Semi OT - Insp.-Exp. Ratio

OSAHell wrote:JDS74: Thanks for sharing your numbers and clarifying the PTF acronym.

M'ohms:

HairyReasoner: What machine do you have because a PSmin of 1 and a PSmax of 2 look pretty weird to me. Also you should look at the "Med" or "Avg" Tv number in the daily view not the min or max as they seem to be pretty useless, in my case anyway. If you zoom in your tidal volume graph with a 10min window and you see some waveform that last for many minutes (30 or more) you might have some form of periodic breathing, check in your Flow Rate graph for the same time stretch, that’s what I saw when I was on CPAP/APAP. On ASV my Tv is a lot more constant because it “fixe” my PB problem.

I just got a PR System One 760 bi-pap with auto capability. The PSMin and PSMax numbers weren't really set as a part of my prescription. My original prescription was for bi-pap--not an auto situation--as a result of a recent sleep study. But, as I feared when I saw the actual numbers prescribed, the prescription is way off. My prescription was for 15 inhale, 11 exhale. But the 11 was so low my airway was collapsing (almost violently) on exhale. 15 is also far lower than my previous prescription of 18 (I had one pressure since it was CPAP). The bottom line is that In order to sleep I had to adjust the numbers myself. Not being able to talk to my doctor right away, I figured the best way to determine a new pressure was to set the machine on auto and get the 90% pressure numbers. That's when I saw the PSMin and PSMax numbers, but the bottom line is they weren't put in as part of my prescription. After reading the discussion here I did bump them up a bit (PSMin=2, PSMax=3.5) Unfortunately, I'm still having difficulty finding a setup that works until I can get in to see my doctor, although my guess is he'll just have me use the 90% pressures anyway.

Thanks for the info on Tidal Volume. I'll check my median and length of the lower TV. Sleepyhead has identified some periodic breathing at times (Cheyne-Stokes), usually only one or twice a night. I did have a bit more of an issue with it the other night, and I'm not sure what was going on.

JDS74 wrote: ...
Perhaps the numbers are an artifact of CPAP therapy???
...
So ... I conclude that either these numbers are an artifact of using ASV technology and can be safely ignored,
Or ... It is an artifact from within SleepyHead and can be safely ignored.

My thought tends to be ASV artifact and ignorable.

Since Encore doesn't report these numbers, is there anyone out there using a ResMed ASV machine and also using ResScan software who can check to see if ResScan also reports Inspiratory and Expiratory times and can shed light on the SleepyHead question?

Hi JDS74, sorry I'm on a Mac and don't have ResScan so I can't really see if numbers are different between ResScan and Sleepyhead. But few months ago I've been "forced" to go back to CPAP (from ASV) and my I:E ratio came really close to 1:1 with the same machine (ASV but in CPAP mode), I also been on a PR S1 in CPAP mode with same pressure for 6 day during that time and the numbers where similar. It's been 6 weeks of hell and decided to go back to ASV mode and my I:E ratio got back close to 1:2 in first night! This is also what I was experiencing with 2 others CPAP/APAP (Resmed Autoset and a F&P) in the past before the ASV with ratio between 2:1 to 1:1 depending of the CPAP/APAP setting. The only thing I see when I look at my Flow Chart graphs between ASV mode and CPAP/APAP mode beside the fact that I have a lot less apnea/hypopnea event during the night on ASV is that, on ASV I have basically no periodic breathing and on CPAP/APAP I have strong PB from maybe 8% to 30% of the time from night to night. I've got some nights with >50% PB and some with nearly 0% but on fixed low pressure (5) most night are between 8-30% PB. The worst "mode" for my PB is an APAP wide open... This is also where my AHI got the highest (>40).

So maybe PB can somehow affect the I:E ratio numbers? Or maybe it's related to the number of events? The more PB I have the higher my AHI is. Also I don't know if the number in Sleepyhead come from the machine or if JediMark "generate" these numbers based on the flow chart or other data... But considering Pugsy's answer I would tend to go with JediMark implemented something in sleepyhead to generate these. If he does use the flow chart and don't exclude the time when you are in a apnea, that can potentially "mess up" the I:E ratio number in my opinion.

