SWS,
I vaguely recall that the 15 BPM backup rate was a statement of requirement to get FDA approval for the machine but in fact it doesn't hold to 15 BPM, it is far more variable.
I would agree wholeheartedly with Snoredog that 15 is just too high a setting as a backup rate for even serious periodic breathers.
DSM
Newbie on AVAPS
Re: Newbie on AVAPS
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)
Re: Newbie on AVAPS
That machine has a published fixed backup rate of 15 BPM. However, it is deployed in a different manner/sequence than conventional BiLevel. Regardless, the backup rate is fixed at 15 BPM, when it is deployed.... and that 15 BPM backup rate can apparently be very disconcerting for some patients.dsm wrote:I vaguely recall that the 15 BPM backup rate was a statement of requirement to get FDA approval for the machine but in fact it doesn't hold to 15 BPM, it is far more variable.
Perhaps your vague recollection of flexibility has to do with that machine's tendency to increase or decrease machine cycling frequency based on PAV measurement criteria. If the algorithm increasingly misses flow targets despite very fluidly adjusting machine pressure and frequency, it will then increasingly deploy that fixed backup rate of 15 BPM. And according to the Resmed factory representative who attended frequen's PSG, that "permeating" or increasingly deployed backup rate of 15 BPM is precisely where she ran into problems.
Anyway, my previous point or thought was that since rise time on that machine is definitely not fixed (rather it fluidly matches recent reference or set points), I doubt that a fixed and short rise time is why the VPAP adapt SV caused your "light sleep". Rather, I suspect that permeating and fixed backup rate of 15 BPM (that the Resmed factory representative identified as problematic for frequen) is bound to also be problematic for other patients---especially those patients who do not respond adequately to conventional PAV treatment criteria entailing fluid F adjustments. The Respironics BiPAP autoSV does not endeavor those fluid F adjustments---but rather deploys a very traditional auto-averaged or manual BiLevel backup rate instead.
Whatever caused your particular "light sleep" I don't see where a short, fixed rise time could have occured unless 15 BPM was progressively deployed because PAV frequency and pressure adjustments repeatedly missed their short-term flow targets. When the VPAP adapt SV flow targets are sustained, then rise time, pressure, and machine frequency all very fluidly key off previous patient breaths (here you have very fluid F adjustments occurring instead of backup rate). However when flow targets are repeatedly missed, that 15 BPM---with its comparatively short associated rise time---is increasingly deployed by the VPAP adapt SV.
Re: Newbie on AVAPS
SWS
That is a pretty good explanation & makes good sense to me.
My impressions of fast risetime were just that & because I was able to replicate the effect with fast risetime on the Bipap Auto SV - it was the best theory I had.
What I may try one night this week is to set risetime=3 & BPM=15 on the Bipap SV & see what I can deduce from the change.
DSM
That is a pretty good explanation & makes good sense to me.
My impressions of fast risetime were just that & because I was able to replicate the effect with fast risetime on the Bipap Auto SV - it was the best theory I had.
What I may try one night this week is to set risetime=3 & BPM=15 on the Bipap SV & see what I can deduce from the change.
DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)
Re: Newbie on AVAPS
Doug, above we have one theory speculating that frequen's problem with that "permeating" 15 BPM may have also been your issue regarding "light sleep". Let's call that theory A for the sake of this discussion...
I'm also thinking back to your former analogy, Doug, that the VPAP adapt SV felt to you as if it were a very tightly controlled race car. That tight control you felt may have been the VPAP adapt SV very actively maintaining machine frequency (variable F) on each breath----as the VPAP adapt SV fluidly nailed up pressure-based rotations---in order to hit each of those reference or flow set points throughout inspiration. That's a description of actively maintaining/adjusting variable F on each breath. But that fluid F adjustment process during each breath differs drastically than any traditional S/T backup----where biologic spontaneous drive is given much more freedom to produce its own flow curve on each breath that backup is not deployed.
