Bi-Level Settings Questions ...

[Slinky]

Okay. I've got almost 2 months under my belt now w/this bi-level auto ... time to start exploring, don't you think? I think so!

Settings are EPAP 8 cms, IPAP 13 cms. Not hard to understand and figure that one out.

But - then there are all these options.

There's the obvious: Mode (choices are VPAP, Spontaneous and CPAP). I'm set at VPAP but am rather curious about this Spontaneous mode. I'm familiar w/the good ole CPAP mode, of course.

But then there's this Pressure Support set at 4.0. Now what the devil is THAT all about?

There's the Ti Maximum 4.0 s. Ti = Tidal volume which is the amount of inhaled or exhaled in one breath.
And the Ti Minimum 0.5 s. These are measured in mls so I ASSUME the s = seconds.
But what occurs if one changes one or both settings? Why would one do so?

Then there is that Exhalation setting, currrently set at Medium, but also w/Low and High options.
What effect would a change to High or Low have? Why would one make a change?

And there is the Trigger set at Medium, again w/additional options of High or Low. I have ABSOLUTELY no idea of what these are all about except perhaps they only pertain to when in Spontaneous mode. But what affect would changes to these settings have and what would inspire one to change them?

And Cycle, again set at Medium w/the additional High and Low options. Same question, what affect, why change, do these only apply to Spontaneous mode?

Aha! A familiar option! Maximum Settling. I quickly changed THAT from 45 minutes to 15 minutes!

I'm curious and not very confident that this new sleep doctor even knows the answers. Plus he's the one who told me I asked "too many unnecessary questions". We've pretty much settled that situation but it certainly doesn't inspire me to bother asking him about much of anything.

[Snoredog]

so what's up with that deal?? now?

You mean to tell us after all that "they can do no wrong" boasting you have done Resmed didn't trust you with the manual??

LOL LOL LOL (please stop me my side is hurting) somehow that doesn't surprise me!

So how many of them down under machines does this VPAP make that hasn't worked?

2? 3?

LOL, sounds like a machine problem to me but then I already told you that didn't I?

hehehe

[-SWS]

May be able to help with some of those, Slinky..

But then there's this Pressure Support set at 4.0. Now what the devil is THAT all about?

That's the pressure gap between IPAP and EPAP (PS = IPAP - EPAP).

Ti Maximum 4.0 s. Ti =

Your Maximum allowed inspiratory time happens to be set at 4.0 seconds

And the Ti Minimum 0.5 s

Your Minimum allowed inspiratory time is set to half-a-second

Then there is that Exhalation setting, currrently set at Medium, but also w/Low and High options.

This sounds like a comfort setting for the Resmed "Breathe Easy" feature (perhaps a comfort feature similar to Respironics BiFlex).

And there is the Trigger set at Medium, again w/additional options of High or Low.

This is likely a sensitivity setting (regarding patient-breath) to trigger the machine to begin IPAP (this is a carry-over trigger/cycle sensitivity setting).

And Cycle, again set at Medium w/the additional High and Low options.

Probably a sensitivity setting (regarding patient-breath) that cycles the machine to begin EPAP (this is a new trigger/cycle sensitivity setting).


Please don't take those answers to the bank since many are just guesses!

[Slinky]

Oh, SnoreDog, you ole fart, I got the VPAP Auto from the local DME supplier and you know darn well the locals don't give us the Clinician's Manual. I was lucky I got the guy to leave the Quick Set Up card. I'm happy w/this VPAP Auto, quit trying to burst my bubble or I'll smack you w/my broom!!! (Besides ... read my manual?? Duh. That is too, too logical!

SWS, thanks for your well thought out reply. Your reasoning and explanation makes sense. But SnoreDog just might be right. (Gads, I hate to admit that! ) Maybe I SHOULD have read thru the manual more carefully than I have. Maybe there is a good explanation of each of the issues I raised that just didn't sink in when I browsed thru it. I'm ashamed to admit I never did sit down and carefully read thru it but rather just browsed thru the highlights. I guess I just didn't expect this much difference from my Elite and Vantage. Over confidence maybe 'cause I really did read thru those manuals. Color me red-faced!!! Me, who has so often preached read your manual, read your mask literature.

