Bad sleep study titration? SpO2 drops...

[Sleeprider]

S9 ST-S http://www.resmed.com/us/dam/documents/ ... er_eng.pdf

Not sure about Aircurve 10 series. In any event, the sustained IPAP pressure and algorithms are appropriate for the described restrictive pulmonary conditions. PR, I don't present myself as a qualified physician, and certainly you are not either. My question was whether the O.P. had raised the question about ST given his hypoventilation. Let's not distract from his positive progress with the Vauto, however I'd be interested to hear what circumstances or conditions you'd consider appropriate for this class of machine, if not for hypoventilation.

[palerider]

i think you are spot on with the ti min and max. especially since getting more air in is my exact problem. i actually notice sometimes that I wish I could breathe in for longer, and I'm sure that's even more important when I'm actually sleeping. it actually reminded me of a post i read back in the day on another forum. guy has the same extrapulmonary condition that i do (kyphoscoliosis):

if it were me, i'd consider bumping up both TiMin and Timax, unless you feel the need to limit your inhalation times, you can crank max up... (mines at 3, because I noticed periods of clipping on my inspiration time chart, where I was hitting the default 2 seconds, and ipap was cutting off, even though my sleeping self wanted longer slower intakes of air... so I raised it up, and no longer see the flat spots on my inspiration time chart.

consistent with the posting you listed, you could also increase TiMin, though it would probably be good to tweak it up a little at a time, perhaps go to 1 second, see how that does and re-evaluate, I don't think I'd go to 1.5 all in one go, and indeed, for you, 1.5 might not be the right number.

I do notice you spent almost zero time at .8 last night, unlike most of the previous nights.

[palerider]

S9 ST-S http://www.resmed.com/us/dam/documents/ ... er_eng.pdf

you mean the combined guide that *clearly* says, right on the cover:
VPAP Auto
VPAP ST
VPAP S
you do realize that those are *three* separate machines, right? no?

where do you get "S9 ST-S" out of that? cherry picking out of the file name "s9-vpap-auto-st-s-h5i"

Not sure about Aircurve 10 series. In any event, the sustained IPAP pressure and algorithms are appropriate for the described restrictive pulmonary conditions. PR, I don't present myself as a qualified physician, and certainly you are not either. My question was whether the O.P. had raised the question about ST given his hypoventilation. Let's not distract from his positive progress with the Vauto, however I'd be interested to hear what circumstances or conditions you'd consider appropriate for this class of machine, if not for hypoventilation.

gee, you mean like the "sustained IPAP pressure"(sic) in the machine he already has?

first, you clearly don't have much of a clue as to what you're talking about, given your confusion about what machines do what, though if you actually *read* the manual you mentioned, or even better, the clinicians manual for it, you'd see that the ST offers exactly *ONE* function that the Vauto doesn't (timed breath, not needed here since raisedfist isn't having centrals at more appropriate pressures), and is missing other functions that the Vauto offers, like, say auto adjusting mode.

I've already said, many times, what conditions the ST class of machine is for, it's for people who need a back up rate when they're not initiating breaths on their own:
ST (Spontaneous/Timed) mode
The VPAP augments any breath initiated by the patient, but will also supply additional breaths should the patient breath rate fall below the set “backup” breath rate.

T (Timed) mode
The fixed breath rate and the fixed inspiration/expiration time is supplied regardless of patient effort.

do you have even the foggiest clue what "hypoventilation" means? it means, in essence, taking breaths that are too shallow. a timed backup rate will not help that condition. do you not get that?

now, would you please quit trying to confuse the issue with your ignorance?

[raisedfist]

i think you are spot on with the ti min and max. especially since getting more air in is my exact problem. i actually notice sometimes that I wish I could breathe in for longer, and I'm sure that's even more important when I'm actually sleeping. it actually reminded me of a post i read back in the day on another forum. guy has the same extrapulmonary condition that i do (kyphoscoliosis):

if it were me, i'd consider bumping up both TiMin and Timax, unless you feel the need to limit your inhalation times, you can crank max up... (mines at 3, because I noticed periods of clipping on my inspiration time chart, where I was hitting the default 2 seconds, and ipap was cutting off, even though my sleeping self wanted longer slower intakes of air... so I raised it up, and no longer see the flat spots on my inspiration time chart.

consistent with the posting you listed, you could also increase TiMin, though it would probably be good to tweak it up a little at a time, perhaps go to 1 second, see how that does and re-evaluate, I don't think I'd go to 1.5 all in one go, and indeed, for you, 1.5 might not be the right number.

I do notice you spent almost zero time at .8 last night, unlike most of the previous nights.

I changed Ti min to 1.0 and Ti Max to 2.0 last night. I am not great at interpretation, but my tidal volume and respiratory rate graphs for the night look pretty smooth.

