VPAP - Trigger function can prevent CA's.

[Kosoku]

When I got my new Resmed AirCurve 10Vauto about 1 month ago, I noticed a large increase of CA's. Typically 20-30 scattered throughout the night. Now I figured that they probably were not real CA's as there were no clusters or any other indicatiors usually present. However, I did want to get my AHI down, as does everyone else. So, I tried a few things, but one night, I switched the trigger to very high from medium and the next morning, I only showed 5 CA's all night long. Since then I hover between 2-3. Now I did wonder if it was coincidence or not, so the other night I bumped the trigger back to "High" and the CA's shot to 20. Last night I bumped it back to "Very High" and I had 3 all night long. Those 3 were after my 5 year old came to bed and woke me up so I may have been moving around more. 
Oh yes I did notice that I tend to sleep more soundly . Less waking and rolling on "Very High". Breathing wise, I cannot feel a difference between the Trigger setting on Very High Vs Medium or High. They all feel the same to me. I do feel a difference in the morning however as the day after on High I was tired.
Not sure why it works but I can only guess that since it does for me, then they cannot be real CA's because I am obviously breathing and the machine is detecting it at a more sensitive setting. I tend to be a slow breather.
All the nights I have taped my mouth, wore my Caldera Neck brace and wore my tennis ball shirt. Pressures may differ slightly as I am still tweaking them.
Including five screen shots

1. Night on "Medium" before ever changing the Trigger Sensitivity.
   
2. Night after changing Trigger Sensitivity
   
3. Typical Night since.
   
4. Night changing Trigger Sensitivity to "High"
   
5. Last night with Trigger Sensitivity back to "Very High"
   

So, not saying that this will work for everyone as we are all different and have different requirements but for those with Atypical CA's on a VPAP it might just help lower them. No harm in trying.

[MyronH]

Interesting. I haven't played with those trigger settings. If you zoom into one of the CA's, what does it look like? Is the waveform flat for flow rate, and mask pressure? Does the respiratory rate drop?

[Sleeprider]

I remember some of the original conversation and it's good to see some followup. What are you using for TiMin?

[Kosoku]

Interesting. I haven't played with those trigger settings. If you zoom into one of the CA's, what does it look like? Is the waveform flat for flow rate, and mask pressure? Does the respiratory rate drop?

See Screen shot #6. the 2 CA's from last night

Sleeprider

I remember some of the original conversation and it's good to see some followup. What are you using for TiMin?

TiMin is default at 0.3s
TiMax is set to 3.0s. When I first go to sleep, sometimes I take deep long breaths and 2.0s cut them off.

In screenshot #4 you can see how I had many CA's on high, then woke up and at 3.45A.M and AHI was 7.something, so  I set it back to Very High and only had 2 subsequently after that.

[alps]

This has been similar to what my experience has been on the Aircurve 10 Vauto.  I have been using it for a little over six months and found early on problems with CA's.  Also Hypopneas were also a problem.

Tried multiple settings but could not get consistent numbers below 5.  Then in mid-April after reading a post about the trigger/cycle settings, I began to change them from the default "Medium" setting.  After various combinations I set the trigger on "Very High" and the cycle on "Very Low" which helped my numbers to really improve.  I also spent a little time tweaking my EPAP/IPAP and PS settings.  I am very happy with the results.  Also I am grateful for those on the forum who helped give me some great advice and direction in the process.

Below are several charts.  One is an overview of my statistics that reflect the overall process of change from January to the present.  I included two recent charts to show the high/low range of my nightly AHI number.

Not everyone needs to change the trigger/cycle but for some like me it was very helpful.

[attachment=6787]  [attachment=6788]  [attachment=6789]

[holden4th]

I found that the trigger settings needed to be changed as well. In my case it was the Ti Max, which wasn't long enough. I found the machine (an S9 VPAP Auto) wanted me to exhale before I had completed my inhale. Upping the Ti Max by half a second solved that. I'll now have a look at the trigger sensitivity thanks to this thread as I do have some CAs and they don't tend to be clustered. I've got an Aircurve arriving tomorrow (according the USPS tracking service) and will set it up with this in mind.

[Kosoku]

This has been similar to what my experience has been on the Aircurve 10 Vauto.  I have been using it for a little over six months and found early on problems with CA's.  Also Hypopneas were also a problem.

Tried multiple settings but could not get consistent numbers below 5.  Then in mid-April after reading a post about the trigger/cycle settings, I began to change them from the default "Medium" setting.  After various combinations I set the trigger on "Very High" and the cycle on "Very Low" which helped my numbers to really improve.  I also spent a little time tweaking my EPAP/IPAP and PS settings.  I am very happy with the results.  Also I am grateful for those on the forum who helped give me some great advice and direction in the process.

Below are several charts.  One is an overview of my statistics that reflect the overall process of change from January to the present.  I included two recent charts to show the high/low range of my nightly AHI number.

Not everyone needs to change the trigger/cycle but for some like me it was very helpful.

   

 
Just got back from a weekend camping trip in the new trailer and figured I would try the cycle on "Very Low" and wouldn't you know it, I recorded my lowest AHI yet of 0.9. Thanks for the tip.

[alps]

That's great to hear!

[yrnkrn]

I switched to trigger high as the VAuto with trigger med was not triggering on low-flow breaths resulting in arousal, like this:



Alternatively, this may be solved by higher EPAP.

[holden4th]

I received my Aircurve VAuto from Supplier #2 today and have just set it up. I am going to try the settings you suggested with a 'very high' trigger and a 'very low' cycle just to see what happens.

The machine only has 445 hours on it which works out to about 2 months max.