Strange flow rate

[tedgreen]

Hi,

I have just zoomed in on my flow rate in Sleepyhead, and see some strange waveform (please see picture attached).

   

As it's not a normal sinus wave, does that indicate any issues?

Thanks,
Ted

[AshSF]

This waveform is normal. The sine wave that you probably referred to is typically used to show breathing in presentations etc. but that's not how you breathe.

We breathe in. And we breathe out immediately after that. But then we typically pause before taking in a breath again. And that's what your waveform shows.

[RichardVT]

   
My flow rate is very similar in appearance to the OP's.
Where does the inhalation begin on the waveform when beginning a new breath of inhalation?
I assumed it was at the lowest valley in which case the leveling off would be in the middle of a breath.

[AshSF]

The inhalation begins when the flow rate > 0. So it typically shows as a rapidly rising wave after a plateau around 0. It rises and falls and then seamlessly goes into exhalation (flow rate dips below 0). Then after exhalation peak rate at the bottom, it slowly crests back up towards 0. Where it stays for a while. And then inhale starts.

[RichardVT]

OK - thank you, that makes sense now!

[OpalRose]

Mine looks similiar.  I've always considered it normal.

[Sleeprider]

In Sleepyhead, you can right-click on the left margin of the flow rate graph, and select Dotted Lines options, then add a zero-line.  The dotted line makes interpreting these graphs much easier, as anything over should be inhale and anything under is exhale.

[RichardVT]

    I understand all of what is happening, however I am not sure exactly where in the breathing process is the lowest point up to the short flat zero line before the next breath?  When the exhalation stops, does the Flow Rate slowly go back to zero on its own, thus the angled-line up to zero from the bottommost exhale point?

In the attached picture, the waveform sections I am questioning are outlined in red.

[Fedman]

I understand all of what is happening, however I am not sure exactly where in the breathing process is the lowest point up to the short flat zero line before the next breath?  When the exhalation stops, does the Flow Rate slowly go back to zero on its own, thus the angled-line up to zero from the bottommost exhale point?

In the attached picture, the waveform sections I am questioning are outlined in red.

If I remember my high school algebra/graphing correctly, everything under the zero line is the exhale portion of the breathing cycle regardless whether the graph is going down (away from zero) or up (towards zero.) What this portion of the graph is showing is simply the flow rate of your exhalation.  So on the downward portion, your exhalation (flow rate) is increasing and the upward portion of the graph shows your exhalation flow rate decreasing. It's not till the graph hits zero that you've stopped exhaling. 

So the waveforms you've outlined in red represent the exhalation portion of your breathing cycle and the flow rate of the exhalation is decreasing up till the the graph hits zero.

I don't know if that made any sense or if someone can explain that better.

[RichardVT]

Ok, thanks, that makes sense. Increasing exhalation moves downward, decreasing exhalation moving upward.

Thank you!