AHI still erratic, time to wingding?

Thank you sludge for the info.

Hopefully what background info on Mom I can supply gives a few more clues to what is going on, while we all are waiting for sleep study data an and more SD card info from her VPAP:

Mom doesn't take any medications for depression, only occasionally has a glass of wine, and is getting outside in the sunlight on a regular basis. In fact, when I call, most of the time she is out with another family member gardening, shopping, out for dinner. We call her the go-go grandma. Jingle the car keys and she's ready to hop in and go.

She's working on the copies of her sleep studies, for what they will be worth. The mask leaked so badly during her last titration that she did not sleep. It will be interesting to see if it shows her getting any sleep that night.

The 3 nights or so I slept with her while on vacation, I was having trouble falling asleep-different bed, fan noise, etc. Mom on the other hand was out like a light in minutes. While I lay awake realizing she was snoring under her mask, and counting how long before she took another breath, she was sleeping. Yes, occasionally she would change position, probably be semi-awake at that moment, and go right back to sleep. No trips to the bathroom. There were times she was all over the bed and seemed to be dreaming, but she didn't seem to wake up. In fact at one point I got up to check and see if I would have more room moving to the other side of the bed. No such luck- double-sized bed and mom was diagonal. She is used to a king size bed and having plenty of room.

For the majority of time, she claims she does not nap or fall asleep during the day. However, before XPAP she could frequently be found unintentionally falling asleep during the day, for as long as I can remember. We always assumed this was from being Mom to very large brood, and all the work of a dairy farming family. I swear our garden alone was 2 acres. I think now, she has had unresolved sleep apnea most of her life.

She goes to bed and gets up on a regular schedule. Since using xpap, she doesn't need to watch TV to fall asleep. She used to have the TV on, on a timer, and have to sleep on a mound of pillows, semi- reclined. Not since xpap. She uses one pillow. While her therapy is far from optimum, at least it is making some positive differences. With an AHI of 20 most nights with APAP last year, I can't imagine what it was without any therapy.

Now she is using a body pillow to try to convince her body to stay on her side and not sleep supine. She thinks this is working. She wakes up in the same position. Input from Pugsy, Sludge, Robysue- anyone knowledgeable can let us know if she should continue to worry about staying on her side or just let her body do what it wants, especially once you all have more data to go by.

She describes her sleep as good more nights than not, especially with her current mask, which doesn't have the leak issues that really bothered her with over 5 other mask-none of which were even the right size. She does say that once she is awake, she is up, but on the usual morning, that is not excessively early. Not before 5 am, usually later.

To sum it up, Mom tells everyone her mind is 36, and her body is much older, but even at that not an 86 year old body. Nobody can guess her age to see her. People are amazed to find she is 86. I really think getting this sleep apnea under control will give mom a good chance of having many more productive and independent years.

Robysue, any of the info I've given you via pm, feel free to share with Sludge, Pugsy, or anyone else who might have reliable feedback. Mom is complicated case, and the more help the better.

I'm at Mom's now. Her AHI was very high last night, over 25. Lots of snoring, no central apneas. I've created a zipfile of the SD card, and will send it to Robysue.

Robysue, feel free to share this with whomever you feel can be helpful (Pugsy, Sludge, etc). You also can post whatever may be helpful to the forum.

I called the DME to get the exact dates of Mom's sleep studies, both the home study and the in hospital titration. When he heard how she's still having problems, he scheduled an appointment to come to Mom on June 17. He does know that I'm talking to all you folks on the forum and that I have made changes to her settings. His comments were along the lines with sludge- "an awful lot of pressure for a little lady." He thought we would be seeing centrals, and sleeyhead is not showing central apneas. He does seem to want to get to the bottom of all this.

FYI: I for one am really benefiting from this discussion and would love it if data got posted here. However, I do understand that is some work. Just thought I would let you know.

College3girls,

Just wanted to let you know that I've not been on the forum much the past few days. But I do keep an eye out on this thread. When I get the data, I will find the time to look at it.

Sorry to hear that your mom had yet another bad night.

After the AHI of 25, she had a 5 the next night, but only about 3 hours of sleep with that. Her diabetic neuropathy was very painful that night, so she didn't sleep well. She took off her mask when she woke up at 3:30 am and did not put it back on. It was one of her rare nights where she did not fall asleep right away,nor stay asleep until a normal hour of the day. Unfortunately, some "dunderhead" who had taken out her SD card to download the date to a file and send to Robysue, forgot to put the card back in the machine.

