Understanding Flow Rate (ASV)

[Uncle Flapp]

Flappy, I don't think we can dismiss this as SWJ, and I apologize for raising that earlier. Could you review your history of therapy treatment and prescriptions? Have you ever tried prescriptions with less pressure support (less fluctuation between IPAP/EPAP? Do I recall correctly you experience some problems with higher EPAP?

Hi Sleeprider. Here is a brief history of my prescription history. Had a UPPP in 2007. After years of neglect and lots of prompting from my wife, decided to seek treatment:

• First sleep study (this go-round) on 10/2013. Untreated AHI of 84: HYP 47; OA 17; CA 13; Mixed 7. Was prescribed APAP 6-16cm but had issues falling and staying asleep. Second study scheduled
• Second sleep study on 12/2013 started CPAP at 4cm and when increasing to 6cm, CAs became longer and more frequent. BiPAP initiated at 9/5 and CSA reached 70 seconds. Backup rate of 10 was applied but I did not tolerate very well and the sleep study ended. Rx for BPAP 11/6. Still did not resolve frequent awakenings and machine showed high CSAs so I initiated a third sleep study
• Third sleep study/ASV titration 2/2014. Prescribed ASV. EPAP 6-15; PS 6-15; Max pressure 25; BPM auto.

None of the sleep studies nor visit to cardiologist indicate any arrhythmias. Only medications I take are Lipitor, Flonase, and Zyrtec. Yes, the higher pressures often wake me up and I'll hit the ramp button to reset EPAP down to minimum of 6cm. Fortunately that doesn't happen very often as 6cm works for me most of the night.

FWIW, I went back over the last several weeks and noticed the same pattern at least once every night even when total AHI was low. Even my best night to date, Jan 06 this year, has an episode:


If you zoom in on the HYP clusters, you see this:


Very well could be REM since it appears nightly but is the abnormal breathing interfering and can anything be done about it?

- Flappy

[palerider]

Tried the oximeter last night but I question the accuracy. Wearing while awake and relaxed spO2 was 95%. Mrs. Flappy, RN tried it and hers too was 95%. "Should have been 98 or more," she said. .

while I'm loath to contradict mrs flappy.... I would point out that most references say that 'normal' spo2 is 95-99%, and you can't just say "well, that's wrong" without some corroboration.

[Uncle Flapp]

while I'm loath to contradict mrs flappy.... I would point out that most references say that 'normal' spo2 is 95-99%, and you can't just say "well, that's wrong" without some corroboration.

Easy for you to say from afar... I know from experience that Mrs. Flappy is never wrong (especially if she will see my post).

Yes, I thought of that and could play with the oximeter some more - but I'm not sure what it will prove. If SpO2 dips, what do I do about it? If it doesn't, does it mean anything?

On another note, PR, isn't this fantastic weather we are having? Had a BBQ over the weekend. Temps got to the upper 80's here in the desert southwest...

- Flappy

[palerider]

Yes, I thought of that and could play with the oximeter some more - but I'm not sure what it will prove. If SpO2 dips, what do I do about it? If it doesn't, does it mean anything?

I hear you, and we shall make no more references to the any possibility of error from she who must be obeyed.

well, if the oximeter is relatively accurate, and your spo2 doesn't dip. then you're good. if it does dip too far, then perhaps supplemental o2, if you're not already using it, or more if you are. I don't remember you mentioning what brand you got, but the so far, the reports I've heard of the CMS models, when someone tried them along with another pricier unit, have always read about the same as the spendy model.

On another note, PR, isn't this fantastic weather we are having? Had a BBQ over the weekend. Temps got to the upper 80's here in the desert southwest...

- Flappy

Krelvin posted temps from his weather station in AZ... it's a bit worrying for the coming summer. I'm not thrilled at running the AC in february *sigh*

[Pugsy]

Next time you visit your doctor take your CMS pulse ox along with you and compare the readings with the pulse ox done in the doctor's office. That way you can see if the baseline awake reading is fairly accurate. I suspect it will be fairly accurate and if it is off it won't be off by much.

it's a bit worrying for the coming summer. I'm not thrilled at running the AC in february *sigh*

Yeah...try living in Las Vegas and running the AC at Thanksgiving...it sucks.

[Sleeprider]

Flappy, I don't have expertise in ASV to make any suggestions. A couple thoughts come to mind and maybe someone with more experience can chime in.

Since you are comfortable at EPAP of 6.0, and experience sleep disruption to reset ramp when that goes higher, why not set EPAP at 6.0 min and 6.0 max?

Your breathing pattern disruption is incomplete hypopnea or apnea and the machine breathing rate is initiating breaths on auto mode. Perhaps, a set breathing rate would help this situation rather than rely on auto? ...again, this is conceptual. I have no basis by which to advise or know how ASV is optimized. Morbius seemed to have some ideas on the breath timing before, but was too cryptic for me to understand the point.

