Newbie on AVAPS

Banned wrote:

Snoredog wrote:
<snip>

It will prepare you for PC AVAPS mode when you get the BiPAP AVAPS.

Banned

Unlikely now that the Aust $ has gone through the floor - cost of an AVAPS just toooo high.

But, I will have a go at setting a backup rate & take the machine off BPM=AUTO.

The patient triggered breathing never worries me on the Bipap Auto SV as if you compare the heart rate data from the SpO2 chart
to the triggered breaths info you can see that most of them are after a normal arousal and thus not any serious sign of respiratory
irregularity.

DSM

On the topic of Tidal Volume & Over ventilation - these charts show BPM up to 26 & 44 (hyperventilation) & Tidal volume as high as 19 L/Min with average 11 L/min (normal ventilation would be just over half that).

So here are what I would call classic examples of hyperventilation, over ventilation, very high BPM and I strongly suspect hypocapnia and centrals induced by the hypocapnia (based on that the backup rate was set to 6 but the machine regularly kicked in because BPM had fallen below the back up rate even though BPM was also averaging in the 20s).

Firstly one might ask why these rather high BPM and MV rates and High AHI
1) The sleep studies clinic wrote 15 for Ipap (titration) when they should have written 13
2) Epap was set too low (shd have been 10) due to lack of understanding at the time
2) The gap between Epap and Ipap was too high contributing to over ventilation
3) Risetime was set too fast

> http://www.internetage.ws/cpapdata/menu_110107.html


This chart shows Epap (set = 10) corrected but the gap still to high & risetime too high ...
> http://www.internetage.ws/cpapdata/menu_120107.html (BPM hits 39 !!! - back rate is only 6 - also see the serious desats )


This chart shows Epap (10) & Ipap (13) at proper settings but still risetime is too high (BPM hits 44 - severe hyperventilation - but backup rate was only 6 !! - so I believe the machine in order to overcome hypocapnia induced centrals was kicking in to trigger ventilation 1.5% of the time or approx 20.7 times an hour (20 * 60 * 1.5%). The AHI score shows 11.8 HI events an hour.
> http://www.internetage.ws/cpapdata/menu_130107.html

Compare now with this chart from early this month using a Vpap Adapt SV - Tidal Volume is almost normal & rate sticking at av of 15 BPM
http://www.internetage.ws/cpapdata/dsm- ... 7nov08.pdf


But despite these numbers SpO2 looks fine and Pulse Rate is acceptable in all these charts
But I believe these charts should indicate that risetime is a critical factor in tuning a bilevel even when epap & ipap are ok and when SpO2 data looks ok.
What is missing is a Co2 reading !!! - that would have alerted to the problem of setting risetime too fast.

DSM

Banned wrote: Doug,

If you haven't already done so why not trial no 'Auto' BPM? Let's have you set your old Breath Rate of 6, perhaps Inspiration Time of 1.8, and a Rise Time of 3 (or 4). It will prepare you for PC AVAPS mode when you get the BiPAP AVAPS.

I'm back on PC AVAPS mode, tonight.

Banned

you mean BPM=Auto? It think that is where he is at. When we talk about BPM above and BPM=14, that is what the machine IS reporting from the SV mode or spontaneous mode. It is the avg. the machine seen for the nightly session. If he went to a manual or fixed BPM mode such as 6 (not recommended on that machine) that would only come into play if he went from Patient triggered breathing to machine triggered breathing and going from 14 (his avg.) to 6 would be like hitting a brick wall. Goal is to avoid going to the machine triggered mode (if you are doing things right on the spontaneous or SV side). BPM=6 may be programmable into a machine but it is impossible to maintain. if you divide those 6 breaths into a minute's time that is 10 second breaths, if you split that into I:E that is 5 seconds for Inhale and 5 seconds for exhale including any pauses. The Adapt SV's targeted peak will NEVER exceed 3 seconds, if it does it cycles or goes into machine triggered mode.

Right now, Doug's respiration is way up there where volumes seen are high but that might be right for his height. If you slow BPM down from say his avg. 14 you only increase those volumes even higher. Breathing too deeply can also put you in hypocapnia. There is a fine line between hypocapnia and hypercapnia rapid breathing can be seen with both. This is also why I believe the BPM or backup mode is somewhat misunderstood from what I have read here (not in this thread but in others).

I think Doug is on the right track and I think he can manipulate it to eliminate that last PB seen on his reports. Like I said get that Patient triggered breath line to be one smooth line and you will have it.

