How Important is the Sleep Study? Self-treat user looking for opinions

[Fetou]

Sleepyhead Capture Aug04.JPG (639.4 KiB) Viewed 14242 times

I think my minimum pressure is almost dialed in optimally. The pressure chart is starting to become more of a straight line and is less choppy than with lower minimum pressures. Snores still appear to be driving the pressure up for a portion of the night, but the event flagging in those periods has stopped.

Only one of the three event lines has any chance of being real. The hypopnea had no flat line, and the first OA flag was definitely along the lines of a roll over with short arousal and normal resuming of sleep shortly after.

Here is the more ambiguous second OA flag:

Sleepyhead Capture Aug04 apnea.JPG (273.17 KiB) Viewed 14242 times

[Pugsy]

Hyponeas don't have to have a flat line to be real.
The definition of hyponea is a flow reduction that is at least 40% (or 50% depending on brand) up 79% (because 80 % and above gets the OA flag) that lasts for at least 10 seconds.

The flow reduction might not be readily visible or easily seen (like the flat line) if the reduction was say 50%.

I have seen hyponeas that I know are real because there is asleep breathing on either side pf the flag and I sit here scratching my head about the apparent lack of anything that I can readily see in terms of flow reduction.
Likewise an OA doesn't have to have a totally flat line. It might just be an 80% reduction in air flow. We don't normally see flat lines unless the reduction is very close to 100% reduction in air flow.

The OA flag you posted just now....looks real enough to me. The double dip thing you see in the breath preceding the flag is sometimes seen and I think is more of a cardio echo kind of thing. I can't explain it very well but some people see those occasionally and some people (about 10%) see a lot of it.

[palerider]

Hyponeas don't have to have a flat line to be real.
The definition of hyponea is a flow reduction that is at least 40% (or 50% depending on brand) up 79% (because 80 % and above gets the OA flag) that lasts for at least 10 seconds.

The flow reduction might not be readily visible or easily seen (like the flat line) if the reduction was say 50%.

What she said... Hypos are hard to spot just looking at the flow trace, looking at the TV trace also may help you see them.

[Fetou]

Good to know about the hypopneas. Any reason why they don't correspond to the flow limitation graph in SleepyHead if that is how they are measured? Or does that graph only show FLs that are not enough to be considered HAs or OAs?

Also, do you think ~10,000 hours is too many for a backup machine? Secondwind CPAP claims that machines can last from 20,000 to 50,000 hours. Not sure what the distribution would look like on that.

[Pugsy]

Flow limitations aren't necessarily the same thing as flow reductions. It's weird I know...Hey PR...I am short on time..where's the video that explains it better?

10,000 hours for a back up machine...depends on how much somebody wants for it.

As for life span..I have a friend that has his first machine he ever started using nearly 30 years ago...well over 35K hours on it and still blowing strong. It's a tank though..huge and he uses smaller newer units when he travels...and he said it's noisy as hell but since he is hard of hearing now...doesn't care.

[Fetou]

Flow limitations aren't necessarily the same thing as flow reductions. It's weird I know...Hey PR...I am short on time..where's the video that explains it better?

10,000 hours for a back up machine...depends on how much somebody wants for it.

As for life span..I have a friend that has his first machine he ever started using nearly 30 years ago...well over 35K hours on it and still blowing strong. It's a tank though..huge and he uses smaller newer units when he travels...and he said it's noisy as hell but since he is hard of hearing now...doesn't care.

I'm thinking to offer $150 on it. It's an S9 VPAP Auto. The vast majority of these machines floating around on the secondary market have very few hours. I wonder what % of the average life span of any given XPAP unit manufactured is spent in a bag in closet.

[palerider]

Good to know about the hypopneas. Any reason why they don't correspond to the flow limitation graph in SleepyHead if that is how they are measured? Or does that graph only show FLs that are not enough to be considered HAs or OAs?

Because flow limitations are a completely different thing from hypopneas.

Flow Limitations are exactly what the name says... a limit to the rate of flow, whereas hyponeas are a reduction on volume.

You can have hypopneas without flow limitations, and you can have flow limitations without even a hint of a hypopnea, or indeed any reduction in tidal volume (which is the amount of air inhaled and exhaled in a breath.

Get a small straw, breathe through it. that's like a flow limitation, you can still take a full lung filling breath, it just takes longer, and you have to work harder for it.... now imagine trying to breathe through that straw normally... when I try it, I start feeling the effort of breathing after a bit... that's why flow limitations are bad, they increase breathing effort and make your sleep less restorative.

Watch this: https://www.youtube.com/watch?v=-gie2dhqP2c

Also, do you think ~10,000 hours is too many for a backup machine? Secondwind CPAP claims that machines can last from 20,000 to 50,000 hours. Not sure what the distribution would look like on that.

Depends on the price.

People usually say cpaps are good for at least 5 years. that's 14610 hours, assuming 8 hour nights.

[Fetou]

Thanks Pale, very helpful and efficient video.