So here we have Resmed very fluidly and actively adjusting machine F on one hand. And Resmed's reference-point by reference-point delivery of machine F is similar to what happens with purely timed more during each breath: the machine delivers each breath on its determined schedule in both implementation (unlike S/T mode where spontaneous drive more actively orchestrates). However, the big difference between purely timed mode and Resmed's per-breath maintenance of machine F, is that the latter is both rounded and slides back and forth a bit in the time domain. By contrast, the Respironics method of traditional backup lays off a couple BPM points to allow the biologic or spontaneous drive to orchestrate each inspiratory flow curve with much more spontaneous freedom. The exception to that last statement, of course, is when a missed breath occurs and that traditional S/T backup needs to kick in.
Thus the difference between Resmed's ever-so fluidly tending to machine F (via those multiple inspiratory reference points), versus Respironics' traditional S/T mode (laying low at a couple BPM points below measured spontaneous drive), may account for that tightly controlled race car comparison of yours, Doug. If that tightly-controlled pressure-delivery sensation is adequate to keep you from sleeping soundly, then we also have theory B as to why you might have slept "lightly" with the VPAP adapt SV.
-----------------------------------------------------------
Summary of Two Theories Regarding Why Doug Slept "Lightly" with the VPAP Adapt SV:
Theory A- short-term flow targets were consistently missed, causing a sleep-disruptive fixed backup rate of 15 BPM to permeate (frequen's documented case)
Theory B- that highly active reference-point based maintenance of machine frequency during each breath is inherently sleep-disruptive to at least some patients (upper airway defensive reflexology or vagal-based disruption perhaps?)
----------------------------------------------------------
I'm sure we'd be able to drum up yet additional theories.
I'm also thinking back to your former analogy, Doug, that the VPAP adapt SV felt to you as if it were a very tightly controlled race car. That tight control you felt may have been the VPAP adapt SV very actively maintaining machine frequency (variable F) on each breath----as the VPAP adapt SV fluidly nailed up pressure-based rotations---in order to hit each of those reference or flow set points throughout inspiration. That's a description of actively maintaining/adjusting variable F on each breath. But that fluid F adjustment process during each breath differs drastically than any traditional S/T backup----where biologic spontaneous drive is given much more freedom to produce its own flow curve on each breath that backup is not deployed.
So here we have Resmed very fluidly and actively adjusting machine F on one hand. And Resmed's reference-point by reference-point delivery of machine F is similar to what happens with purely timed more during each breath: the machine delivers each breath on its determined schedule in both implementation (unlike S/T mode where spontaneous drive more actively orchestrates). However, the big difference between purely timed mode and Resmed's per-breath maintenance of machine F, is that the latter is both rounded and slides back and forth a bit in the time domain. By contrast, the Respironics method of traditional backup lays off a couple BPM points to allow the biologic or spontaneous drive to orchestrate each inspiratory flow curve with much more spontaneous freedom. The exception to that last statement, of course, is when a missed breath occurs and that traditional S/T backup needs to kick in.
Thus the difference between Resmed's ever-so fluidly tending to machine F (via those multiple inspiratory reference points), versus Respironics' traditional S/T mode (laying low at a couple BPM points below measured spontaneous drive), may account for that tightly controlled race car comparison of yours, Doug. If that tightly-controlled pressure-delivery sensation is adequate to keep you from sleeping soundly, then we also have theory B as to why you might have slept "lightly" with the VPAP adapt SV.
-----------------------------------------------------------
Summary of Two Theories Regarding Why Doug Slept "Lightly" with the VPAP Adapt SV:
Theory A- short-term flow targets were consistently missed, causing a sleep-disruptive fixed backup rate of 15 BPM to permeate (frequen's documented case)
Theory B- that highly active reference-point based maintenance of machine frequency during each breath is inherently sleep-disruptive to at least some patients (upper airway defensive reflexology or vagal-based disruption perhaps?)
----------------------------------------------------------
I'm sure we'd be able to drum up yet additional theories.
Last edited by -SWS on Sun Nov 16, 2008 2:46 pm, edited 1 time in total.