Doug,

My opinion is you did much better with the settings used here:

http://www.internetage.ws/cpapdata/dsm- ... 1oct08.pdf

Only like 3 events logged, report shows 1 central apnea, 1 obstructive hypopnea and 1 central hypopnea.

The report from last night shows mainly central events. Keep in mind the central events can be caused by breathing or just show up
during transitional stage changes. Both not really bad just the one on Oct had fewer events.

Your next question probably will be how can I tell the difference between the obstructive and central events? especially the hypopnea?

If you magnify the report and align and follow the events down to the Patient Triggered breathing you will see some events caused BPM to kick in and others did not. Since on that machine BPM mode ONLY controls central dysregulation or central events, dips will be seen on that line for each central event. The obstructive events won't cause it to go to BPM mode (in which case you have it set for Auto).

The important thing to know about that is they are central and not go chase them with increased pressure thinking they were obstructive.

There are a few blips on that Patient triggered line with no events corresponding to them above, I suspect the machine is gaining spontaneous info and testing BPM mode sorta like the AutoCPAP circuit on the Auto.

I don't know how you feel between those two, but going by the raw numbers I'd say these settings work better for you:

EPAP=11
IPAP MIn=14
IPAP Max=20
BPM=Auto
------------------------------------
Avg. working peak IPAP = 16.0
Avg. BPM seen 15.6

Patient Triggered Breaths=99.6

Can't get much better than that, volumes are up, AHI=2.0 and I would call that one success. If it changes from that
it could be due to allergies or something else.

Banned wrote:We have another winner.. last night's data scored 0 AHi in PC AVAPS mode!

11-14-08 settings:
Mode: PC AVAPS
EPAP: 15
IPAP Min: 19
IPAP Max: 25
Tidal Volume: 520 ml
BPM: 6
Inspiration Time: 1.6sec
Rise Time: 4

Okay, I understand what you are using above, but when you compare your result below to the above,
it is totally ignoring your BPM: 6 when you compare what you dialed in to the machine and what it
actually came up with below, you really can't ignore that finding if what is shown below
is an average finding.

Banned wrote: Encore results:
Apnea Count: 0
Average EPAP: 15
Average IPAP: 19.7
Average (Exhaled) Tidal Volume: 518.3 ml
Average BPM: 16.1

The improvement is that I sleep better and have a guaranteed increased Tidal Volume of 4-5% over the Adapt SV.

Tonight, I'm going back to retrial S/T (only) mode at EPAP 15 and IPAP 19, Inspiration Time 1.6, Rise Time 4 (previously IPAP 14, EPAP 17, Inspiration Time 3sec, Rise Time 6). I want to get another read on actual Tidal Volume in S/T (only) mode since I never used EPAP 15 and IPAP 19, and I was using those ridiculous Inspiration Time 3 sec and Rise Time 6.

Banned

That will be interesting one to see, does the S/T mode give you avg. results like the above?

Snoredog wrote:Doug,

My opinion is you did much better with the settings used here:

http://www.internetage.ws/cpapdata/dsm- ... 1oct08.pdf

Only like 3 events logged, report shows 1 central apnea, 1 obstructive hypopnea and 1 central hypopnea.

The report from last night shows mainly central events. Keep in mind the central events can be caused by breathing or just show up
during transitional stage changes. Both not really bad just the one on Oct had fewer events.

Your next question probably will be how can I tell the difference between the obstructive and central events? especially the hypopnea?

If you magnify the report and align and follow the events down to the Patient Triggered breathing you will see some events caused BPM to kick in and others did not. Since on that machine BPM mode ONLY controls central dysregulation or central events, dips will be seen on that line for each central event. The obstructive events won't cause it to go to BPM mode (in which case you have it set for Auto).

The important thing to know about that is they are central and not go chase them with increased pressure thinking they were obstructive.

There are a few blips on that Patient triggered line with no events corresponding to them above, I suspect the machine is gaining spontaneous info and testing BPM mode sorta like the AutoCPAP circuit on the Auto.

I don't know how you feel between those two, but going by the raw numbers I'd say these settings work better for you:

EPAP=11
IPAP MIn=14
IPAP Max=20
BPM=Auto
------------------------------------
Avg. working peak IPAP = 16.0
Avg. BPM seen 15.6

Patient Triggered Breaths=99.6

Can't get much better than that, volumes are up, AHI=2.0 and I would call that one success. If it changes from that
it could be due to allergies or something else.

