help reading (understanding) data from s8 auto

[halb]

I set my s8 auto to auto mode 10.8 - 14. after 8 hours my stats were
ahi = 8.5 ai=1.8 hi=6.7 pressure 95% -12 leak .14 median 11.0 leak .02 max 12.6 leak .42. I do not understand why my ahi is so hi on auto mode .looking at my data i see between 4:45 and 5:45 alot of apneas with 2 of them being 37 sec and 8 of them around 15-17 seconds. When I exported the data I see that it jumped from 11 to 12.6 then went slowly down back to 11.6 . Why is it not dealing with the apneas. Is it because it senses that these are central apneas? On my sleep study i had mostly hyponeas and no central apneas. If it senses that the higher pressure is not helping does it just stop and lower? Can this mean that I have a problem with central apneas or is it that the pressure is too high and causing central ?If I just had another sleep study with cpap on will they be able to tell me if there is a central apnea problem. I have not seen the doctor yet but the tech said she had me up to 14

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CPAPopedia Keywords Contained In This Post (Click For Definition): AHI, auto

[SelfSeeker]

Hello halb,

I am not familiar with your machine.

I have a remstar and will go by its data, to try to answer some of your questions.

Do you see anywhere somewhere about non responsive apnea/hypopnea, those most likely would be centrals. At least on the remstar. Since a a couple of increases of pressure did not stop them.

Do you have the full data, that shows what happened at each pressure?
Or any of the graphs?

I think what most people do is set their auto at a pressure to avoid having the apneas happen. But then still have the auto for any that may happen at a higher pressure. I once asked this question. I will find it and post the topic from that discussion for you. I was a similar question.

This is where I may be wrong, so someone may need to correct me: On the Remstar the apneas and hypopneas that are shown are dealt with but are still recorded at the pressure it took to deal with them. I am not sure if it is the same with your machine because apneas of 37 seconds seems long to me for the machine to be dealing with.

Edit: Link about Autos, pressure and apneas:

viewtopic.php?t=14155&highlight=auto+apnea

Hope this helps.

[GoofyUT]

The ResMed AutoSet Vantage is designed to do NOTHING in the face of an apnea. The thought behind that design is that abruptly increasing pressure while an apnea is occurring either runs the risk of arousing or awakening you (thus fragmenting your overall sleep architecture), or else runs the risk of provoking or making an apnea which is CENTRAL in origin, worse. So, ResMed S8 autos are designed to pre-empt the occurence of apneic events by sensing flow limitations or degradations of the flow waveform and applying increased pressures to ward off the occurence of apneas. The algorithm is designed to increase pressure sharply, and it is also designed to reduce pressure gradually, again to avoid arousing you. Some find that design to be objectionable. I did, and switched to a REMstar Auto and achieved much better success.

AutoScan v5.7 does NOT score any event as "non-responsive", which is EncorePro's classification for an event that doesn't respond to pressure increases and therefore, might be central in origin. NO APAP can actually score a "central" without first measuring exertion of chest and abdominal expansion to determine whetehr you are "trying" to breathe or not, when a flow limitation occurs. So, NO, your S8 does not score "centrals", but neither does any other xPAP. Respironics xPAPS do try to make a guess, based on non-responsiveness to pressure increases.

Hope this helps.

Chuck

[SelfSeeker]

Chuck are you saying it does not increase the pressure to open the airway?

Which is what I think you are saying, but does not make sense to me. Would you not want to get the air passages open to stop the apnea. I understand about the centrals, I thought that is why an upper limit is set.

So then with someone with this machine, the lower limit would need to be increased to avoid the apneas?

halb when do you see the doctor again?

[GoofyUT]

That's right. ResMed's are designed to do nothing and to let the apnea it detects resolve itself, either through your shifting position while you sleep, or arousing yourself (often with a bolus of adrenaline), thereby re-opening the airway. Thereafter, the ResMed is adesigned to AGGRSSIVELY increase pressure to ensure that another event DOESN'T HAPPEN.