I woke during the night, thinking, " did I forget that card? I think I did!", so Mom got it back in the machine the next morning. Since the RT is coming on Tuesday, I haven't contacted mom to see how things went last night. Tuesday is just around the corner.

college3girls,

I hope that Sludge sees this post and comments on it.

To Sludge: college3girls has posted her mom's VPAP SD cards to GoogleDocs. What's the best way of sharing the folder with you?

I've gone through the data tonight and what I've noticed are the following things that I'd appreciate some insight on:

1) The clusters definitely seem to occur at pressures above 20/16. There are times when the pressure gets that high and a cluster doesn't go on for an extremely long time, but I don't think I saw any seriously long cluster at pressures below 20/16. The worst clusters seem to get started with, during or after pretty impressive pressure increases. A pretty typical start to a cluster looks like this:



That's a 10cm increase in pressure in just under 8 minutes. (My poor stomach can't even imagine dealing with such an increase.) Clearly part of why the machine keeps increasing the pressure is that it keeps scoring OAs. In the worst clusters, once that pattern is established, it keeps on going:



Is it possible that what's really going on is college3girls's mom's breathing is just plain becoming unstable due to the pressure increase? Would that mean the string of OAs are actually CAs? And if that's the case, what should college3girls and her mom be discussing with the RT when they meet with them on June 17?


2) When the flow limitation curve is indicating there's flow limitations going on, the individual breathing does look pretty ragged. The squared off inhalations in this shot are pretty typical of what many of the highest points on the flow limitation look like when you zoom in on the wave flow graphs:



And what's going on here? Is this most likely obstructive in orign?


3) Finally I zoomed in on almost every apnea in most of the clusters for which there is wave flow data on the SD card. I don't know if what I'm seeing is just the FOT in action or if it might be cardiogenic oscillations or a combination of the two, but the same kind of pattern is there in all the apneas regardless of whether they're scored as OAs or CAs. Some of the hypopneas also seem to have the pattern. If this pattern does represent cardiongenic oscillations, does that indicate the apneas are more likely to be central in nature even though they're scored as OAs? Rather than show just one of these OAs, I thought I'd include a pretty typical collection gathered from across all the nights with wave flow data. I've included the pressure graph so that you can see almost all of these events are happening during clusters that are occurring at pretty high pressures.

Close ups of typical OAs in the data:









****************************
Here are close ups of a pair of typical CA from the data for the sake of comparison:





So Sludge are you willing to take a look at college3girls's mom's data? (Let me know how to share the GoogleDocs folder with you.) And is this still looking like unstable breathing caused by the high pressure??

robysue wrote: Finally I zoomed in on almost every apnea in most of the clusters for which there is wave flow data on the SD card. I don't know if what I'm seeing is just the FOT in action or if it might be cardiogenic oscillations or a combination of the two, but the same kind of pattern is there in all the apneas regardless of whether they're scored as OAs or CAs.

Robysue, looking at the mask pressure waveform can give you a better clue about what the FOT is doing.

I can usually eyeball an event between the airflow and the mask pressure and have a good guess whether it's an OA or CA...
the variance in the mask pressure when the FOT kicks in is more pronounced and spikey if it's a OA, and much more subtle in a CA.

a couple screengrabs from my vpap auto.

Central:


OA:

palerider wrote:

robysue wrote: Finally I zoomed in on almost every apnea in most of the clusters for which there is wave flow data on the SD card. I don't know if what I'm seeing is just the FOT in action or if it might be cardiogenic oscillations or a combination of the two, but the same kind of pattern is there in all the apneas regardless of whether they're scored as OAs or CAs.

Robysue, looking at the mask pressure waveform can give you a better clue about what the FOT is doing.

I can usually eyeball an event between the airflow and the mask pressure and have a good guess whether it's an OA or CA...

This is something that I'll look at this evening. As someone who has not used an S9 in several years, I tend to forget about the Mask Pressure graph. On a PR System One like mine, there is no FOT to mess up indications of cardiogenic oscillations in the wave flow data.

Thanks for pointing this trick out to me palerider.

palerider wrote:

robysue wrote: Finally I zoomed in on almost every apnea in most of the clusters for which there is wave flow data on the SD card. I don't know if what I'm seeing is just the FOT in action or if it might be cardiogenic oscillations or a combination of the two, but the same kind of pattern is there in all the apneas regardless of whether they're scored as OAs or CAs.

