No announcement yet.

AHI readings out of control?

  • Filter
  • Time
  • Show
Clear All
new posts

  • AHI readings out of control?

    My AHI readings have increased, for a week or so now, from under 5 to about 25.
    It may have been a slow increase over the previous 2 weeks, this period being the last time I checked the readings; and found them to be under 5.
    These results were using a RESMED AIRSENSE 10 AUTOSET.
    For 2 of the seven nights I switched machines to use a BMC Resmart G2 which produced similar results.
    I have tried a Pillow mask, a full facial mask and a mask in conjunction with a Mandibular Advancement Advice (now failing due to permanent jaw advancement over 10 years). Have just acquired the full facial mask hence am not used to it.
    Have reset the RESMED to factory condition to compensate for any changes made by me. Still reading about 25.
    This suggests that it is not the machinery but me that is the cause.
    My medication and state of mind (poor) has not altered.
    The NHS department who supplied the RESMED have no suggestions though they say 25 AHI is nothing to worry about till it is safe to see me after the Covid lockdown.
    Any ideas? Please?

  • #2
    Good Morning,

    Thank you for your post.

    Can you advise if the Airsense10 auto CPAP machine is set with a lower pressure of 4.0cmh20 and an upper pressure of 20.0cmh20. Do you have a ramp enabled, and if so for how long?

    The type of mask you use is purely down to how you breathe. If you breathe through your nose only, then you can use a nasal mask. If you breathe through your nose and mouth (ie if you snore) then you would need a fill face mask.

    The key thing with a mask is to get a good fit, ie ensure you check the sizing guide to ensure you have the right size mask for your face. Do you know which mask you are currently using? I would also suggest watching a fitting video for your mask on youtube to ensure you are putting it on and adjusting it correctly.

    Have you created an account on the ResMed MyAir website/app and linked your CPAP machine to be able to review your CPAP therapy data? If so, are you able to create an report and email it to me at to be able to look at and see what is going on. If not, I would suggest doing this.

    Alternatively once you have used the full face mask for at least 10-14 nights, then email me the date.

    Generally most issues are with the mask that people use, and by looking at the data we can normally see what the issue is.

    If you have any questions, then please do let me know.



    • #3
      Sorry for the delay, Kelly. Long story.

      It seems these events are, according to an OSCAR chart I downloaded, ''Central Apnea''.

      Yes, I can supply clips from ''My Air'' though they don't seem to include Central Apnea.

      Rather, should I send screen clips from OSCAR? And if so which ones?

      Thank you, Peter


      • #4

        Thank you for your post.

        Are you able to pull a report from MyAir or from Oscar which shows your CPAP therapy data



        • #5
          Since it's a prescription devices, factory reseting won't necessarily rule things out unless it has the exact same prescription. If you are all of a sudden developing central apnoeas, it really does need looking at by HCP (healthcare pro), but here are a few things to keep in mind.
          1. The software is not as accurate as human reading the flow rate data. This is why you really need to either learn how to read it yourself, or go to a HCP.
          2. If the pressure is too high, it can cause central apnoeas in some. Default auto settings of 4-20 cmH2O is a catchall, but it's not very good and better practise is to cap the top pressure to a more reasonable number avoiding runaway pressure events. This could minimise central apnoeas as it won't be able get too high. What that top number should be depends on card data and your sleep apnoea, but it maybe that CPAP can't provide the pressure you need to breath without causing central apnoeas. If this is the case, you'd have to switch to Bi-PAP.
          3. You could try a "Poor Man's Bi-PAP" which is were you turn the EPR up to 3 and see if central apnoea's improve. You'd still need to cap the top pressure to a lower point where you can still get reasonable therapy.
          Hope this helps,



          • #6
            Thank you for the input Reno.
            2 screenshots attached.

            Feb 16 shows the peak, so far, of the Cheynee Stokes events.

            The following night switched from FFM to Pillows. There were no CS events but they too steadily increased up to, as yet, last night's results, shown as Feb 22.

            Am told Cheynee Stokes indicates heart failure. A recent scan shows heart to be fine.

            The numbers seem low but, nonetheless, I can feel exhausted during the day. Is that due to the duration of the events rather than the quantity, perhaps?

            So it looks like ''Treatment Emergent'' apnea and I may require adaptive servo-ventilation therapy.

            Any advice, please, before I approach my NHS Sleep Lab... again?


            Attached Files


            • #7
              Hi Peter,

              You would need to zoom in on the flow rate data during the time of the event, like a 30-60 second window, as it’s impossible to see what the individual events when looking at the whole night at once.

