Any advice on this flow rate pattern?

[doickle]

Good Morning,

I was looking through my data from last night when I noticed an odd pattern to my breathing flow rate that is not something I have seen in my data before and I have not seen it as an example of a typical flow rate.
This doesn't really correspond to an apnea event or a flow restriction so it makes me curious.
I do have a very deviated septum which I believe is causing some of my issue with flow limitations (surgery is on the 23rd and I'm optimistic to see some improvement).
The screenshot of the data is attached here:



Any thoughts?

[Sleeprider]

That cutoff and slope on inspiration is mild FL followed by normal expiration with a 1-1.5 second zero-flow ahead of the next inspiration...looks normal to me. What are you seeing?

[doickle]

Thanks for the reply.
Typically I don't see the two stages with a flow limitation.
Normally during periods with FL my inhale looks like a textbook picture with a single plateau then exhale. I don't usually have the second stage of inhalation at the end.
I guess with the different signature made me curious but perhaps it is the variation with breathing with the deviated septum that can cause these irregularities.

Thanks

[justMongo]

That kink (change in df/dt) is likely where EPR kicks in. It's really a rather normal flow wave.

[Sleeprider]

Thanks for the reply.
Typically I don't see the two stages with a flow limitation.
Normally during periods with FL my inhale looks like a textbook picture with a single plateau then exhale. I don't usually have the second stage of inhalation at the end.
I guess with the different signature made me curious but perhaps it is the variation with breathing with the deviated septum that can cause these irregularities.

Thanks

The nice curved breath in the middle is probably your normal.  Nothing unusual about the ones we were commenting on, but it is very mild FL, and would not even show up in statistics. It's nothing to worry about, and you're fortunate that your normal is normal. 

JM, the I'm not sure what d/f d/t is?  EPR kicks in as inspiration ends and the line crosses the zero-flow line. Pressure falls rapidly and the rate of decrease slows near the end of expiration.   This particular graph would be good to look at with the Mask Pressure graph below the flow rate like this. Here you can see the peak of IPAP is reached just before the flow line crosses zero, then EPAP kicks in, and begins to increase pressure following the beginning of inhale. Note that during apnea, no pressure increase occurs until the apnea ends.

[PaytonA]

df/dt is the slope of the curve. df being the small change in flow rate for a corresponding small change in time, dt.

Best,

PaytonA