Snoredog,

I agree too & tonight will be right back to epap=11 ipapmin=14 risetime=3 & will leave BPM=AUTO am certain the results will look pretty good tomorrow (tis 10pm here so am off to dreamland).

Doug

Snoredog wrote:Only like 3 events logged, report shows 1 central apnea, 1 obstructive hypopnea and 1 central hypopnea.

The report from last night shows mainly central events. Keep in mind the central events can be caused by breathing or just show up
during transitional stage changes. Both not really bad just the one on Oct had fewer events.

Your next question probably will be how can I tell the difference between the obstructive and central events? especially the hypopnea?

If you magnify the report and align and follow the events down to the Patient Triggered breathing you will see some events caused BPM to kick in and others did not. Since on that machine BPM mode ONLY controls central dysregulation or central events, dips will be seen on that line for each central event. The obstructive events won't cause it to go to BPM mode (in which case you have it set for Auto).

The important thing to know about that is they are central and not go chase them with increased pressure thinking they were obstructive.

Without ballistocardiography or forced oscillation technique, how does it know they are central events? All that thing sees is a straight line.

SAG

Snoredog wrote: That will be interesting one to see, does the S/T mode give you avg. results like the above?

S/T (only) mode:
11-15-08 settings:
Mode: S/T
EPAP: 15
IPAP: 19
BPM: 6
Inspiration Time: 1.6sec
Rise Time: 4

Encore results:
Apnea Count: 2
Average EPAP: 15
Average IPAP: 19
Average (Exhaled) Tidal Volume: 559.7 ml
Average BPM: 16.1

AVAPS does not allow the luxury of setting BPM = 'Auto' or BPM = 'OFF', other than perhaps Spontaneous Mode (S, S AVAPS).

In almost every mode you need to dial-in a Breath Rate (BPM). I have dialed in a BPM = 6 in every mode since pulling the AVAPS back out of the closet (BPM = 6 was a number I got from one of dsm's earlier posts). A setting of 6 Breathes Per Minute functionally 'disables' a Back-Up Rate and allows for pt. initiated spontaneous breaths in S/T, S/T AVAPS, and PC, PC AVAPS modes.

BPM = 6 obviously would not work well in Timed Mode (T, T AVAPS0.

To date, the hybrid Bi-level/NPPV capability of AVAPS adequately compensates for the periodic breathing (gasping) episodes without a 'functional' Back-Up Rate, if you will. I have had no known periodic breathing episodes. Breathing on AVAPS appears to be deep, solid, and very stable.

Banned

Banned

Re 6 BPM, I too chose that back in my bilevel days as the issue I had (& so does banned) is that if we were breathing through our congested nasal passages, 10 BPM is just too fast. But if we wanted the confidence of some backup rate 6 was at least there even if it is a rather slow one.

My data from last night is back to the stability I was after - felt that sleep was 'sound' and not 'light' as happens with too fast a risetime & that I am now associating with varying levels of hypocapnia. To me, 'light' sleep is now a warning of some level of hypocapnia, but too deep a sleep is the opposite, so the balance is tuning the therapy to some mid point and if the daytime is good (no drowsiness & a clear head) then the right point has been located.

The main point from the data below is the lowish AHI & the consistency of the pulse rate even though SpO2 varies a bit (stages of sleep) - but varying in an acceptable band. But also note the jump in Tidal Volume from night before 570 up to 630 at the same time that av BPM dropped by 1. All this improvement coming about by increasing epap by 1 and IpapMin by 1 CMs ! quite a difference !.

http://www.internetage.ws/cpapdata/dsm- ... 0nov08.pdf Bipap AutoSV data

http://www.internetage.ws/cpapdata/oxim ... 0nov08.jpg Oximeter Report

DSM

That looks a lot better Doug, if that thing has .5 cm pressure increases, I would bump IPAP Min from 14.0 to 14.5 leaving everything else the same. You had no PB which is good.

But if AP frequency increases, I could be wrong and you are still a tad over ventilated, in which case I would drop IPAP Min to 13.5 cm everything else the same.

StillAnotherGuest wrote: Without ballistocardiography or forced oscillation technique, how does it know they are central events? All that thing sees is a straight line.

SAG

My guess:

1. It assumes all obstructive events are taken care of by EPAP.
2. It clearly states BPM is only for control of central dysregulation.
3. It applies PS if it doesn't resolve it goes to BPM, that should also be seen in the report. Hey, I use
your old technique, I blow up the report and select the event.