[-SWS]

So who reads the instructions these days?
.

[dsm]

Slinky

SWS beat me to it - his answers are pretty well spot on. The Vpap III (Enhanced model) had 2 sets of sensitivity for transitions - from ipap to epap & epap to ipap & from what I can see your machine has these too.

Pressure support is the common word used to describe the amount of pressure added in support of epap to bring pressure up to ipap. The SV models have a 2nd level of Pressure support thus in my eyes making them the 1st tri-level machines

Their 2nd level of support is called IpapMax and is what the Ipap can go up to if the machine thinks Ipap alone is not keeping the sleeper breathing the reight volume of air (flow).


In general, trigger relates to the sensitivity of the airflow used to initiate the epap to ipap switch, risetime adjusts how fast the transition takes place and cycle is when the machine goes from ipap back to epap.

Applying these principles to your machine I'd say that trigger & cycle are the same. But exhalation relates to risetime as well as the speed of return to epap as this in turn impacts the EasyBreath feature. Is there a 1,2 & 3 setting for EasyBreathe ? (does your model have EasyBreathe ?).

DSM

[Slinky]

Thanks, DSM. Yup, it does have EasyBreathe technology according to the literature.

And now I have a REAL CONFESSION to make ...

I have the Clinician's Manual in .pdf

I'm reading thru it right now - I forgot a VERY KIND SOUL had e-mailed it to me and hadn't gotten around to printing it out and putting it into a notebook.

When SnoreDog kicked me in the shins and tried to pick on my precious Resmed again the dim light in my beady old brain started to come on and I went searching amongst my Resmed e-mails .......

I haven't been able to come up w/any excuse except senility .... yet. If I come up w/a reasonable excuse I'll post it.

[Snoredog]

[quote="Slinky"]Oh, SnoreDog, you ole fart, I got the VPAP Auto from the local DME supplier and you know darn well the locals don't give us the Clinician's Manual. I was lucky I got the guy to leave the Quick Set Up card. I'm happy w/this VPAP Auto, quit trying to burst my bubble or I'll smack you w/my broom!!! (Besides ... read my manual?? Duh. That is too, too logical!

SWS, thanks for your well thought out reply. Your reasoning and explanation makes sense. But SnoreDog just might be right. (Gads, I hate to admit that! ) Maybe I SHOULD have read thru the manual more carefully than I have. Maybe there is a good explanation of each of the issues I raised that just didn't sink in when I browsed thru it. I'm ashamed to admit I never did sit down and carefully read thru it but rather just browsed thru the highlights. I guess I just didn't expect this much difference from my Elite and Vantage. Over confidence maybe 'cause I really did read thru those manuals. Color me red-faced!!! Me, who has so often preached read your manual, read your mask literature.

[Slinky]

I know, SnoreDog, and I really didn't expect you to torture yourself by resisting.

Its hard enough for you to resist a Resmed post much less a Resmed post w/my name tacked to it. I'm so irresistable, you know.

Actually, nothing is going wrong. I'm just getting less intimidated by all these unfamiliar terms and stats and curiosity is taking over. I figger I've gotta have some understanding of what they are and do before I really understand their data in the software. A lotta that data I've been ignoring 'cause I wasn't sure of their significance, etc.

And, no, I am NOT blonde and never have been, naturally or outta the bottle.

[dsm]

Slinky,
(actually for anyone interested as I know slinks has this off pat by now )

Some interpretations/comments

1) The Vpap Auto uses the A10 algorithm - that is for pure apneic events (blocks), it won't raise pressure above 10 CMS to avoid a false interpretation of a central. But it will still raise pressure if apneic pre-cursor events are detected (snore and pre apneic flow lims).

2) The Spont mode is normal bilevel mode with an epap and an ipap.

3) VAuto Mode - epap and ipap are adjusted between EpapMin & IpapMax and Pressure support (see manual info below).

DSM


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Operating Modes
The VPAP Auto provides three therapy modes: CPAP, Spontaneous (S) and VAuto. In CPAP mode a fixed pressure is delivered. VAuto and S modes are considered bilevel therapies with a higher pressure provided during inspiration (IPAP) and a lower pressure during expiration (EPAP). This expiratory pressure relief can make therapy more comfortable for patients by reducing breathing effort.

