Report on recent lab rat activity ...

[dsm]

Hi all,

Haven't fallen off the planet, just been very busy with a major project.

But, in the past 2 weeks have been pulling apart & trialling ...

- Polaris ISP9800 Flying saucer
- RemStar Plus w h/h
- Puritan Bennet PB318
- RemStar BiPap Pro2 with BiFlex
- Puritan Bennet Knightstar 330 BiPap

The one machine I can't seem to figure out how to change settings on is the PB318. When pulled apart I see lots of old style components (what we used to call discreet components - resistors, capacitors etc:). My description of the insides is "built like a Panzer Tank - looks like one too" - big heavy & a real workhorse.

The really interesting thing for me though was how vastly different the RemStar Plus is to the RemStar AUTO with Cflex & The RemStar BiPap Pro2 with BiFlex. The only common thing among them is the case & the placement of a motherboard. The inside plumbing & motherboard components are very different from one to the other. There was similarity between all the pressure sensor tubes between the AUTO & BiPap but no similarity in the fan & air pressure control. The RemStar plus appears to have *no* air pressure sensors at all. I don't know how it knows if it is at the right pressure. There is *only* a cable from the motherboard to the fan motor. It seems it relies on being set up correctly & adjusts to the current cms setting by adjusting the set speed of the fan.

A potential eyeopener is realising that there appears to be a *major* shift to a new approach in the newest RemStar units with the intro of the current RemStar AUTO & possibly the new BiPap AUTO where they now rely on inflight varying of the motor speed rather than varying the direction of the air to obtain different pressures while in use.

The older BiPap Pro 2 with Biflex (and also the RemStar Plus) have no noise baffling inside like the current AUTO with Cflex does. The fan is not surrounded by foam as in the AUTO unit. Both the RemStar Plus & the BiPap (Pro & Pro2) run the fan at a constant speed & air output The AUTO has a variable speed fan and that is how it changes the output pressure (as does the ResMed S7 line & S8 Line of AUTOs & AUTO upgradables and also the Puritan Bennett lines).

The other interesting thing re the BiPap Pro2 is that to adjust pressure between the Inhalation & Exhalation settings they use a solenoid controlled air valve that slides between two positions based on the hi/lo pressure currently set (a bit like the way a loudspeaker cone is driven). This mechanism is very similar to the valve used in the Polaris models that have 'SoftFlex' (ISP3000 & ISP4000). I once speculated that the Polaris may have been a rebadged F&P unit. Well clearly this is not so. The Polaris ISP9800 is a nice well built unit. I think the SoftFlex on the ISP3000 ISP4000 has to be as good as the BiFlex on the RemStar BiPap w BiFlex.

Re Respironics, I believe that in order to introduce their next gen machines they may have abandoned the solenoid controller that is combined with the fixed speed/output fan (although it is an excellent approach) and switch to using a fan that changes its speed using a hi powered brushless motor fan.

QUESTION:
>>
Can anyone with the new AUTO BiPap say if their fan stays at a constant speed (like the BiPap Pro2) or does the fan speed fluctuate like the RemStar AUTO with Cflex fan does.
<<

The solenoid controller (as in the Polaris ISP3000) redirects excess air back into the fan input. As it slides back and forward (controlled by inhale then Exhale), it effectively sends max setting of cms to the output port or lowers the cms by redirecting the excess air back into the input to the fan.

I haven't taken apart the PB330 yet (it is quite a complex machine - sooo light & sooo quiet). It seemed like a bucking bronco when I 1st tried it. My very 1st test was with a plain hose (PB require hoses with a built-in pressure line). Because it could not detect pressure it went to max (30 cms) & for a minute I thought I was about to be inflated like a ballon. Scary!. From then on I would only try it with the proper hose (borrowed from my PB420s). I would hate to be asleep & have the pressure line pull off at the machine end. Whooooop!!!.

The I/E function is highly tunable (compared to the RemStar BiPap Pro2).
The S/T function isn't behaving how I thought it should so I need to do a lot more testing on that.

One thing I did try was to compare the PB330 to the RemStar BiPap Pro2 in I/E BiPap mode. The particular test I wanted to try was to see what happened when I deliberately slowed & stopped breathing (one of my issues). On exhalation with breathing stopped , the RemStar did seem to just sit there at times like it was waiting & the slightest inhale it would puff a burst of air & then go to the Inhale CMS. The PB330 seemed to wait a short time then it would send a burst of increased pressure & ramp up to the Inhalation pressure based on the preset rise time (both PB & RemStar allow you to set the rise time of E to I cms).

The abve description of PB330 I/E behaviour is what I thought S/T mode would do - again I need to do more research on it.

I will soon be switching to the PB330 with a Humidaire H/H as my regular machine. Am expecting that to be an experience .

Cheers

DSM

PS have had a couple of episodes with my RemStar AUTO where it does the 'runaway' trick. This seemed to happen when I had my f/f mask & was getting continuous leaks. I awoke to find the machine sitting at the max pressure. Analysis of the download data confirmed this. Not good. In fact about a month back I gave up using AUTO mode as I found that whilst I was not snoring & seemed to sleep ok, I was feeling sluggish & dopey during the days just as had happened pre xPAP therapy. After I switched back to CPAP mode I seemed to get the energy & wakefulness back.

I am suspecting that AUTO only works for some people. I appear to be one who needs the titration setting - but I am hoping to learn more from using the PB330.

Also am willing to make the following observations re BiPap vs Cpap vs Auto ... (these remarks relate to my own experience & I don't expect that to be the same as other's, even under similar circumstances) ...

> BiPap is a great effect & gives a good feeling. For me it *is* better than CFlex/EPR but,
> CFlex/EPR are also good value to folks particularly us on higher CMS or who may get regular nasal congestion.
>I no longer plan to use AUTO mode unless I get to try a new S8 Vantage AUTO (the Autoset Spirit seemed fine except the fan noise seemed to have become a marital problem )

D

#Update - Still haven't worked out how to pull an S8 apart. Screws come out ok but top part shows no signs of loosening from bottom part. Just don't want to force it.

Also have actually almost completely dissasembled the fan motor in the RemStar BiPap. Am still trying to find how to remove the central rotating part (shaft) (this BiPap I obtained was cheap because the fan motor had noisy bearings, possibly from water damage. All else works 100%)


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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, resmed, bipap, hose, Puritan Bennett, cflex, Titration, CPAP, Ramp, auto

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, resmed, bipap, hose, Puritan Bennett, cflex, Titration, CPAP, Ramp, auto