How frequent are pressure pulses supposed to be

[tetragon]

I know from the manual that my machine sends out pressure pulses as part of deciding on whether to classify an event as obstructive or clear airway, but I keep getting them even when there is no nearby logged apnea. Which suggests that it takes less to trigger a pulse. How frequently is this supposed to happen? In a six hour night, I get 150 - 250 of these pulses (last night was near the 250 end of that range), but my typical reported AHI is around 3.5 (mostly CA).

[davelikesbeer]

I get in the order of 10 - 15 pressure pulses per night. And when I look at the flow rates at the times in SleepyHead, I usually see what appears to be a short apnea where the flow rate is 0 for some time. However, since it does not stop for 10 seconds, it is not considered an apnea (by the machine). As a result, very few pressure pulses correspond with "apneas".

What do you see when you look at the flow rate data in SleepyHead?

Dave.

[tetragon]

So, trying to respond again (MySQL ate my last attempt).

Most of the pressure pulses do happen when the flow is 0, but there are some instances with 0 flow and no pulse and some pulses that appear to have non-zero, non-pulse flow.

I had 224 pressure pulses last night, so I have plenty of examples to choose from.

[davelikesbeer]

So, trying to respond again (MySQL ate my last attempt).

Most of the pressure pulses do happen when the flow is 0, but there are some instances with 0 flow and no pulse and some pulses that appear to have non-zero, non-pulse flow.

I had 224 pressure pulses last night, so I have plenty of examples to choose from.

...

Yes, those are very similar to mine, but a lot more frequent. I am certainly no doctor, but if I had such frequent flow stops as that, I'd consider raising my pressure a cm or two. Although, I'm not terribly certain about it since your data show 0 obstructive and 3.02 clear airway apneas per hour. If all those short apneas are potential clear airway apneas, then increasing your pressure will not help and may make it worse!

Perhaps one of the veterans will chime in with some advice.

[tetragon]

I am certainly no doctor, but if I had such frequent flow stops as that, I'd consider raising my pressure a cm or two. Although, I'm not terribly certain about it since your data show 0 obstructive and 3.02 clear airway apneas per hour. If all those short apneas are potential clear airway apneas, then increasing your pressure will not help and may make it worse!

I know that in my titration, they did try 8cm, which stopped snoring (as opposed to my current 7cm that stopped apnea). For some reason unbeknownst to me, my prescription ended up as 7cm. I don't know much more than that.

[tetragon]

I mentioned waking up feeling like I can't breathe when I was at my DME picking up my third mask (which actually has happened a few times). Now, I'll be bringing my data card back in to be checked next week. I wonder if any of this fun will show up when the data is scanned in.

[moresleep]

Interesting. You might be a candidate for a BiPap. Are you using Flex? If it were me, I would experiment with Flex before changing pressure. While you would think Flex would always help, in fact, for a lot of people, turning it off improves the numbers--there's a study someplace that tries to explain why. Whichever way you have Flex now (on or off), I would try it the other, just to see.

When you woke up feeling you couldn't breath, were you able to look at the waveform data, to see if you were experiencing events? If no events, I might suspect the low pressure--you get better CO2 washout with slightly higher pressure. But, as pointed out above, be cautious about raising pressure, with those central events...

[tetragon]

When I got this machine, the RT locked the flex setting to CFlex+ at 3, claiming that most people found that setting the most comfortable. This was in the same visit that I hauled my original S9 Escape back and mentioning that I had woken up a few times feeling that I couldn't breathe and that EPR was active when I woke up (they switched the Escape for my current unit due to the annoying clicking noise the H5i makes). Normally, I wouldn't feel too badly about changing that setting, but I've been on CPAP for not quite a month, and I'm not sure about how Big Brothery they're going to be about settings.

Without any visible clocks, I haven't been able to determine an actual time at which I wake up like that. I can think of a number of ways of rigging up a simple time logger that I could use without getting out of bed, the simplest methods having potential light issues.

[Pugsy]

When I got this machine, the RT locked the flex setting to CFlex+ at 3, claiming that most people found that setting the most comfortable.

Can you see me rolling my eyes in disgust.

The Flex settings are for patient comfort and even if "most" people found it more comfortable, that certainly doesn't mean you would. I have tried Flex settings of 3. Makes me feel like I am breathing too fast. Almost like hyperventilating. From comments here from other members, I am not alone in that feeling. There should be a demo available in the Flex menu so you can test all settings. Of course you would have to unlock the Flex setting in the clinical menu to be able to access it. That would be the very first thing I would do.. Unlock it and see if I liked another setting better.

