ResMed S9 coming soon?

[JohnBFisher]

Read the LED. ? What LED? !!

Some days even the glasses don't help!

Hey! I resemble that remark!!

[Guest]

Well since someone felt compelled to remove my post on the subject I will simply answer the original posters question.


March 1st.......enjoy!

[cpappro]

s9comfort dot com

[Ms.Snuffleupagus]

Thanks robmax.

And here it is in English at their UK site:

http://www.resmed.com/uk/products/s9_se ... nc=dealers

I just noticed that I can't open this link. It says that based on my location, I am unable to access this site and redirects me to the Canada/US Resmed site. I was able to view the UK site when Rested Gal first posted it.
Hummmm...

[dsm]

The specs as an image

DSM

[dsm]

Hmmmm

Questions that come to mind are ...

1. How is the FOT implemented (what frequecy) - I have seen all sorts of values discussed between 4 cycles/sec up to 3000.

2. I see they have implemented an SD card - am guessing that can go up to 8GB or 16GB but 2GB would still probably be tons of space (most currently offered SD adapters support up to 16GB i.e. mobile phones etc: that do it with MicroSD )

3. Clearly the wireless link is an accessory just like ResLink was - so is it WiFi or 3G ? - if it connects to the 'cloud' it could be either

4. What will the new ResScan software look like - guess we will see that soon enough

5. Wonder what the implications of that smaller dia tube will be - certainly a fraction cheaper to mfg

6. So now we have both F&P & Resmed with heated hoses (can't recall who else)



DSM

(can't say I find it an exciting shape )

[robmax]

If I remember right, the UK version had a brick . . .

[dsm]

In reviewing the data on the new machine it appears the the old A10 algorithm is no more.

The new algorithm with its FOT sensing no longer sees 10 CMs as a limitation in responding. According to the tech data sheet the older A10 based models would increase pressure even when Central apneas were occurring (up to 10 CMs). The new algorithm stays the same pressure any time it determines (via a FOT burst) that the detected apnea is a closed airway event else it increases during the following inspiration time. Also, it will raise pressure for Mixed Apneas.

What will be interesting is to see how quickly it will raise pressure. The older A10 was pretty quick.

The new machine appears to have added a way to reduce the noise of the air in the air circuit (the hose). This is one of the 'comfort' features plus of course the heated hose option.

DSM

[Slinky]

What is the FOT burst? I don't like the sound of that. I had enough trouble and never could successfully use my VPAP Auto in Spontaneous (straight bi-level) mode due to a "puff" at the end of inhalation, beginning of exhalation. One mask I tried whilst still on the S8 AutoSet Vantage had a tendency to "pump" up and down w/the change in pressure. I HATED it and couldn't get to sleep.

[dsm]

What is the FOT burst? I don't like the sound of that. I had enough trouble and never could successfully use my VPAP Auto in Spontaneous (straight bi-level) mode due to a "puff" at the end of inhalation, beginning of exhalation. One mask I tried whilst still on the S8 AutoSet Vantage had a tendency to "pump" up and down w/the change in pressure. I HATED it and couldn't get to sleep.

Hi Slinky

Well, a FOT burst is a pulse of vibrating air that is added onto the air being pumped down the airhose.

The key aspects of it are the frequency & the duration. It is difficult to make sense of the info in the tech spec
re the duration but the way FOT works can vary a little but lets assume this is how Resmed's FOT works

1) normal monitoring of breathing rate & minute ventilation
2) A slowing / cessation of air flow is detected during what should be the inspiration phase
3) A very low frequency signal (inaudible & hopefully at a frequency that is not be sensed by the sleeper) is added to the airflow by way of a transducer (like a tiny speaker)
4) The machine then looks for the rebound (reflection) of the signal & analyzes it for an added heartbeat signal

If the airway is open the heartbeat will be readily seen if not then it won't or will be very faint.

If the airway is open then *don't raise pressure* but flag the event in the data & wait it out.

If the airway is closed then use normal AUTO pressure raising adjustment during the next inhalation phase.
(this should happen for OSA & Mixed Events). Because a Mixed event involves the airway being closed at some
point, it is treated like an OSA event but flagged as a Mixed event.

DSM

#2

The above is purely me speculating on how it might be done on the S9. AFAICT there are 2 approaches - one looks for the heartbeat in the returned signal & the other looks at the signal to determine impedance in the airway. I have guessed that Resmed are using heartbeat sampling but this may not be exactly how it is being done. I have access to some highly relevant docs & will look deeper & post back what I find.