CPAP Mode
In CPAP mode the VPAP Auto delivers fixed-positive pressure room air via tubing to the mask that is worn by your patient. The continuous air stream "splints" open the upper airway, preventing airway collapse.

S Mode
In S mode, you may set two treatment pressures—one for inspiration (IPAP) and one for expiration (EPAP). The VPAP Auto senses when the patient is inhaling and exhaling and supplies the appropriate pressures accordingly. The difference between IPAP and EPAP levels helps determine the tidal volume.

VAuto Mode
The treatment pressure required by your patient may vary through the night, and from night to night, due to changes in their sleep state, body position and airway resistance. In VAuto mode the VPAP Auto provides only the pressure required to maintain upper airway patency. The bilevel waveform gently increases pressure on inspiration and decreases on expiration to maximize comfort. You may set the difference between the inspiratory and expiratory pressures using the Pressure Support (PS) setting (see “Pressure Support”).

AutoSet pressure is a conceptual value. The patient is delivered an auto-titrated inspiratory and expiratory pressure based on the AutoSet algorithm, which has the AutoSet pressure as its midpoint. The AutoSet pressure is reported in data management and efficacy results information. You may also restrict the range of pressures in which the AutoSet algorithm operates, using the Min EPAP and Max IPAP settings respectively (see “Min EPAP and Max IPAP” on page 9). The VPAP Auto analyzes the state of the patient’s upper airway on a breath-by-breath basis and the AutoSet algorithm adjusts the AutoSet treatment pressure within the allowable range, according to the degree of airway obstruction. The AutoSet algorithm adjusts treatment pressures according to apnea, snore and inspiratory flow limitation.

In VAuto and S modes, the VPAP Auto senses when the patient breathes in and when the patient breathes out. The device follows the patient’s spontaneous breathing rate to supply the appropriate pressure.


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Apnea
Treatment pressure increases based on the duration of the apnea event (defined as 75% decrease in recent ventilation, averaged over 100 seconds, for at least 10 consecutive seconds).

The AutoSet pressure will not rise above 10 cm H2O when an apnea is detected to prevent an inappropriate response to central apneas. Initially, the pressure increases rapidly, but the rate of increase diminshes as AutoSet pressure approaches 10 cm H2O. When no further apneas are detected, therapy is reduced towards the minimum pressure (the set Min EPAP and Pressure Support) over a 20-minute time period.

Inspiratory Flow Limitation
Flow limitation indicates silent partial obstruction of the airway and usually precedes snoring and airway obstruction. Detection of this flow limitation enables the VPAP Auto to increase the pressure before obstruction occurs, making treatment pre-emptive. If no further flow limitation is detected, therapy is reduced towards the minimum pressure over a 20-minute time period.

Snore
The AutoSet algorithm assigns an arbitrary value between 0 and 2.0 to the
average amplitude of the snoring detected for the past 5 breaths. A value of 1.0 is equivalent to approximately 75 dBA, measured 4" (10 cm) from the nares.

Treatment pressure increases by up to 0.2 cm H2O per second (proportional to the severity of the snore) for snore that is at least 0.2 snore units. When snore is less than 0.2 snore units, therapy is reduced towards the minimum pressure over a 20-minute time period.

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Triggering and Cycling
(S mode, VAuto mode) To provide comfortable treatment it is important to maximize the synchronization between the breathing rhythm of the patient and the pressure pattern supplied by the device. Synchronization is achieved by the device quickly and reliably detecting when the patient inhales and when the patient exhales. The VPAP Auto uses pressure and flow transducers to accurately sense the patient’s inhalation and exhalation efforts.

The VPAP Auto detects the beginning of the patient’s inspiratory effort by measuring the increase in flow. When inspiratory flow increases above a certain level the device changes from EPAP to IPAP. This change from EPAP to IPAP is called triggering.

Similarly, the VPAP Auto changes from IPAP to EPAP when the inspiratory flow decreases below a certain level. The change from IPAP to EPAP is called cycling.

IPAP and EPAP
(S mode) In S mode, you can set values for IPAP and EPAP. The difference between IPAP and EPAP is known as Pressure Support (PS).