Re: Newbie on AVAPS
SWS,
I am not able to follow this completely & will need to read it a few times. When I read your comments I usually try to relate each aspect to a particular capability of the machine in question (that helps me clarify the points).
What I am aware of at the moment, is for a week now I have had a shorter risetime on the Bipap Auto SV and 2 nights back changed it from risetime =1 (100 millisecs) to =2 (200 millisecs). Reason being that I just feel I am sleeping too lightly - best way to explain this is that during an arousal I will feel very awake vs sluggishly awake before I changed the risetime. Even with a setting of risetime=2 am still feeling this way.
But, am not feeling any tiredness during the day & SpO2 data all looks very stable, steady & good values.
But, aerophagia is once again becoming a problem.
This is exactly how it feels with the Adapt SV (but usually even more so).
So, tonight as an experiment I will trade off epap & IpapMin by 1 (10/13) & leave risetime = 2. I am expecting this adjustment to allow for that slightly deeper sleep without introducing increased daytime tiredness (the juggling act). If it doesn't behave as I expect it will, I'll revert back to 11/14 & risetime=3.
I believe Banned is doing a very similar sort of balancing act with his AVAPS machine & this is why following what he does is particularly interesting. If any of us can fairly accurately predict the effects on a Bipap Auto SV or a Bipap AVAPS what settings changes will interact with other settings & why, then it seems to me we are gaining better understandings of the various machines & their capabilities.
In particular, it has always interested me that Banned started off with such enthusiasm for the Vpap Adapt SV, then bought an updated version because he wasn't 100% satisfied. I know I discussed with him as to if he was getting 'deep' vs 'light' sleep. Banned can correct me if I am wrong but he subsequently agreed that the 'lightness' of sleep was indeed something he was very aware of and not happy about. You may also recall another past regular Lubman who went through a very similar cycle with his Vpap Adapt SV (I am pretty sure he went through 2 models). We met here in Sydney just under 2 years back & he showed me his set up which included a deadspace adaptation very similar I believe to Frequen's setup as I also recall Frequen having a deadspace issue & think she to ended up with a deadspace addon. Christine Quilts is one person who seemed very happy with her Vpap Adapt SV - it would be great to hear from her now as to how it has gone these past couple of years.
DSM
I am not able to follow this completely & will need to read it a few times. When I read your comments I usually try to relate each aspect to a particular capability of the machine in question (that helps me clarify the points).
What I am aware of at the moment, is for a week now I have had a shorter risetime on the Bipap Auto SV and 2 nights back changed it from risetime =1 (100 millisecs) to =2 (200 millisecs). Reason being that I just feel I am sleeping too lightly - best way to explain this is that during an arousal I will feel very awake vs sluggishly awake before I changed the risetime. Even with a setting of risetime=2 am still feeling this way.
But, am not feeling any tiredness during the day & SpO2 data all looks very stable, steady & good values.
But, aerophagia is once again becoming a problem.
This is exactly how it feels with the Adapt SV (but usually even more so).
So, tonight as an experiment I will trade off epap & IpapMin by 1 (10/13) & leave risetime = 2. I am expecting this adjustment to allow for that slightly deeper sleep without introducing increased daytime tiredness (the juggling act). If it doesn't behave as I expect it will, I'll revert back to 11/14 & risetime=3.
I believe Banned is doing a very similar sort of balancing act with his AVAPS machine & this is why following what he does is particularly interesting. If any of us can fairly accurately predict the effects on a Bipap Auto SV or a Bipap AVAPS what settings changes will interact with other settings & why, then it seems to me we are gaining better understandings of the various machines & their capabilities.
In particular, it has always interested me that Banned started off with such enthusiasm for the Vpap Adapt SV, then bought an updated version because he wasn't 100% satisfied. I know I discussed with him as to if he was getting 'deep' vs 'light' sleep. Banned can correct me if I am wrong but he subsequently agreed that the 'lightness' of sleep was indeed something he was very aware of and not happy about. You may also recall another past regular Lubman who went through a very similar cycle with his Vpap Adapt SV (I am pretty sure he went through 2 models). We met here in Sydney just under 2 years back & he showed me his set up which included a deadspace adaptation very similar I believe to Frequen's setup as I also recall Frequen having a deadspace issue & think she to ended up with a deadspace addon. Christine Quilts is one person who seemed very happy with her Vpap Adapt SV - it would be great to hear from her now as to how it has gone these past couple of years.
DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)
Re: Newbie on AVAPS
Good points, Doug. I'm thinking the above are two different reasons that someone might sleep lightly on the VPAP Adapt SV. There may be other reasons as well. And of course, of the two reasons I have above, frequen's PSG case so far is the only known/documented possibility. The other case I have above is pure conjecture regarding the biologic nuance itself (that nuance in response to tightly-controlled PAV-driven machine F adjustments, which are not at all conjecture) .
With that said, difficult SDB cases will undoubtedly make their way to both SV machines. My hunch is that neither machine will be an SDB panacea, so to speak. But I also agree that the BiPAP autoSV entails more configuration options than the VPAP adapt SV. It's thus the more versatile PAP machine option of those two.
Curious, besides yourself do we have anybody else who is sleeping exceptionally well on either SV model at this early stage of comparison? Would love to hear from Christine as well. Sure do miss her posts...
With that said, difficult SDB cases will undoubtedly make their way to both SV machines. My hunch is that neither machine will be an SDB panacea, so to speak. But I also agree that the BiPAP autoSV entails more configuration options than the VPAP adapt SV. It's thus the more versatile PAP machine option of those two.
Curious, besides yourself do we have anybody else who is sleeping exceptionally well on either SV model at this early stage of comparison? Would love to hear from Christine as well. Sure do miss her posts...
Re: Newbie on AVAPS
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
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
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
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
AVAPS: PC AVAPS, EPAP 15, IPAP Min 19, IPAP Max 25, Vt 520ml, BPM 10, Ti 1.8sec, RT 2 (Garage)
BiPAP Auto SV: EPAP 9, IPAP Min 14, IPAP Max 25, BPM 10, Ti 2sec, RT 2 (Travel Machine)
VPAP Adapt SV: EEP 10.4, Min PS 4.4 (Every Day)
Mask: Quattro
BiPAP Auto SV: EPAP 9, IPAP Min 14, IPAP Max 25, BPM 10, Ti 2sec, RT 2 (Travel Machine)
VPAP Adapt SV: EEP 10.4, Min PS 4.4 (Every Day)
Mask: Quattro
Re: Newbie on AVAPS
Banned,
Good news & great progress. Tha acid test after your experiments will be to get consistent results over about 6 months.
Do you have a Pulse Ox ? If yes - what is it telling you ?
My Ohmeda 3740 died & I bought a CMS-50E - the complete screen & recoding unit is in the probe which is the same size as most
SpO2 finger probes. It will capture 24 hrs data in one go & is rechargeable. It downloads the data to a PC & produces great
reports plus puts the data into an xl file in case you want to create a different style of graph.
DSM
Good news & great progress. Tha acid test after your experiments will be to get consistent results over about 6 months.
Do you have a Pulse Ox ? If yes - what is it telling you ?
My Ohmeda 3740 died & I bought a CMS-50E - the complete screen & recoding unit is in the probe which is the same size as most
SpO2 finger probes. It will capture 24 hrs data in one go & is rechargeable. It downloads the data to a PC & produces great
reports plus puts the data into an xl file in case you want to create a different style of graph.
DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)
Re: Newbie on AVAPS
Snoredog,Snoredog wrote:yeah man bet it is, that is a bit rapid, 4 second breaths. how long is the typical pause time after exhale last?-SWS wrote: My hunch is that factor three---fixed backup rate of 15 BPM---just may be a somewhat common patient-discomfort issue with that machine.
At the beginning of AVAPS trials I timed my resting inspiration cycle at 2 seconds. It took me awhile to understand the correlation between Inspiration Time and Rise Time.
I now understand that when I adjust Inspiration Time and Rise time, they better equal 2 seconds!