Robysue, looking at the mask pressure waveform can give you a better clue about what the FOT is doing.

I can usually eyeball an event between the airflow and the mask pressure and have a good guess whether it's an OA or CA...
the variance in the mask pressure when the FOT kicks in is more pronounced and spikey if it's a OA, and much more subtle in a CA.

OK, but "IMHO", all that says is:

If FOTResMed "sees" a central apnea, it "calls" it a central apnea (refrain: obstructive).

"IMHO"2, the question that really needs to be asked is:

Is the eyesight of FOTResMed 20/20 at high pressures?"

Therefore, if we attempting (in this case anyway) to label FOTResMed inaccurate, there should at least be some logic to do so.

...(conventional FOT is) not designed to operate under external pressure load

http://www.ersj.org.uk/content/8/7/1222.full.pdf

Thus, if may be that at a certain base pressure level (and 17 cmH2O could arguably be just that) the obstruction is always there, regardless of airway status.

Sludge wrote:

palerider wrote:Robysue, looking at the mask pressure waveform can give you a better clue about what the FOT is doing.

I can usually eyeball an event between the airflow and the mask pressure and have a good guess whether it's an OA or CA...
the variance in the mask pressure when the FOT kicks in is more pronounced and spikey if it's a OA, and much more subtle in a CA.

OK, but "IMHO", all that says is:

If FOTResMed "sees" a central apnea, it "calls" it a central apnea (refrain: obstructive).

"IMHO"2, the question that really needs to be asked is:

Is the eyesight of FOTResMed 20/20 at high pressures?"

Therefore, if we attempting (in this case anyway) to label FOTResMed inaccurate, there should at least be some logic to do so.

...(conventional FOT is) not designed to operate under external pressure load

http://www.ersj.org.uk/content/8/7/1222.full.pdf

Thus, if may be that at a certain base pressure level (and 17 cmH2O could arguably be just that) the obstruction is always there, regardless of airway status.

Meaning that there's reason to suspect the Resmed FOT algorithm might not be all that accurate at distinguishing between CAs and OAs very high pressures???

robysue wrote:Meaning that there's reason to suspect the Resmed FOT algorithm might not be all that accurate at distinguishing between CAs and OAs very high pressures???

Specifically, EPAP (since FOT is not generated at IPAP)(except in C3GMM's case:

Sludge wrote:

...(conventional FOT is) not designed to operate under external pressure load

http://www.ersj.org.uk/content/8/7/1222.full.pdf

Thus, if may be that at a certain base pressure level (and 17 cmH2O could arguably be just that) the obstruction is always there, regardless of airway status.

I actually read through that paper, trying to determine what you were getting at... and came across your exerpt, expanded:

In this work, we developed a clinically applicable system to measure the frequency dependence of Zrs in mechanically-ventilated patients over a wide frequency band ranging 0.25–26 Hz during end-expiratory pauses at different PEEP levels. Measuring in such conditions is not possible with conventional forced oscillation devices, since they are not designed to operate under extenal pressure load. In fact, disconnection of the ventilator from the patient was required in previous measurements in intubated-paralysed patients.

referring to the attempt to measure reasonance of a patients airway, in situ, with the then existing equipment available to create forced oscillation pressure waveforms which were not designed to operate with the pressure load created by a ventilator, thereby forcing them to design their own FOT device that could operate under load.

I don't see how that quote out of a 20 year old paper is relevent, however, I do note that you are regarded with high esteem around these parts, so I've got to wonder what I'm missing.

palerider wrote:I don't see how that quote out of a 20 year old paper is relevent, however, I do note that you are regarded with high esteem around these parts, so I've got to wonder what I'm missing.

I would say the first thing would be to realize is that old does not equate to irrelevancy.

Meanwhile:

Leak and oral expiration were frequent findings in the group of patients studied overnight and are common in routine practice despite improvements in the interfaces available. We believe that these issues are the main limitation to the application of FOT in this setting.

http://www.atsjournals.org/doi/full/10. ... 6EjuvmSySo

and in looking at mask leak characteristics:

Another of my wonderments is where is the cutoff for central vs obstructive event is.

Now, finding obstruction in a big ol' fat guy is easy, and you can even optimize CPAP using FOT:



http://www.atsjournals.org/doi/pdf/10.1 ... .5.9710026