[musculus]

I think that's the typical pattern
sleep get deeper => airway resistance =>arousal (airway open and flow rate is high) => your sleep get a little deeper again =>airway resistance

CAs are normal after several breaths with huge flow rate.

[palerider]

it's a bit worrying for the coming summer. I'm not thrilled at running the AC in february *sigh*

Yeah...try living in Las Vegas and running the AC at Thanksgiving...it sucks.

you mean people don't NORMALLY run the ac at thanksgiving???

[musculus]

I get the same thing occasionally. It is periodic breathing or Cheyne Stokes Respirations. You don't want to see a lot of that. It can be a component of central apnea and indicates a waxing and waning of respiratory effort.

Here is my version from last night...not good, but probably SWJ.

Sleeprider,

I would think this is a period of sleep disturbance with frequent microarousals caused by airway resistance. You can tell the breathing/airflow after a microarousal, which is very much like the waking airflow, with basically no latency to inhalation (the flat line before inhalation) after the exhalation.

[-SWS]

Flappy, I don't think we can dismiss this as SWJ, and I apologize for raising that earlier.

No need to apologize. There's not enough evidence in this thread to effectively determine sleep or wake states. On that basis of uncertainty, SWJ can't be ruled out.

[Uncle Flapp]

This morning was rough. I slept 7.5 hours but had 6 of these things and was real groggy for a while. Wife even commented about how tired I look.

Since you are comfortable at EPAP of 6.0, and experience sleep disruption to reset ramp when that goes higher, why not set EPAP at 6.0 min and 6.0 max?

I often wake when EPAP rises above 10 but not always. Or it could be that I wake up from something else and find the pressure uncomfortable. Chicken or the egg - not sure which comes first. As far as these abnormal breathing patterns, they occur at the lower EPAP (6cm) and exhale pressure rises only minimally. IPAP ramps up presumably to treat the hypopneas and we see the increase in machine triggered breaths.

Next time you visit your doctor take your CMS pulse ox along with you and compare the readings with the pulse ox done in the doctor's office. That way you can see if the baseline awake reading is fairly accurate. I suspect it will be fairly accurate and if it is off it won't be off by much.

Great idea - why didn't I think of that?

Thanks to you all for your thoughts on this. I appreciate the help.

- Flappy

[Sleeprider]

This morning was rough. I slept 7.5 hours but had 6 of these things and was real groggy for a while. Wife even commented about how tired I look.

Since you are comfortable at EPAP of 6.0, and experience sleep disruption to reset ramp when that goes higher, why not set EPAP at 6.0 min and 6.0 max?

I often wake when EPAP rises above 10 but not always. Or it could be that I wake up from something else and find the pressure uncomfortable. Chicken or the egg - not sure which comes first. As far as these abnormal breathing patterns, they occur at the lower EPAP (6cm) and exhale pressure rises only minimally. IPAP ramps up presumably to treat the hypopneas and we see the increase in machine triggered breaths.

I think when you narrow down something that might be a problem, you don't want to do that. So, maybe raise the minimum pressure? Stay out of hypopnea and the cycle of increasing pressure that triggers CA, and see where that takes you. Go for 7.0 as a minimum. The worst you can do is have to reset it because it doesn't work as well (unlikely). The potential reward of a little experimentation seems pretty high.

[Uncle Flapp]

Thanks, Sleeprider, I am certainly open to a little trial and error. Risk vs. Reward seems pretty favorable but I'm not sure what to tweak. During these episodes my EPAP starts at 6cm and creeps up only a bit, maybe to 7cm, since there are no OAs. I guess IPAP will also increase 1cm if I don't change min PS. With nuthin' to lose, I'll give it a shot tonight and wear the oximeter...

Another thing worth a look is the backup rate being set to auto - maybe it should be something static and the forced breaths are actually the problem. Any thoughts there? Is that something I would want to dork with?

- Flappy

[Sleeprider]

One thing at a time, and then go for the breath rate another day.

You have an average breathing rate, and I don't know when the auto triggers a breath, but I suspect it's a conservative slower rate that waits until you have not taken a breath within several seconds of when it expects you to, based on some kind of moving average, or to maintain a minimum like 10 btm. Wish I knew. Manual settings no doubt can be a bit more aggressive.

This is kind of interesting: http://www.resmed.com/assets/documents/ ... ow_eng.pdf

[Uncle Flapp]

Good read. I'm using a PRS1 but from what I have read they are pretty similar.

Couldn't find a way to export SH detailed data into Excel but a spot check showed my backup rate is a forced breath every 5-7 seconds, 6 being the norm (10 breaths/min). Anyway, I am not comfortable playing with that now. EPAP is now set to 7cm, all others left alone.