Question on sleep titration study -- arousal index, uars

[Sleeprider]

For a healthy male that is 6'-1" I would expect tidal volume to be over 500, but would not be overly alarmed unless you were typically in the upper 200s to lower 300s. Mine is generally in the 600s. There are many reasons for volume to be less, and we would have to look at minute vent respiratory rate and other statistics to judge. Your doctor can very quickly perform a spirometry test during routine physical exam to determine if your expiratory volume is in a normal range, of course when we sleep different dynamics come into effect. The fact you have generally low SpO2 according to your sleep test makes me suspect a fair amount of upper airway resistance or potentially pulmonary issues. Without a health history or seeing the flow rate charts, it would be very hard to know.
The wiki on flow limitation may apply to you. http://www.apneaboard.com/wiki/index.php...Limitation
http://www.apneaboard.com/wiki/index.php..._and_BiPAP
http://www.apneaboard.com/wiki/index.php...ailed_look

[dcg494]

Thanks for the responses everybody. RE the 02 levels, I have a CMS 50F and have used it a lot and my oxygen levels with Xpap almost never fall below 92.

Sleeprider, do you have any more information on hypoventilation ? Any indications in sleepyhead that would point to an issue with ventilation ?

FYI, i hardly ever have centrals pop up on sleepyhead. 

I don't really know how to read into minute ventilation and tidal volumes to interpret those, but would like to learn more. Both seem to mirror what's going on in the flow rate graph -- which is why i never bothered reading them -- because the flow rate seems to give the same + more information. 

I must have UARS, since the first diagnostic study I had an arousal index of ~40, almost all RERAs. 

Wish I could post more info, but I don't have any of the graphs etc, unfortunately, and the study is 4 years old.

[Michaely6]

Any good recommendations for an oximeter that is compatible with sleepyhead and a Macbook pro?

I have the CMS50I and am very happy with it.  The accuracy is very good and its data lines up well with my CPAP data easily in SleepyHead.

Do you have a link to wear you got yours from? Sorry to the original thread starter i don't mean to hijack your thread with questions about an oximeter

[Sleeprider]

Thanks for the responses everybody. RE the 02 levels, I have a CMS 50F and have used it a lot and my oxygen levels with Xpap almost never fall below 92.

Sleeprider, do you have any more information on hypoventilation ? Any indications in sleepyhead that would point to an issue with ventilation ?

FYI, i hardly ever have centrals pop up on sleepyhead. 

I don't really know how to read into minute ventilation and tidal volumes to interpret those, but would like to learn more. Both seem to mirror what's going on in the flow rate graph -- which is why i never bothered reading them -- because the flow rate seems to give the same + more information. 

I must have UARS, since the first diagnostic study I had an arousal index of ~40, almost all RERAs. 

Wish I could post more info, but I don't have any of the graphs etc, unfortunately, and the study is 4 years old.

One of the articles I linked discusses UARS and bilevel. This is where I think you should be.  If your doctor prescribes CPAP, by all means INSIST on getting a Resmed (preferably Autoset). At least the exhale pressure relief on that machine is like bilevel and can help with flow limitation and volume. 

You have experience with CPAP. How has it been for you? Do you feel comfortable and that it has been effective? If you can post some charts, and especially flow rate graphs, we can probably help you with interpretation. I'd like to see you get into a treatment scheme that will be more effective, and in my opion that would be bielvel (i.e. BiPAP or VPAP). Have you discussed your concerns about low SpO2 and tidal volume with your doctor?

[Michaely6]

For a healthy male that is 6'-1" I would expect tidal volume to be over 500, but would not be overly alarmed unless you were typically in the upper 200s to lower 300s.  Mine is generally in the 600s. There are many reasons for volume to be less, and we would have to look at minute vent respiratory rate and other statistics to judge.  Your doctor can very quickly perform a spirometry test during routine physical exam to determine if your expiratory volume is in a normal range, of course when we sleep different dynamics come into effect.   The fact you have generally low SpO2 according to your sleep test makes me suspect a fair amount of upper airway resistance or potentially pulmonary issues.  Without a health history or seeing the flow rate charts, it would be very hard to know.  
The wiki on flow limitation may apply to you. http://www.apneaboard.com/wiki/index.php...Limitation
http://www.apneaboard.com/wiki/index.php..._and_BiPAP
http://www.apneaboard.com/wiki/index.php...ailed_look

Thank you as always.

[dcg494]

Thanks Sleeprider, yeah I've been using CPAP with flex for last 4 years. Tried almost everything -- all settngs, with a MAD -- but still tired many days, and never 100%.

Tried the latest philips bipap for two months, but felt like the machine was off. Maybe I'll give it another shot. 

Recently also had the chance to try the airsense 10 for her, but couldn't get the pressure up beyond 7.5 without bloating. Seems flex works better for me than the EPR in that respect. 


I can post some graphs tomorrow or the day after, one with my usual setup and maybe another with bipap. 

After a lapse in insurance no one wants to cover my SDB, so I'm on my own. But monitored SPO2 many times and it's definitely ok. Tidal volume is always around 440, min ventilation around 7.5, seems normal ?

[Sleeprider]

The stats seem fine, and it seems you tolerate fairly low pressure. Bloating is most likely aerophagia, so you may be between a rock and a hard place when it comes to pressure. If you were using the Airsense 10 For Her with 7.5 pressure and EPR and still getting air in your stomach, it's going to be tough finding a therapy that works and doesn't fill you up.

[dcg494]

Thanks Sleeprider, yeah it's a tough one. Tried bipap again at 5.5/9 last night and aerophagia was horrible. Maybe if I stop the nicotine that will help.

Just one more question, why did you think the arousal index went up at 9cm pressure in the titration study ?

Do you think it has to do with inability / anxiety to expire at 9cm or ?

I think I may need a titration study w bipap, do you think ?

Or probably cheaper for me w/o insurance, is get an autobipap or avs and self titrate.

[Gideon]

Even those of us who have established norms and low numbers see variability day to day. My norm is just over .5 and this morning I have a 2.1. If that continues I'll take a deeper look. It could be the same number of events but since it is the shortest period the index is higher. It could be you changed your sleeping position. It also could be your apnea is consistently inconsistent.


As I said not a worry. That is something that will show when you start posting nightly data and we are getting you dialed in.

[Sleeprider]

I can only speculate why your titration study showed an increase in arousal, but it's a dramatic increase.  I doubt a 1-cm change in pressure could cause such a significant increase in arousal and desaturation. It may be that there is a thereshold for your aerophagia at 9.0 and this causes arousals and apnea?  If so, then your bilevel experiment might be better at 8/4.5 pressure.  Does your bilevel have data?