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Exp time vs. insp time - Printable Version

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Exp time vs. insp time - dizzny - 03-05-2019

Hello everyone, 

I have been using my cpap for about 8 months now. At times it feels like i'm having difficulty exhaling, which led me to look at other users charts specifically the insp and exp times posted here and compared them to mine. Almost all of my charts reveal that my insp time is higher than the exp time by at least .25-.5 each night. Everyone else I see has just the opposite with exp higher than insp time. I raised and lowered the pressure, but that doesn't have any affect. Is there something else that I could do? A recent typical chart result attached.


RE: Exp time vs. insp time - SnoringInOregon - 03-05-2019

I didn't know this was something I needed to be concerned about. Have you read somewhere that this is an issue?

My times generally match yours. E.g. most recent night from Sleepyhead for me:

Min Med 95%
Insp Time 0.80 2.44 3.00
Exp Time 0.54 1.54 2.14


RE: Exp time vs. insp time - Sleepster - 03-05-2019

I don't like the looks of your leak rate graph, dizzny. Have you tried a chin strap?


RE: Exp time vs. insp time - dizzny - 03-06-2019

(03-05-2019, 11:59 PM)Sleepster Wrote: I don't like the looks of your leak rate graph, dizzny. Have you tried a chin strap?

Yes, I tried using one or two, but it didn't seem to help much and was quite uncomfortable. I use mouth tape. Also, I've had issues with the straps on my mask causing headaches, so with the loosening of the straps comes more air leakage.


RE: Exp time vs. insp time - ajack - 03-06-2019

You may need to get a full face mask, if the leaks can't be resolved. Once you have the leaks fixed. There is not a lot you can do about an inverse inspiration time with APAP. You can have the EPR at 3 and with the chart you have now. You could have the min at 9 and max 15. See if that supports your breathing more.

It may be just how you are, ask your doctor. To do any more may require a change of machine. You have a median tidal volume of 480 with a breathing rate of 13, giving a minute vent of 6.3 litres of air per minute. I think the 95% and max tidal volume shows you have good lung capacity.


RE: Exp time vs. insp time - mesenteria - 03-06-2019

(03-06-2019, 12:23 AM)dizzny Wrote: ... Also, I've had issues with the straps on my mask causing headaches, so with the loosening of the straps comes more air leakage.

I worry about two messages, or conclusions which seem to follow necessarily from the quoted text:

Your straps are too tight; and/or

You are wearing an unsuitable headgear for your particular head.

Firstly, you will get more, not fewer, leaks with headgear that is over-tightened.  You should be able to lift the cushion off of your face by just enough to break contact and to cause a gross leak.

Secondly, I think the location and construction of the headgear around your cranium and facial bones may be the cause of discomfort as much as, or more than, the tightness of the strapping.  We're all built a bit uniquely, and there's a wide variety of configurations for the headgear.  I wonder if you shouldn't go back to the proverbial drawing board and test out several different masks...overnight.  There is such a thing as 'pressing my nerve', or pressure points, and I'm beginning to suspect the general precursor to leaks in your case isn't necessarily tightness and poor fit so much as discomfort from the headgear that causes you to move or to struggle with sleeping well.  Agitation can cause deflection and deformation of the cushion.  Ergo, leaks.

I may have missed it by a mile, but I thought I would pipe up in case it is useful somehow.


RE: Exp time vs. insp time - Dormeo - 03-06-2019

Dizzny, about E and I times, you might want to take a look at this thread:

http://www.apneaboard.com/forums/Thread-I-E-ratio-and-FL-questions

and then zoom in on some of your breath-by-breath flow rates to see whether the same phenomenon is happening for you.


RE: Exp time vs. insp time - Sleeprider - 03-06-2019

If you can provide us with a zoomed view of the flow rate at a resolution of about 2-minute segments, we will be able to see the actual wave form and understand more about your unbalanced I:E ratio. Your machine appears to be set to 5.4 minimum to 12 maximum with EPR at 3. Your leak rate stands out as just under the large leak threshold, so your machine should be able to maintain the pressure. Flow limitation in your case does not look very severe, but we should look closer at the flow rate to see what is going on.


RE: Exp time vs. insp time - dizzny - 03-06-2019

(03-06-2019, 02:29 PM)Sleeprider Wrote: If you can provide us with a zoomed view of the flow rate at a resolution of about 2-minute segments, we will be able to see the actual wave form and understand more about your unbalanced I:E ratio.  Your machine appears to be set to 5.4 minimum to 12 maximum with EPR at 3.  Your leak rate stands out as just under the large leak threshold, so your machine should be able to maintain the pressure. Flow limitation in your case does not look very severe, but we should look closer at the flow rate to see what is going on.

Yes, attached is a more recent chart showing 2 minute segments, with a 5.8 minimum. Thank you Sleeprider.


RE: Exp time vs. insp time - Gideon - 03-06-2019

that is 45 minutes,  can you repeat with 2 minute segments so we can see the waveforms