I wasn't feeling very good from a terrible sore throat so I didn't use my pulse ox since I had to get up once or twice in the night. About 12:30AM is when I actually fell asleep. I actually woke up feeling "well ventilated" and I had no tightness in my chest.

[palerider]

I changed Ti min to 1.0 and Ti Max to 2.0 last night. I am not great at interpretation, but my tidal volume and respiratory rate graphs for the night look pretty smooth.

I wasn't feeling very good from a terrible sore throat so I didn't use my pulse ox since I had to get up once or twice in the night. About 12:30AM is when I actually fell asleep. I actually woke up feeling "well ventilated" and I had no tightness in my chest.

well, that sounds promising.

it does seem to be a more 'calm' night than you were having with previous settings, and if you're feeling any better (apart from the throat) that's great.

it'll be interesting to see how it's affecting your spo2 throughout the night.

[raisedfist]

I changed Ti min to 1.0 and Ti Max to 2.0 last night. I am not great at interpretation, but my tidal volume and respiratory rate graphs for the night look pretty smooth.

I wasn't feeling very good from a terrible sore throat so I didn't use my pulse ox since I had to get up once or twice in the night. About 12:30AM is when I actually fell asleep. I actually woke up feeling "well ventilated" and I had no tightness in my chest.

well, that sounds promising.

it does seem to be a more 'calm' night than you were having with previous settings, and if you're feeling any better (apart from the throat) that's great.

it'll be interesting to see how it's affecting your spo2 throughout the night.

Unfortunately I had a pretty sustained desaturation event grouping last evening even with an AHI of 0.0. Do you think increasing PS to 12 might help? Last night, and the night before that, the EPAP maxed out around 9.5 - so that should give some wiggle room. The IPAP maxed out around 19.5 - 20.0 as well the last two nights.

Edit: it looks like Max PS available is 10.0 in Vauto mode

[palerider]

Unfortunately I had a pretty sustained desaturation event grouping last evening even with an AHI of 0.0. Do you think increasing PS to 12 might help? Last night, and the night before that, the EPAP maxed out around 9.5 - so that should give some wiggle room. The IPAP maxed out around 19.5 - 20.0 as well the last two nights.

Edit: it looks like Max PS available is 10.0 in Vauto mode

import the spo2 into sleepyhead so we can get some idea what was happening.

and remember, the basic theory, increase epap for oxygenation, increase ps for co2 reduction.

[raisedfist]

Palerider and company, is there any way to tell what kind of apneas are flagged when I have EasyBreathe/FOT turned off, based on the graphs? It looks like smooth flowrates outside of near the flagged events. Assuming that those are centrals? What's interesting is that there were no noticeable oxygen desaturations until a sustained group of events around 5:30AM.

I would turn on EasyBreathe, but for whatever reason if I use an EPAP of 4.0 with it enabled, my mouth pops open off and on all night. I think maybe it softens the pressurization too much? It does not do that with EasyBreathe disabled. So, I cannot use the same exact settings of 16/4 that I tried last night.

For me it was a pretty good night, basal sp2o of 93.5% and 2 minutes out of the night were under 88% SpO2 with only 4 events under 88%. I slept pretty solid through the night as well.

Let me know if further screenshots are helpful.

[palerider]

Palerider and company, is there any way to tell what kind of apneas are flagged when I have EasyBreathe/FOT turned off, based on the graphs? It looks like smooth flowrates outside of near the flagged events. Assuming that those are centrals? What's interesting is that there were no noticeable oxygen desaturations until a sustained group of events around 5:30AM.

there's no way to tell, that I know of, with the machine in S mode.

if you had it in vauto mode, it should test and tell you.

my guess is that they're obstructive, since it looks like there's very tiny attempts at inhalations in the flow, but that is purely a guess.

[raisedfist]

Palerider and company, is there any way to tell what kind of apneas are flagged when I have EasyBreathe/FOT turned off, based on the graphs? It looks like smooth flowrates outside of near the flagged events. Assuming that those are centrals? What's interesting is that there were no noticeable oxygen desaturations until a sustained group of events around 5:30AM.

there's no way to tell, that I know of, with the machine in S mode.

if you had it in vauto mode, it should test and tell you.

my guess is that they're obstructive, since it looks like there's very tiny attempts at inhalations in the flow, but that is purely a guess.

If I increase the PS by raising IPAP and keeping EPAP at 4.0, the AHI for "unknown apneas" goes up - the AHI pretty much doubles for every 2cmh2o increase in IPAP only. That's why I was guessing they were centrals. I get an AHI below .5 when I drop the pressures down to 13-14/4. All the while keeping EPAP the same.

I don't feel comfortable with the EasyBreathe on, so I haven't been using the vauto. I seem to breathe easier with a set rise time for whatever reason. And I'm not sure exactly with the same settings, the EasyBreathe makes my mouth pop open and wake me up all night.


