ResMed vs Respironics

[JeffH]

This is a question for people that have used both.

Do Resmed machines seem to blow a little more aggressively than Respironic machines?

Since I've had my eye problem I've gone back to the Remstar Cpap plus. Patty is using the Resmed and we both seem to think that it blows harder than the Remstar.

Anybody?


JeffH

[Arizona-Willie]

If both are set to the same pressure they should blow the same.

If you have a manometer you could test both units to make sure they are blowing the correct pressure.

[JeffH]

If both are set to the same pressure they should blow the same.

If you have a manometer you could test both units to make sure they are blowing the correct pressure.

I agree, but both of us feel the Resmed blows harder. Only have a home made manometer and haven't tried it yet.

[Velbor]

There is a difference in the way they start up.
One seems to "hold its breath" for a moment and then punch in almost immediately at full pressure.
The other "gradually" builds up (only a second or two) to the set pressure.
It was interesting to watch the two different behaviors on a column of water in a manometer.
Unfortunately, I don't remember which is which!

After the start-up, each blows "equally hard" to maintain the set pressure.

[dsm]

JeffH,

This is a valid question and one that has been discussed many times over the years here at cpaptalk. Below I will try to do an objective analysis of the possibilities in this regard.

Lets look at different devices :-

1st straight cpap (lets set it to 11 CMs) ...
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The issue of one brand of cpap blowing more aggressively than another is difficult to argue except in about 2004/5, cpaps had nearly all been fitted with pressure sensors at the air exit port and in particular these machines then had the ability to lower the speed of the blower as the user breathed out - a users breathe-out pressure (which at the mask has to be greater than the incoming cpap pressure) gets added to the cpap blower-out pressure to push the reading of the pressure detected at the air exit port, higher than the current pressure setting, so the blower motor would slow a little to maintain the machine set CM pressure (i.e. 11 CMs) at the air exit port. (you can often hear this as a slight change in the hum from the blower).

If one brand of cpap were to speed up faster than another when the user slows their breathing out & starts to breathe in, then that machine may appear to be more aggressive even though it is only a cpap. NOTE this is purely theoretical but could explain a perception that one cpap might be more aggressive than another.


2nd an Auto set to say min=8CMs & max = 15 CMs ...
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Here there can be clearly a difference between how fast one machine's algorithm raises pressure vs another's. I believe it is an accepted knowledge that the Resmed Autos tended to raise pressure faster than the Respironics, when an apnea was detected. Many people have commented here over the years about
this and the typical characterization has been that the Resmed's were more 'aggressive' in their pressure responses.


3rd Bilevels ...
=============
The change in pressure between epap & ipap can be set with a 'risetime' BUT, the shape of the waveform is not dependent on the risetime & one brand of machine that has a 'shaped' waveform can feel quite different from one that has say, a square waveform (where pressure rises as a straight line (slope) rather than as a curve). That curve of the rising pressure (epap to ipap) is noticeable & manufacturers began to add extra settings to 'soften' the pressure rise (change the risetime slope to a curve) and this softening was separate from the risetime period. e.g. Resmed's 'Enhanced VPAP III' had such an extra adjustment added.

The Vpap Adapt SV took this whole question of the shape of the pressure rise to a different level by introducing a shaped waveform that was called the sharkfin shape. That then got added to their cpaps in the S8 II models.



SUMMARY
========
It is quite feasible that one brand appears to be more aggressive than another in delivering pressure changes no matter what the reason. But, I would be inclined to say that since the S8 II models, Resmed machines may be less prone to doing this than they were before the S8 II models appeared.

DSM

[Catnapper]

When I started with OSA therapy, I first had a ResMed Escape for 6 weeks, then whatever the auto version (Vantage maybe?) was for 6 weeks. I asked for the Respironics M Series auto to get the C-flex, and was able to switch, and had that for 5 months. Finally I had the M series auto bi-pap. At the time I wanted softer, gentler, effortless and more natural breathing. I was so much happier with the switch to the M series machines. They were much more comfortable to me. I noticed a big change at first and even better with bi-pap.

Now it seems logical that the same pressure would feel the same, I agree. Maybe it is in the difference in the transition from inhale to exhale. Maybe there is a variation from machine to machine. I can only report on my experience.

Since I wrote this, I see a better explanation.

Catnapper - Joanie

[JeffH]

Another difference is the fine and foam filter for the Remstar vs. the single fiber filter that goes in the Resmed. I noticed more nose "stuff" when using the Resmed. I NEVER have boggers with the Remstar.


JeffH

[JohnBFisher]

... Another difference is the fine and foam filter ... I NEVER have boggers with the Remstar. ...

Succinct! I love it.

[rested gal]

Maybe it is in the difference in the transition from inhale to exhale.

I think you nailed it, Joanie. Respironics' C-Flex, C-Flex+, A-Flex vs ResMed's EPR, Easybreathe... any of those could affect the "feel" of pressure from one brand to the other, even if the therapeutic pressure setting is ultimately the same number of cm H2O. At least that's my take on it.

And even those comfort features can feel different to different people.

I've tried them all except "C-Flex+".

Respironics' A-Flex felt noticeably softer and more gentle in its transitions to me than ResMed's EPR/Easybreathe. Others have reported an opposite experience.