I have been watching your thread. I can't offer any ideas as to why so many pressure pulses except that the machine obviously wants some help in determining what to call the events. CA Index of 3 is not alarmingly high but you really don't have much obstructive component at all. I can't see any reason to increase the pressure from 7 cm because it won't help the CA index and while in theory might make the "centrals" increase, I don't see it really happening.

If you awaken often during the night with these feelings of distress I wonder how many of the reports CAs are sleep transition and not the centrals that we would worry about (if you had a whole lot more of them).

Anyhow, I would suggest that you try a different Flex setting or even turn it off...there is the remote chance that Flex doesn't suit you well. Will it make any difference with the pressure pulses? I don't know but changing the Flex setting won't hurt a thing and I am betting the DME won't even notice... I am not sure there is even a setting choice in Encore PRO for Flex. I don't remember seeing one. I will look later to make sure. For sure not on the ordinary reports.

Edit: I scoured Encore Pro... I couldn't find anything that would point to whatever Flex setting showing on the reports or any of the patient prescription stuff. It is simply never mentioned anywhere on the reports or settings choices in Pro.

[tetragon]

Can you see me rolling my eyes in disgust.

Would it surprise you to hear that in that same visit to the DME, they told me that the main difference between the S9 Escape and the S9 Elite is auto-on/off?

On a more serious note, most of the awakenings that I remember were merely changing position (to avoid being stabbed in the nose by an Opus 360: step 1, grab short hose; step 2, change position whilst maintaining the short hose's relative position; step 3, fiddle with short hose position until stable, quiet, and not nose-stabby). The times when I do wake up feeling like I can't breathe feel like they're separate from remembered awakenings, but given how imprecise memory can be, who knows. With the rough sorts of correlation possible with the tools I have at hand, all I can say is that the pulses are (probably) scattered thoughout not-deep-sleep, but not in deep sleep (possibly).

I think I'll hold off of switching the Flex setting for now as I have made yet another mask switch (my Swift FX for Her finally came in, and the DME took away all my previous masks), and would rather not change too much at once.

[Pugsy]

Would it surprise you to hear that in that same visit to the DME, they told me that the main difference between the S9 Escape and the S9 Elite is auto-on/off?

Not one bit especially after taking away all the other masks. Jeezz. You are much nicer and have way more patience than I would have. I know they do things differently in Canada but that's no excuse for flat out lies.
I would have told them where to stick the machine and you can imagine it wouldn't have been nice.

Good luck with the Swift FX. I have done very well with mine. Sounds like you are over due for some good luck.

[tetragon]

Good luck with the Swift FX. I have done very well with mine.

I'm hoping that this Swift FX for Her will work. One of the two masks the DME took from me was the Swift FX (not for Her) that the RT initially fitted me with (even though it was too large for me to use comfortably) (and only gave me small pillows with, she tossed the non-small into a drawer and fished out more small pillows). This time I have more sizes, so, based off of what I felt when trying different pillow sizes with the Opus, I will try the extra small tonight.

As for the differences between the Escape and Elite, if all you look at is the "Welcome Guide", it becomes eminently clear that the two differences between the models is auto-on/off and mask fit. Which is why the RT, after telling me to bring in my card next week for a reason unrelated to compliance, frantically tried to remember whether I had the Escape or Elite.

[tetragon]

I don't know but changing the Flex setting won't hurt a thing and I am betting the DME won't even notice... I am not sure there is even a setting choice in Encore PRO for Flex. I don't remember seeing one. I will look later to make sure. For sure not on the ordinary reports.

I'm now back from my most recent trip from the DME. I didn't learn much from it, other than that my average VS index is in the forties, and that they can see my Flex setting. They used Encore Anywhere to grab the data, and that includes the Flex setting in one of the graphs.

[Pugsy]

that they can see my Flex setting. They used Encore Anywhere to grab the data, and that includes the Flex setting in one of the graphs.

Hmm. Perhaps Encore Anywhere has a different software base. My Encore Pro reports only show a generic "AFlex" on the graphs at the top right hand corner as being used and another on first page of all the reports as being used but doesn't say an actual setting.

I just now looked through all the pages that Encore Pro produces. It shows AFlex as being used but no setting number.

No big deal though. Just interesting.