Flow rate morphology and mask type?

[Shin Ryoku]

I've been looking through the last couple weeks of SleepyHead data, and I think I'm noticing a trend where the shape of my flow rate curve has a more rounded inspiratory portion when wearing a standard nasal mask (N20) than when I wear nasal pillows (P10).

These three are from the N20:








And these are from the P10:








My AHI is about the same with both masks (~3-4 most days).

I could be mistaken.  Will continue to switch back and forth and see if it is reproducible.

The N20 looks more like normal breathing, right?  Does it matter?

[Walla Walla]

No telling what causes the difference. Size of the pillows or maybe the machine mask settings. Even the length of the close ups can affect it somewhat.

I'll be interested to see what you find.

[Sleeprider]

I have never used anything but the nasal pillows and the morphology of our flow rate graphs on that mask are very similar. It could be the increased volume of the nasal mask and probably FFM, mutes the transitions, and rounds out the flow curves. The machine is graphing what it detects at the sensors all the way back inside the flow generator, so increased volume and damping in the patient interface would have an effect similar to an expansion tank on a hot water line.

[Apnea Infant]

Hey

Have nothing to say about your flow rate morphology except that it looks perfect wave form whilst mine, in comparison, seems like wild dancing.

[Shin Ryoku]

I have never used anything but the nasal pillows and the morphology of our flow rate graphs on that mask are very similar.

That is reassuring.  I wasn't sure if I was breathing abnormally when using the nasal pillows.

[HalfAsleep]

Wow! You get to breathe evenly like that? Lucky butt.....  


Do the waveforms change with different pressures?

[zzzZorro]

Shin; Interesting point about the shape of the Flow Rate waveform, but I would be more concerned about the actual AHI comparison.  Be curious to know what it was for each waveform?

Before reading your post I was sitting here wondering what the effect of FFM vs Nasal vs Pillow may have in varying the AHI..

[Shin Ryoku]

I vary my gear and settings a lot, but most of the time I use BPAP auto (VPAP auto) with a min EPAP of 17, max IPAP 24, and PS 4.

With those settings, I get an AHI in between 2 and 5 most days, regardless of whether I use nasal pillows (P10) or nasal mask (Dreamwear or N20).

Up to half or sometimes even more of my AHI is from CAs, but the great majority of my CAs appear to be false positives (surrounded by junky breathing or while awake).

Hey

Have nothing to say about your flow rate morphology except that it looks perfect wave form whilst mine, in comparison, seems like wild dancing.

Wow! You get to breathe evenly like that? Lucky butt.....  


Do the waveforms change with different pressures?

My breathing is not always quite as even as the examples I posted but mostly is close to that unless I'm having events or arousals. At low pressures I can see some obstructive flattening of the inspiratory portion of the curve.

[Walla Walla]

The more I look at the charts the more it looks like your respiratory rate is a little faster with the P10.

[Sleeprider]

I have never used anything but the nasal pillows and the morphology of our flow rate graphs on that mask are very similar.

That is reassuring.  I wasn't sure if I was breathing abnormally when using the nasal pillows.

Here is a sample of my wife's, and mine.  Like you, I also have some bizzare, uneven and flow limited crap as well as wake breathing, but this is typical deep sleep.  The first one is my wife on P10 pillows. Almost a blend between your nasal pillow and nasal mask. I orginally posted this because hers is an Airsense 10 Autoset and mine is Aircurve 10 Vauto.