical mafia is somewhat stuck in the past, and wants to do profitable $leep $tudie$.

In US, different machines are billed by different billing codes and different criteria for different machines
You cannot jump from one machine to the next level without doctor (not mafioso) consultation and proper diagnoses
lol, viva la difference

[Sleepster]

In US, different machines are billed by different billing codes and different criteria for different machines
You cannot jump from one machine to the next level without doctor (not mafioso) consultation and proper diagnoses
lol, viva la difference

Yes, you still can buy whatever machine you want to buy. You may have to go off the grid and buy it on craigslist, but at least for now our nanny state isn't stopping us from doing that.

[archangle]

In US, different machines are billed by different billing codes and different criteria for different machines
You cannot jump from one machine to the next level without doctor (not mafioso) consultation and proper diagnoses
lol, viva la difference

Yes, you still can buy whatever machine you want to buy. You may have to go off the grid and buy it on craigslist, but at least for now our nanny state isn't stopping us from doing that.

US insurance usually won't pay for bilevel without a specific bilevel prescription, or ASV without ASV prescription. I'm not sure there's a legal requirement for a bilevel prescription. I think the online sellers will sell you any CPAP or bilevel, including ASV with just a "cpap" prescription. Local DME's may have different policies, even for self pay. Ventilators may require a different prescription.

[robysue]

My sleep study was on the old Resmed machine I believe that's S8. The test was done with a mask and with a something around my chest.

The data from the chest (and abdomen) belts was used to determine whether each apnea scored was a central apnea or an obstructive apnea. And that's a more reliable way of determining the nature of the apnea on a full PSG that's monitored by a sleep tech than just relying on the FOT algorithm built into the Resmed S9.

The data from the belts allow the tech to determine whether you are making an effort to breathe during the apnea. If there's effort to breathe, but no air getting into the lungs, the problem is an obstructed airway and the apnea is classified as an OA. If there's no effort to breathe being made, the problem is with the brain forgetting to send the signal to breathe to the diaphragm and lungs, and the apnea is classified as a CA.

If your original problem was OSA, then it's quite possible that no central apneas were scored on the diagnostic part of the test. If you had a split test with a CPAP mask on for part of the night, it's also possible that pressure induced centrals did not emerge as a problem during the limited amount of testing time, but that they did start to emerge once you started PAPing every single night. And the fact that your sleep doc looked at the data from your PAP and noticed the centrals is a good sign.

The study was done last December 2013. My doctor then read a readout from my machine two months later and he saw the centrals. That was when he Asaid that I needed an ASV machine. My DME will not give me the ASV machine because somehow they weren't in the sleep study.

You need to do the following:

1) Contact the doctor's office IMMEDIATELY and tell them that your DME will not honor the doc's script for an ASV machine. Request a hard copy of the script for the ASV machine that includes the doc's instructions for the ASV settings.

2) Contact your insurance company and find out whether the doc or the DME has contacted them about authorizing payment for an ASV machine. If so, find out whether the insurance company has denied coverage, and if so, why.

3) When talking with your insurance company, get a list of "in-network" DMEs that work with your insurance company. And report the problem with the DME that refuses to set you up with the needed ASV machine. The DME could not care less about losing your individual business. But if your insurance company threatens to not renew their contract with the DME because it will not correctly fill scripts written by their in-network doctors, the DME will take notice and that may be enough to get them to behave.

[robysue]

I've noticed that I can create centrals by merely swallowing while fully awake. Is that normal?

Yes, it's normal.

If you are using the machine and the airflow into your lungs suddenly decreases by 90% or more from baseline for at least 10 seconds, the machine will score an apnea of some sort. For many people, swallowing while fully awake will show up as a CA. For me, experiments show that if I hold my breath while awake for 10 seconds or more, the false event is more likely to show up as an OA than a CA. So how the machine will record this kind of a false event all depends on just how you go about swallowing as near as I can tell.

Incidentally, I use a small digital audio recorder to record my sleep sounds and it seems that all of my centrals are occurring when I'm awake. I mean as best I can determine I'm awake since I breathe much differently when awake and do things like clear my throat. I also mention things like "I'm turning over to my side now" so it sorta proves that I'm awake. I'm just ready to bet my centrals are all phony alerts created by my swallowing spit to keep from drowning.

A lot of people will have false CAs scored during the times you describe. The thing to keep in mind is this: Most people sleep well enough where the total number of these kinds of false CAs is relatively small---as in there's maybe a dozen or so at most scored for the entire night, which results in an overall CAI of maybe 2 or 3 at most.

But Kate, the OP, reports a CAI of 7 or so. So if Kate is using the machine for 6 or 7 hours each night, that means her machine is scoring between 40 and 50 events every night instead of 12 or so. And that's too many CAs to simply assume that they're all "false" CAs.

Edit: I have also noticed that a farting mask can be mistaken for a snore event. Makes sense, so it pays to review the leak reading when you see a snore event. I think it pays to check all readings in reference to any event markers just to help understand how these machines work.

Machine can score snoring under a wide variety of circumstances and this does not surprise me. If the hose is rubbing against a hard edge of a bedside table, that can also trigger snores to be scored. On the PR machines, the machine can also score snores if the hose is lying against a bedpartner (or pet) that is snoring.

I think I'll just deduct my centrals from the AHI score in order to get a more meaningful score.

This is perfectly reasonable when the CAI is not very elevated and you are relatively sure that there's a high probability of your being awake or semi-awake at the time the CAs are scored. But again, in the case of Kate (the OP), the number of CAs is high enough where it's not reasonable to just dismiss them all as false events.

[surferdude2]

Thanks for your confirmation robysue. I feel better knowing that what I thought about those CAs is likely correct, at least in my case. I realize that it makes a difference if these CAs appear during sleep and will score them accordingly, assuming I can peg them accurately.

There is no inexpensive device to determine when one is actually asleep. My digital audio recorder works to some extent. I considered asking my wife to stay awake and record that event but decided it would cost way too much.