Hence, Inspiration Time of 1.6 sec and Rise Time of 4 (400 millisecs) equals 2 seconds. Conversely, Inspiration Time of 1.7 sec and Rise time of 3 (300 millisecs) equals 2 seconds. etc. So, when I adjust the Rise Time, I also adjust the Inspiration Time.
My breath rate appears to be 16 BPM. You're thinking 15 BPM is rapid. I'm wondering if my 16 BPM is a bit rapid!
Banned
AVAPS: PC AVAPS, EPAP 15, IPAP Min 19, IPAP Max 25, Vt 520ml, BPM 10, Ti 1.8sec, RT 2 (Garage)
BiPAP Auto SV: EPAP 9, IPAP Min 14, IPAP Max 25, BPM 10, Ti 2sec, RT 2 (Travel Machine)
VPAP Adapt SV: EEP 10.4, Min PS 4.4 (Every Day)
Mask: Quattro
BiPAP Auto SV: EPAP 9, IPAP Min 14, IPAP Max 25, BPM 10, Ti 2sec, RT 2 (Travel Machine)
VPAP Adapt SV: EEP 10.4, Min PS 4.4 (Every Day)
Mask: Quattro
Re: Newbie on AVAPS
As I recall, my last '05 CPAP psg O2 registered in the 90s. I have never owned a Pulse Ox. I will look into getting a CMS-50E, since I know nothing about it and would rely on your technical knowledge for setup and operation.dsm wrote: I bought a CMS-50E - the complete screen & recoding unit is in the probe which is the same size as most
SpO2 finger probes. It will capture 24 hrs data in one go & is rechargeable. It downloads the data to a PC & produces great
reports plus puts the data into an xl file in case you want to create a different style of graph.
Last night in S/T (only) mode, EPAP 15 and IPAP 19 resulted in AHi 2 and a surprising 560 ml Average Tidal Volume.
Just before getting up this morning, I briefly slipped the machine into PC AVAPS mode and was surprised that I felt better ventilated (with what I'm sure was the 518 ml Average Tidal Volume) as experienced the day before.
Tonight, I will retrial S/T AVAPS mode at Tv 520 ml, Inspiration Time 1.6sec, and Rise Time 4.
I'd like to see the results using the same settings in PC AVAPS, S/T AVAPS, S AVAPS, and (heaven forbid) T AVAPS modes.
Banned
AVAPS: PC AVAPS, EPAP 15, IPAP Min 19, IPAP Max 25, Vt 520ml, BPM 10, Ti 1.8sec, RT 2 (Garage)
BiPAP Auto SV: EPAP 9, IPAP Min 14, IPAP Max 25, BPM 10, Ti 2sec, RT 2 (Travel Machine)
VPAP Adapt SV: EEP 10.4, Min PS 4.4 (Every Day)
Mask: Quattro
BiPAP Auto SV: EPAP 9, IPAP Min 14, IPAP Max 25, BPM 10, Ti 2sec, RT 2 (Travel Machine)
VPAP Adapt SV: EEP 10.4, Min PS 4.4 (Every Day)
Mask: Quattro
Re: Newbie on AVAPS
Banned,
I'm doing some playing too - last night tried risetime=2 & epap=10 ipapMin=13. Report in the morning showed AHI of 2 plus 1 short score of PB. Have been fine all day but didn't really enjoy the sleep. Av Tidal volume had dropped to 566.
http://www.internetage.ws/cpapdata/dsm- ... 8nov08.pdf
SpO2 data (taken from the CMS-50E) was ok but I've seen better (seems to be linked to tidal volume - as TV went up so did SpO2 sat).
http://www.internetage.ws/cpapdata/oxim ... 8nov08.jpg
Tonight it is back to the trusted & reliable risetime=3 epap=11 & ipapMin=14 (IpapMax is also now back to 20 as while I have seen SV pressure support go to 19/20, it has *never* gone above that.
Good luck with your efforts.
