ASV, Jaw Drop, Nasal Pillows, and LL

[Uncle Flapp]

Greetings all.

I recently switched from the Quattro Air to the P10 and love minimal foot print of nasal pillows. I have seen a reduction in AHI, am more comfortable, and most importantly I sleep better. I've taken to the P10 like fish to water - or so I thought. This morning my wife told me that over the course of an hour, she witnessed several "jaw drops" and heard air rushing out. With each instance, she lifted my jaw to close my mouth.

Since she told me it occurred three times between 5:30am and 6:30am, I thought leaks would be easy to identify in SH. I was wrong - no indication. Not unexpectedly, the LCD screen on the machine reported 0% LL (as always). Even Encore showed no large leak flags.

Is the reason large leaks were not flagged due to the short duration of just a few breaths? Makes me wonder how often this happens unnoticed and if my therapy is compromised. I appreciate your thoughts.

- Flappy

[Pugsy]

I would suspect that these times are of such short duration that they aren't registering during the recording cycle.
If they are that short then they really aren't going to impact therapy very much at all.
As long as I was sleeping well and feeling decent and they didn't wake me up I wouldn't worry about it.
If it's big enough and prolonged enough to impact therapy it will show up on the leak graph.

[palerider]

Is the reason large leaks were not flagged due to the short duration of just a few breaths? Makes me wonder how often this happens unnoticed and if my therapy is compromised. I appreciate your thoughts.

I believe that the leak reporting is a moving average, not an instantaneous measurement, so, your idea that it's not showing up is because of the short duration fits in with that

[robysue]

Flappy,

I don't know exactly how often the leak data is sampled on the PR machines. But it is not "continuously" sampled. Meaning the machine checks the leak rate at a fixed periodic time interval. That interval is longer than just a couple of breaths, but I don't know if it is sampled at 4 times a minute (15 second intervals) or 10 times a minute (6 second intervals) or at some other interval.

But if a leak is shorter than the sampling interval and no sample is taken during the leak, then the leak ain't gonna show up in the Leak graph.

As for whether your therapy is or is not compromised by numerous very short, but potentially large leaks: If your jaw is dropping often enough for the resulting leaks to affect the efficacy of your therapy, it seems highly unlikely that all the resulting leaks would be too short and too well timed for the machine to detect over the full course of the night. In other words, if you are experiencing large numbers of very short large leaks all night long that are caused by your jaw dropping for 2-3 breaths at a time, there's a very, very high probability that some of those large leaks would occur when the machine happens to sample the leak rate. And the you'd see some spikes in the leak graph.

[Uncle Flapp]

Thanks for the quick replies! Other than annoying the wife, I won't worry about it too much.
Interestingly, the Encore summary report for the week shows:
Average Time in Large Leak Per Day 0 secs.
Average Percent Night in Large Leak 0.0%

You must be right about sampling as opposed to constant monitoring. Thanks again.

- Flappy

[QualityDMEGuy]

If you have full access to your therapy data, consider looking at the detailed data and seeing where your pressure maximums are going. If you're on ASV there may be more going on than to look only at the leak data.

If you're happy with pillows, maybe consider using a chinstrap with the interface to prevent the mouth venting. I'd usually suggest full masks when on ASV to eliminate any possibility of missed treatment, but that's also just personal preference and experience.

[Uncle Flapp]

If you have full access to your therapy data, consider looking at the detailed data and seeing where your pressure maximums are going. If you're on ASV there may be more going on than to look only at the leak data.

Not sure I follow you on this one. Are you suggesting there may a correlation between maximum pressure and jaw drop?

I'd usually suggest full masks when on ASV to eliminate any possibility of missed treatment, but that's also just personal preference and experience.

My sleep doc was concerned about nasal pillows retaining less CO2 than a FFM thus causing more centrals but I haven't found any ill effects. To the contrary, I have fewer awakenings since the pillows are far more comfortable and easier to manage leaks.