[aroche]

I can't speak to the Forced Oscillation or anything like that, but as a person with knowledge of firewalls and routers, if this thing wants to "phone home" with my data I will be blocking it real fast. I want the data for me to use, and if there is anything I need more info on THEN I will contact my Doc or RT.

I do have to say it does look pretty sleek and dressy, better than most pictures I have seen out there.

[dsm]

I can't speak to the Forced Oscillation or anything like that, but as a person with knowledge of firewalls and routers, if this thing wants to "phone home" with my data I will be blocking it real fast. I want the data for me to use, and if there is anything I need more info on THEN I will contact my Doc or RT.

I do have to say it does look pretty sleek and dressy, better than most pictures I have seen out there.

The wireless option is just that - a plug-in module. So if you don't buy that module / & you don't plug one into the machine,
it won't call anyone.



DSM

[Slinky]

Thanks, Doug - for the explanation of FOT.

[dsm]

Thanks, Doug - for the explanation of FOT.

Slinky

I have more but it is very challenging reading - here is one sample

****************
[0015] A sinusoidal (e.g. 4 Hz) pressure oscillation is applied at the input to the airpath, while flow and pressure is measured both at the input and output of the airpath. Based upon the two port model or the more theoretical hose drop model, the admittance is determined from the AC component of the patient airflow (found by subtracting the AC components of vent flow and leak) and the AC component of the mask pressure. The vent flow, in turn, is determined from an improved quadratic relationship to mask pressure in the case of the two port model, or a linearized calculation in the more theoretical hose drop model. The leak is determined from an estimated leak coefficient. The calculation of AC components of these quantities is improved over prior estimations by using Fourier sine and cosine components at the input oscillation frequency rather than by approximating an orthonormal set of functions by square waves.
****************

I'll post more as I work through it. I haven't seen ref to heartbeat sampling yet so am initially thinking that is not how they are doing it. Also I am surprised at the low frequency of the oscillations. Much lower that I had expected.

Cheers

Doug

#2
What I am reading is a 2007/8 patent the Resmed filed on determining a closed/open airway & this line here may be the key to how they are doing the sampling which is looking more like impedance sampling ...

"determining a patient admittance from said measured flow and pressure of air and said capacitive component; "

#3
This data leaves me more sure it is impedance based sampling as the periods mentioned match the times in the S9 Tech data sheet.

>>
[0063] All quantities are determined over a 6 second sliding window (the "admittance window") symbolically indicated as t=0. An admittance calculation can in principle be made at the algorithmic sampling frequency (say 50 Hz), but for clinical purposes this is not essential, and the calculation may be efficiently performed at the end of every 4 Hz cycle. Alternatively, calculation of admittance at 2 Hz or even 1 Hz frequencies is reasonable for clinical purposes.
<<

#4

It seems this 2007/8 patent was preceded by an earlier 2006 one & interestingly, this one says the prior patent used sampling at the mask whereas this new patent describes sampling at the flow generator so I am even more confident this is the technique in use.

>>
Prior Use of the Forced Oscillation Technique

[0009] "Detection Of Apnea And Obstruction Of The Airway In The Respiratory System" describes various techniques for sensing and detecting abnormal breathing patterns indicative of obstructed breathing, including the determination of airway patency by a forced oscillation technique (FOT) in which an oscillatory pressure waveform of known frequency is applied to a patient's airway and the magnitude of the component of an airflow signal at the known frequency induced by the oscillatory pressure waveform is calculated and compared with a threshold value. The present invention is an improvement of the methods and apparatus disclosed in the '345 patent.

[0010]The use of pressure oscillations at frequencies of the order of 4 Hz to determine airway patency was used in the ResMed AutoSet Clinical automatic CPAP device and the PII Plus. In these machines which used FOT, the pressure was measured at the mask, and the flow was measured very close to the mask, on the patient side of the mask vent. The present invention finds an advantage in measuring pressure and flow at or near the flow generator at least for analyzing the effect of the forced oscillation technique.

[0011]The prior art implementations of FOT are less accurate in distinguishing between closed and open apneas when there is present moderate leak and moderate "resistance" in the airpath between the flow generator and the patient. For example, a passive patient simulation consisting of a 3-4 cm H.sub.2O/(l/s) resistance, with an adjustable leak, would indicate an open airway at a leak of 15 l/min and a closed airway at a leak of 20 l/min. What is needed is a system that more accurately distinguishes between open and closed apneas. In particular what is needed is a system that goes beyond treating the components of the airpath simply as nonlinear resistances and which utilizes an algorithm that takes into account the capacitive and inductive components of the airpath impedance.
<<

[fadedgirl]

Awesome info, thanks DSM!!!