changing mask and minute ventilation/tidal vol

[gertrude]

About 2 1/2 weeks ago, I changed masks from a nasal mask (Mirage FX for her) to nasal pillows (Mirage Swift) because of an open infected sore on my nose. In exploring Sleepyhead data, I noticed a drop in the maximum values for minute ventilation and tidal volume that coincides with the switch in my mask. By playing with the custom range feature, I got average values for the time I've spent with each mask. The max average for tidal volume dropped from 1345 to 1023 and the max average minute ventilation dropped from 14.37 to 9.70. The 95% level and median dropped only a very small amount. There also seems to be less variation in these parameters with the nasal pillows. Nothing else has a consistent change that conincides with the new mask.

Could anyone explain exactly what tidal volume and minute ventilation signify? Any ideas why the maximum levels would drop and if it has any meaning? Are there normal ranges for these measures? (And for the other resiratory measures?)

Thanks in advance. I haven't posted often, but I read a lot on this forum and it has been incredibly important to persisting with this. I'm still struggling, but not nearly as irritable or having as much trouble with cognitive tasks as I was in the first month. BTW, the doctor had no explanation for those symptoms. My current hypothesis is that the APAP has been waking me up more at night than my untreated apnea was. During my titration study my time awake after sleep onset was elevated, with a decreased sleep efficiency of 66% and an increased awakening index.

[Pugsy]

If you google each term (tidal volume or minute ventilation) and go to the web Wiki definition you will see that there are wide ranges of norms for the respiratory functions. Short or tall, large or small, man or woman and even altitude will affect the norms. If I were going to pay much attention to these numbers I would only look at the overall averages.

In my signature is a link to a GLossary where the basic definition for these terms is offered but to get much more details you need to Google each and look up the Wiki definition.

[gertrude]

Thanks for this advice, Pugsy. The resources online do help a little, but they are not geared to someone with air blowing down their throat! And I am not sure what units are used in the Sleepyhead graphs.

What I'm taking away is that at my maximum breathing I am not exchanging as much air, or at as high a rate, with the nasal pillows as I was with the nasal mask. Probably no significance, but I'm curious why that might be the case as I still try to figure out what mask is best for me.

Any RTs out there with insight?

[Pugsy]

The units for each category are available in SleepyHead.
Scroll mouse over each category and a box pops up with units...like tidal volume is ml...