Love My AHI Going Down But What About Time in Apnea and sleep quality?

[Geer1]

You should be having a number of desaturations as that is a normal occurrence especially in someone with SDB. In my data I rarely have hypopneas but when I do they often correlate with desaturations like in this example. 

   

I also get them with Reras and moments of odd breathing that don't trigger flags like these. 

   

And I also get what I would consider fake desaturations due to SPO2 levels normalizing after increasing to an elevated state after arousal breathing. Like this example. I believe this wouldn't count in a sleep study since I wouldn't be flagged as asleep at the time.

   

On that night of data I only had 17 apnea, hypopnea and rera combined but had 43 desaturations (according to oximeter report). 


It may be possible that all your hypopnea being recorded are mild and do not create desaturation or arousal but I do not believe that is normal/common and if true perhaps brings into question the accuracy of PR hypopnea scoring (at least in your case).

[S. Manz]

Wow, your SpO2 is really sensitive to your events!
I can't make a clear correlation with mine, with either my Resmed ASV or DS ASV.
This is most likely because my oxygen level doesn't get a chance to drop with every single event, since the machine breaks it up. (note backup breath markers prior to each event)
   
however if I sleep without the machine, my median drops.
My device persistently shows a median of 94-95 average on the machine and a 96-97 average during the day, which is why I'm gonna get me a Masimo below;
   
PS,
Desaturation happens at different rates in different people.

[Geer1]

Overall your hypopneas don't look that bad and they definitely are partially treated central apnea as you can see all the machine triggered breaths surrounding them. Your O2 levels are bouncing around though and at 3:44 you have ~ 3% desat, 3:48 a 4-5% desaturation followed by a rise and then another ~ 3% desat, 3:50 around a 3.5% desat. Your O2 levels are staying in a good 90+% range and it probably isn't an issue as long as arousal is not also occurring with these hypopnea (looks like there may have been one around 3:49:20). I don't think desats are usually much of an issue unless spending extended time below 85% or drops to like 60/70 range, I think it is usually the CO2 and associated arousals that cause the symptoms in most people rather than the oxygen levels.

One thing I do want to point out is how sharp and fast both your inhalation and exhalation periods are even during periods of spontaneous breathing (3:45:30). That is only a short period of spontaneous breathing but if all your spontaneous breathing looks like that it isn't ideal. Exhales often look sharp but inhales should be nice rounded tops akin to the few breaths at 3:47 which occurred during a period of depressed respiratory effort. These fast sharp peaks imo support too high of a min PS blowing yourself up like a balloon. Just something to think about and look at in your data if you ever do try a lower PS again. I really do think it would help which is why I continue to mention it.

Edit: Jmo but I wouldn't bother buying another oximeter. I don't think you need it and think you worry a little bit too much about oxygen levels. Yours stay pretty good and if you keep your apnea in check shouldn't need to worry about checking O2 levels.

[S. Manz]

Great observations , I am impressed.
I like the way this conversation is going because now I can show you how it is that I don't do well with my Resmed ASV.
The screenshot below is a similar 7 minute window as my last post's attachment from my DS ASV.
   
Note how flow, pressure and resp.rates are all over the place and then see how the DS stabilizes everything in comparison. Good grief, look at my Resp.Rate. It hits off my scale at times, off the chart on Resmed. (Off the chart values are less than 4 at times) !!!
Both machine settings are similar, settings wide open as per manufacturer's standard recommendations.
Even my sat. levels are lower on Resmed, all to say that there are good reasons why I eventually went back to my DS.
I will truy titrating Ps Mins but tonight I will reduce the backup rate on the DS by 1/min and see if machine generated breaths will reduce overall as I expect then to behave.
We will see tomorrow.
Great conversation.

[Geer1]

If that is your typical Resmed data then yes I agree something is conflicting with your personal case. Perhaps the backup rate which is a frustration that it can't be adjusted. The one other potential is that because Resmed algorithm is more aggressive your average PS may have been even higher and causing more respiratory depression and the uglier graph.

Trying a lower backup rate was another idea I had which does similar to reducing PS min by lowering base ventilation support the machine provides and in theory both should reduce machine initiated breaths and help stabilize breathing.

I actually almost commented about checking your backup rate because in that example you posted the one small section of spontaneous breathing had a respiration rate very close to backup rate. I wasn't sure if that is a true representation of your spontaneous breathing though as it was only a few breaths and no information on PS being supplied at that moment(needs to be min value to be true spontaneous breathing). When posting these zoomed in examples I always like to be able to see mask pressure to get a good idea as to what the machine is providing for intervention.

Setting PSmin and backup rate is a bit of a balancing game. If you set PSmin higher your body is going to depress respiratory effort, slow your respiratory rate (to the point of apnea at times) which means a lower backup rate is required. If you set backup rate at a high PSmin then when you try a lower PSmin your backup rate may be too low because your breathing may have changed back to true spontaneous rate.

