Lower Resmed Airsense apnea score might be misleading

[tiredofbeingtired]

So I'd read a lot on this forum that people seem to get fewer apneas on the Resmed Airsense than the Phillips Respironics Dreamstation so I finally tried an Resmed Airsense 10 out and I have a theory on why that is the case. 

First off, I'll note it is definitely the case. I had an average AHI of 3 on the Phillips and 1.5 on the Resmed. But I didn't feel any better, and when I looked closer I realized that Resmed 10 will only score an apnea if it meets the (stupid and arbitrary) definition of it being at least 10 seconds in duration. The Phillips will score ones in my case as few as 6 seconds in duration. And sure enough, when I went through the waveforms on the Resmed, I found a ton of sub 10 second apneas that were not counted. 

So if your score magically got better when you switched to Resmed from Phillips, don't assume it's actually treating your apnea better. It might just not be counting short duration apneas that the Phillips machine is scoring as apneas. 

Some other things I like about the Phillips Dreamstation apnea detection is that it seems to detect hypopnea a little better, isn't as bothered by leakage and will still record full data if you forget to insert the SD card back in. 

The experience using the machines is a bit different too. With the Phillips, the fan seems to accelerate a bit when you take a deep breath. You can hear it accelerate and I've heard people complain about this noise, but to me it feels like my breathing is a little bit less restricted. I found you really notice this if you use a wide hose and mask that connects directly to the hose so that there are no restrictions in it. The Resmed seems to keep a much more constant pressure that is not affected so much by breathing. 

In favor of the Resmed, it seems better made, is more stable on the bedstand, is a little more intuitive to use, is more reactive to detected apneas, doesn't blind you with blue light, and seems to be a little bit more compatible with the Oscar and Sleephead software. I've had two Phillips Dreamstations break now (what made me finally give the Airsense a proper trial). The brand new Phillips machine I got from my insurance actually arrived defective, and annoying so. It works fine for a couple of hours and then just drops in pressure. I took it in and they tested the pressure and said it works fine, but they wouldn't run it for several hours like I asked so are taking my word and sending a new one. If I hadn't been using a CPAP for years I doubt I would notice it though so I wonder if a lot of people are getting malfunctioning machines and not realizing it. The fan weakened on the old one too without any notification from the machine, though immediately upon turning it on which isn't so hard to figure out. It's
frustrating that these machines will malfunction in such a way that could mislead people into thinking they work fine if they are not paying close attention to their data.  

Anyway, just thought I'd share my thoughts for anyone trying to decide between machines.

[Ockrocket]

Interesting.

I've had no problem to date with my Dreamstation, four years of use so far.

I don't know what blue light you are referring to, mine lights up with a normal white light screen when it switches on or off.
On auto start/stop the machine doesn't light up when it starts, and does light up when it shuts off.. the light goes out after 60 seconds on manual start and both auto or manual off.

I have noticed the fan does seem to speed up with a big in breath, but uncertain if it is the machine increasing fan speed or the inhale causing it to spin easier and therefore faster.

I have never had a problem uploading data to either Sleepyhead or Oscar.

If the Resmed reads less apnoea events that would be good for compliance to the medical conditions requirement for my professional driver endorsements.. but not necessarily good for my overall health.  

[SarcasticDave94]

You can argue about the defining aspect of apnea being 10 seconds as long as you want, but this is the medically accepted parameter of defining apnea. As for reporting accuracy, OSCAR just reports the input data it's given. It's entirely probable that ResMed vs Respironics report events differently. They each tend to handle therapy differently.

One reports you had an AHI of 3, the other says 1.5. The problem is you can't say this is for the same sleep session, so the exact same sleep and events that happened aren't presented in the results. Note that each night is a bit different, and the results will differ as well.

I think the bottom line is this: choose which machine provides the best sleep therapy for you. This is graded by quality of how you feel after a nightly sleep session. If the Respironics makes you feel better consistently, that is the right machine. And vice versa as well for the ResMed.

[Ockrocket]

An excellent summary Dave.. just like a car, both machines do much the same thing, but with slight differences.. one fits some people, the other fits others. 

I seem to recall reading somewhere that Resmed and Philips use different treatment algorithms in their machines, so it stands to reason the effectiveness can vary along with what the machines report.