Accuracy of machine software

[MRH]

I have a question for all you experts out there. I read the data from last night and there were a couple hypopneas that showed up when I know I was awake watching tv. So how reliable is the rest of data? I had a RT at the DME tell me that Respironics only says their data is accurate when used with one of the Respironics masks, that they were calibrated to their own machines. I have a hard time with that one

Mark

[cpapernewbie]

that happened to me too - when I was wide awake I "ex
perienced not only apneas but also snoring

I think the algorithm of all those HI, Snore etc are all not that reliable, and that's why Respironics and Resmed are not happy to let us use the software

[jimbassett]

You have to remember the clocks are set to GMT time and run on a 12noon to 12 noon day. So you would have to figure what your time was in relation to the clock time. Bet you will find you were sound asleep when it recorded your HIs. Happy breathing
jim

[Bookbear]

What he said! Often, DME's do not set the machine's clock (forgetting to?), although cpap.com obviously looked at my shipping address and checked to see what time zone I am in and set the machine accordingly... both the original and my recall/replacement machine arrived correctly set to PDT, not GMT. The S-8 must have an internal battery or cmos chip that retains the information, since when I travel, it;s unplugged for a while while flying or on the road. It's always read the right time. I am not sure about other machines, but I suspect that any data-capable machine would have such a setup. Check the time readout on your machine.

[Goofproof]

Even to the machines are only 75% correct, That's 50% more correct than your DME or Doctor, guess based on Nothing but a number they pulled out of their hat, or other orrfice.

The machine isn't designed to measure your breathing while you are awake, but you probably going to breath anyway. The data is to give you a idea of what's happening, when you are not asleep you aren't breathing the same, as when you sleep. Jim

[Slinky]

Say what? My Resmed S8 Elite AND Resmed S8 AutoSet Vantage allow me (intended for my DME supplier) to set their internal clock to my time zone time. And my AutoScan software produces graphs showing my actual time zone time, not GMT. The time my xPAPs and the software show me donning my mask and turning my xPAP are the actual time in my time zone that I did so. Eastern Daylight Time.

[Snoredog]

figure it out, its either you had the event or you didn't. Take those Hypopnea that were scored, what is a Hypopnea?

Hypopnea: 50% reduction in airflow lasting 10 seconds or longer associated with at least a 3% drop in oxygen levels, so in a lab they may look at 3 characteristics to determine the event.

Since there is no pulse oximetery data to see the 3% drop in SAO2 levels, machines rely on the remaining 2 characteristics in determining what the event was. In the case of your machine that is 50% reduction in flow lasting 10 seconds. How hard is it to hold your breath for 10 seconds? If you do, it should score a Hypopnea. You can drag your hose across the mattress rib and it can score that as a snore.

How good is the machine at differentiating a central apnea from an obstructive one? Not very good. But if you are not having a lot of those there is nothing to worry about.

If anything, autopaps are overly sensitive to events seen and more likely to score an artifact as an event.

[Goofproof]

Respironics products have internal clocks inside battery backed. The clock is set to GMT time, it is not adjustable by the user, the dealer or Joe Blow. It has to be sent to the Respironics factory for reset as part of the repair process.

The Encore Pro software and the computer it's running on convert the time, and in the software you can set the time you want your recording day to start. Jim

The machine isn't meant to be a clock, K-Mart has those a lot cheaper and they keep better time. XPAPS don't keep good time, neither does your computer, unless you have it set to sink with a time site.

[Slinky]

Goshes, I've been known to forget to check my data before noon and go in to my Resmed and reset the time for an hour previous. Check my data or download it to the card. Then go back in and reset the time again.

[extremeliver]

Snoredog makes a lot of sense.

It seems weird, but it seems like at times I simply forget to breath while I am awake. I spose that I could forget to breath for 10 seconds quite easily.

I think I forget more when I am nervous. I once had a dentist that would always remind me to breath when she was working in my mouth.

[billbolton]

I read the data from last night and there were a couple hypopneas that showed up when I know I was awake watching tv.

The algorithms in any of the APAP machines are designed to work with the autonomous breathing that occurs when you are asleep.

Any efficacy "results" you get from breathing through your APAP while you are alert/awake are meaningless.

Cheers,

Bill

[plaws]

I read the data from last night and there were a couple hypopneas that showed up when I know I was awake watching tv.

The algorithms in any of the APAP machines are designed to work with the autonomous breathing that occurs when you are asleep.

Any efficacy "results" you get from breathing through your APAP while you are alert/awake are meaningless.

So, was the original poster awake without the CPAP at the time or awake with the CPAP?

I read it as they had the CPAP on and were watching TV, but maybe not.

As you say, the algorithms in the firmware are not designed for an awake person ...

My ResMed S8 had "DME time" set so I fixed that (set it to my local time).

The only thing that upset is the counter that tells how many nights out of the total nights since new that I've used the machine. It's now something like 29/28.

[Slinky]

I think that "something like" 29/28 means that its been 29 nights since the first time you used your machine and the 28 means either the number of nights total that you've used it or the total number of nights you've used it more than 4 hours a night.

Was there one night you didn't use your CPAP at all after once starting to use it? Or was there only one night you used it less than 4 hours?

[plaws]

I think that "something like" 29/28 means that its been 29 nights since the first time you used your machine and the 28 means either the number of nights total that you've used it or the total number of nights you've used it more than 4 hours a night.

I'm pretty sure that in my case, it's an improper fraction because I changed the time. AFAIK, I've been on it > 4 h every night since I got it. If not, I would expect it to say "28/29" ...

[MRH]

plaws, I was awake with the cpap hooked up and running while I was watching tv relaxing. On the first hour on the Encore chart it showed 2 marks in the hypopneas, and I know I was still awake during the first hour. That is what made me wonder.

Mark