The maximum PS value is 10 cm H2O. The EPAP setting will automatically be constrained to ensure the PS limit (10 cm H2O) is not exceeded. The IPAP setting will be preserved. When EPAP is automatically constrained, a message will appear on the LCD.


Rise Time Adjustment
(S mode) Rise Time is the time taken for the pressure to increase from EPAP up to IPAP. Rise Time can be set to MIN (the fastest Rise Time) and then in 50-unit increments from 200 to 900. This will control the rate of pressure increase when the VPAP Auto switches from EPAP to IPAP.

Generally this feature is adjusted to achieve maximum patient comfort. The patient should feel that they are receiving adequate flow but not be startled by each transition to the IPAP level. The higher the Rise Time setting, the longer it takes for the pressure to increase from EPAP to IPAP. If the patient has a high ventilatory demand then the Rise Time should be set to MIN, as this is the fastest Rise Time setting.

Notes:
• The Rise Time should not be set so that it is longer than the time spent in IPAP (otherwise the IPAP pressure would never be reached). For this reason, Rise Time cannot exceed the Ti Max setting.
• The Rise Time scale can be approximately read as ‘milliseconds’ (eg, 200 is approximately 200 ms). The actual rise time achieved is influenced by several factors, such as compliance, resistance, leak, pressure differential, and patient breathing patterns.
• Rise Time can not be set so that it is longer than the Ti Max setting (otherwise the IPAP pressure would never be reached).

Min EPAP and Max IPAP
(VAuto mode) These settings allow you to restrict the range of pressures in which the AutoSet algorithm can operate, using the Min EPAP and Max IPAP settings (see Figure 3, Setting Min EPAP and Max IPAP pressures in VAuto mode, on page 9 and Figure 4, Pressure Support in VAuto mode, on page 10).

The AutoSet pressure will vary across the session according to the patient’s needs. It responds to apneas, snoring and flattening of the patient’s flow curve.

Min EPAP and Max IPAP can be adjusted to limit the upper and lower AutoSet pressure limits.

The pressure range in VAuto mode is 4–20 cm H2O.

Note: The device will stay at Min EPAP (with the selected amount of pressure support) during the Settling time (if selected) at the beginning of a session.

Pressure Support
(VAuto mode) Pressure Support allows you to set the difference between inspiratory and expiratory pressure. This value can be adjusted for patient comfort. A maximum PS value of 10 cm H2O can be selected.

In VAuto mode, if Pressure Support is above 6 cm H2O, treatment efficacy may be reduced.

Note that the actual delivered pressures will be AutoSet pressure ± 0.5 x pressure support (as set by the clinician).

Exhalation
(VAuto mode) You can adjust the Exhalation rate so the rate of pressure drop is at a level that is most comfortable for the patient. The medium rate is usually most comfortable. If required, you can select a rate that is faster or slower.


DSM

[Slinky]

Thanks, DSM. Yep, I've read thru them in the Manual and again in your post. Several times in fact. I'm having a problem wrapping my stiffening ole brain around some of it and really grasping what's being said, much less remembering it. But ... time heals all wounds. I'll blame it on having out of town company the last two weeks and worry about it later. All is going well w/this VPAP so what the hay. Sometimes ignorance can be bliss .. at least for the time being.

[dsm]

Thanks, DSM. Yep, I've read thru them in the Manual and again in your post. Several times in fact. I'm having a problem wrapping my stiffening ole brain around some of it and really grasping what's being said, much less remembering it. But ... time heals all wounds. I'll blame it on having out of town company the last two weeks and worry about it later. All is going well w/this VPAP so what the hay. Sometimes ignorance can be bliss .. at least for the time being.

Slinky,

This should b fairly easy then, just highlight which bit you would like clarified & I assure you the team (Snoredog and all ) will help explain it.

DSM

[Slinky]

Thanks, DSM. I will most likely do just that. HOwever, for the time being I don't know how long my friend will be staying so I'm not gonna be able to concentrate and really "get into" this for the time being. She's visiting her mom and brother up north this weekend after we "did" the dog show yesterday so I'm gonna just "chill out" and enjoy the beautiful weather.