Bad sleep study titration? SpO2 drops...

[raisedfist]

Are those figures for wake breathing? In normal sleep breathing, the TV goes decreases by about 13-15%.

That is the reported value after a night of sleep, once you look at the results.

Has any problem with your tidal volume ever been officially diagnosed?

I have been diagnosed with nocturnal sleep-related respiratory failure due to nocturnal hypoventilation

Do you have a known breathing disorder that involves your tidal volume or your alveoli?

I have restrictive lung disease due to kyphoscoliosis (hunchback syndrome - an upper and lower curvature of the spine)

[raisedfist]

Raisedfist, you have a complicated situation. I am not an expert, but I have seen similar results before and based on those I feel I can offer some suggestions.

First, judging by the sharp return to 0 of the expiratory portions of most of your flow rate wave forms, it looks to me as if you are exhaling through your mouth quite a bit. See this thread for more on wave shape: viewtopic.php?f=1&t=112758&p=1085906#p1085906

If you are exhaling through your mouth, then it is likely that you, at times, are inhaling through your mouth as well. Inhaling through the mouth for more than 10 seconds (3 or 4 breaths) while wearing a nasal mask will result in an apnea being scored because the machine does not detect any flow. This could account for some of the UA's that you've been experiencing.

Additionally, the inspiratory portion of your flow rate waves show very sharp leading edges and seemingly short duration overall. Here, I might suggest increasing Ti Max to the something around 3.0 and not have the trigger and cycle settings be too aggressive, perhaps high and Low respectively or the default, Med and Med. And maybe, turning Easy Breathe on, if available. (Check the manual for trigger/cycle sensitivity labeling)

To reduce mouth exhalation, I suggest a cloth mouth cover such as the headband example mentioned in the same thread above here: viewtopic.php?f=1&t=112758&p=1085906#p1086296 The cloth cover reduces the amount of oral expiratory flow and tends to inhibit mouth inhalation. Since the cover does allow some exhalation through the mouth, chipmunk cheeks are not as likely to form as with tape and the ability to blow off excess co2 through mouth (unlike tape), is retained when called for to naturally adjust respiratory dead space.

As an alternative to a cloth mouth cover, a Full Face Mask could be used. However, in my opinion, a nasal mask and mouth cover is a much better solution for a variety of reasons.

So to recap, I suggest increasing Ti Max, using less than the most aggressive trigger and cycle settings, and a cloth mouth cover. Let's see if anyone agrees.

Very interesting - I had never thought about the inhaling/exhaling through the mouth. I've managed to bring down the leaks with the nasal pillows mask, by improving the fit, but I haven't used a full-face mask in a while. I noticed that when I did try mouth taping, the tape was still in tact when I woke up but that for whatever reason, a lot of moisture would build up and the tape would be moist, and I would also have this weird dry film around the edges of my mouth. I was also curious about the mouth taping, since I watched a few instructional videos on it, and it did say that due to the slower/less breathing by promoting nasal breathing, that less CO2 would be washed out. Which in my case is probably an issue since I need to blow it off, and I assume I need a high respiratory rate at times to aid in ventilation (respiratory rate and minute ventilation = more co2 blown off I believe).

I currently have my trigger/cycle on high/low instead of very high/very low.

I am going to try the full-face mask for tonight since I have one laying around and it would be interesting to see the results! I will work on the cloth mouth covering.

[Jay Aitchsee]

So, did your results change with a different mask or mouth cover?

[raisedfist]

So, did your results change with a different mask or mouth cover?

Haven't been able to effectively test it yet. The Mirage Quattro I own does not seal properly. I am going to test out my new Airfit F20 today that I just got in the mail. I also need to shave my wolverine beard.

[raisedfist]

So, did your results change with a different mask or mouth cover?

Using the same settings, 16/4.

With FFM the first night, cut my AHI, re: unknown apnea/clear airway, down to less than 2.

With FFM the second night, EasyBreathe enabled, no unknown/clearway events and .8, .7 of the AHI obstructives, and .1 was hypopneas. There was a flow limitation of 0.03%

I am thinking with the nasal pillows, the mouth opening and closing was causing the "unknown apneas" - which could easily be obstructive, or who knows how the machine chooses to flag them.

