Posted by: Jan | August 7, 2010

Respironics Data Tutorial

The Philips Respironics System One Auto PAP with A-Flex that I use is a great machine.   It’s whisper quiet, comfortable, and easy to use.  The biggest complaint I have is that the LED screen gives very little data, and it’s hard to read.  The only useful data you can get from the screen is 7 and 30 day averages for AHI’s, and because they are averages, these readings aren’t really that useful at all.

I wasn’t too happy about having to spend $100 out of pocket to buy the Encore Viewer 2.0 software that is required to read the data card, and I’m green with envy for the people who have Resmed S9 machines that show so much data on an easy to read, colorful, LED screen right on the machine.  It’s cumbersome to remove the data card from my machine, plug a card reader (fortunately, the PR S1’s use a standard SD card that can be read by any SD card reader), fire up Encore Viewer, upload the data to my computer, then generate a report (zzzzzzzzzzzzzzzz) that takes time and gives a buttload of data for a week at a time.  Cumbersome!

Nevertheless, the process makes up for itself in that you get a lot of useful data.  When I was having problems with waking in the middle of the night, I could see the graphic representation of exactly why, and understanding what was going on allowed me to fix the problem instead of complaining about it.

Each Encore Viewer report is about 13 or 14 pages right now.  I think these reports will go ever longer, since the software does not allow the user to select any parameters for data except choosing the week for daily details.  The first few pages show compliance information, pressure trends, long-term sleep therapy trends, and patterns of use that always default to starting from the very beginning of CPAP usage to the present time.  Currently it is taking 2 pages to show patterns of use–I suspect that this will take up more and more pages as time goes on.  I’m not quite sure what the point of that is, because this is information for me, the patient (hello, remember me?), NOT a clinician.  I know how much I use it and when.  I could care less about a graphic representation that takes up so much bandwidth.

Finally, on page 6 now, I get to the first page of “Daily Details”.  That is the meat–this shows me exactly what happened during a particular night on my machine.  That’s the useful data.

(To steal a phrase from my favorite knit blogger, click on a graph to “enbiggen”)

Let’s look at leak data first:

The green line at the top of the graph means “Normal Mask Fit”.  So why is the graph shoing leaks around 25-28 LPM?  Every mask has an “acceptable leak rate” depending on the pressure.  If not, no air would come out the CO2 vent.  You can find a chart showing the acceptable leak rate for your mask by looking in the information booklet that came with your mask or looking it up online.  In this case, I was using the Swfit FX mask, and you can see a copy of the chart here (see chart on page 5 called “Pressure Flow Curve”)

Resmed machines show the leak rate as 0 if the leaks are within the acceptable leak rate, but PR’s show the actual leak rate.  In this case, the average leak rate was 26.0 LPM, well within the masks range for the pressures I was using this night.

If you notice a break in data, that’s because I was watching t.v. in the evening and–realizing I was probably going to fall asleep–I put my CPAP on.  When I woke off, I turned it off and got ready for bed, and then put my mask back on for a real sleep.

Pressure data is what I look at next:

My pressure range is 9 to 15 cm H20.  This was a good night, and my pressures stayed fairly low.  Here’s an example of a different night:

It’s very rare for me to bump up against the top pressure like that now that it’s set at 15.  I was having a lot of nasal congestion.  Despite all that, my machine did a great job–my AHI was only 0.2.

Here’s my best night ever:

AHI was 0.0.  July 4, 2010  No fireworks while I slept ;o)  I went to bed around 11:30 (O on the graph) and between 2:30 and 4:30 a.m. (hours 3 to 5 on the graph) I was probably in deep REM sleep.  You can see that the machine handled it beautifully to stop any OA’s CA’s or hypopneas from occurring.

Then I look at the Daily Events Per Hour:

This chart isn’t particularly useful for me at this point in time, but it could be very useful if you are having problems.  For example, someone who is having a lot of central apneas (also called “clear airway” apneas) can look to see if they are being induced at a particular pressure.  Or, if the pressure is too low, it might show increased obstructive apneas and hypopneas a the lower pressures.

Next, there are “Sleep Therapy Flags”:

This chart can be useful to show “cluster” events.  For example, some people may have clusters of OA’s, CA’s, or Hypopneas during REM sleep.  It’s possible to have a fairly low AHI, but if the events are all clustered at a particular time of the night, that can be useful to determine what might be going on if you are not feeling the benefit of your therapy.

Finally, when there’s a problem, it’s helpful to look at the entire page of Daily Details. 

Mine is not particularly useful because since I have such good therapy there’s nothing much to see, but if you look at all three of the top graphs together they can tell you a lot.  For example, if your leaks go up on the leak chart, you might expect to see increases in the events recorded on the Sleep Therapy Flags chart at the same corresponding time, or wild pressure increases.  Or, if you have a sudden and prolonged apnic event, you can expect to see big changes in the pressure to combat it.

If I were to run my machine in straight CPAP mode, the pressure data would be reflected as a flat line, unless I used the ramping feature.

Take a look at your data (you DO have a data capable machine, don’t you????) and see what you can learn.  It’s very useful information.



  1. Just a point to note for newbies. Different PR machines give you slightly different data. For instance, I have a different, straight CPAP machine and I don’t get the chart with daily events. And of course, the pressure line stays straight!

  2. Great idea for a post, I’ve been wondering about some of those charts in my report.

  3. Good point, Donna.

    I should also point out that Respironics Series M machines can use the same software, but some of the data is not collected, like the green line on the leak chart.