Backup rate should be 2 BPM lower than true spontaneous breathing rate. Best way is to find sections of good spontaneous breathing, determine average/lower end of respiration rate at those times, subtract 2 and set that as your backup rate. If you try to set it closer or faster than spontaneous rate you will always see lots of machine initiated breaths as the machine prematurely interferes when it isn't actually needed.

On that topic respiration rate is actually a good indicator for PS min. As is minute vent statistics. If raising PSmin decreases RR and has no effect on MV then it means your body does not want the extra ventilation and is trying to counter act it by slowing RR. If RR does not change and MV increases it is a sign that the extra PS is perhaps helpful. The one time this isn't necessarily true is in cases of UARS where there is high restriction causing an elevated respiratory rate and level of effort and one of the goals is just to reduce breathing effort/respiratory rate. Based on your previous posts you believe you only have central apnea which is why I would say that RR decreasing is a sign of too high PSmin and not a good sign that it is reducing respiratory effort because of UARS.

[S. Manz]

Well noted.
As for last night's experiment, I dropped the backup rate by 1 and also raised my T1 from 1.8s to 1.9s. T1 is the time that DS allocates machine generated backup inspiration (all medians are comparisons to previous 7 days of data)
As expected my average patient initiated breath rate went up by a median average of 13%.  
(Its noteworthy to mention that when I increased my PS-min from 4 to 6 a while back, the median PIBR went up by some 30% , which is what I was aiming for however it also went up by another 13% last night after dropping the Backup rate down by 1)
My RR median also went down by exactly 1 /min
My MV median went down by exactly 2 l/min as well (not shown on this screenshot, but take my word for it).
   
and here's a 7 min segment (included is mask pressure as requested)
   

My conclusion is that although lowering the backup rate produces a desired outcome in my PIBR, the reduction in RR and naturally MV as a side-effect is counterproductive.
In short the reduction in BR results in a an elevated PIBR of only about 13%, because i am fighting for more air 13% more of the time.
At 30% increase for a 2cm rise in PS-Min however, appears that elevation of PS-Min has a more profound impact on my PIBR, than does lowering of Backup Rate.

Ps.
In regards to a new Oximeter, I changed my mind about Masimo after finding out that a pack of 10 disposable sensor tapes cost over $400 , which is how they make their money.
I am however actively looking to setup a direct Nonin rig to my DS1 as my machine is already equipped with a Cellular/Oximetry module. (current cost of additional hardware is about $500, so I am looking for a refurbished deal which could take a while, but if I eventually get it, then all my numbers will be generated by the same firmware and they will all be uniformly right or wrong, but at least they would be right or wrong at similar rates.
   

In regards to my Resmed ASV being all over the place with my data, I honestly think that Resmed firmware is not up to snuff when it comes to CAS therapy. The thing is that since it does not monitor a whole host of inputs that the DS-1 does, it simply cannot keep up with my rapidly changing respiratory dynamics, but then again I would have never known that if I didn't have a Dreamstation.

[Geer1]

My conclusion is that although lowering the backup rate produces a desired outcome in my PIBR, the reduction in RR and naturally MV as a side-effect is counterproductive.
In short the reduction in BR results in a an elevated PIBR of only about 13%, because i am fighting for more air 13% more of the time.
At 30% increase for a 2cm rise in PS-Min however, appears that elevation of PS-Min has a more profound impact on my PIBR, than does lowering of Backup Rate.

You can never use one night of data to try and draw any conclusions especially in cases of severe central apnea like yours. Central apnea is notoriously inconsistent and you probably need to average a week of data at each setting before trying to draw any conclusions from it.

I personally disagree with your conclusion if you only have central apnea. MV should not decline that significantly unless you were previously over ventilating yourself or you have a hypoventilation issue in which case your oxymetry data should have shown noticeably lower oxygen levels. If oxygen levels were stable then simply put you did not need that oxygen/ventilation. 

Imo the problem is that you are viewing your breathing issue as if you need an actual ventilator not just a little bit of ventilatory support that these machines are supposed to provide. You are already near maximum machine settings and thinking you need to maintain or get more from them whereas the recommendation is always to use the minimum settings possible and Phillips Respironics recommends a starting point for central apnea/ASV use as a PSmin of 0 (can see in following link). The reason behind this is because high PSmin is contradictory to the majority of central apnea cases, its like giving a diabetic a snack when their sugar levels are spiking.  

PR titration guide.

https://www.documents.philips.com/assets...3de0e6.pdf

Did you start your PR titration with recommended settings or just jump into high settings because that is what you had worked up to with the Resmed that wasn't working for you (Edit: keyword you, many people with CSA do very well on Resmed machines, best not to draw blanket conclusions based on singular personal experiences).

[S. Manz]

Imo the problem is that you are viewing your breathing issue as if you need an actual ventilator not just a little bit of ventilatory support that these machines are supposed to provide. You are already near maximum machine settings and thinking you need to maintain or get more from them whereas the recommendation is always to use the minimum settings possible and Phillips Respironics recommends a starting point for central apnea/ASV use as a PSmin of 0 (can see in following link). The reason behind this is because high PSmin is contradictory to the majority of central apnea cases, its like giving a diabetic a snack when their sugar levels are spiking.  

