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Therapy using Lumis 150 ST
#1
Therapy using Lumis 150 ST
My apologies, this is long. I am splitting things across two posts to be able to include a whole lot of images.  This first post deals with history and my most recent sleep study, the next post deals with my new machine and its settings.
 
I was diagnosed with Sarcoidosis in 2009, which went “into remission” by 2013.  However, I still had ongoing fatigue and more, so that is when I was first sent for a sleep study.  This was just the first of four sleep studies between 2013 and 2017 that gave similar results – low AHI during NREM but high AHI with associated oxygen desaturations during REM sleep.  I tried CPAP in 2013 but could not keep it on for more than about 2.5 hours, so I did not continue.  I finally tried again in 2017 and succeeded this time because I was put on fixed pressure, not Auto with a silly range.  It worked to bring my AHI down below 2 but I never woke feeling better.
 
The Philips debacle led me to change from a DS1 to a ResMed and introduced me to Facebook groups, which led me to both OSCAR and an O2ring.  OSCAR helped me fix my mask leaks and the O2Ring showed that my oxygen levels desaturated roughly every 90 minutes, down to less than 85% with an average of 10 minutes below 90% every night.  I consulted my respiratory specialist who claimed everything was fine, simply because my AHI was below 5.  When I disagreed and put OSCAR charts in front of him, he sent me for a sleep study and put me in direct contact with the sleep tech.
 
The sleep study (images attached) showed that:
  • CPAP was satisfactory at controlling obstructive events. 
  • Hypoxia was observed while using CPAP in the absence of obstructive events (but during REM)
  • Transcutaneous CO2 levels of 50 mmHg (i.e., high) were measured during CPAP therapy even with no oxygen desaturations occurring at the time. 
  • BiPAP with AVAPS was effective at reducing CO2 and preventing oxygen desaturations.
 
The study recommended BiPAP (mode not specified) with EPAP = 5, PS = 5 to 15 (i.e. IPAP = 10 to 20), backup rate of 10 bpm, Ti = 1.9 s and Vt = 580 to 600 ml.  It should have been straight forward from there, but it was not (long story, new specialist required, leave it at that).  Nevertheless, I managed to get a ResMed Lumis 150 ST.   
 
I will pause here and continue in a second post about he machine and its settings.  Please read on ...


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#2
RE: Therapy using Lumis 150 ST
This is where I start asking for help checking my translation of settings from Philips to ResMed.  No, I cannot and will not go back to the same respiratory specialist and it will take time to find and see a new one.  The CPAP supplier did his best with confusing information, with me being partly to blame in relaying a conversation that I had with the sleep tech following the study, which led to the wrong mode being set.  So, I have been “learning” on my own since.  Where I am up to so far is:

  • I have set the mode to iVAPS, which is the ResMed equivalent to the Philips AVAPS mode, because it uses volume targets.
  • I have set Ti min to 1 s, with rise time of 900 ms, and Ti max to 2.5 s.  When I ran in S mode with EPAP = 6 and IPAP = 9, these settings gave me a mask pressure waveform that was closest to the AS 10 Elite with pressure = 9, EPR = 3.  Image attached to illustrate.
  • The standard backup rate setting is not available in iVAPS mode.  Instead, you set an “intelligent backup rate” (iBR) which the clinical manual says should be “the patient’s average spontaneous rate”.  Historically, I have always had a median respiratory rate of 12 to 13 bpm, so I have tried both those values successfully whereas 14, which I also tried, was uncomfortable.  I think 13 might be better in the long run, but it depends on the volume and pressure settings as below.
  • iVAPS operates with a target alveolar volume (Va), which is calculated based on patient height.  Using the iBR, it then calculates the resulting minute vent (MV), tidal volume (Vt) and tidal volume per kg of ideal body weight.  I have found that the tidal volume is calculated to be 584 ml when the target Va setting is either 5.5 l/min with iBR = 12 or 6.0 l/min with iBR = 13.  This gives a tidal volume per kg of ideal body weight of 8.4, which is within the range of 8 to 9 mentioned in the sleep study.
    It is probably worth my while saying that I understand my primary objective with this machine to be to achieve adequate tidal volume to reduce CO2.  I have already seen that doing this achieves objectives for reducing AHI below 5 and maintaining oxygen saturation above 90%.  I also get that I can reduce CO2 by too much, which would cause central apneas, so that is something that I would need to monitor.
  • I have EPAP set to a fixed 5 cmH2O, as recommended by the sleep study.  However, I have noticed some flow limitations at times that I can see from the shape of the flow wave – unfortunately the Lumis does not produce a Flow Limitation chart, so that is all I have to go on.  On one hand, I am thinking of simply increasing my EPAP to a fixed value of 6 since that is effectively what I always had when using fixed CPAP with EPR.  On the other hand, the Lumis has an AutoEPAP ability, so I am considering setting an EPAP range of 5 to 6, or maybe 5 to 7.  Suggestions about this welcomed.
  • I am still working on the pressure support (IPAP) settings.  I have previously experienced aerophagia at pressures of 13, including when trialling a BiPAP on ST mode with EPAP = 5, so I am being cautious about my IPAP max and how quickly I change that.  My strategy has been to increase PS max by 1 every few days until I can achieve the desired volumes with pressures consistently less than IPAP max.  So far, I have reached settings of PS = 4 to 9 (i.e., IPAP = 9 to 14 since EPAP = 5), which looks close to an acceptable IPAP max, but with iBR = 12.  Since I want to set iBR to 13 (and have done that for tonight), that may still need to increase.  I am mindful, however, that I had an increased number of hypopneas when I changed IPAP max from 13 to 14, so I will need to consider that too.
  • I have set PS min = 4 (IPAP min = 9) simply because my set pressure on fixed CPAP was 9.  However, I am wondering if the range between PS min and max should be reduced?  Looking at the time-at-pressure charts in OSCAR, there seems little benefit in having PS min set so low.  Again, suggestions welcomed.
 