Snoredog wrote:That looks a lot better Doug, if that thing has .5 cm pressure increases, I would bump IPAP Min from 14.0 to 14.5 leaving everything else the same. You had no PB which is good.

But if AP frequency increases, I could be wrong and you are still a tad over ventilated, in which case I would drop IPAP Min to 13.5 cm everything else the same.

Snoredog,

The bain of these Respironics Bipaps is that they only adjust in 1 CM increments (I know some will do 0.5 CMs). That is one of the things I like about Resmed machines is they can do 0.2 increments and that can be very helpful when fine tuning.

If I had my way they would all work in 0.2 increments. 1 CM is actually a very big shift. Doing adjustments in 1 CM increments gets to be like trying to balance on a ball.

DSM

Snoredog wrote:That looks a lot better Doug, if that thing has .5 cm pressure increases, I would bump IPAP Min from 14.0 to 14.5 leaving everything else the same. You had no PB which is good.

But if AP frequency increases, I could be wrong and you are still a tad over ventilated, in which case I would drop IPAP Min to 13.5 cm everything else the same.

No matter what I do (vary epap up/down by 1 - vary ipapmin up/down by 1) that AP stays at around 1.0 to 2.0

Actually, that data from last night is more accurately AHI = 1.2 but for some reason Encore pro will score those 10 events for the night as 2.0 rather than 1.2.
If there were 1 HI event it calls that 1.0 rather than 0.2 - so the AHI is usually lower than shown on the chart.

I am pretty sure those apparent AP scored events are merely post arousal centrals that cause a momentary increase in breathing followed by a slowdown that the machine reasonably scores as an AP event - if you look at the SpO2 chart at the pulse rate spikes, they coincide with those AP scores so in fact I would more accurately score last night as AHI = 0.0 even though those same AP scores show up as machine triggered breaths -

This is what I believe happened (and is typical) ...

1) Normal sleep arousal (these occur at regular intervals through the night - perhaps around 8-10 or so)
2) Sleeper momentarily wakes & turns over or moves or whatever
3) Pulse Rate goes up (which is normal) as user takes a few deep breaths and moves
4) Then as user settles again respiration drops back quickly to slower & shallower breathing (post arousal central)
5) BUT machine reacts - RATE ALERT !!! - user is outside target rate range - ACTIVATE CYCLING !!!
6) Machine initiates a backup cycle
7) Machine scores AP event & registers a machine triggered breath

Did it need to ? - no ! - does it matter - no ! - in fact it is reassuring that the machine is there & willing to help even if in reality the help is not really needed for a post arousal central.

DSM

Just wanted to add a comment re periodic breathing ..

This topic came up indepth during Bev's thread where she tried a Bipap AutoSV. There are two common topics to do with xPAP and types of respiration
one being VARIABLE breathing and the other being PERIODIC breathing

Just want to reiterate what came out of looking at published data on the meanings of these two types of breathing.

1) VB - Variable breathing (erratic breathing)
this is when the persons respiratory rate varies erratically - it may happen for a few minutes or it may continue for a few hours. The depth (or volume) of the breathing may not necessarily change much but the speed of respiration does change - breathing rate becomes erratic - Some AUTO CPAPs detect this erratic pattern (scored as VB in the data charts) and try to clear it by 1st moving pressure slowly in the opposite direction the machine was going in prior to detection & if that fails then trying the other direction & if that fails by locking pressure as it was for a while (say 15 mins). Erratic breathing can destabilize an AUTO machine so modern AUTOs try the above before locking.

2) PB - Periodic breathing (periods of breathing)
This is characterized as being waxing and waning of respiration and does involve varying volume. The real definition is periods of breathing typically with centrals in between. The classic form of periodic breathing (but not the only type) is Cheynes-Stokes Respiration (CSR) which typically occurs with people who have experienced Congestive Heart Failure (CHF). It is typified by a period of breathing that increases in intensity (waxes) then decreases in intensity (wanes) - often followed by a central - then the cycle repeats itself. S/T Bilevels used to be considered to be the solution for Periodic breathing but over time Resmed and Respironics in particular, perfected SV machines to handle this type of problem. SV is now considered the preferred therapy for periodic breathing. An SV machine will score it as PB in the data charts.

DSM

Doug: then I would leave it, not enough events to mess with, that last report looked pretty good.

How do you feel using those settings?