I've always had the trigger setting on "very high." I tried setting it to just "high" last night - i thought maybe during my sleep the trigger is so sensitive that if I cough or sigh maybe it's pressurizing the IPAP even if I'm not trying to take a breathe. I was thinking maybe that causes some dyssynchrony. But I noticed a few times while awake it seemed the work of breathing to inhale seemed higher during those times, so back to "very high" it goes.

[robysue]

If I increase the PS by raising IPAP and keeping EPAP at 4.0, the AHI for "unknown apneas" goes up - the AHI pretty much doubles for every 2cmh2o increase in IPAP only. That's why I was guessing they were centrals. I get an AHI below .5 when I drop the pressures down to 13-14/4. All the while keeping EPAP the same.

Asking an obvious question: If the AHI is below .5 when you use EPAP = 4 and IPAP = 13 or 14, then why are you raising the IPAP in the first place?????

Why not just set the machine at 13/4 or 14/4 with EasyBreathe turn off??

[palerider]

Palerider and company, is there any way to tell what kind of apneas are flagged when I have EasyBreathe/FOT turned off, based on the graphs? It looks like smooth flowrates outside of near the flagged events. Assuming that those are centrals? What's interesting is that there were no noticeable oxygen desaturations until a sustained group of events around 5:30AM.

there's no way to tell, that I know of, with the machine in S mode.

if you had it in vauto mode, it should test and tell you.

my guess is that they're obstructive, since it looks like there's very tiny attempts at inhalations in the flow, but that is purely a guess.

If I increase the PS by raising IPAP and keeping EPAP at 4.0, the AHI for "unknown apneas" goes up - the AHI pretty much doubles for every 2cmh2o increase in IPAP only. That's why I was guessing they were centrals. I get an AHI below .5 when I drop the pressures down to 13-14/4. All the while keeping EPAP the same.

well, I did say it was just a guess

they may be centrals. without FOT, there's no way, that I know of, to tell.

[raisedfist]

If I increase the PS by raising IPAP and keeping EPAP at 4.0, the AHI for "unknown apneas" goes up - the AHI pretty much doubles for every 2cmh2o increase in IPAP only. That's why I was guessing they were centrals. I get an AHI below .5 when I drop the pressures down to 13-14/4. All the while keeping EPAP the same.

Asking an obvious question: If the AHI is below .5 when you use EPAP = 4 and IPAP = 13 or 14, then why are you raising the IPAP in the first place?????

Why not just set the machine at 13/4 or 14/4 with EasyBreathe turn off??

i was concerned about low tidal volume. i get a reported tidal volume of about 260-280 but i have unique circumstances - i have kyphoscoliosis, so a very noncompliant stiff chest wall, and i am only 57 inches tall (spine has been fused since I was 13 so that was the end of growth pretty much for me).

according to the ideal body weight charts, it looks like for a male my height that i am on target for a volume of 6mL/kg. 8mL/kg would be 345.

maybe that higher amount is inappropriate for me in itself, since just because there is more volume of air, it doesn't mean the percentage of air participating in gas exchange would be increased.

i think it may be more helpful to focus on increasing inspiration time...which probably as a result will increase tidal volume, without me having to increase the PS. and allow more time for the recruitment of and holding open of the alveoli.

[robysue]

If I increase the PS by raising IPAP and keeping EPAP at 4.0, the AHI for "unknown apneas" goes up - the AHI pretty much doubles for every 2cmh2o increase in IPAP only. That's why I was guessing they were centrals. I get an AHI below .5 when I drop the pressures down to 13-14/4. All the while keeping EPAP the same.

Asking an obvious question: If the AHI is below .5 when you use EPAP = 4 and IPAP = 13 or 14, then why are you raising the IPAP in the first place?????

Why not just set the machine at 13/4 or 14/4 with EasyBreathe turn off??

i was concerned about low tidal volume. i get a reported tidal volume of about 260-280 but i have unique circumstances - i have kyphoscoliosis, so a very noncompliant stiff chest wall, and i am only 57 inches tall (spine has been fused since I was 13 so that was the end of growth pretty much for me).

according to the ideal body weight charts, it looks like for a male my height that i am on target for a volume of 6mL/kg. 8mL/kg would be 345.

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

maybe that higher amount is inappropriate for me in itself, since just because there is more volume of air, it doesn't mean the percentage of air participating in gas exchange would be increased.

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

i think it may be more helpful to focus on increasing inspiration time...which probably as a result will increase tidal volume, without me having to increase the PS. and allow more time for the recruitment of and holding open of the alveoli.

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

[Jay Aitchsee]

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 agressive trigger and cycle settings, and a cloth mouth cover. Let's see if anyone agrees.