ResScan for Vista

[billbolton]

I called Resmed Technical Support in Sydney today and asked about the Vista compatible release of of ResScan. I was told that it is now scheduled for Mid-March.

I left my mobile phone number and they said they would call me when it becomes available.

Cheers,

Bill

[dsm]

I phoned them today to ask for their input on if the A10 algorithm used in the late 1990s (the Autoset-T) is still in use unaltered on the new Vantage II S8 just released.

Whenever I see the comments on the A10 algorithm, I can never find a reliable trace back to a source that doesn't refer to the old Autoset-T & the now obsolete S7 Spirit.

Tech support haven't got back to me yet - but if you ever get the chance to speak to them can you too ask about this - if they (as I believe they will) say that the software has evolved (as it has with other brands) can you get them to supply the details in an email.

If I get the info first I'll post it here.

Cheers

DSM

[ozij]

DSM,

This is from United States Patent 6,988,498
Berthon-Jones , et al. January 24, 2006
Administration of CPAP treatment pressure in presence of apnea

Inventors: Berthon-Jones; Michael (Leonay, AU), Farrugia; Steven Paul (Lugarno, AU)
Assignee: Resmed Limited (New South Wales, AU)

Appl. No.: 10/958,854
Filed: October 5, 2004

<snip>
Closed airway apneas are most likely to occur at low CPAP pressures, because high CPAP pressures splint the airway partially or completely open, whereas pressure-induced open airway apneas are most likely to occur at high CPAP pressures, at least partially because high CPAP pressures increase lung volume and thereby stimulate the Hering-Breuer reflex, leading to inhibition of breathing. Therefore, the lower the existing CPAP pressure, the more likely an apnea is to be of the closed airway variety, and the more appropriate it is to increase the treatment pressure, whereas the higher the existing CPAP pressure, the more likely an apnea is to be of the open airway variety, and the more appropriate it is to leave the CPAP pressure unchanged. Generally apneas of less than 10 seconds duration are regarded as non-pathological, and there is no need to increase CPAP pressure, whereas very long apneas require treatment. The present invention will correctly increase the CPAP pressure for most closed airway apneas, and correctly leave the CPAP pressure unchanged for most open airway apneas.

The present invention can be combined with an independent pressure increase in response to indicators of partial upper airway obstruction such as snoring or changes in shape of the inspiratory flow-time curve. In this way it is possible in most subjects to achieve pre-emptive control of the upper airway, with pressure increases in response to partial upper airway obstruction preventing the occurrence of closed airway apneas. In the minority of subjects in whom pre-emptive control is not achieved, this combination will also correctly increase the CPAP pressure in response to those closed airway apneas that occur at low CPAP pressure without prior snoring or changes in the shape of the inspiratory flow-time curve. Furthermore, the combination will avoid falsely increasing the CPAP pressure in response to open airway apneas induced by high pressure.


<snip>

4. A method for the administration of CPAP treatment pressure comprising the steps of: supplying breathable gas to the patient's airway at a treatment pressure; determining a measure of respiratory airflow; and determining the occurrence of an apnea from a reduction in the measure of respiratory airflow below a threshold, and, if having occurred, (i) determining the duration of the apnea; and (ii) increasing the treatment pressure by an amount which is an increasing function of the duration of the apnea, and a decreasing function of the treatment pressure immediately before the apnea.

5. The method of claim 4, wherein the increase in treatment pressure is substantially zero if the treatment pressure before the apnea exceeds a pressure threshold.

6. The method of claim 5, wherein the increase in pressure below the pressure threshold is an increasing function of the duration of the apnea, multiplied by the difference between the pressure threshold and the current treatment pressure.

7. The method of claim 6, wherein said increasing function of apnea duration is linear on apnea duration.

8. The method of claim 5, in which the pressure threshold is substantially 10 cm H2O.

All added emphasis mine.

I think there are enough names and numbers here to give you a handle on further searches, and it does indicate Resmed is still thinking along the same lines.

Since this patent includes a sensor tube, I wonder if it's not part of the ASV,


It falls in with this: VPAP adapt SV technology

• the underlying end expiration pressure (EEP) is clinician
adjustable from 5 to 10 cm H20, helps reduce obstructive
events and can also reduce central events.
Support when it’s needed
When a central hypopnea/apnea occurs and ventilation
suddenly drops below the target:
• pressure support rapidly increases over a few breaths to
keep ventilation at the target
• the default maximum pressure support value of 10 cm H20
will fully ventilate a centrally apneic patient with an open
airway and normal lungs.

O.

Edited to add bold on filing date.
_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): resmed, CPAP

[billbolton]

Filed: October 5, 2004

Why did you choose to highlight the issue date rather than the filing date?

Not to mention totally ignoring the Foreign Application Priority Data of Nov 07, 1997!

This is just the US application and grant for patent coverage of a method which had been initially patented elsewhere several years previously.

It indicates nothing much at all about whether the method is still the sole algorithmic basis, or even any basis, of any current Resmed model.

