Hello Guest, Welcome to Apnea Board !
As a guest, you are limited to certain areas of the board and there are some features you can't use.
To post a message, you must create a free account using a valid email address.

or Create an Account


New Posts   Today's Posts

Flow Limitation
#1
I have been using CPAP for about 6 weeks which has made a huge improvement in my sleep. My AHI for the entire period is 4.01.

Yesterday when I saw the doctor I asked that the machine be set to APAP at a range of 8-16, instead of a fixed 8.0 to see if I could improve my AHI. he was reluctant to do so saying it might be difficult to adjust to, but ultimately agreed.

I did not sleep particularly well last night, and noticed this morning in the Sleepy Head stats, that there were 11 "flow limitation" events recorded. In the prior 6 weeks none were recorded. So I was surprised by the occurrence and the number.

What exactly are "flow limitation" events? Do they suggests some sort of machine failure, for example to cope with the higher pressure settings. (The max pressure was 12 or so from 6-7 AM. Most of the night the pressure was in the 8-9 range.) Or something biological...

Thanks

BillMar
Post Reply Post Reply
#2
From what I read Flow limitations can be a precursor to OSA which will tell the machine to adjust its pressure accordingly to avoid an OSA event. Stuff noses can also cause flow limitations as well.
Post Reply Post Reply
#3
A simplistic way to look at it is a spike in flow limit indicates an apnea event that never had the chance to grow up and become a hypo, or oa.

The fact that you didn't sleep all that well is predictable. It takes a little time whenever you make any changes for your body to figure out the "new you."

What was your apnea events last night, (oa, ca, hypop) compared with previous nights? Not that you can tell anything conclusively based on one night, but might be interesting.

Lastly, I'm not sure I'd have gone from straight 8 to 8-16. I think I would have chosen 7 for the low, and not more than 12 for the max to begin with. But you're ok where you're at, it'll just take a little adjusting.

Post Reply Post Reply


#4
(03-19-2015, 02:59 PM)retired_guy Wrote: A simplistic way to look at it is a spike in flow limit indicates an apnea event that never had the chance to grow up and become a hypo, or oa.

The fact that you didn't sleep all that well is predictable. It takes a little time whenever you make any changes for your body to figure out the "new you."

What was your apnea events last night, (oa, ca, hypop) compared with previous nights? Not that you can tell anything conclusively based on one night, but might be interesting.

Lastly, I'm not sure I'd have gone from straight 8 to 8-16. I think I would have chosen 7 for the low, and not more than 12 for the max to begin with. But you're ok where you're at, it'll just take a little adjusting.

Thanks for input. Helpful. The last 30 days I have been on CPAP the results are:

4.15 AHI composed of CA 2.22; OA .62; HA 1.31 and 0.0 Flow Limitation Index
With the new pressure settings (last night)
4.78 AHI composed of CA 3.53; OA .23 ; HA 1.02 and flow limitation index of 1.02 (11 events)

More than 50% of the AHI index over the time I have been on CPAP has been CA events.

Post Reply Post Reply
#5
yes. as noted above, the flow limitations are biological. it means the air that you wanted to go thru a nasal passage or throat was slowed down based on a restriction in the flow path, whether it was congestion, relaxed muscles, the long-haired cat lying on your face, the pillow placed lightly over your nose and mouth by a partner that needs to muffle the noise.

QAL
Dedicated to QALity sleep.
You'll note I am listed as an Advisory Member. I am honored to be listed as such. See the fine print - Advisory Members as a group provide advice and suggestions to Apnea Board administrators and staff concerning Apnea Board operation and administrative policies. Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment.
Post Reply Post Reply
#6
(03-19-2015, 01:43 PM)BillMar Wrote: there were 11 "flow limitation" events recorded. In the prior 6 weeks none were recorded. So I was surprised by the occurrence and the number.

I'm not sure, but perhaps flow limitations are recorded only when you're in auto mode. They are used by the machine to make adjustments to your pressure. Flow limitations can consist of reductions in air flow, or changes in the shape of the inspiratory (positive) portion of the flow rate graph. The claim is that they precede obstructions and therefore the pressure is raised in an attempt to prevent them.

How much time are you spending at pressures above 8?
Sleepster
Apnea Board Moderator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Post Reply Post Reply


#7
Bill, I believe that as you get used to your new settings the CA's will calm down. So keep in touch and let us know what your results are for the next few days.

It was kind of interesting to see your OA and Hypop's dropped rather correspondingly to increase in flow limit events. Not surprising, and your numbers are really very good indeed. So good work, and know you'll get a good nights sleep tonight now that you're a "pro" with the auto settings.

Post Reply Post Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  [CPAP] Understanding Flow Rate Bruce456 5 120 41 minutes ago
Last Post: justMongo
  SD Card Not Recording Flow SideSleeper 2 127 01-31-2017, 05:47 PM
Last Post: SideSleeper
  Flow Rate Graph Resizing nadprok 2 174 01-18-2017, 04:37 PM
Last Post: nadprok
  Source of Resmed S9 EPR reverse flow whistle! neal 5 384 12-01-2016, 07:22 PM
Last Post: klv329
  Flow Rate Interpretation nadprok 2 335 11-13-2016, 06:08 PM
Last Post: nadprok
  [Equipment] Modding Resmed FX pillow mask, no turbo air flow DaveDog 9 513 10-23-2016, 08:09 PM
Last Post: PaulaO2
  Any way to determine REM sleep from Flow Rate? Roy289 18 1,390 08-31-2016, 10:35 AM
Last Post: o1bob037

Forum Jump:

New Posts   Today's Posts




About Apnea Board

Apnea Board is an educational web site designed to empower Sleep Apnea patients.

For any more information, please use our contact form.