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

Why are many OAs not in sync, roughly, with explanatory snores or flow limitations?
My snores are few and often do not result in an OA. Frequently I see OAs that can't be matched, even roughly, to times of flow limitations; that happens with snores too. My SH graph ordinate scales for both Snore and Flow Limit are large enough. Is this simply a sampling artifact?
Post Reply Post Reply
I'm super curious about this!

Could you share a screenshot of the data?
Post Reply Post Reply

Snores and flow limitations are not a necessary condition for OAs. They are precursors to OAs. They are what Resmed and PR use to signal the need for a pressure increase in order to head off OAs. The logic is when significant snores or flow limitations occur and no changes are made, sooner or later OAs will start to occur. OAs can and do occur without precursors sometmes.

If you see a rapid increase in your pressure, check your flow limitations and you will probably see some significant flow limitations just before and/or during the rapid pressure increase. If the machine has gotten enough pressure increase in time, you will have no OA because the machine headed it off.

Best Regards,


Admin Note:
PaytonA passed away in September 2017
Click HERE to read his Memorial Thread

~ Rest in Peace ~
Post Reply Post Reply

(03-23-2017, 03:18 AM)Hydrangea Wrote: I'm super curious about this!  

Could you share a screenshot of the data?

I'm not adept with imgur. Here is an attempt at showing the most recent among many clear incidents, sometimes there are multiple incidents.

Note that I cut out  a block of the graphs' time lines before the OA; that to get the OA near center screen rather than at extreme right.

I believe PaytonA's post (thank you PaytonA) below explains OAs do arise without indication of a causal FL or Snore. I'd like to understand why.

[Image: Z78eIEtl.jpg]
Post Reply Post Reply
The event posted above looks like an arousal and change of sleep position (holding your breath), it is not characteristic of a true obstructive apnea. First, you can see the arousal preceding the event. The breath immediate ahead of the OA does not have an exhale (lungs full). The event is about 18 seconds, and breathing resumes gradually and increase in amplitude in response to the minor desaturation visible on the SpO2 line. There was no FL or snore, and the event is not characteristic of OA, but appears to be an arousal. In fact, not a single breath in the posted wave form has the appearance of a flow limit.
Post Reply Post Reply
Thank you SleepRider; a great lesson in interpretation of the graphs.

I've improved my treatment and reduced those annoying leaks, having learned from so many on the Board after registration.
Post Reply Post Reply

Possibly Related Threads...
Thread Author Replies Views Last Post
  Need help with Flow Limitations Allessio77 6 102 Yesterday, 02:05 PM
Last Post: Allessio77
  Limitations of AHI as a diagnostic tool HalfAsleep 9 382 11-23-2017, 10:17 PM
Last Post: HalfAsleep
  Help deceasing flow limitations yankees123 6 201 11-20-2017, 10:59 PM
Last Post: yankees123
  [Treatment] Flow Limitations, a problem or not? storywizard 9 352 09-23-2017, 08:34 AM
Last Post: Sleeprider
  CPAP user, had my wife try the Oximeter, since she snores. Should she get to a Dr.? mogulman 9 382 08-27-2017, 11:50 AM
Last Post: Sleeprider
  Flow Rate Readings holden4th 5 313 08-07-2017, 07:53 AM
Last Post: Walla Walla
Question Impact of flow limits? CTcentrals 5 334 08-07-2017, 01:05 AM
Last Post: CTcentrals

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.