              I am concerned that I can’t see a correlation between the pressure and the CA events, which makes me think it is not treatment emergent csa, but remember I am not a HCP, nor do I have a medical background. I’m some random guy with only training in managing computer/servers. So take what I say with a pinch of salt.

              You are right that cheynes stokes is usually associated with heart failure. If it isn’t that, it’s usually stroke, but could even be carbon monoxide poisoning, altitude sickness, low salt in your blood, etc…

              If it is cheyne stokes, you defo need to see a HCP, but that’s good advice if CA suddenly appears too.

              Sorry I cant be of much help,



              • #8
                Thank you very much for your comments, Reno.

                I increased min pressure (advice from elsewhere) from 5 to 8 and set the EPR, as you advised, to 3 last night.

                And this morning, after 9 hours use, saw an AHI of 0, nothing, zilch!

                A fluke; time will tell. Will send OSCARS if you're still interested.

                Ironically I was using full EPR till my local NHS Lung-Fung suggested disabling it to reduce the CSA...


                • #9
                  Originally posted by Pedrx View Post
                  Ironically I was using full EPR till my local NHS Lung-Fung suggested disabling it to reduce the CSA...
                  That's really weird, since the treatment for "treatment emergent CSA" is ASV/BiPAP. That's where the pressure drops to a set amount on exhale. Those machine can have larger differences in pressure between inhale and exhale than a normal CPAP machine.

                  For standard CPAP with EPR, you can drop the exhale pressure by up to 3cmH2O. So say you pressure that is at 8cmH2O with EPR at 3, that's 8cmH2O on IPAP (inhale) and 5cmH2O on EPAP (exhale). Hence why it's sometimes referred to as "poor man's BiPAP" as you're using your CPAP machine as a mild BiPAP setup.

                  An AHI of 0 is outstanding. If it stays like that I think it's problem solved.

                  - Reno


                  • #10
                    Originally posted by Reno View Post
                    An AHI of 0 is outstanding. If it stays like that I think it's problem solved. - Reno
                    Thanks Reno but it hasn't as you will see from shots.

                    April 8 _A.jpg April 8_B.jpg

                    April 8_C.jpg

                    The graphs are typical of the way my apnea is developing.

                    The NHS sleep clinic, who supplied and wirelessly monitor the machine, recently stated in a report to my GP, that the apnea is well controlled though there is evidence of leakage and I should seek advice as to how to fit a mask.

                    In my later email correspondence with this NHS unit I enclosed similar to these above graphs. Their reply tells me that: the events are ''only a snapshot and if feeling tired I should see my GP.

                    They also state that they obtain this information from 'My Air' and sent me a copy of this basic data.

                    I can supply their emails here to show the full replies if you wish, the text alone.

                    All very puzzling therefore:

                    Will you please give me your thoughts on this matter and advise what steps you believe may be taken. (For now I'll keep my own thoughts to myself).


                    • #11
                      So it's been a little while so I went back over the posts and the images.

                      Please remember I'm not a HCP and have no clinical experience. This is just my opinion/perception.

                      I definitely can't see anything close to cheyne-stokes in your latest ones which is good. I'm not really sure what was happening back then and I cant see the flow rate data back in February so can't really say anything on that.

                      In the new charts, those do look like typical obstructive apnoea events and they happen when you cap out at 14cmH2O. This makes me think your upper pressure is capped too low. I'd try increasing the top pressure to 15cmH2O and see what happens, then reevaluate. It may need to go higher, which can be a bad idea with central apnoeas, but your charts from February do show your AHI is worse at a cap of 14cmH2O (AHI 15.11) but when top pressure is 15cmH2O your AHI is only 7.19; even 'central apnoeas' decreased. So I wonder if the leaks got the machine to miscount an OA as a CA because of mask leaks (which were more of a problem in your old data compared to your new).

                      That's my two pence,



                      • #12
                        Worth trying again given the changing circumstances. Thank you.

                        Perhaps I should repeat the above in a new thread to attract some interest in the text of the post.


                        • #13
                          As soon as someone replies, it’s should bump up the list of threads, so making a new thread won’t make it better seen. Only reason I see to start another is if this one is too long and complicated for people.


                          • #14
                            Originally posted by Reno View Post
                            As soon as someone replies, it’s should bump up the list of threads, so making a new thread won’t make it better seen. Only reason I see to start another is if this one is too long and complicated for people.
                            Hello again Reno. No replies yet. I wonder why.

                            Perhaps, as you, despite your valuable guidance, have avoided responding to the text of the post, will know why?


                            • #15
                              It’s not a very active forum.