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

Respironics 9 minute cycle with no events.
I have a respironics system one. Generally, everything is working fine, according to sleepyhead AHI is usually less than 2. My main problem is compliance, as I already have a strong tendency towards insomnia, and cpap tends to make it worse. However, when I can fall asleep with the mask on, everything is good. I have pressure set at 5 to 15.

My question relates to what the machine records: whenever I'm asleep for an extended period with no events recorded, the machine seems to go through a 9 minute cycle where it ramps the pressure up from 5 to 6 over a 3 minute period, then ramps it back down to 5 over 1 minute. Then it waits 5 minutes before repeating the process. According to sleepyhead, no events are recorded during this time, and I can't see anything in the recorded data that looks different.

Does anyone know why the machine is doing this? Once again, it's not causing a problem, I'm just trying to get a better understanding of how the machine is working.

I've attached a screen shot showing the pulses.

Attached Files Thumbnail(s)
Post Reply Post Reply

Donate to Apnea Board  
Hi, pixpop. I have a PR System One machine and asked the exact same question the first time I ran it in Auto-Trial mode (my machine is a 460, a fixed-pressure CPAP).

I think it's called a "search algorithm", with the machine making changes in the pressure to try to determine whether or not an improvement in breathing is detected. I know that the machine can detect less-than-perfect breathing that still doesn't meet the requirements to be scored as apnea events or even flow limitation. I'm not clear whether the search algorithm's pressure changes are in response to something it detects or whether it just automatically tries higher pressure to see what happens.

There's a short bit about the search algorithm in the Beginner's Guide to SleepyHead wiki:
Quote:Question: Why is my pressure increasing when there don't seem to be any events?
Answer: APAPs (and Auto bi-levels) increase pressure in response to OAs, Hs, snoring, and flow limitations. The Philips Respironics System One APAP and BiPAP Auto also increase pressure in response to RERAs. The Philips Respironics System One also has a "search" routine built into its Auto algorithm, and it will periodically increase the pressure as a "test" to see if the shape of the wave flow improves, even if nothing is being scored. Those test increases show up as saw-teeth on the pressure curve.

Post Reply Post Reply
Hi pixpop,
WELCOME! to the forum.!
Good luck to you as you continue your CPAP therapy.
Post Reply Post Reply

Possibly Related Threads...
Thread Author Replies Views Last Post
  Plotting OA events vs time Bripin 3 55 1 hour ago
Last Post: ShaunBlake
  Resmed S10 Airsense vs. Respironics Dream Station Weird Tolkienish Figure 132 53,525 10 hours ago
Last Post: cam
  Respironics Dreamstation - noisy motor? bernie01 27 842 03-13-2018, 12:53 AM
Last Post: bernie01
Sad [Equipment] Respironics DreamStation Humidifier Heat problem superkid 8 275 03-11-2018, 04:40 AM
Last Post: superkid
  RERA events after increase of minimum pressure MisterM 9 195 03-07-2018, 07:24 AM
Last Post: ajack
  [Equipment] Phillips Respironics system One [beeping] Dwalms 6 157 03-06-2018, 07:32 AM
Last Post: Sleeprider
  Machine settings advice for my report [central events] airoutlaw 15 373 03-05-2018, 08:16 PM
Last Post: trish6hundred

Forum Jump:

New Posts   Today's Posts

About Apnea Board

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