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I take the SV seriously enough that I am looking for a used one to keep as a spare. I found a new one, with HH, for under $3500 so far.

I have a prescription. I will keep looking.

Tired ... the oral surgery has impacted me a lot harder than I thought it would.

Banned wrote:

goose wrote:Interesting stuff Doug. Thanks for posting such detailed info

Yeah, I'm so moved it's even bringing tears to my eyes. i had to dig out , dust off, and fire up the old REMstar Plus with C-Flex so I could remember what it was like in the old days. You will never get to EPAP 11 and IPAP 13 on the Adapt. The closest the Adapt will get you is EEP 10 + MIN PS 3 = (IPAP) 13.

Banned

[quote="dllfo"]I take the SV seriously enough that I am looking for a used one to keep as a spare. I found a new one, with HH, for under $3500 so far.

I have a prescription. I will keep looking.

Tired ... the oral surgery has impacted me a lot harder than I thought it would.

The SpO2 data from the night 22-23 Apr 2008

http://www.internetage.com/cpapdata/dsm ... pr08-2.jpg 22-23 April 08.

DSM

dsm wrote: One bet I will make is that on a Resmed machine with the added sensing tube, you can set the CMS epap & ipap (or equivalent) to 1 CMS lower than any Respironics machine as in my testing using a dial manometer, the machines with sensing lines to the mask are spot on in real CMS settings whereas those without are 1 CMS lower at the mask than what the LCD on the device says.

Machines that deliver exactly the same CMS at mask as on the LCD are

PB330
PB420x
Vpap AdaptSV
Resmed Autoset-T (old model)

Machines that are 1 CMS lower at the mask than the LC shows are ...

Vpap II & Vpap III
All Bipaps
Most other brands of Cpap that don't have a mask sensing tube (proximal line on the SV).

This is no big deal but it does make it a tad difficult to compare across these two types unless one allows for the 1 CMS difference.

DSM

Doug, I wonder if the BiLevel machines measuring 1cm below set values are lacking calibration. I sure could be wrong, but I thought clinician procedures for those BiLevel models (w/o proximal sensor) entailed calibrating the displayed or set pressure to match the pressure measured at the mask during machine set up.

dsm wrote: One bet I will make is that on a Resmed machine with the added sensing tube, you can set the CMS epap & ipap (or equivalent) to 1 CMS lower than any Respironics machine as in my testing using a dial manometer, the machines with sensing lines to the mask are spot on in real CMS settings whereas those without are 1 CMS lower at the mask than what the LCD on the device says.

Machines that deliver exactly the same CMS at mask as on the LCD are

PB330
PB420x
Vpap AdaptSV
Resmed Autoset-T (old model)

Machines that are 1 CMS lower at the mask than the LC shows are ...

Vpap II & Vpap III
All Bipaps
Most other brands of Cpap that don't have a mask sensing tube (proximal line on the SV).

This is no big deal but it does make it a tad difficult to compare across these two types unless one allows for the 1 CMS difference.

DSM

Doug, I wonder if the BiLevel machines measuring 1cm below set/displayed values are lacking calibration. I sure could be wrong, but I thought clinician procedures for those BiLevel models (w/o proximal sensor) entailed calibrating the displayed or set pressure to match the pressure measured at the mask during machine set up.

-SWS wrote:I thought clinician procedures for those BiLevel models (w/o proximal sensor) entailed calibrating the displayed or set pressure to match the pressure measured at the mask during machine set up.

Interesting concept, but I don't think any setup manual suggests calibrating pressure at the mask.

http://global.respironics.com/UserGuide ... 043629.pdf

http://global.respironics.com/UserGuide ... 042977.pdf

http://global.respironics.com/UserGuide ... 040200.pdf

Banned

DSM--
My current situation with the SV is, once again, caused by outside forces. The oral surgery is healing well, but I now have a toothache all the time. I got together with the surgeon and my Pain Med dr. and increased my opiate levels ..... pain is an odd enemy. I have also wondered about going to a full ventilator.

I will be seeing my Pulmonologist today. Last night's read outs are more of what I sent you.

Banned wrote:

-SWS wrote:I thought clinician procedures for those BiLevel models (w/o proximal sensor) entailed calibrating the displayed or set pressure to match the pressure measured at the mask during machine set up.

Interesting concept, but I don't think any setup manual suggests calibrating pressure at the mask.

http://global.respironics.com/UserGuide ... 043629.pdf

http://global.respironics.com/UserGuide ... 042977.pdf

http://global.respironics.com/UserGuide ... 040200.pdf

Banned

Thanks much for those links, Banned! I recall that some of the CPAP and APAP models have manual calibration capabilities.

I just now looked through a BiPAP autoSV Provider manual (106 pages). The pressure-loss compensation procedure for this model seems to be exactly what Doug has been doing: measure delivered pressure at the mask and adjust settings accordingly (despite what the readout on the display says).

BiPAP autoSV Provider Manual wrote: The BiPAP autoSV automatically compensates for pressure drops associated with a 6-foot smooth bore tube and bacteria filter. Additional pressure drop will occur when restrictive elements are added to the patient circuit.

BiPAP autoSV Provider Manual wrote:Note: Always use a manometer to verify patient mask pressure.

Substituting a longer and/or corrugated hose for that specified 6-foot smooth bore hose, for instance, should slightly increase pressure drop because of added tube resistance. Adding an external humidifier should also increase resistance (and therefore also increase the end-to-end pressure drop). Conversely running without the bacteria filter (while using the factory-specified hose) should decrease end-to-end pressure loss compared to the factory's pre-calibrated baseline circuit mentioned above.

IMO Doug's procedure of setting up by utilizing manometer pressure readings at the mask is correct for any machine that does not offer manual calibration (presumably most machines).