PR titration guide.

https://www.documents.philips.com/assets...3de0e6.pdf

Did you start your PR titration with recommended settings or just jump into high settings because that is what you had worked up to with the Resmed that wasn't working for you (Edit: keyword you, many people with CSA do very well on Resmed machines, best not to draw blanket conclusions based on singular personal experiences).

Actually I am not at max or min. I am somewhere in between both ends .
The machine is set wide open as per Respironics recommendation.
As for my rather high Hypopnea, increasing PsMin is exactly what the doc and Respironics both recommend 
(see the fine print in the titration brochure that you just linked):
"• If numerous hypopneas are noted, maintain PS > 4 cm H2 O"..... which in my case, they are "well noted" and again, PS Min of 4 is what is normally recommended for severe cases.
That should answer your last question too. I didn't dream up the settings, clearly (except for max EPAP which I keep a bit lower than recommended because I don't really need it to go that high)

As for my sat levels, they actually (surprisingly) stayed steady last night at 95% median but I think that median is mainly kept up by high sat levels while I was awake wearing my O2Ring, 3 hours before going to bed .
My sat levels took a dive in the middle of sleep session and went as low as 89% for about 20 minutes or so.
But I think that you have a point in that one night isn't enough spread to draw any conclusions, which is why I'm going to continue with the lowered backup rate for another week and see how that will pan out.
You are correct in that CAS is a very complex issue because there's absolutely no pattern to its flareups. (unless one is a regular opioid user or an alcoholic),
 Some nights my hypopnea events are so low (especially when I use my Resmed  ) that it seems I may even not need a machine and most nights my hypopnea events are all over the place. 
The issue with 4 months of using Resmed therapy was that at full spectrum settings (like Resmed recommends for ASV and Auto ASV modes) there was no way that I could get a good night sleep which meant that I had to restrict the settings however that meant that I was not receiving full ASV therapy.
This is something that I do not have to do with DS.

[S. Manz]

You can never use one night of data to try and draw any conclusions especially in cases of severe central apnea like yours. Central apnea is notoriously inconsistent and you probably need to average a week of data at each setting before trying to draw any conclusions from it.

UPDATE-2nd Night Results:
So I continued with the lowered backup breath rate of 8 for the second night.
My O2 saturation dropped to a new all time low, from a consistent median of 94%-95% to 92%
(FYI my CAS was diagnosed in all 3 lab studies over a one year period with an average AHI of 58 and a median O2 sat level drop to 82% , breathing on my own, so no I did not dream up my CAS and I do tend to believe doctors and clinicians more so than anyone else ).
   
FYI my MV RR and other parameters remained at their new lows since I lowered the backup BR by 1/min.
     
Moving forward if this trend continues, I will of course increase the backup rate to its previous setting as this experiment will have concluded as per my expectations.

In regards to your comment to the effect that CPAP machines are only intended to provide "a small amount of respiratory support" , I tend to agree to the extend that CPAP itself is an old school technology that is intended to keep the upper airways open (via maintaining an EPAP pressure) for the treatment of OAS, much like your own machine. (if indeed your profile states the correct machine).
ASV technology however takes CPAP machines up closer to Ventilator type technology in that they operate based on "Servo" feedback (feedback from patient).
I also think that more and more doctors will be prescribing ASV machines in near future which will mean elevated supplies which also means lowered pricing. One day soon therefore there will be no normal PAP machines in the market and mainstream home PAP therapy will have moved towards ventilator type of therapy . We already see this trend in the making by companies like Philips introduction of their AVAPS line for home use. A dreamstation AVAPS looks exactly like any other dreamstation with the exception that it can be used as non-invasive ventilator therapy right out of the box and with a little modification (addition of appropriate air circuits), it can even be rigged as a full invasive Ventilator.
ASVs ARE a step towards home ventilator therapy, period. This is also why they are prescribed for the treatment of CAS.
   

[Geer1]

Yes I saw the note about higher PS for remnant hypopnea. Using the higher PS to treat remnant hypopnea is a crutch like using supplemental oxygen, it is only necessary if you can't find better settings that resolve the issue to begin with. You have to first try low PS on the PR machine to see if you have remnant hypopnea at those settings before can know it is required and to my knowledge you just carried over settings from failed Resmed titration and haven't used low PS on the PR yet (if you have just posting a couple examples may satisfy my curiosity). 

The drop to 89% SPO2 is potentially relevant to these discussions depending on what caused it. Did it happen during a period of hypopnea, spontaneous breathing or machine initiated breathing? I would be curious to see an OSCAR shot if you aren't sure. 

You might be right about some of these settings being better/required but without seeing data to back it up I just can't support it, not when the data you do post shows high sharp peak inhalations and your MV being propped up by machine settings. Trialing lower PSmin tells us a lot about not only these settings and how your body reacts to them but also more about your specific breathing issue which appears to be more complicated than the average CA case.