DSM
I'm doing some playing too - last night tried risetime=2 & epap=10 ipapMin=13. Report in the morning showed AHI of 2 plus 1 short score of PB. Have been fine all day but didn't really enjoy the sleep. Av Tidal volume had dropped to 566.
http://www.internetage.ws/cpapdata/dsm- ... 8nov08.pdf
SpO2 data (taken from the CMS-50E) was ok but I've seen better (seems to be linked to tidal volume - as TV went up so did SpO2 sat).
http://www.internetage.ws/cpapdata/oxim ... 8nov08.jpg
Tonight it is back to the trusted & reliable risetime=3 epap=11 & ipapMin=14 (IpapMax is also now back to 20 as while I have seen SV pressure support go to 19/20, it has *never* gone above that.
Good luck with your efforts.
DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)
Re: Newbie on AVAPS
That report looks much better than your others I've seen, a lot less stress seen on that report compared to others, but then you threw a monkey wrench into it by not feeling rested, that is a bummer.dsm wrote:Banned,
I'm doing some playing too - last night tried risetime=2 & epap=10 ipapMin=13. Report in the morning showed AHI of 2 plus 1 short score of PB. Have been fine all day but didn't really enjoy the sleep. Av Tidal volume had dropped to 566.
http://www.internetage.ws/cpapdata/dsm- ... 8nov08.pdf
SpO2 data (taken from the CMS-50E) was ok but I've seen better (seems to be linked to tidal volume - as TV went up so did SpO2 sat).
http://www.internetage.ws/cpapdata/oxim ... 8nov08.jpg
Tonight it is back to the trusted & reliable risetime=3 epap=11 & ipapMin=14 (IpapMax is also now back to 20 as while I have seen SV pressure support go to 19/20, it has *never* gone above that.
Good luck with your efforts.
DSM
Your peak and tidal volume seem to be way up there, maybe too much ventilation?
wonder if that is not why you didn't feel as good?
I would log your peak and tidal volumes seen and rank them on how you "feel" the next day. Maybe rank your next day EDS on a 1 to 5 scale and write it on the reports and compare. Those "AP" says to me your Peak is a bit too high at 45ml (my theory) will be interesting to see what happens to those AP's with the higher epap and pressure support.
someday science will catch up to what I'm saying...
Re: Newbie on AVAPS
Snoredog,
Over ventilation is a possibility - last night's report was identical to the one shown above but risetime was at 3 & last night I did feel the 'deep' sleep. But it turns out I hadn't increased epap to 11 nor IpapMin to 14 as I believed I had done ? - dunno what happened there. To night I'll revert (just went & treble checked the settings) so I will have two near identical nights to compare. I keep coming back to risetime around 1 or 2 as a cause I can see for light sleeping.
Thanks for looking over the data & thanks for the feedback.
DSM
Over ventilation is a possibility - last night's report was identical to the one shown above but risetime was at 3 & last night I did feel the 'deep' sleep. But it turns out I hadn't increased epap to 11 nor IpapMin to 14 as I believed I had done ? - dunno what happened there. To night I'll revert (just went & treble checked the settings) so I will have two near identical nights to compare. I keep coming back to risetime around 1 or 2 as a cause I can see for light sleeping.
Thanks for looking over the data & thanks for the feedback.
DSM
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)
Re: Newbie on AVAPS
I would think your Rise Time would be approximately one-half of the breath duration (including any pauses). Your Encore report shows avg. BPM=14, if we do the math on that, it is 60/14=4.285 seconds per breath, if you divide that by 2 you end up with 2.14 seconds for Inhalation and 2.14 seconds for exhalation for the I:E ratio. So if you adjust one you take away from the other, so if you think you are getting too much oxygen vs. CO2 by shortening the IT you lower the oxygen and increase the CO2 (should decrease peak and increase tidal volumes seen on report). IF you manipulate the settings to increase/decrease BPM you also adjust that ratio (shorter breaths vs longer ones).dsm wrote:Snoredog,
Over ventilation is a possibility - last night's report was identical to the one shown above but risetime was at 3 & last night I did feel the 'deep' sleep. But it turns out I hadn't increased epap to 11 nor IpapMin to 14 as I believed I had done ? - dunno what happened there. To night I'll revert (just went & treble checked the settings) so I will have two near identical nights to compare. I keep coming back to risetime around 1 or 2 as a cause I can see for light sleeping.