  4. Very helpfull indeed. This kind of information is valuable and important because DME’s and doctors don’t provide this.

  5. Thanks for sharing all this info. For a newb like me it is extremely valuable.

  6. This has been most helpful. Just started therapy (4 days) and got software yesterday. Not sure about what I was looking at on the graphs, but now I would have to say it appears I need a lot of “adjustment.” I’ll need to call the doc on Monday but at least I have some idea as to what I need to ask.

  7. I’m glad it’s helpful

  8. Thanks for the info.


  9. Hi Roger,

    When you get your software, let me know if you need help figuring it all out.

  10. Thank you this was great information. Both my wife and I are on CPAP and quants so this was very helpful.

    Much appreciated.


  11. This is just what I need! Thank you so much. I use an m-series, but this translates easily and will really help me refine my therapy.

    • I’m always happy to hear when something is helfpul!

  12. You are admirable for doing a report…It’s a good tip making report so that when you encounter problems, it’s easy for you to trace where you got wrong…So impressive, it really helps a lot..

  13. Mask Arrayed,
    Thanks for your superb report. With this help I’ll now take the plunge and buy the EncoreViewer 2.0 software.

    • If you haven’t bought Encore Viewer yet you should be aware that there are two open source software alternatives available for free if you search on the forum.

  14. Can you post a link to where we can download the alternative program/s? There are mentions of the programs all over the place but no links to where you can get it 😦

    • I’m not comfortable posting a link to sites where you can download programs, but if you do a search on my favorite apnea forum (you can guess which one if you read my posts) you will find ways of getting to these.

  15. I just stumbled across this blog because I have finally replaced my Resmed S8 “brick” with a Respironics System One with Auto Set and A-flex.

    I’ve gotten a hold of the encore reader software and it seems I am having issues with leaks,

    Should I set the resistance setting? I am using the Resmed Swift FX mask with nasal pillows and if I read the manual with it correctly any number on the leak chart above 43 at my pressure is considered a leak.

    I’m actually considering switching to the Respironics mask because of the “compatibility” with the machine.
    I’d appreciate any tips you can give me,


    • The resistance settings on the System one do not seem to make much of a difference, I leave mine set to 0 since I don’t use Respironics masks. There’s no nice equivalent for a Swift FX in the REspironics line, so if you like that mask, you are not going to be happy with switching to a Respironics brand mask–and it’s unnecessary. .

      First, make sure that leaks really are a problem. Respironics reports TOTAL leak rates, not only “unintentional ” leak rates (that is the amount of leakage over and above the usual rate from the exhalation vent). So you have to go to the booklet that came with your mask OR the ResMed Swift FX website to see what the expected leak rate for your mask is at your pressure settings. Only leaks over and above the average expected leak rate at a particular setting are a problem.

      Second, Swift FX is very compatible with the PR S1, but if you are having significant leakage you need to fix it. In my experience, leaks in the Swift FX can be from:
      1. Nasal pillows are not fit correctly–i.e. wrong size nasal pillows–try going UP one size if you think this is an issue.
      2. Mask is not adjusted properly and either: a) movement pulls the pillows away from your nose (best cure is to hang the hose!) or b) too tight so the pillows don’t properly inflate and seal–loosen it up!
      3. Your nostrils are long and slotted and simply cannot seal with this particular brand of nasal pillows, OR
      4. You are MOUTH BREATHING (this is the most likely reason, BTW).

      One other thought is that if you have a wide range on your Auto settings or you are still using the ramp, you may be adjusting your pillows at too low a pressure and they leak when higher pressures are reached. Make sure your settings are not too wide apart (5 to 6 cm difference between low and high pressures is recommended), and then you should fit the mask at the highest pressure. This may require you to go into the clinician’s mode, set the machine for straight CPAP at your highest pressure with NO ramp, fit the nasal pillows at that high pressure, and then return the settings to what you normally have. It’s a PITA–I’m envious of people with S9 Autosets and the mask fit feature those machines have!

  16. Thank you so much. I saw the Respiratory therapist today and she said my leaks looked ok. She had no idea about the mask resistance setting so I’m going to disable it.

    • Gunny, I always recommend educating yourself on what the acceptable leak rate should be. The respiratory therapist doesn’t know about the mask resistance settings, so are you sure you trust her on the issue of acceptable leak rate? If YOU look it up (there’s a chart in the booklet that came with your mask or you can find it on here on page 5:–leaks over and above those shown on the chart are what you need to worry about) then YOU will know what is acceptable or not for the pressures you are running. This way you empower yourself and make sure that your health is optimal.

      Sometimes the leaks cause problems without showing up as “large leaks” on the software printout (which will show a BLACK leak line). You RT may not think leaks are an issue unless the black line appears, but if your leaks are over and above the acceptable leak rate as shown on the chart but below “large leak” status they could still be a problem–some of this will depend on how you are feeling, too. That’s why it’s important to know this for yourself.

  17. Thanks a bunch. I got a new mask today so I’ll be starting data collection over from scratch and get a picture of what’s happening.

    LOVE this blog. Great resource for the newbies and the CPAP veterans like myself.

  18. FYI for Respironics PR System 1 auto CPAP users, there is no need to go into the clinician menu, change to straight CPAP and set a max pressure in order to fit test your mask to your max pressure. The unit has a mask fit feature. You simply need to hold down the ramp button for about 3 secs and release. The unit will perform a fit check and let you know if it passed with a check or failed with a check.

    • Thanks, that must be on the new 560 Auto. I’m still on the old 550 and it does not have the mask fit feature.

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