[Equipment] Airsense 10 Different AHI Experience from Dreamstation

[drobinson02199]

Background:  Untreated AHI:  104.5, used Dreamstation with setting 5/20 since 2018

My average AHI with the Dreamstation was 5.5, with a range of 3.5 to about 8.5.  Would still nod off while reading in the afternoon, but no issues driving.

When recall hit, I scrambled and got an Airsense 10.

Have been using it for 5 nights now.  Same settings (until last night, see below).  Average AHI below 1.0; feel markedly better in the afternoon (which leads me to believe that this is real improvement -- not just a measurement difference).

I have read that the Airsense 10 algorithm is different from the Dreamstation.  Can anyone shed any light on why I'd have such a transformationally different experience with the Airsense 10 vs. Dreamstation?

Started using Ocsar with the Airsense 10, and based on what I see, last night I changed from 5/20 to 7/20, with a 5 minute ramp from 6.0 to 7.0.  AHI .4, and down from the previous night (which was my high on this machine).  But my AHI has been low from the start on the Airsense 10 compared to the Dreamstation.

Anyway, I love the machine given the results.  Maybe the recall has done me a favor.

Regards,
David

[SarcasticDave94]

It's been proven by members here that switch from Respironics to ResMed that most will have lower AHI. A big part is that ResMed attacks events faster and add it keys in on flow limits versus whatever Respironics looks for. It's a better treatment.

I'm not too surprised that results weren't the greatest though. 5-20 pressures are almost default and bring basically wide open pressures isn't optimal for the vast majority. Despite these machines being able to adjust pressures, it's still required to optimize the pressure set per individual.

[clownbell]

To original poster - if you will post your OSCAR data, the experts here will give you guidance on pressures. Be sure to post in the order specified in the wiki Standard OSCAR Chart Order -- see SarcasticDave's signature above for a link to the wiki.

[KSMatthew]

To the OP - my understanding:

I might be wrong here so everyone is free to correct me - I’d like to know:

Your CPAP autoranges, so it will hunt until it finds the optimal pressure for your situation.  You have yours set to range from 5-20.  Tomorrow, or before you use it tonight, check on the display for the pressure your machine ended up using.  If it ended up using, say 10, then it had to work its way there.  During that search time, you were having events.  The longer it took to find the best pressure, the more events you had.



Some brands are more aggressive about that search than others and get there faster.  A trick that worked for me was to raise my low limit closer to the average “best” pressure so it didn’t have to search so far.  My new machine searches more quickly and it looks like I can lower my low limit without a penalty and get the bonus of a potential lower pressure if conditions permit.

Note: I also had the DreamStation and switched to AirSense and saw a similar behavior to what you experienced.

[drobinson02199]

KS Matthew:

I'm looking at my Oscar data daily. Based on what I saw from the first couple of days, I raised the range from 5/20 to 7/20. I also put in a 5 minute ramp from 6 to 7, but I may eliminate that. The machine does spend some time between 7 and 9, so I want to watch it before kicking it up further.

I also loaded my Dreamstation data, and the pressure curve is more terraced -- goes up like a ziggurat. The Airsense 10 is more of a direct sawtooth curve, and it seems to rise more quickly. But I need to collect more data than I have to get a better fix.

Regards,
David

[clownbell]

To OP -

While I am absolutely not an expert, my understanding is on the same page with KSMatthews. As I understand it (and am willing to be corrected by experts), an APAP device uses a maximum and minimum pressure ‘window’. The machine will operate within these parameters using an algorithm to deliver the least amount of pressure needed with any given breath. The machine starts at the programmed minimum pressure on inhale. It will rise as needed up to the maximum pressure setting to stop apneas excluding centrals. User can get lower exhale pressure by using Exhale Pressure Relief (EPR), which subtracts from the prevailing pressure to determine the exhale pressure at any given point in time. Example: If prevailing pressure is 7 and EPR is 3, exhale pressure would be 4 making it easier to exhale. On beginning the next inhale, the machine returns to a pressure of 7 and will go higher only if there is an obstruction and will raise only to the amount needed to open the airway (up to whatever the maximum setting is). APAPs wait until the apnea or hypopnea is over before it increases the pressure. ResMed has a more aggressive algorithm that acts more quickly than Respironics.

An expert should come along presently to provide any additional info needed.

[SarcasticDave94]

These explainers have got it right as far as I'm reading it.

How about an OSCAR and we'll see what's going on. First let's clarify 2 things, then we'll get on with making it even better. Do you have your detailed diagnostic report, that's the sleep study without mask? If so consider posting it in redacted form. Next which ResMed AirSense 10 did you end up with? Look at the bottom right in the front of the PAP and tell us what the metallic lettering states. ResMed...xxxxx

[Mutineer]

I can only speak from personal experience here.

I had been using a PR System One Auto set at 11-15 and EPR set at 1 until the proverbial hit the fan, AHI was almost always in the 0.4 - 0.8 range and very, very rarely over 1.5 AHI. I also have a Resmed S9 Autoset that I bought because people on this site were saying they were a superior machine but set at the same settings as the PR System One Auto My AHI ranged from 1.5 at best to 3.5 AHI so obviously it became my back up machine.

I bit the bullet a couple of weeks ago when Foamgate began gathering legs and purchased a gently used Resmed S10 Autoset (60 hours) from Supplier No.2 who I've bought all my CPAP machines from in the past and have found them to be excellent to deal with.

Long story short after 3 nights on the Resmed S10 Autoset my AHI's have been 3.0 on Thursday night, 3.7 on both Friday and Saturday nights.

[Geer1]

KS Matthew:

I'm looking at my Oscar data daily.  Based on what I saw from the first couple of days, I raised the range from 5/20 to 7/20.  I also put in a 5 minute ramp from 6 to 7, but I may eliminate that.  The machine does spend some time between 7 and 9, so I want to watch it before kicking it up further.

I also loaded my Dreamstation data, and the pressure curve is more terraced -- goes up like a ziggurat.  The Airsense 10 is more of a direct sawtooth curve, and it seems to rise more quickly.  But I need to collect more data than I have to get a better fix.

Regards,
David

Resmed's algorithm is much more aggressive in large part because it reacts to flow limitations. 

At your pressures ramp is unnecessary imo, 6 cm to 7 cm is not a significant difference (if it feels like it the main thing you are likely noticing is increased EPR in which case you can try EPR of 2 if that feels more comfortable).

Careful chasing pressures up, no matter what you set min pressure at your pressure will often increase. Your best treatment will occur at the minimum pressure required to treat issues so if your AHI is low and you feel good don't worry about increasing pressure just because machine spends time at a higher range. That is the joys of a more responsive machine, you don't have to do as much work to get ideal treatment.

[drobinson02199]

Geer1:

Thanks -- that's good advice.

Regards,
David