Anonymous wrote:
Doug, I wonder if the BiLevel machines measuring 1cm below set values are lacking calibration. I sure could be wrong, but I thought clinician procedures for those BiLevel models (w/o proximal sensor) entailed calibrating the displayed or set pressure to match the pressure measured at the mask during machine set up.

Steve,

I can sjow the 1 CMS difference using a dial manometer & running at a 12 CMS pressure. The losses only show when the machine is in use not if the air pressure is measured and the air line blocked off.

I ran extensive test on this last year & repeated the results as often as I did the tests.

DSM

dsm wrote:

Anonymous wrote:
Doug, I wonder if the BiLevel machines measuring 1cm below set values are lacking calibration. I sure could be wrong, but I thought clinician procedures for those BiLevel models (w/o proximal sensor) entailed calibrating the displayed or set pressure to match the pressure measured at the mask during machine set up.

Steve,

I can sjow the 1 CMS difference using a dial manometer & running at a 12 CMS pressure. The losses only show when the machine is in use not if the air pressure is measured and the air line blocked off.

I ran extensive test on this last year & repeated the results as often as I did the tests.

DSM

Thanks, Doug. There's a lot to be said for placing a proximal sensor at the mask.

Last nights Bipap AutoSV data


http://www.internetage.com/cpapdata/dsm ... 4apr08.pdf

The data shows the IpapMin up by 1 CMS but still showing AIs (but *no* HIs).

I'll up epap by 1 more CMS tonight.

DSM

Must say that I am getting what I call very solid nights sleep & am finding myself feeling far more alert.

I am not waking up quite so repeatedly like I was doing prior to using the AutoSV. Also I notice that the SpO2 charts are the most consistently stable I have seen in all the data I have gathered over the past 2 years.

Still need a good period of time to view all this data but as of now, this machine appears to me to have elevated the quality of my therapy noticably.

DSM

BALANCING ACT


Last night was an interesting one because the CMS average for peak Ipap jumped by 1 CMS to 16 CMS

I determined a long time ago that around 15 CMS was a critical cut-over point for me (and I suspect a lot of people) in that no matter what mask I used, 15 CMS was the point where leaks & squeaks start happening & last night was no exception.

I believe we all have this critical cut-over CMS setting & it is determined by a few factors but by far the biggest is the actual CMS pressureat 14-15-16 CMS. The lesser factors are the shape of the face, the type of mask (nasal, nasal prongs, fullface etc: ).

#2 correction here - original words were back to front ...
Also I have noticed that if my weight goes up a few kgs, this critical cut-over CMS goes down a little (I put this down to my face getting fatter & fitting the mask better) conversely if my weight goes down, there is a point where my face gets thinner & the mask doesn't fit as well & leaks & squeaks happen at lower pressures (say 14 CMS rather than 15-16 CMS).

Depending on the factors mentioned, this critical CMS point can vary up or down by 1 or even 2 CMS points but mostly 15 is pretty well it.

So last night my peak Ipap went to 16 & the squeaks started & they also woke me up a few times. The other bane of cpappers is aerophagia & thus far, even these higher pressures aren't bringing that effect on but it is also normal for me to experience aerophagia from 14 CMS up when on a CPAP & 16 CMS up when on a bilevel and with ipap is set to 15-16 CMS. So again the Bipap AutoSV seems to be better at preventing aerophagia than other machines I have used.

So there comes a point where chasing a better AHI reading can create more problems that it solves. To that end I will eventually drop my main epap & IpapMin settings back again by 1 CMS (to epap 10 and ipapMin to 13 or 14). But tonight I will up epap to 12 as one more experiment (just want to see 0.0 AHI so I can record it & point to it as being possible by fine tuning - even if those of us who understand the real usefulness of a AHI measure might say "so what"

Tuning this cut-over CMS point is why having a machine that can do partial adjustments (like 0.2 cms or at least 0.5 cms) is of value. (NOTE to Respironics designers, please please allow for partial adjustments of at least 0.5 CMS on the Bipap AutoSV (you do it on other Bipaps ! )).

Point of this post is to highlight that tuning for low AHI and putting up with the consequences of adjustments is a balancing act & there are times when the side effects outweigh the benefits one might seem to gain with increased pressure settings.

DSM


Cpap therapy killers include ...

1) Mask leaks & squeaks (they skew the therapy & wake the sleeper plus partner, being woken repeatedly disrupts sleep & minimises the benefits of cpap )

2) Air getting into the stomach - creates pains, causes burping, sleep arousals, flatulance (which in turn agitates partners)


D

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CPAPopedia Keywords Contained In This Post (Click For Definition): respironics, bipap, CPAP, AHI, aerophagia

The SpO2 data from the night 23-24 Apr 2008

http://www.internetage.com/cpapdata/dsm ... pr08-2.jpg 23-24 April 08.

Still looking very stable - nice narrow band of pulse data (the bursts are arousals or movement (turning over etc:)

The Spo2 is a little more varied than the night before but still looks pretty good.


While I am saying I am happy with that data, I really don't know if it is good or bad but from 2 years of collecting this info - this looks the most stable & consistent I have seen. I can only credit that to the Bipap AutoSV.

DSM

dsm wrote: Tuning this cut-over CMS point is why having a machine that can do partial adjustments (like 0.2 cms or at least 0.5 cms) is of value. (NOTE to Respironics designers, please please allow for partial adjustments of at least 0.5 CMS on the Bipap AutoSV (you do it on other Bipaps ! )).

Maybe the BiPAP Algorithm doesn't allow for more sensitive measurement? Could the proximal sensor tube on the Adapt SV have anything to do with incremental cms?

Banned