BTW, there is NO NEED to adjust pressures because of this design. The algorithm is designed to do that for you. You simply have to choose whether this algorithm provides the best and most effective treatrment for you. Many worldwide, have decided just that.

[Guest]

The ResMed AutoSet Vantage is designed to do NOTHING in the face of an apnea. The thought behind that design is that abruptly increasing pressure while an apnea is occurring either runs the risk of arousing or awakening you (thus fragmenting your overall sleep architecture), or else runs the risk of provoking or making an apnea which is CENTRAL in origin, worse. So, ResMed S8 autos are designed to pre-empt the occurence of apneic events by sensing flow limitations or degradations of the flow waveform and applying increased pressures to ward off the occurence of apneas. The algorithm is designed to increase pressure sharply, and it is also designed to reduce pressure gradually, again to avoid arousing you. Some find that design to be objectionable. I did, and switched to a REMstar Auto and achieved much better success.

AutoScan v5.7 does NOT score any event as "non-responsive", which is EncorePro's classification for an event that doesn't respond to pressure increases and therefore, might be central in origin. NO APAP can actually score a "central" without first measuring exertion of chest and abdominal expansion to determine whetehr you are "trying" to breathe or not, when a flow limitation occurs. So, NO, your S8 does not score "centrals", but neither does any other xPAP. Respironics xPAPS do try to make a guess, based on non-responsiveness to pressure increases.

Hope this helps.

Chuck

that is the most convoluted explanation I have ever seen. You must not understand the A10 algorithm at all.

[GoofyUT]

Sorry Dog! Why don't you give it a shot.

Chuck

[Bookbear]

Halb, how are you feeling? Worse? Better? That is really the most important gage of your response to treatment. Also, remember that anyone can have an 'off' night. One night's data doesn't necessarily indicate a problem, Rather, look at trends over at least a week, preferably longer.

GoofyUT makes some good points. It cuts both ways, though... for some people, the ResMed algorithm provides treatment better suited to their needs than Respironics' does. People differ. I would add that the ResMed machines have a reputation for being more aggressive in their scoring of hypopneas than other machines (as I understand this, something that another machine's algorithm would pass as a normal variation in breathing, the ResMed counts as a hypopnea). Also, in my own experience, I have the most hypopneas in the last hour of my sleep, and most of all just before awakening. This explains why, if I am awakened before the end of my normal 8.5 hour sleep period by the dogs next door, I have a noticably lower HI (and therefore a lower AHI) than I do if I wake normally. This has been consistant with me for the six months I have been on CPAP therapy, so I am assuming it is normal for me. By far the greatest part of my AHI is hypopneas. So far this month, my average AHI is 4.4, with the AI being .2, making the HI 4.2. I tend to think that the apneas are more of a concern than hypopneas, so I am content.

Hope this helps, and good luck!

[GoofyUT]

Bookbear's points are, as usual, very well taken! I do want to make it clear that the ResMed algorithm has proven to be VERY EFFECTIVE for many, and is VERY WELL VALIDATED in many studies in the professional literature. As I have also frequently stated here before, I respect enormously ResMed's scientific candor and self-respect in making available not only the citations for the articles that have evaluated their equipment on their web-site, but also have taken the extra step of including hyper-links to the actual articles to allow the inteersted reader, be they professional or end-user, to read the actual article and evaluate them FOR THEMSELVES. Respironics on the other hand, lists articles evaluating their equipment on their web-site, but includes links only to ABSTRACTS of those articles that Respironics themselves (not the authors or journal editors) have written.

I found that the sharp attack of the ResMed algorithm would arouse or awaken me, and therefore, was NOT a good match for me. Respironics' step-wise increases proved to be a better match FOR ME. Others however, find that Resmed's sharp attack is just what they neeed to knock down up-coming SDB events, and that the ResMed algorithm is FAR more effective for them than the Respironics algorithm is, simply because of its rapid response to flow degradations.

