Low Tidal Volume

[michael9346]

I have been on Cpap going on 2 years and this forum has been a huge help in improving my numbers. I have used at least 10 different masks over the years and have gone from FFM's to pillow masks. I receive my best numbers from my pillows. My most comfortable FFM has been the Airfit and Airtouch F20 with Tidal Volumes around 430. I recently switched over to the P10 and alternate it with the Nuance Pro. My tidal volume is very low using pillows at around 340 to 360. I know they have a lot to do with respiration and possible other respiratory problems, so my question is should I be concerned? My numbers usually fall in at <1.00 and also receive many 0.00's but I am curious if this may be a warning of other problems? I appreciate any comments on this matter.

[attachment=10904][attachment=10905]

[Gideon]

I am no expert on these issues but to have more data to answer your questions with add Tidal and minute vent and respiration to your charts and zoom in to a 3 minute view so we can see details.

[michael9346]

Thank you Bonjour. I have attached the 2 days with about a 3 minute spread as you requested.
[attachment=10910][attachment=10911]

[Gideon]

Now cut the window to 2 minutes and on the flow rate tighten the scale. I think I'm seeing flow limitation so persistent that there is no baseline to to judge the reduction against.

[Sleeprider]

The real question in all of this is, are you adequately ventilated. Tidal volume is one piece of the the three-parts to be considered. A tidal volume of 380 mL is not very impressive for a male, but combined with the over 19 breaths per minute, it results in the minute vent of nearly 8 L/min which is pretty good. I don't see a problem here that we can resolve by looking at Sleepyhead. If your capacity is somehow limited by a pulmonary restriction or other problem, then a simple pulmonary function test (spirometry) to determine FEV1 / FEV2 should be on your request list the next time you have a routine physical exam. Actual oxygenation can easily be quantified using a recording oximeter to measure SpO2 and pulse.

Your charts suggest you have the tidal volume on-call when you need it, but are taking shallow, relatively rapid breaths. That may be your normal, and I don't know how we might change that through the settings of an auto CPAP. It might be possible to encourage greater respiratory volume using a bilevel machine, but not the CPAP. Considering an AHI of zero, unless you have some kind of pulmonary impairment that would be considered medically important by your doctor, I think the best way to look at it, is it's normal for you, and not abnormal at all.

[michael9346]

Not sure what "tighten" meant so I hope I did it correctly.
[attachment=10912][attachment=10913]

[Gideon]

Close enough, it looks better at this scale.

I wouldn't touch anything unless you are having issues. How do you feel?

[michael9346]

Thanks Sleeprider. I will throw this at my sleep doctor and my cardiologist. I doubt my sleep dr will be of much help. Last time I seen him he seemed so impressed with my AHI number he proclaimed me "cured" and told me to make another appointment in one year. I told him if I am "cured" I don't need him anymore.

[michael9346]

How do I feel? Since I've already had a heart attack, bypass surgery, Hi blood pressure, diabetes, Afib, prostate cancer, arthritis and overweight I would be hard pressed to think OSA is going to be victorious in sending me to the pearly gates.

[Sleeprider]

Close enough, it looks better at this scale.

I wouldn't touch anything unless you are having issues.  How do you feel?

I'm sure you see the same flow limitation I do.  Once again, the wrong machine (Dreamstation), but not medical "necessity" to change it.