Breathing Not Detected 24.75%

[fwg1947]

I don't know what to make of the SleepyHead charts for last night.  "Breathing Not Detected" is shown for 24.75% of the night, which would be almost 2 hours.  I have not seen anything like this before.  What does this signify?  Could it be an error or some sort of anomaly?  SleepyHead reports 0.00% Large Leaks and Maximum Leak Rate of 32.0, so it does not appear to be caused by mask leaks or mouth breathing.

Here is the chart:

[Sleeprider]

Your leaks are at or near the large leak threshold during this period, however I have seen BND reported in a arbitrary way with Philips machines. Anytime the sensors do not have adequate feedback this can be reported, and I also have not seen a consistent reason for this. The machine appears to be maintaining pressure in spite of the leaks. Also, check out the snore graph leading up to this. Could there have been a leak somewhere in the humidifier or tube?

[fwg1947]

Your leaks are at or near the large leak threshold during this period, however I have seen BND reported in a arbitrary way with Philips machines.  Anytime the sensors do not have adequate feedback this can be reported, and I also have not seen a consistent reason for this.  The machine appears to be maintaining pressure in spite of the leaks.  Also, check out the snore graph leading up to this.  Could there have been a leak somewhere in the humidifier or tube?

How significant is it that leaks are near the large leak threshold, considering that both SleepyHead and Encore Pro report zero large leaks for the entire night?

I did the Mask Fit check on the machine just before going to bed, and it indicated that Mask Fit was ok.  I woke up a lot of times during the night (which is unusual for me), but did not feel any air blowing where it shouldn't or hear any unusual sounds suggestive of leaking. 

I have had Large Leaks in the past 2 months up to 3.5% of the night without the level of BND events seen last night.  The previous BND events have been short (1 to 3 minutes) and infrequent (1 to 3 per night during only a few nights over the past 2 months).  I cannot see any correlation between the previous BND events and Large Leaks occurring the same night.

Another unusual SH statistic I noticed was that there were 242 Pressure Pulse events last night, with each pulse varying in duration from 1 minute to 24 minutes.  Could all these Pressure Pulses be the reason for waking up so many times during the night?

I don't know if this will help, but here are the first 2 pages of the Encore Pro WaveForm graph for last night, showing the transition from fairly normal breathing to some of the BND and Pressure Pulse events:

[Sleeprider]

That is an extraordinarily unbalance inspiration/Expiration ratio. 2:1 which is completely the reverse from expected.

BND is a phenomenon of Philips machines, and it has been reported since the M-Series. I never had it, and don't pretend to understand why it occurs, but it is mostly associated with periods of large leaks. This was discussed in June and my comment was

It seems to be confined to Philips machine data, and I haven't seen a good reason that it occurs. This Apneaboard thread earlier this year discussed the topic and it seems the consensus was to ignore it. I continue to believe it is an unimportant anomaly in the data. http://www.apneaboard.com/forums/Thread-...ted--16571

http://www.apneaboard.com/forums/Thread-...ad-Version

BND is only briefly discussed in robysue's guide to sleepyhead, and it was associated with large leaks there as well. http://www.apneaboard.com/wiki/index.php...SleepyHead I'm sticking with my original assumption that it is related to large leaks and is not particularly significant of itself.

[quiescence at last]

That is an extraordinarily unbalance inspiration/Expiration ratio.  2:1 which is completely the reverse from expected.  

.

I have seen this in most of the Phillips Respironics devices.  It is primarily because the delay in breathing seen after most of the exhales is not counted as part of the inhale or of the exhale time.  exhales, unless restrained, are usually a shorter duration.  some nights I have restriction to exhales (thru nose) due to nasal resistance or nasal passage collapse.  I do not find it pleasing, but then there is more exhale time than inhale, and my I:E ratio is about 1:1.  I do not feel that a lower ratio on this machine type corresponds to better sleep situation, rather the opposite.

Just another talking hose-head.

QAL

[Sleeprider]

Totally agree. Closeup examination of the flow graph usually shows that is improperly reported. It is however often associated with other issues. I don't think it is relevant to the BND in this case.