Semi OT - Insp.-Exp. Ratio

The quote you cite is dealing with a low ratio. I'm kind of curious what you found out about a high ratio. I looked at mine in Sleepyhead and it seems to be closing on 2:1. Does having a longer inhale time than exhale time mean anything? Also, I know few software applications are perfect, and Sleepyhead seems to be pretty good, but Is it possible Sleepyhead could inadvertently be flipping the two around?

The SleepyHead data corresponds to what I feel when I wake up at night. Inhale is longer,exhale is quite short in comparison. I am so sorry that the referenced article disappeared. I don't have a copy on my iPad but I'll search my desktopto see if I saved a copy.

What I got from the whole article is that this inversion is related to COPD.

Edit:
Looking at the site, it appears as if this set of pages were intended to be private and someone messed up. Then, between july 9th and 11th, they corrected the problem.

That being the case, I cannot post the whole page because of copyright issues.

JDS74 wrote:The SleepyHead data corresponds to what I feel when I wake up at night. Inhale is longer,exhale is quite short in comparison. I am so sorry that the referenced article disappeared. I don't have a copy on my iPad but I'll search my desktopto see if I saved a copy.

What I got from the whole article is that this inversion is related to COPD.

Edit:
Looking at the site, it appears as if this set of pages were intended to be private and someone messed up. Then, between july 9th and 11th, they corrected the problem.

That being the case, I cannot post the whole page because of copyright issues.

I'm a bit confused. My understanding is that a *low* I:E ratio corresponds to COPD (say, 1:2,it takes longer to exhale than to inhale). A normal I:E ratio falls between 1:1 and 1:2. An inverted ratio would mean it takes less time to exhale than to inhale (i.e. 2:1). So an inverted ratio would not seem to me to be indicative of COPD.

I'm confused also. All the articles I found were related to folks on ventilators including the one that disappeared and not "normally" breathing ones. According to my Edit: PFT reports, I suffer from mild COPD, not enough to treat.

I can't find the link right now, but there was a prior thread in August 2013 on this same subject that I had forgotten.
There, I mentioned asking my pulmonary doctor of the significance of the inverted ratio. He said with an OK minute vent, it was medically not significant. I'll ask again tomorrow when I see him next.

Perhaps the numbers are an artifact of CPAP therapy???

JDS74 wrote:I'm confused also.
...
There, I mentioned asking my pulmonary doctor of the significance of the inverted ratio. He said with an OK minute vent, it was medically not significant. I'll ask again tomorrow when I see him next.

Perhaps the numbers are an artifact of CPAP therapy???

+1 in the confused clan!

How are your tidal volume numbers compared to your height? I ask this because my Minute vent seem to be ok (low normal range I think 5-6), but my mean tidal volume is really low (320-340) for my height (6 feet) on CPAP/APAP and on ASV with a "PS min" of 3 or lower. An interesting fact in my case is that when my tidal volume start go in the 400-500 range (i.e. when setting PS min at 4 or 5), I feel like I have more energy doing more physical stuff... I did 2 small test (about 2 weeks each) in the past with those setting and it was one of the primary sign I noticed. I'm now in a more extended "experiment" period to see if it was just some placebo effect or coincidence.

Also can you tell me what the PTF acronym stand for? So I can do some googling on that! At some point before ASV I looked at COPD but didn't seem to have the more commun symptoms. COPD was also a little worry since it seem that ASV is not recommended for COPD patient but never really found if it was just for moderate and severe COPD...

OK, my dyslexia got me. PTF should have been PFT (Pulmonary Function Test).

At 6'1", my Mean Tidal Volume (Vt) varies from a low of 680 to a high of 902. When it was really high, I was experimenting with EPAPmin of 10 cmH2O and PSmin of 8 cmH2O. Increasing EPAPmin to 14 and lowering PSmin to 4.5 dropped the Vt down below 700. I'm currently at EPAPmin of 12.0 and PSmin of 7.5 and Vt last night was 800.

I'm doing these experiments because, while my centrals are low, my hypopneas are all over the place. I was hoping to control them as well as I have the OSA events controlled. I suspect that my hypopnea numbers are an artifact of my frequent arousals and awakenings during the night and pressure changes will not have any effect. At least that seems to be what the data indicates. When all is done, I'll probably go back to the lowest numbers that completely suppress the OSA events and bring down the Hyp's somewhat.

I'm running PS min 5 because my doc wanted my TV to come up to 500 (I'm 5'8"). I can't seem to get it above 430 on avg. My MinV consistantly runs at 6. I don't know if this is good or bad. I've tried raising my min PS to 5.5 in an effort to raise TV, but the air in my gut is just too painful.

M'ohms wrote:I'm running PS min 5 because my doc wanted my TV to come up to 500 (I'm 5'8"). I can't seem to get it above 430 on avg. My MinV consistantly runs at 6. I don't know if this is good or bad. I've tried raising my min PS to 5.5 in an effort to raise TV, but the air in my gut is just too painful.