As far as I can tell Resmed has not made any mention at all of utilising the "A10" algorithm since circa 2003.

Cheers,

Bill

[ozij]

Filed: October 5, 2004

Why did you choose to highlight the issue date rather than the filing date?

Cheers,

Bill

Distraction - I've fixed it. -

Edit 2:This was my response to Bill's pre-edited post.

O.

[ColinP]

Oz, you do find the most interesting things! Which search engine do you use (or is it just that I'm clueless and nothing to do with my version of google?)

Colin

[ColinP]

I see from reading the patent that the whole 'don't increase pressure for an apnea above 10cm' is not strictly correct. It will not increase pressure if the pressure before the start of the event was above 10cm. That means that it will go over 10, but only if it was below 10 before the apnea. Not quite the same as I read in some of the recent posts on this subject. Not radically different, but possibly significant.

Colin

[ozij]

Filed: October 5, 2004

Why did you choose to highlight the issue date rather than the filing date?

Not to mention totally ignoring the Foreign Application Priority Data of Nov 07, 1997!

This is just the US application and grant for patent coverage of a method which had been initially patented elsewhere several years previously.

It indicates nothing much at all about whether the method is still the sole algorithmic basis, or even any basis, of any current Resmed model.

As far as I can tell Resmed has not made any mention at all of utilising the "A10" algorithm since circa 2003.

Cheers,

Bill

[ozij]

Oz, you do find the most interesting things! Which search engine do you use (or is it just that I'm clueless and nothing to do with my version of google?)

Colin

I use the Google toolbar and Google scholar.
e.g. (I'm putting the terms in brackets) [resmed + algorithm] (the space before the second word was a lucky coincidence...)


I also change the search terms when a document has a more promising one. So I changed [cpap +"central apnea"] to [cpap +"open airway"] when I ran into the latter term.

It you've ever learned to focus good binoculars - you start with the major focus for one eye, and then do the micro focus for the other eye - my search strategy is more or less like that.

O.

[dsm]

My recollection of A10 was what ColinP said, and IIRC that it would only go up 3 CMS max if the event started while the machine was below 10.

IIRC the original rationale was that increasing pressure past a particular point (3CMS when already near 10CMS) and that this was not producing clearing of the event 'pattern', that any increase in CMS was considered to be going to cause more problems for the user than it was solving as the event pattern was looking like either a CA or a pressure induced CA (and was not responding).

I believe there are a few papers published on the problem of trying to treat a central as an obstruction.

So rather than post references to years old data (which may be right but just as probably may not be), I took the view I would talk to someone at Resmed (once they return the call) to clarify these points ...

1) The status of A10 in the current models
2) How the machines progress CMS past 10 in the current models.
3) How does their machine differentiate a Central from an OSA event.

DSM

[dsm]

<snip>


Since this patent includes a sensor tube, I wonder if it's not part of the ASV,


It falls in with this: VPAP adapt SV technology

• the underlying end expiration pressure (EEP) is clinician
adjustable from 5 to 10 cm H20, helps reduce obstructive
events and can also reduce central events.
Support when it’s needed
When a central hypopnea/apnea occurs and ventilation
suddenly drops below the target:
• pressure support rapidly increases over a few breaths to
keep ventilation at the target
• the default maximum pressure support value of 10 cm H20
will fully ventilate a centrally apneic patient with an open
airway and normal lungs.

O.

Edited to add bold on filing date.

[ozij]

I phoned them today to ask for their input on if the A10 algorithm used in the late 1990s (the Autoset-T) is still in use unaltered on the new Vantage II S8 just released.

Whenever I see the comments on the A10 algorithm, I can never find a reliable trace back to a source that doesn't refer to the old Autoset-T & the now obsolete S7 Spirit.

Tech support haven't got back to me yet - but if you ever get the chance to speak to them can you too ask about this - if they (as I believe they will) say that the software has evolved (as it has with other brands) can you get them to supply the details in an email.

If I get the info first I'll post it here.

Cheers

DSM

So, a week has passed, has Resmed tech support answered?

O.

[ozij]

Posted: Thu Feb 28, 2008 9:35 am

I phoned them today to ask for their input on if the A10 algorithm used in the late 1990s (the Autoset-T) is still in use unaltered on the new Vantage II S8 just released.

Whenever I see the comments on the A10 algorithm, I can never find a reliable trace back to a source that doesn't refer to the old Autoset-T & the now obsolete S7 Spirit.

Tech support haven't got back to me yet -

No new info yet?

O.

[hobbs]

I called Resmed Technical Support in Sydney today and asked about the Vista compatible release of of ResScan. I was told that it is now scheduled for Mid-March.

I left my mobile phone number and they said they would call me when it becomes available.

Cheers,

Bill

Bump. I do not want to get the XP version IF a Vista one is on the "near" horizon.

[BarryKaraoke]

What is the ResScan upgrade policy...if any?

If you own 3.3 and they release a vista fix, will they give it to you free? Or are you expected to pay the entire amount again?