Overall, the new machine and settings are working to eliminate the regular (REM-related) oxygen desaturations that I experienced when using fixed CPAP.  Of course, I have no confirmation of how my CO2 levels have responded and do not know of anything I could use at home to measure them. 
 
I do understand that this all suggests an underlying neuromuscular disorder.  I’m not sure if the resolved Sarcoidosis explains that or if there is something else, though several possibilities have already been excluded over the years.  This is still a matter for future discussions with doctors. 
 
I have attached a standard and advanced chart from last night for information.
 
Thanks in advance.


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#3
RE: Therapy using Lumis 150 ST
It's really late here, but before I signed off, I came across your post. I'll swing at one item for the time being, that is backup rate. Even though you use iBR, it is user adjustable correct? If yes, drop it 2 below what your normal spontaneous breath rate is. If you say yours is 12-13, choose 10 or 11. You want assisted breathing to be under the value of what you do yourself normally. In other words, your iBR shouldn't equal your normal, spontaneous breath rate.
Dave

OSCAR
Standard OSCAR Chart Order
Mask Primer
Dealing With A DME
Soft Cervical Collar Wiki
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEBSITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#4
RE: Therapy using Lumis 150 ST
(04-16-2022, 01:05 AM)SarcasticDave94 Wrote: It's really late here, but before I signed off, I came across your post. I'll swing at one item for the time being, that is backup rate. Even though you use iBR, it is user adjustable correct? If yes, drop it 2 below what your normal spontaneous breath rate is. If you say yours is 12-13, choose 10 or 11. You want assisted breathing to be under the value of what you do yourself normally. In other words, your iBR shouldn't equal your normal, spontaneous breath rate.

Intelligent backup rate has had me confused.  It works between two values, the "Target Patient Rate", which is the actual parameter that I can set, and two thirds of that. As I understand it, if I set the Target Patient Rate to my normal spontaneous rate, as it says I should,  I should be able to breathe normally with some variability in my respiratory rate and without the machine interfering.  But you can see from the chart that I posted that my respiratory rate is quite regulated around 12, which is what I had set for the Target Patient Rate.  So, I am not entirely sure.  I do know that my respiratory rate was far more variable using fixed CPAP, but then that is probably something that I do not want anyway.

I came across a setting since I posted that shows me how to get data from the machine for just one day.  It reports that I spontaneously triggered breathing (inhalation) only 5% of the time but spontaneously cycled (exhalation) 87% of the time.  Trouble is that it also says "Measured from the last 20 breaths", which does not sound useful.

I have attached some snips from the manual for the proper explanation.  Perhaps someone can get more from it than I can. 

I have also just had a thought that I can adjust the trigger sensitivity, a setting that I have been ignoring so far.  The default is medium but I think that if I set it to very low, it will be quicker to detect inhalation.  I won't do that tonight, but I will  do some more reading to see if it might help and if very low is the correct way to go.


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#5
RE: Therapy using Lumis 150 ST
Okay, I found something about trigger sensitivity on the Resmed site.  Image attached.

It would appear that changing the trigger setting to low or very low will allow more time for inhalation to occur spontaneously and be detected instead of being automatically initiated.  For restrictive lung diseases, such as Sacoidosis or neuromuscular disorders, low or very low triggering may be appropriate. So, that might be worth testing sometime.  Not tonight though - one change at a time and I have already taken the suggestion to set my target patient rate to 10, with Va changed to 4.8 L/min in order to get Vt = 600 ml.  I will report back in the morning.