Thanks for looking over the data & thanks for the feedback.
DSM
So on the Resmed machine with the fixed BPM=15, they must be trying to limit/control the duration of the breath, by controlling the BPM you control the ventilation rate seen.
Normal BPM for you (according to the Encore report) is 14. What we don't know is if that BPM=14 is your natural BPM or a BPM influenced by the current machine settings. IF I want to slow your breathing down (make you take deeper breaths) I lower the BPM, as a lower breaths per minute extends the duration of each breath during that minute. A higher BPM (i.e. 16 vs 14) results in shorter rapid breaths, more breaths you have per minute the more CO2 you exhaust with each breath.
Assume Rise Time is from bottom of exhale to peak of inhale, then inspiration time is the duration of that peak (how long it is held) but all of it is part of the total breath cycle/duration, in your case 4.285 seconds on average. If you use 2.0 IT that leaves 2.285 seconds for exhale (4.285-2.0=2.285). Keep in mind if you keep the BPM the same, you keep the duration of each breath the same, any changes within that I:E ratio gives you either more/less oxygen and more/less CO2. Get too much oxygen (vs. CO2 ratio) and you go into variable or periodic breathing which leads to central dysregulation. Centrals attempt to control that ratio by retaining more CO2. So it is BEST to use settings that avoid PB (reason I had a problem with yours and Bev's PB seen).
The goal is to get that I:E ratio set to avoid the PB and Central Dysregulation. I see that (on the report) as less activity. You have to assume with your Adapt SV that EPAP is taking care of all obstructive apnea. The rest of the machine is controlling your breathing. IF part of controlling that breathing is going from one end of its spectrum to the other then something is wrong. So when I see those dips where the machine goes from patient triggered breathing to machine triggered breathing that says to me with current settings machine cannot control your breathing.
Ideal is straight smooth line on Patient Triggered Breathing (i.e. no visits to Backup mode), maybe that is an impossible task, but that would be my goal as achieving it says the settings used to control breathing is working optimally. Maybe that is impossible to ask/achieve and you end up on a AVAPS like Banned which looks at different aspects to control breathing.
Whenever you shift that ratio, you need to keep in mind (as stolen from Wiki):
and the opposite:Hypocapnia or hypocapnea also known as hypocarbia, sometimes incorrectly called acapnia, is a state of reduced carbon dioxide in the blood. Hypocapnia usually results from deep or rapid breathing, known as hyperventilation.
Hypocapnia is the opposite of hypercapnia.
Even when severe, hypocapnia is normally well tolerated. However, hypocapnia causes cerebral vasoconstriction, leading to cerebral hypoxia and this can cause transient dizziness, visual disturbances, and anxiety. A low partial pressure of carbon dioxide in the blood also causes alkalosis (because CO2 is acidic in solution), leading to lowered plasma calcium ions and nerve and muscle excitability. This explains the other common symptoms of hyperventilation —pins and needles, muscle cramps and tetany in the extremities, especially hands and feet.
Hypocapnia is sometimes induced in the treatment of the medical emergencies, such as intracranial hypertension and hyperkalaemia.
Because the brain stem regulates breathing by monitoring the level of blood CO2, hypocapnia can suppress breathing to the point of blackout from cerebral hypoxia. Self-induced hypocapnia through hyperventilation is the basis for the deadly schoolyard fainting game. Deliberate hyperventilation has been unwisely used by underwater breath-hold divers to extend dive time but at the risk of shallow water blackout, which is a significant cause of drowning.
Hypercapnia or hypercapnea (from the Greek hyper = "above" and kapnos = "smoke"), also known as hypercarbia, is a condition where there is too much carbon dioxide (CO2) in the blood. Carbon dioxide is a gaseous product of the body's metabolism and is normally expelled through the lungs.
