Thanks for any insight on this problem...

I finally have my setup complete, with my VPAP Auto 25 fitted with a USB module and connected to a PC with ResScan 3.7. I've been downloading my data just fine and all the numbers are populating in ResScan properly. However, the pressure display is always flat! Yes, I *am* using the machine in VAuto mode, but the pressure data always seems to be the Min EPAP pressure + Pressure Support. All the pressure numbers show up as that number, the Median, 95th Percentile, and the Maximum -- even the detailed graph is flat at that number -- I don't get it! I've tried different min and max pressures over the past week, even different pressure support amounts, but the pressure data always shows up as min+support. Shouldn't the pressure vary in VAuto mode? And shouldn't that variation show up in ResScan, especially in the detail graph? I've even tried simulating straight BiPAP in VAuto by specifying min: 17, max: 22, pressure support: 5, so it will vary between 17 and 22. While using the machine, I *know* that the pressure is varying properly between EPAP and IPAP, but the data shows a flat 22! What gives?!

How am I supposed to "zero in" to my ideal pressure range if I can't get accurate numbers? Am I missing something obvious?!

bump

falvesjr wrote:Thanks for any insight on this problem...

I finally have my setup complete, with my VPAP Auto 25 fitted with a USB module and connected to a PC with ResScan 3.7. I've been downloading my data just fine and all the numbers are populating in ResScan properly. However, the pressure display is always flat! Yes, I *am* using the machine in VAuto mode, but the pressure data always seems to be the Min EPAP pressure + Pressure Support. All the pressure numbers show up as that number, the Median, 95th Percentile, and the Maximum -- even the detailed graph is flat at that number -- I don't get it! I've tried different min and max pressures over the past week, even different pressure support amounts, but the pressure data always shows up as min+support. Shouldn't the pressure vary in VAuto mode? And shouldn't that variation show up in ResScan, especially in the detail graph? I've even tried simulating straight BiPAP in VAuto by specifying min: 17, max: 22, pressure support: 5, so it will vary between 17 and 22. While using the machine, I *know* that the pressure is varying properly between EPAP and IPAP, but the data shows a flat 22! What gives?!

How am I supposed to "zero in" to my ideal pressure range if I can't get accurate numbers? Am I missing something obvious?!

Falvesjr

This may be the answer ... One gothcha with ResScan is that the default is to only produce reports based on the minimum data. The software will extract all the detail off the machine but you have to then check a box that stipulates you want detailed reports.

I can't recall at what point it asks you to do this but if you open ResScan & select a day & then request a report I believe it is at this point you get asked what type of report & that is when you select that you want a detailed data report.

Am sure someone else who has the software in front of them can confirm this. It is a PITB but that was how they made ResScan work in the later versions.

Goodluck

DSM

The difference between breathe-in pressure and breathe-out pressure is not what the charts are designed to show you. The charts are there to show you how the two pressures moved up or down together in unison as they attempted to deal with events. Maybe the PS setting pinned down the pressures, or maybe the machine saw none of the events that it would choose to react to, in view of how high those pressures are.

A ResMed machine set at 22 maximum IPAP and 17 minimum EPAP with 5 as the PS will, just as you indicated, always deliver 22 IPAP and 17 EPAP, all night, as you noted when you spoke of using it in auto mode but as a straight bilevel. In order for the two pressures to have room to move together in a way that would show that on the charts, the PS (pressure support, or delta) has to be a number lower than the distance between the numbers set for maxiumum IPAP and minimum EPAP, on that brand of machine anyway.

That being said, even if the machine is set up in way that the linked pressures have the room to move, they still may not, if you are not having the type of events it reacts to. For example, if your minimum EPAP setting (which is always locked in sync with IPAP) is high enough for both the breathe-in and breathe-out pressures to stop the snores and flow limitations that the machine looks for before raising pressure, it will not move but will instead deliver the same set of pressures all night, which shows up as a straight line in the chart, even though obviously the IPAP (breathe-in pressure) and EPAP (breathe out pressure) were always different pressures exactly the PS-setting-distance apart from each other.

It may be that lowering Min EPAP would make the two pressures move around, but then that might also increase your AHI. So it depends on what you are trying to accomplish, as far as how low you set your Min EPAP on that machine. The question may be: "Are you going for comfort or for lower AHI?" That is assuming you are treating stictly plain vanilla OSA, nothing more.

That is how I understand it as a fellow patient, anyway.

jeff

I understand everything that's been brought up so far... So, before going any further, I'm going to try different settings tonight and will report back tomorrow. Thanks to all so far!

Try the different settings for a few days or a week, and then report. It will give you a better idea if the setting changes are working or not.

tattooyu, this was more of a test of the machine than the effectiveness of the therapy, so no need to run for a week...

What I did last night was to set the machine to VAuto min: 5 max: 25 pressure support: 5, and it did work as expected. The pressure varied depending on need and I didn't get a flat line on the graph. So the machine seems fine, but therapy for me does not work well at this "total auto" setting. My numbers were horrible! So it's back to the "proper pressures" for me, even if I get flat line graphs. After all, this is about good therapy, not pretty graphs!

Yeah, I hate that straight line pressure graph too. But - it FEELS so good .... *sigh*

falvesjr wrote:tattooyu, this was more of a test of the machine than the effectiveness of the therapy, so no need to run for a week...

What I did last night was to set the machine to VAuto min: 5 max: 25 pressure support: 5, and it did work as expected. The pressure varied depending on need and I didn't get a flat line on the graph. So the machine seems fine, but therapy for me does not work well at this "total auto" setting. My numbers were horrible! So it's back to the "proper pressures" for me, even if I get flat line graphs. After all, this is about good therapy, not pretty graphs!

You may find a happy a medium. I leave my max IPAP all the way up too, since the pressure never runs away. I keep my pressure support at 4 (fairly common Rx for that). And I try to set my Min EPAP a few cm below the pressure that would give me a flat line all night. That way, I get good AHI numbers but slightly less pressure for most of the night, for added comfort. Not that comfort has ever been an issue for me with ResMed bilevel therapy, but still.