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[Diagnosis] What are my unclassified apneas?
RE: What are my unclassified apneas?
(07-05-2021, 02:15 PM)Geer1 Wrote: The oximiter is helping as it does show desats even though there aren't obvious apnea. You may be right about the obesity hypoventilation syndrome or something similar being part of the issue. The issue appears to be what looks like small inhalations (although still larger then mine for example), your exhalations are very fast (potentially due to restrictive nature of breathing in and weight on chest etc) and I am guessing your respiration rate is high because body is trying to maintain CO2/O2 levels by increasing respiration rate to keep up with demand since the inhalations are probably their natural size but not enough to keep up with O2 requirements.

I would change trigger back to normal as very low is causing IPAP to appear late in inhalation. I am thinking should try a lower rise time (say 500) as well as that will give more ventilatory assistance then raising IPAP will. I am also thinking increase EPAP to 8 and IPAP to 12 (same 4 cm PS but slightly higher pressure).

As you have made these changes has anything stood out as being obviously better or worse? Specifically curious about the rise time and pressures (if anything has ever felt uncomfortable. Even the 29th when you tried high PS at a low rise time did that feel ok (until the next morning)?

Edit: I am sure you already know this but perhaps seeing this data has been a bit of an eye opener. Trying to lose some weight does appear like it could make a significant difference in remedying this issue.

I changed the trig, rise time, Ti_Min/Max, by doing deep breathing exercises, while connected to the machine. Sitting upright at the kitchen table, not in bed. Deep inhale was cut short, the iPAP was shutdown while I was still breathing in. And long deep exhale was stopped by a new cycle of iPAP starting, before I stopped exhaling. I did not inhale. I played with everything but the rise time and pressure settings. My resp_rate looks better.
The 29th test was not a good sleep, I woke tired, and the whole day was bad.
Increasing the Rise Time was good. I think the oxy recorder will work now, just needed some tape on the finger sensor.
I am going to work on RR, my weight, and I ordered a inclined foam wedge to sleep on.
Too early to say "obesity hypoventilation syndrome", that was wishful thinking on my part. I have a deep fear of having a Central Apnea condition.
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RE: What are my unclassified apneas?
Adjusting settings when awake or sitting isn't necessarily comparable to when you are asleep, similarly doing it while taking deep breaths isn't ideal. When asleep your body minimizes respiratory effort and your breathing becomes more shallow because of it. This is what I believe is actually the issue in your case, when asleep you use fewer muscles and less effort and this reduced effort causes small breaths so your body speeds up respiration to try and deal with it. If you want to try settings while awake again would be best to try and mimic sleep conditions laying down and taking shallower breaths.

My comments about the timing settings are based on the data you posted. As you can see in the following attachment the pressure waveform is lagging the breath waveform. 


Using a higher trigger sensitivity moves the pressure start point to the left closer to the start of your breath and a shorter rise time will make it so you get pressure support earlier in the breath. Right now the increasing pressure isn't doing all that much to influence you to take larger breaths so these changes should in theory help improve oxygen levels by creating more full breaths. I would try trigger normal and try to find the shortest rise time you are comfortable with (and once we get dialed in a bit more you can even try adjusting this to see if/how it affects your oxygen levels). Using too high of a trigger sensitivity could have been causing the early pressure increases you noted, this can be triggered by the little bumps you see at end of exhalation period and these are called cardiogenic oscillations which are flow rate affects caused from pulmonary blood flow. With them present high trigger wasn't ideal but we should try to maximize trigger as possible. 

The very low cycle is good, it is the reason that the pressure is ending after you have already started exhalation meaning inhalation pressure is going to be maintained as long as possible. Your exhalations are very powerful (it is what causes the pressure spikes you see on each pressure waveform) so breathing out against pressure is not an issue for you like it is for some people.

The Ti min is close to your average inspiration length and is affecting some breaths. In most spontaneous breathing cases you want to avoid this but in your case you do have hypoventilation and it might help. The downside of longer Ti min is that if the machine triggers a breath at the wrong time it will hold the pressure, if this is a problem I would lower it again (0.8 at least). 

The higher Ti max you put in should never come into play, even the old 1.5 setting was almost never coming into play during sleep (except on the 28th after 2:30 when you started over ventilating for some reason). 1.5 could actually help avoid over ventilation issues so it might be worth considering lowering it. 

I don't see any signs of central apnea anymore and the early apnea could have been obstruction or perhaps centrals caused by the square wave form. If you had a serious central issue it your AHI the night of the 28th would have been through the roof during the period you over ventilated. I don't know if OHS is the correct name for your situation but you do have hypoventilation contrary to my thought/comment earlier in the thread (hypoventilation is the cause of your lower oxygen levels) and it could be caused by weight. Normally we see oxygen level drops associated with obvious apnea but in your case they slowly drop because breathing isn't keeping up with bodies demand. Eventually it drops too low and this causes an arousal and recovery breaths (23:40, and 4:30 last night).
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RE: What are my unclassified apneas?
On a side note one advantage of your machine if you switch back to ST mode and turn backup rate on is that it would have supplied pressure and helped you breath better during the hypopnea at 1:21. The original setting of 12 BPM was a bit low for your spontaneous breath rate, 16 is probably closer to what should be used if you want to turn that back on.
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RE: What are my unclassified apneas?
Sessions not shown: 
#1  7/3  length_3:30_hrs  AHI_9.43  28_Hypopnea  5_Unclassified  0_Obstructive
#2  20/10  length_1:20_hrs  AHI_22.78  0_Hypopnea  30_Unclassified  0_Obstructive

Session shown
Sleep OK, on my back, normally on my side.
Mode_S  12/8  TiMax_3.0  TiMin_1.5  RiseTime_500  Trigger_Med  Cycle_Med
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RE: What are my unclassified apneas?
A local VAuto is available. Should I switch from the ST?
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RE: What are my unclassified apneas?
It would have some advantages, primarily the ability to tell what type of apnea is occuring and ability for the machine to automatically adjust pressure to overcome obstructive breathing issues. Has a more comfortable breath waveform as well although the square wave potentially has some advantages in maintaining your oxygen levels (which were better in session shown). If it is a good deal I would probably grab it.

In that zoomed example you posted breaths were now triggering too early, I guess try trigger on low. You should probably change Timin back to 1 sec, I wouldn't go higher then that.

Are the other sessions not shown because they didn't record for some reason or you turned them off? Would be good to see that data to try and understand why the higher ahi.
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RE: What are my unclassified apneas?
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RE: What are my unclassified apneas?
Just a bit concerned on the SpO2 data. It showed a drop to 88% several times. I don't see an actual duration for that low level of 88.

The other concern is the hypopnea are quite high at times, and at other times the very high level of unclassified apnea appear. Old square waves not exactly doing the best IMO.

The VAuto maybe would help with treating you.

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RE: What are my unclassified apneas?
Both the hypopneas and apneas were treatment induced centrals imo. I believe there were primarily caused by too high of Ti min driving your respiration (hence the flat line inspiration at 1.5 sec).

I would try same settings with trigger low and Ti min back to 1 sec to see if that does better.

Your oxygen levels were better so getting close just need to get everything in sync properly I think.
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RE: What are my unclassified apneas?
mode_s  12/8  tmax_2.0  tmin_1.0  rise_600  trig_low  cycle_low
sleep was OK, position on back, no pillow
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