I increased pressure again trying to clean up some of the flow limitations and arousals. Seems to have worked pretty well. Without the wake time at the beginning of the chart, AHI was around .50 again. Going to stick with these settings for a few more nights I think.

Sleepyhead Capture Aug05.JPG (696.67 KiB) Viewed 14170 times

[palerider]

Thanks Pale, very helpful and efficient video.

I increased pressure again trying to clean up some of the flow limitations and arousals. Seems to have worked pretty well. Without the wake time at the beginning of the chart, AHI was around .50 again. Going to stick with these settings for a few more nights I think.

Sleepyhead Capture Aug05.JPG

That's pretty good. anything under 1.5, I'm pretty happy with.

[Fetou]

Thanks Pale, very helpful and efficient video.

I increased pressure again trying to clean up some of the flow limitations and arousals. Seems to have worked pretty well. Without the wake time at the beginning of the chart, AHI was around .50 again. Going to stick with these settings for a few more nights I think.

Sleepyhead Capture Aug05.JPG

That's pretty good. anything under 1.5, I'm pretty happy with.

Is there anything to be done about the snoring other than exploring posture/elevation options? Not sure if snores can even be resolved with pressure

[palerider]

Thanks Pale, very helpful and efficient video.

I increased pressure again trying to clean up some of the flow limitations and arousals. Seems to have worked pretty well. Without the wake time at the beginning of the chart, AHI was around .50 again. Going to stick with these settings for a few more nights I think.

Sleepyhead Capture Aug05.JPG

That's pretty good. anything under 1.5, I'm pretty happy with.

Is there anything to be done about the snoring other than exploring posture/elevation options? Not sure if snores can even be resolved with pressure

the solution to snores is... more pressure.

[Fetou]

Thanks Pale, very helpful and efficient video.

I increased pressure again trying to clean up some of the flow limitations and arousals. Seems to have worked pretty well. Without the wake time at the beginning of the chart, AHI was around .50 again. Going to stick with these settings for a few more nights I think.

Sleepyhead Capture Aug05.JPG

That's pretty good. anything under 1.5, I'm pretty happy with.

Is there anything to be done about the snoring other than exploring posture/elevation options? Not sure if snores can even be resolved with pressure

the solution to snores is... more pressure.

Interesting. Does it just push the hanging/sagging parts that are making contact with the airway and vibrating further out of the way?

[palerider]

the solution to snores is... more pressure.

Interesting. Does it just push the hanging/sagging parts that are making contact with the airway and vibrating further out of the way?

That's the idea, and why auto machines raise pressure when they detect snores.

[Stom]

Flow Limitations are exactly what the name says... a limit to the rate of flow, whereas hyponeas are a reduction on volume.

You can have hypopneas without flow limitations, and you can have flow limitations without even a hint of a hypopnea, or indeed any reduction in tidal volume (which is the amount of air inhaled and exhaled in a breath.

Hypopneas are flagged on ResMed machines based on reductions in flow, not on a calculation of volume.

Apneas and hypopneas measured per hour for one day. An apnea is when the respiratory flow decreases by more than 75% for at least 10 sec. A hypopnea is when the respiratory flow decreases to 50% for at least 10 sec. The Apnea Index (AI) and Apnea-Hypopnea Index (AHI) are calculated by dividing the total number of events that occurred by the total mask-on therapy period in hours.

-Resmed Airsense 10 Clinical manual.

ResMed uses a scaled low-pass-filtered absolute value of respiratory flow and uses a root mean squared (RMS) technique of the variance of the flow from the mean to compare one moving time period to another.

Treatment of sleep-disordered breathing with positive airway pressure devices: technology update
Karin Gardner Johnson, Douglas Clark Johnson

Likewise, the AASM scoring critera for hypopneas are also based on flow, but with added criteria:

1A. Score a respiratory event as a hypopnea if ALL of the following criteria are met:

a. The peak signal excursions drop by ≥30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative hypopnea sensor (diagnostic study).

b. The duration of the ≥30% drop in signal excursion is ≥10 seconds.

c. There is a ≥3% oxygen desaturation from pre-event baseline and/or the event is associated with an arousal.

OR
Acceptable

1B. Score a respiratory event as a hypopnea if ALL of the following criteria are met:

a. The peak signal excursions drop by ≥30% of pre-event baseline using nasal pressure (diagnostic study), PAP device flow (titration study), or an alternative hypopnea sensor (diagnostic study).
b. The duration of the ≥30% drop in signal excursion is ≥10 seconds.
c. There is a ≥ 4% oxygen desaturation from pre-event baseline.

https://aasm.org/aasm-clarifies-hypopne ... -criteria/

[palerider]

Flow Limitations are exactly what the name says... a limit to the rate of flow, whereas hyponeas are a reduction on volume.

You can have hypopneas without flow limitations, and you can have flow limitations without even a hint of a hypopnea, or indeed any reduction in tidal volume (which is the amount of air inhaled and exhaled in a breath.

Hypopneas are flagged on ResMed machines based on reductions in flow, not on a calculation of volume.

:Sigh: once again, you're arguing about things you don't understand, based on poorly worded documents.