Shallow breathing waveform

[notam2]

I'm trying to help out a friend of mine who recently started using cpap.  Downloaded her data to Oscar and noticed this weird 10 minute waveform.  Any ideas as to what caused this or what it is?  My friend didn't remember anything unusual happening that night, and the AHI numbers are otherwise perfectly good.  I was thinking this may have been leak related, but I've never seen a leak that small cause the flow rate to become inaccurate.  Any chance that the flow rate was inaccurate?  Kinda wish I had oximetery data on this one.

Thanks in advance for looking.

[Sleeprider]

You are using an older version of Oscar, current is 1.3.1. The low respiratory volume is consistently associated with a relatively high leak rate. I think there is a combination of leaks and oral breathing going on.

[Gideon]

What were the pressures. That is an important part of this picture since the settings displayed do not match up with the statistics.

There obviously is a very strong correlation between the leak rate and flow rate. Assuming, this is a big assumption, running at machine min it seems the small leak could easily interfere with accuracy. BUT the stats and settings are in disagreement and pressure chart is not shown.

[notam2]

Thanks for the replies.  Ignore the part in the attachments that indicates PS 0.0 over 4.0-4.0.  That's a side effect of the method that I use to import data.  She's using a vAuto but its configured as an auto cpap with pressure set to 7.0 to 8.0 with EPR=1.  More specifically, the machine is configured with min EPAP of 6.0, max IPAP of 8.0, and PS=1.

After I posted this I started wondering if it was a brief mouthbreathing event.  Seems like that could be a plausible explanation -- I don't have any issues with that myself and never noticed anything similar in my own oscar data so this looked foreign to me.

Edit: pressure chart is attached for the same night.

[Sleeprider]

The pressure chart was previously missing, and it helps to see what is going on. The only events are like double-tap obstructive apnea which suggests a brief positional event, but nothing I would address through settings or a collar. The respiration rate is flat-out high, and I think this is a person experiencing enough flow limitation that additional pressure support is in order. I would raise the maximum pressure to 12 unless there is aerophagia or something going on that affects comfort, and increase PS to 3. This is going to help the flow limits, increase Vt and slow respiration rate with minute vent remaining about the same. I suspect pressure will settle in at about 10/7 to 11/8.

[notam2]

Thanks for the feedback.  These charts are actually for Mrs. Notam and I was also thinking that a little more pressure support might be in order, but was thinking to go slow with any changes as comfort, compliance and getting accustomed to cpap (it's only been a week) are bigger concerns of mine than chasing down those flow limitations and snores.  I'm also trying to keep a tight leash on the machine so that there are no big pressure swings and prevent it from running away while giving the machine a chance to give some feedback via watching the auto adjustments.  I think I'll suggest bumping the min EPAP to 7, max IPAP to 10 and PS to 2 and see what that does to those flow limitations.  It's only been a week now on cpap and as she gets more accustomed to it I can suggest further tweaking if needed.

Question though -- how would you interpret that nightly respiratory rate chart?  Most of the night it was under 25 but there was a period when it was quite variable -- bad dream?  Maybe more importantly, does the high respiratory rate indicate anything in particular and why does increasing pressure/pressure support drive the respiratory rate down?

Thanks again.