With my full-face mask, highest leak rate in the second night was 7 l/m, and 95% was 4 l/m.

Excellent seal, but I think I need a medium cushion instead of the large one I bought - the nose bridge part kept moving while laying down and left a nice indentation upon waking up, and was in a decent amount of "pain."


I am going to try 17/5 tonight - +1 cmh2o for IPAP for hypopnea and flow limitation, and +1 cmh2o for obstructives. And to keep the same PS level.

[Jay Aitchsee]

I am thinking with the nasal pillows, the mouth opening and closing was causing the "unknown apneas" - which could easily be obstructive, or who knows how the machine chooses to flag them.

Most likely. When one inhales through the mouth while wearing a nasal mask the machine does not detect any flow. If mouth inhalation continues more than 10 seconds, 2 to 4 breaths, an apnea will be scored.

Exhaling through the mouth produces a recognizable waveform (which yours did). I know of no way of positively identifying apneas scored due to mouth inhalation with our equipment, but in the presence of mouth exhalation, I think mouth inhalation should be suspect. Sometimes a flat line lasting less than 10 seconds can be seen between two exhales. I think it most highly probable that those are mouth inhales and can be picked out by zooming in on the flow rate graph.

[raisedfist]

I am thinking with the nasal pillows, the mouth opening and closing was causing the "unknown apneas" - which could easily be obstructive, or who knows how the machine chooses to flag them.

Most likely. When one inhales through the mouth while wearing a nasal mask the machine does not detect any flow. If mouth inhalation continues more than 10 seconds, 2 to 4 breaths, an apnea will be scored.

Exhaling through the mouth produces a recognizable waveform (which yours did). I know of no way of positively identifying apneas scored due to mouth inhalation with our equipment, but in the presence of mouth exhalation, I think mouth inhalation should be suspect. Sometimes a flat line lasting less than 10 seconds can be seen between two exhales. I think it most highly probable that those are mouth inhales and can be picked out by zooming in on the flow rate graph.

and i forgot to mention: but with the same settings, i felt less of a headache upon waking this morning. the reported tidal volume exhaled was about the same, but the sleepyhead data showed it being pretty consistent throughout the night, the graph looks very smooth.

the easybreathe waveform is really weird at first, it feels like a restriction in airflow, but after an hour or so i did seem to get used to it and it was okay - plus a lot quieter.

I think with the FFM, perhaps it is beneficial to those who have chronically high CO2 like me. I was watching a few videos about mouth taping, one by a dentist and another by a respiratory person, and they were saying that by breathing less and also slower, it allowed better oxygenation but also more CO2. Maybe keeping my mouth shut isn't a good thing. These are just (potentially ignorant) thoughts, I have no specific knowledge about what I am talking about.

I am still going to try the cloth mouth cover though, the nasal pillows are minimal on my face which is nice. The FFM isn't bad - I need to exchange for a medium cushion though.


My cardiologist said my restrictive lung disease process has allowed the sleep-related respiratory failure to occur. I am excited to further tweak until I get all the settings right, hoping to reverse at least some of the effects.

[raisedfist]

Last night at 17/5 with easybreathe enabled

i had an AHI of 1.8, 1.2 being obstructive and .6 being clear airway event. Highest leak was 7l/m.

I noticed after a few hours of seemingly interrupted sleep, then I started waking up seemingly every 15-30 minutes. I think the clear airway part could be junk after waking up from the obstructive apneas. Weird that raising the EPAP seemed to cause more obstructives. Although with just one night of data I guess it is pointless to assume things.

[Pugsy]

Although with just one night of data I guess it is pointless to assume things.

Yeah, one night doesn't mean much because we can have that much variance even without changing a single setting.
We just don't sleep the same each night and the AHI can vary, sometimes significantly, just as the normal variance without changing a thing. That's why we say that people should give a change several nights before doing any trend or pattern evaluation.

[Jay Aitchsee]

Although with just one night of data I guess it is pointless to assume things.