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#6
RE: Therapy using Lumis 150 ST
I'm pretty certain if you set trigger to low it's going to be less sensitive to begin inhalation. The setting names correlate with how sensitive the action will be for either trigger or cycle.
Dave

OSCAR
Standard OSCAR Chart Order
Mask Primer
Dealing With A DME
Soft Cervical Collar Wiki
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEBSITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#7
RE: Therapy using Lumis 150 ST
(04-16-2022, 06:01 AM)SarcasticDave94 Wrote: I'm pretty certain if you set trigger to low it's going to be less sensitive to begin inhalation. The setting names correlate with how sensitive the action will be for either trigger or cycle.

Yes, that is what I have worked out.  Less sensitive / slower to trigger a machine initiated breath and more opportunity for a spontaneous breath to be initiated.  

It would appear that might be a good idea for me, the opposite to those with central apneas as far as I can see.
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#8
RE: Therapy using Lumis 150 ST
If you choose to do so, try the edit and if it's not what you expected then return it to the prior setting. Should be just a few seconds to edit this.
Dave

OSCAR
Standard OSCAR Chart Order
Mask Primer
Dealing With A DME
Soft Cervical Collar Wiki
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEBSITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#9
RE: Therapy using Lumis 150 ST
Okay, that was interesting.  The change that I made was to set target patient rate (upper limit of iBR) to 10.  I also needed to set Va to 4.8 so that Vt would be 600.  I did not change the trigger or cycle setting. 

The machine reports that I spontaneously triggered 85% of the night and cycled 92% of the night.  Just by those numbers, it would seem that change worked, but it is not necessarily that clear to me.  I had a split night, which is quite unusual for me, and the two periods are quite different.  

I woke after about 5 hours (it was still dark outside) and lay there for a while expecting that I would go back to sleep but that did not feel like it was going to happen.  It didn't help that my nose was hurting between my nostrils against the mask (Evora full) - I think I had a nose hair trapped and pulling because it stopped hurting when the mask came off!  So I stopped and took my mask off and almost immediately felt like I could go back to sleep.  I just lay for a while before getting up to empty my bladder, then went back to bed, but this time I put on a Vitera mask.  I did get back to sleep.

In the first period, my respiration appears to be mostly spontaneous, even being higher than 15 at times.  But in those periods, the tidal volume is around 400 ml.  I would imagine that this is because the iVAPS mode targets alveolar volume (L/min), which would, i am guessing, be achieved by controlling tidal volume in response to the uncontrolled respiratory rate. 

In the second period, my respiratory rate is almost entirely controlled by the machine. It does not make sense that this could be related to the mask change.  I can only think that it is a response to the period of time where I stopped the machine and took the mask off, but I do not have any theory about why or how.

I noticed one other interesting thing. There was a bit of cyclic breathing around some of the hypopneas.  I used to see a lot of that when on fixed CPAP but have not seen much of that since starting to use the Lumis.  I suspect that it is because my IPAP at the time was only 9, so I am considering the need to increase PS min.  Still just a thought, not highest priority in my mind at this time.


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#10
RE: Therapy using Lumis 150 ST
Another night, another set of results.  I decided to see the effect of setting the Trigger to Very Low.  That meant that I also reverted back to a Target Patient Rate (upper limit of iBR) of 12 and Va of 5.5 - same as two nights ago.  The machine tells me that it did very little to help, it reported spontaneous trigger of 6% and spontaneous cycle of 91%.  The charts show the same thing.  Most of the time the machine controlled: pressure at or near IPAP max, respiratory rate close to 12, tidal volume around 580 and minute vent quite consistent. 

My AHI was low, only two hypopneas.  The first was following a disturbance of some sort, so it provides little information.  The second is right at the start of a period where flow rate seems to be reduced, which is visible on the flow chart but also reflected in both tidal volume and minute vent.  I have attached a 3 minute chart for the event (is this the preferred time?). As I understand the shape of the flow wave,  it looks as though there are some quite significant flow limitations.  My thinking is that I probably rolled onto my back and that my EPAP is too low for that situation.  Since pressure support is added to EPAP, I might experiment with that first and then review pressure support later.

My current EPAP is 5, as per the sleep study, but I had an effective EPAP of 6 when using fixed CPAP with pressure = 9 and EPR = 3 and, of course, it was higher whenever I tried higher pressures.  I have also just looked at my statistics from mt DS1, which had pressure  = 9 and CFlex = 1  My average EPAP  for the last year that I used it was 7.4 (probably explains why AHI was typically <1 with the DS1 but only <2 with the AS10).

Open to better suggestions but I am thinking that tonight I will experiment with AutoEPAP with a small range from 5 to 6, keeping pressure support at 4 to 9, so  IPAP  may range from 10 to 15 instead of 9 to 14.


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