Hypercapnia is generally caused by hypoventilation, lung disease, or diminished consciousness. It may also be caused by exposure to environments containing abnormally high concentrations of carbon dioxide (usually due to volcanic or geothermal causes), or by rebreathing exhaled carbon dioxide. It can also be an initial effect of administering supplemental oxygen on a patient with sleep apnea. In this situation the hypercapnia can also be accompanied by respiratory acidosis. [1]
someday science will catch up to what I'm saying...
Re: Newbie on AVAPS
Here are the charts from last night.
Snoredog
Bipap SV epap=10 IpapMin=13 risetime=3
http://www.internetage.ws/cpapdata/dsm- ... 9nov08.pdf
Oximeter
http://www.internetage.ws/cpapdata/oxim ... 9nov08.jpg
The only difference between the above data & the prior nights data is that risetime is = 3 above & night before risetime = 2.
Also - I have spent most of the past 9 months on the BipapSV with epap=11 & ipapMin=14 & risetime=3 and that worked very
well but took a dive just over 6 weeks ago with a rapid change in temperature. Daytimes are back to normal now but I have
been doing some fiddling since Bev's thread & matching her settings on my machine to get a sense of what she was dealing
with.
I'll go through your points carefully as it is an interesting line of investigation. I am working on the belief that if I can accurately
predict what my sleep will be like by individually tweaking epap / ipapmin / risetime - that I may then be able to predict what
many others may expect or why they are experiencing particular results.
The issue of light sleeping vs deep sleeping seems to impact quite a few people. From the line you have opened it seems to me
there is a likely link between light sleeping & reduced CO2 vs regular sleeping & normal CO2 - risetime seems to be a key.
DSM
PS Banned - I hope you don't mind this deviation in your thread but am certain you will be especially interested in where this line is heading - Doug
#2 PS this below chart is from 1st Oct and is what I consider a good night - note the av peak flow & tidal volume are quite a bit higher that the past 2 nights. Note the settings risetime=3 epap=11 & ipapMin=14 - I will be reverting to these settings tonight.
http://www.internetage.ws/cpapdata/dsm- ... 1oct08.pdf OCTOBER 1 2008
Snoredog
Bipap SV epap=10 IpapMin=13 risetime=3
http://www.internetage.ws/cpapdata/dsm- ... 9nov08.pdf
Oximeter
http://www.internetage.ws/cpapdata/oxim ... 9nov08.jpg
The only difference between the above data & the prior nights data is that risetime is = 3 above & night before risetime = 2.
Also - I have spent most of the past 9 months on the BipapSV with epap=11 & ipapMin=14 & risetime=3 and that worked very
well but took a dive just over 6 weeks ago with a rapid change in temperature. Daytimes are back to normal now but I have
been doing some fiddling since Bev's thread & matching her settings on my machine to get a sense of what she was dealing
with.
I'll go through your points carefully as it is an interesting line of investigation. I am working on the belief that if I can accurately
predict what my sleep will be like by individually tweaking epap / ipapmin / risetime - that I may then be able to predict what
many others may expect or why they are experiencing particular results.
The issue of light sleeping vs deep sleeping seems to impact quite a few people. From the line you have opened it seems to me
there is a likely link between light sleeping & reduced CO2 vs regular sleeping & normal CO2 - risetime seems to be a key.
DSM
PS Banned - I hope you don't mind this deviation in your thread but am certain you will be especially interested in where this line is heading - Doug
#2 PS this below chart is from 1st Oct and is what I consider a good night - note the av peak flow & tidal volume are quite a bit higher that the past 2 nights. Note the settings risetime=3 epap=11 & ipapMin=14 - I will be reverting to these settings tonight.
http://www.internetage.ws/cpapdata/dsm- ... 1oct08.pdf OCTOBER 1 2008
Last edited by dsm on Tue Nov 18, 2008 4:59 pm, edited 1 time in total.
xPAP and Quattro std mask (plus a pad-a-cheek anti-leak strap)