Yeah, one night doesn't mean much because we can have that much variance even without changing a single setting.
We just don't sleep the same each night and the AHI can vary, sometimes significantly, just as the normal variance without changing a thing. That's why we say that people should give a change several nights before doing any trend or pattern evaluation.

I agree. In fact, I wrote a post yesterday in response to the below advising you to go slow on the "tweaking" and let your body adjust to the changes in therapy, but it got lost, as posts sometimes do.

I am excited to further tweak until I get all the settings right,

[raisedfist]

I am back after a hiatus in messing with . I managed to get my hands on a lightly used ResMed S9 VPAP ST-A with iVAPS machine so I have begun to fiddle with that. I am no longer bound by insurance as I decided to buy my own machine and do everything myself. I returned all my rented equipment and man that felt good.

I have abandoned my previous beliefs that a low EPAP is beneficial for me. I realized that no matter how crazy I went with the IPAP or Pressure Support value, I would still have desaturations.

I found a study on ventilation and kyphoscoliosis (the condition I have) that found that an EPAP of 5 - 10 cmh2o was necessary in order to facilitate effective ventilation in the patients studied.

My current settings in iVAPS mode are the following:

IPAP Min: 16cmh2o / IPAP Max: 25cmh2o

EPAP: 10cmh2o

In a 7.5 hour sleep period last night, the lowest recorded oxygen saturation was 87%, and only 3 other recorded data points that were 88-89%. The rest of the night was above 90%, with a basal SpO2 of 94.9%.

With an increase in EPAP I have experienced more leaks. I am going to order the suggested mouth covers from Jay and try those out this weekend.

[palerider]

in it's most basic sense, when not dealing purely with OSA, bilevel ventilation has two elements that can be summed up with:

increase epap to increase oxygenation, increase ipap to increase blowoff of co2.

so, low EPAP isn't going to help with oxygenation.

[raisedfist]

in it's most basis sense, when not dealing purely with OSA, bilevel ventilation has two elements that can be summed up with:

increase epap to increase oxygenation, increase ipap to increase blowoff of co2.

so, low EPAP isn't going to help with oxygenation.

I should have listened to this from the beginning. What a bunch of wasted time! I used an EPAP of 11.0 last night and almost the entire 9 hours was spent above 90% SpO2. 2 measly events below, with short duration, when before I was struggling to even stay above the baseline of 88%, and the amount of events hovering between 85 - 89% was in the dozens.

I think I was stubborn because of the fact that my AHI is pretty much 0.0 almost all the time, so without recorded obstructive apneas for whatever reason I refused to raise the EPAP.

Once I see an entire night above 90% SpO2 I think I might cry.

[palerider]

in it's most basis sense, when not dealing purely with OSA, bilevel ventilation has two elements that can be summed up with:

increase epap to increase oxygenation, increase ipap to increase blowoff of co2.

so, low EPAP isn't going to help with oxygenation.

I should have listened to this from the beginning. What a bunch of wasted time! I used an EPAP of 11.0 last night and almost the entire 9 hours was spent above 90% SpO2.

this might help to understand better: https://www.youtube.com/watch?v=BdeOiDJmbrk

[raisedfist]

in it's most basis sense, when not dealing purely with OSA, bilevel ventilation has two elements that can be summed up with:

increase epap to increase oxygenation, increase ipap to increase blowoff of co2.

so, low EPAP isn't going to help with oxygenation.

I should have listened to this from the beginning. What a bunch of wasted time! I used an EPAP of 11.0 last night and almost the entire 9 hours was spent above 90% SpO2.

this might help to understand better: https://www.youtube.com/watch?v=BdeOiDJmbrk

Yes Sir. I have finally made it in my journey to optimize my bi-level therapy.

Two nights in a row I've kept my SpO2 above 88% and the vast majority of the time I was above 90% (about 1.5 mins out of ~8 hours each night was 88 - 89%).

I have found that the FFM works best for me as it produces the best results - two nights in a row with a 95% leak rate of 0.0 L/min and my patient triggered breaths were 98 and 99%.

I don't have any plans to ever visit a sleep doctor again. I learned everything I needed here for free.