HairyReasoner wrote: I just got a PR System One 760 bi-pap with auto capability. The PSMin and PSMax numbers weren't really set as a part of my prescription.
...
Thanks for the info on Tidal Volume. I'll check my median and length of the lower TV. Sleepyhead has identified some periodic breathing at times (Cheyne-Stokes), usually only one or twice a night. I did have a bit more of an issue with it the other night, and I'm not sure what was going on.

Sorry, I can't really help you with bi-level machine, I don't have any experiences with those and did really limited research on it. But I thought that an auto bi-level had a EPAPmin, EPAPmax and a PS (and maybe a Max pressure), I didn't thought there where a PSmin and a PSmax setting... I've only used CPAP/APAP and ASV so far and did a bit of research on machine for COPD patient. Anyway, your doc will probably shed some light on your setting since he is the one that prescribed it to you.

When you say that SH show 1 or 2 CSR a night, are you talking about 1-2% CSR or 1-2 stretch of time in CSR? If it’s not %, what is SH showing for CSR % numbers? It should be on the left side of SH window where you have all the numbers for events, leaks, etc.

Also, when looking at the "length", it's not the length of the lower Tv but the length of consecutive time your Tv is in a waveform shape.

OSAHell wrote:

HairyReasoner wrote: I just got a PR System One 760 bi-pap with auto capability. The PSMin and PSMax numbers weren't really set as a part of my prescription.
...
Thanks for the info on Tidal Volume. I'll check my median and length of the lower TV. Sleepyhead has identified some periodic breathing at times (Cheyne-Stokes), usually only one or twice a night. I did have a bit more of an issue with it the other night, and I'm not sure what was going on.

Sorry, I can't really help you with bi-level machine, I don't have any experiences with those and did really limited research on it. But I thought that an auto bi-level had a EPAPmin, EPAPmax and a PS (and maybe a Max pressure), I didn't thought there where a PSmin and a PSmax setting... I've only used CPAP/APAP and ASV so far and did a bit of research on machine for COPD patient. Anyway, your doc will probably shed some light on your setting since he is the one that prescribed it to you.

When you say that SH show 1 or 2 CSR a night, are you talking about 1-2% CSR or 1-2 stretch of time in CSR? If it’s not %, what is SH showing for CSR % numbers? It should be on the left side of SH window where you have all the numbers for events, leaks, etc.

Also, when looking at the "length", it's not the length of the lower Tv but the length of consecutive time your Tv is in a waveform shape.

I generally don't seem to have more than one or two CSR events per night, although one night in the past week I had three. When I have CSR events, I believe the machine usually reports 1 - 2% periodic breathing.
I'm not sure I'm understanding the Tidal Volume part. My TV graph doesn't really look like a waveform shape to me, maybe a rough one. It seems to vary quite a bit. I don't know what that's telling me. I'll look at it again the next time I log on to the computer with Sleepyhead.
I had run in auto mode for several nights, and after observing the 90% pressures I set my machine to fixed bipap with pressures at 16.5 inhale / 15 exhale. The funny thing is that I woke up this morning feeling like I was going to see a really high AHI, but when I loaded the data into sleepyhead it turned out my AHI was only .83. Last night I only had 2 obstructive apneas, 3 hypopneas, and 1 Central according to Sleepyhead. The machine identified no CSR. I'm not sure why I felt tired upon waking this morning, although I think I may have been a slight bit less sleepy during the day today (although my eyes did get pretty heavy for a while this afternoon).

HairyReasoner wrote: I generally don't seem to have more than one or two CSR events per night, although one night in the past week I had three. When I have CSR events, I believe the machine usually reports 1 - 2% periodic breathing.
I'm not sure I'm understanding the Tidal Volume part. My TV graph doesn't really look like a waveform shape to me, maybe a rough one. It seems to vary quite a bit. I don't know what that's telling me.
...

HairyReasoner: If your CSR only go in the 0-2% range it's unlikely that you have periodic breathing and you'll probably won't see any long stretch of your Tv like the waveform shape I was talking about. In my case, Tv waveform become quite apparent when I hit the 7-10% range for CSR. I'm really not an expert on Tv so I can't really comment more than that. If your AHI is around 1, I would stay on those setting and maybe look at something else like sleep hygiene or meds if you still fell tired. But if you want some advices or help on your pressure setting, maybe you can start a new thread with something like "bi-level pressure setting help" in the title so people with more experiences and knowledge with those machines can comment.