I've only recently started being able to read my own data, so I'm realizing how much I don't know. I see my TV get to 500 - 600 at times, but I often see it down in the 200 - 300 range--even the 100's. I didn't know there is a relationship between the Pmin and tidal volume. Am I correct in understanding increasing Pmin will tend to increase tidal volume? I guess it stands to reason that air blown in at higher pressure will more readily come back out into a lower pressure. Does Pmax affect it also? I think my Pmin is set to 1 and the Pmax is set to 2.

what are you calling pmin?

Pressure minimum? in which case it doesn't go down to 2, or
Pressure Support minimum, PSmin.

yes, more PressureSupport would encourage greater tidal volume.

palerider wrote:what are you calling pmin?

Pressure minimum? in which case it doesn't go down to 2, or
Pressure Support minimum, PSmin.

yes, more PressureSupport would encourage greater tidal volume.

Oops, I did mean to say PSMin. As I understand it that's the minimum pressure difference between the inhale pressure and the exhale pressure.

HairyReasoner wrote:

palerider wrote:what are you calling pmin?

Pressure minimum? in which case it doesn't go down to 2, or
Pressure Support minimum, PSmin.

yes, more PressureSupport would encourage greater tidal volume.

Oops, I did mean to say PSMin. As I understand it that's the minimum pressure difference between the inhale pressure and the exhale pressure.

that is correct. more pressure support, generally = more tidal volume. a few people overventilate with as little as 2 or 3, some people need more.

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

M'ohms: It's interesting that your doc would look at your Tidal Volume. When I spoke about this to all the Docs and sleep apnea respiratory techs I saw in the past 2 years no one seem to care. Many (resp. tech mostly) simply told me they don't know enough or at all about Tv and one finally told me it could be normal if I have small lung. The Docs are a lot more evasive in their answers but you can feel they try to remember when they (probably) learn that at school and some finally simply say that's not that important. One was a pulmonologist with sleep apnea certification and simply ignored my comment saying it's not something they look at for apnea patients... Based on my past research on Tv I can tell you that those who care about the Tv often seem to make the mistake to calculate the Tv based on your actual weight, but it should be based on your "ideal" body weight for your height and sex. And a "normal" value can be in a wide range depending on those value. i.e. a range between 500-800 would be normal for my height if I remember correctly.

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 can't tell for others on the effet of PS on Tv but I would tend to say as palerider, higher PS would encourage higher Tv. In my case it do that, when I'm on CPAP/APAP (No PS) Med Tv is 340-320 on a daily basis, on ASV with PSmin at 0 or 3 Med Tv is 340 and sometime 360, at PSmin 4 Med Tv is 440, at PSmin 5 Med Tv is in the 500-540 range and at PSmin 6 Med Tv is in the 600s. What's happening, in my case anyway, is that Minute Vent stay about the same (between 5.5 and 6.5) but my Respiration Rate go down with higher PSmin setting going from a Med 18-20 Breaths/min on CPAP/APAP down to low 9 with some 8 Breaths/min with a PSmin of 6. Note that those numbers are while I'm asleep most of the night, with PSmax at 10 and at least 1 week at the same setting. Also EPAP changes doesn't seem to do much on my Tv. When I tried ASV while fully awake Med Tv and Med Minute vent. are a lot higher at around 8-9 for the Minute vent. and in the 700-800 range for the Med Tv.

JDS74 wrote:I'm confused also. All the articles I found were related to folks on ventilators including the one that disappeared and not "normally" breathing ones. According to my Edit: PFT reports, I suffer from mild COPD, not enough to treat.

I can't find the link right now, but there was a prior thread in August 2013 on this same subject that I had forgotten.
There, I mentioned asking my pulmonary doctor of the significance of the inverted ratio. He said with an OK minute vent, it was medically not significant. I'll ask again tomorrow when I see him next.

Perhaps the numbers are an artifact of CPAP therapy???

OK still somewhat confused by it all. Saw my pulmonologist this morning and discussed the inverted numbers.
So, he said that however accurate the numbers are, they cannot reflect reality of breathing patterns. If I was really having this inverted ratio, then I would be suffering from hyper inflation of my lungs. But, my PFT shows this not to be the case. Further, for his pulmonary patients who need, for medical reasons, to have their ratios inverted, he keeps them sedated because this is very uncomfortable.

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?

Remember I am using the Adapt 36007 model.
ResScan doesn't do I:E ratios on my Adapt (the old VPAP auto did and those matched Sleepyhead) .
I have blank dotted lines where I:E ratio is shown on ResScan statistics. So the block is there but no data at all.
SleepyHead gives me inspiration and expiration time in seconds.
For the most part it appears that I and E are almost identical in the seconds...with inspiration being slightly longer than expiration...... they are real close.
Like 1.76 vs 1.88 E or 1.74 I and 1.76 E

Thanks OSAHell for your imput. JDS, your discussion with your doc is interesting. I don't remember reading anything about inversion being painful. Your theory about ASV artifact seems very plausible. I hope someone can address the ResMed side of this issue.