Though I've switched to a REMstar Auto for my home usage, recently I had the occasion to travel with my S8 AutoSet Vantage to attend a professional meeting. Not only did I find the S8 Vnatage/H3i to be DELIGHTFUL to travel with, but I used it in CPAP mode and experienced AHIs at the same <0.3 that I do with my REMstar in auto mode. And I was able to see that instantaneously on my ResMed's LCD screen, which I can't on my REMstar without downloading. Plus, I used EPR for the first time, and found it to be WONDERFUL, and MUCH more soothing than Respironics' C-Flex is.

I agree that ResMeds are aggressive in terms of scoring hypops, particularly in AutoSet mode when "Settling" is NOT enabled, and therefore, AHIs with LOTS of hypops should be taken with a grain of salt.

Chuck

[Snoredog]

I set my s8 auto to auto mode 10.8 - 14. after 8 hours my stats were
ahi = 8.5 ai=1.8 hi=6.7 pressure 95% -12 leak .14 median 11.0 leak .02 max 12.6 leak .42. I do not understand why my ahi is so hi on auto mode .looking at my data i see between 4:45 and 5:45 alot of apneas with 2 of them being 37 sec and 8 of them around 15-17 seconds. When I exported the data I see that it jumped from 11 to 12.6 then went slowly down back to 11.6 . Why is it not dealing with the apneas. Is it because it senses that these are central apneas? On my sleep study i had mostly hyponeas and no central apneas. If it senses that the higher pressure is not helping does it just stop and lower? Can this mean that I have a problem with central apneas or is it that the pressure is too high and causing central ?If I just had another sleep study with cpap on will they be able to tell me if there is a central apnea problem. I have not seen the doctor yet but the tech said she had me up to 14

I agree with Bookbear, one night doesn't mean anything, you should look at longer term stats, use the weekly or monthly avg instead of the last session. That machine will always score higher hypopnea count as they are calculated and it doesn't respond to them. The AI or apnea index is what you want to look at, if your AI indice is below <5 then you are effectively treated but some like it even lower than 2. Your pressure can hover +-1cm and it doesn't mean anything, allergies, glass of wine with dinner can all effect the outcome of a single night.

You will see more apnea's in the early morning hours of sleep because as you progress through the night you spend more and more time in REM especially right before you awaken. REM is also one of the areas where more SDB events are likely to occur.

The weekly stats should give you a better picture of how you are doing. You should also base your settings on how you feel.

[halb]

Thanks for all the responses. I understand that an auto will not change pressure during an apnea. However what I can not figure out is why in the hour between the hour of 4:45 to 5:45 after I had several hoponea then an apnea of 37 seconds followed by about another 8 apneas in that hour of between 15-30 seconds .(plus many 10 hypo). Shouldn't the auto increase pressure during this time to prevent further apnea? Or does it sense that the higher pressure is doing nothing and just starts lowering pressure even though there are alot more apnea. Software for resmed does not show about non-responding apnea . If I use in straight cpap does this mean i should not increase my pressure beyond what it says is 95%. I should be seeing the doctor in about 3 weeks . However these doctors do not seem to be able to read the printed data that i have - One doctor told me before she'll have to give it to the tech to read . They only know how to read the overnight studys- The tech told me that they do not have the software to download from peoples machines - they have their own software (mind you this is at a teaching hospital). I did not use my auto for the whole night last night because i was suffocating in the middle . The data that I have is a little bit better but I still see 5apnea within a 45 minute period and wondering why after the first long one again of 37 seconds doesn't it control the later ones - thanks to everyone for their help. Can someone tell me I tried to change the clock back an hour on my machine but unless i delete all data it does not seem to listen and reverts to the old time ( I'm not talking about the time on the old data, I'm talking about changing the time now and afterwards it says delete all data yes or cancel . If I cancel it cancels my time change also.thanks