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When your machine died .... did your AHI go up? - Printable Version

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When your machine died .... did your AHI go up? - Cpapian - 07-14-2020

A couple of nights ago, machine gave a high-pitched sawing sound on every inhale.  Very disturbing.  Checked water chamber - in correctly, tried a different one; filter clean, door closed properly, changed hose, changed mask, put towels under machine - still there.  Gave up went to sleep without the machine.

Next night, it was still there, but quieter.  And the night after quieter again.  But the air flow felt weak.

Machine is under warranty and DME is ordering a replacement.

in the last little while, my AHI has been higher.  For the longest while it was pretty good, +/- 1, but now it will go up to 2 and 3 some nights.

is it possible my machine has been dying for a while and that has been the cause of the higher AHI?  Or do I need adjustments.

Here is last night's OSCAR.


RE: When your machine died .... did your AHI go up? - Sleeprider - 07-14-2020

I think your pneumatic block (blower) is shot. Even if it maintains pressure it is probably not responding as quickly to the inhal/exhale transitions, and that is what feels off. Nice you still get a 0.0 AHI. The fan in the unit is able to change speeds rapidly, but if bearings are failing it makes noise and loses performance.


RE: When your machine died .... did your AHI go up? - Cpapian - 07-14-2020

(07-14-2020, 03:49 PM)Sleeprider Wrote: I think your pneumatic block (blower) is shot. Even if it maintains pressure it is probably not responding as quickly to the inhal/exhale transitions, and that is what feels off. Nice you still get a 0.0 AHI.  The fan in the unit is able to change speeds rapidly, but if bearings are failing it makes noise and loses performance.

Ouch!  I posted the wrong screen shot.  3.29 AHI last night.  I am glad they are supplying a replacement.


RE: When your machine died .... did your AHI go up? - Sleeprider - 07-14-2020

Take a look at the Mask Pressure chart up close, and compare a before and after shot. If the machine is acting lazy, it would show up in there first. Is your pressure usually that "choppy" and have the pressure statistics changed?


RE: When your machine died .... did your AHI go up? - Cpapian - 07-14-2020

[attachment=24604 Wrote:Sleeprider pid='358238' dateline='1594763433']Take a look at the Mask Pressure chart up close, and compare a before and after shot.  If the machine is acting lazy, it would show up in there first.  Is your pressure usually that "choppy" and have the pressure statistics changed?

I am not sure if my pressure is more choppy than usual.  I have attached a screen shot with pressure and mask pressure from last night and another from last week.  Also, I have a screen shot of more detail from last night.  To me, I don't see a lot of difference, but I got out of the habit of looking at my results and I seem to have forgotten a lot.  Old age - that's my excuse.


RE: When your machine died .... did your AHI go up? - Sleeprider - 07-15-2020

Something to keep in mind is that your minimum pressure of 6.0 is not sufficient to provide effective therapy, and results in a great deal of pressure fluctuation through the night. You really need to set the minimum closer to the median pressure of your therapy, and that is going to be closer to 10 cm. By doing that, you will avoid a large number of events and experience less disruption to your sleep. I don't know if your median pressure has changed over time, but I encourage you to try a higher minimum pressure, certainly above 8.0.


RE: When your machine died .... did your AHI go up? - Gideon - 07-15-2020

I'd go for the 10, at least 9, 8 will only make a difference in your first 40 minutes. 10 is best.


RE: When your machine died .... did your AHI go up? - Cpapian - 07-15-2020

(07-15-2020, 08:03 AM)Sleeprider Wrote: Something to keep in mind is that your minimum pressure of 6.0 is not sufficient to provide effective therapy, and results in a great deal of pressure fluctuation through the night.  You really need to set the minimum closer to the median pressure of your therapy, and that is going to be closer to 10 cm.  By doing that, you will avoid a large number of events and experience less disruption to your sleep.  I don't know if your median pressure has changed over time, but I encourage you to try a higher minimum pressure, certainly above 8.0.

Thanks Sleeprider and Bonjour.  I will try increasing pressure tonight.  Hopefully the additional pressure won't blow the machine up.  It isn't even 3 years old.  Thank goodness it was still under warranty.


RE: When your machine died .... did your AHI go up? - Cpapian - 07-16-2020

Last night, I upped the minimum pressure to eight ( Smile out of an abundance of caution Smile ).  My AHI is lower 1.74 vs. 3.29 two nights ago.  My median pressure was 9.96 vs. 110.04 two nights ago.

There were more events marked clear airway .97  than those marked obstructive .68.  I don't think the events market clearway are central because they didn't look right to me.  I suspect it was just me turning over and not breathing while doing so.  

I will move the minimum up to nine tonight and see what happens.

The first thumbnail is a closeup of some clear airway events.  The second and third are for last night.  I have a small screen, so I need two screen shots to get all the boxes.


RE: When your machine died .... did your AHI go up? - Sleeprider - 07-16-2020

I think the median pressure is still near 10 so in spite of the increased proportions of CA I think this is on the right track.  The whole point is to be comfortable and sleep better with fewer events. I think this will settle in at an average of less than 1.0 AHI with some variation from night to night. 9.0 is looking closer to optimal than where this started.  The next challenge is leaks.