CPAPtalk.com

Also, it seems as though flow transducers and pressure transducers are being used interchangeably. If we had a flow transducer, then everything above -0- (or "x") would be inspiration:

Wow that's big....

Sludge wrote:Wow that's big....

Haha yeah.

I think what I was trying to say is "up" doesn't mean inhalation - as you can see, there's parts of that flow signal that are "up" that are actually exhalation.

It's all very confusing though isn't it!

However, in the example of a pressure transducer (and this is not a normal breath):



the initial exhalation extends into the inspiratory portion simply because it can't get out of there fast enough (if the line is vertical, then little or no time was actually spent doing anything).

Perhaps a helpful example would be a BiPAP with a square waveform. When you inhale, Bang! here comes 60 L/M. When it's done, door slams shut. Consequently, initial inspiration and expiration are vertical:

sleepstar wrote:I think what I was trying to say is "up" doesn't mean inhalation - as you can see, there's parts of that flow signal that are "up" that are actually exhalation.

It's all very confusing though isn't it!

I believe the confusion is occurring because different technologies (pressure vs. flow) are being discussed (BTW, there is (at least) one more waveform, that of the plethysmography belts:



I think for the most part, those in the "above the -0- line" camp (and you need to say -0- and not x to make this point clear) are correct in labeling this inspiration because they are pulling flow waveforms off CPAP machines (which tend to be flow), whereas Swanson is talking about nasal pressure transducers.

That said, his expiratory line needs to be vertical in order to order to have a chance of labeling any of it expiration in the > 0 area.

Here is an example of a nasal pressure transducer (this is the Embletta HST, it's nasal pressure waveform recording flow). This person, a Master's Level Athlete, has a little FL. Inspiration and Expiration are color coded (as defined by the software) and the -0- line is present:



I think this shows that while Swanson's example might show exhalation beginning at end-plateau, in practice that rarely happens (there tends to be a brief end-inspiratory pause which allows the inspiratory waveform to return to -0-, and not an instantaneous initiation of exhalation.

Consequently, that makes Swanson's original example (which is a pretty normal breath) incorrect in it's identification of beginning exhalation:

sleepstar wrote:

OhHelpMe wrote:
****SHOCKED**** That people with as many posts as the two of you have this badly wrong.

Correct answer,

Points above the x axis are during inhale and points below the x axis are during exhale

Actually, you're incorrect too.

No, I am correct, you are confused. You need to follow the context which was about this ->

EMTunit31 wrote:The machine was set on 8 to 16 and I think I had one of my better nights. My leaks are very good.

https://www.dropbox.com/s/6lbhe9s57djac ... 0.jpg?dl=0

immediately follow by the question,

EMTunit31 wrote:Can someone explain the "Flow Rate" to me?

The question that was being answered was about Flow Rate in referenced SleepyHead chart. And the answer is what I said,

Points above the x axis are during inhale and points below the x axis are during exhale.

Try to understand the context first and then you might not get so confused.

When I called in my icode today I ask the lady if she could guide me through lowering the high pressure. She said not without the doctor telling her to do so. She called me back about a half hour later and said I should keep it set on high because my readings are still very bad. The average pressure is 19. She said I need a different machine because this one is not benefiting at all. I ask her to forward the report to my sleep doctor (Esky) so he can push for my insurance to cover in lab testing. He is in our town tomorrow so we will see what happens.

I went to my primary care doctor today and for the first time we are all on the same page. We all agree that I need an in lab sleep study. With all of them battling with my insurance co, BCBS Anthem, I would hope they listen and agree to pay for it. If not, then why are we charged premiums every week. And expensive ones!