Help me interpret this event from last night.

Last night I had an episode where I woke up and tore my mask off, feeling like I was out of breath or hadn't been breathing. This screen capture below is the event.

Does this look like I wasn't breathing for almost a minute before waking up and taking the deep breath?



Here's a closer look.

looks like you went into Large leak and the machine could not detect breathing. The leak line went into large leak area.

Was the large leak blank area when you removed the mask?
Are you referring to the period right before the blank area?
Looks like the machine called that a hyponea...and yeah, it appears to be rather long duration.
Hyponeas are usually some air is flowing but the reduction isn't as much with the OAs but it looks like the machine tried to help you out...see the spikes in the mask pressure line during this time?
Looks like it did it's job but this time you still woke up in a panic.

There are several things that I notice about this event:

1) Before the minute long apnea/hypopnea happens there are two exceptionally large inhalations. And after the second extremely large inhalation there is no attempt to exhale. If I had to speculate, I'd be wondering whether you had an arousal/mini awakening followed by a minute of breath holding. Moreover---when the event ends, it ends with an exhalation, which is a bit unusual. It's possible that those two big inhalations at the start blew off too much CO2 and without the CO2-trigger, the brain "forgot" to send the diaphragm the "inhale now" signals during that minute. Certainly the ASV responded as if it believes that's what happened. You can see the IPAP drastically increase in the "Mask Pressure" graph on 9 inhalation cycles that don't correspond to any inhalation activity in the flow rate graph.

2) You have a really large exhalation to end the event, followed by two breaths that are larger than your normal sleep breathing, but not as large as the two inhalations just before the event begins. At that point the Flow Rate and Mask Pressure graphs have a gap, but the Total Leak/Leak graphs and the Pressure graph have gaps in them.
Question: What does the Session data in the left side bar say about the beginning and ends of each of the Sessions for the night? In other words, was the machine ON or OFF between 00:31:45 and 00:32:45?

3) When the Flow Rate and Mask Pressure graphs resume at around 00:32:45, the breathing pattern looks to be pretty normal sleep breathing and the Mask Pressure graph shows that the IPAP pressure has gone back to your IPAP min = 12.5.

4) The leak rate started to increase about 00:30:00, which is about 45 seconds before the event starts. The leak rate continues to increase through out the entire event when the machine is drastically increasing the IPAP in an effort to trigger you to inhale. Part of that increase in total leak rate has to be caused by the fact that the IPAP bumps on the Mask Pressure mask go from 12.5cm to 25cm in about 15 seconds just as the machine starts responding to the event. You can see this in the mask pressure graph if you look at the three Mask Pressure bumps that are right around 00:30:45.

5) The maximum point on the Total Leak graph is reached just after the end of the event. At and near the max of the Total Leak graph, the Total Leaks are up around 110 L/min. That's certainly pushing official Large Leak territory, even though the machine did NOT flag it as an official Large Leak. At that point, the machine starts to lower the Max IPAP pressure level, possibly in an attempt to "fix" the much larger than normal leak, but possibly also because those breaths at the end of the event also convinced the machine you were breathing on your own again.

6) The normal sleep breathing pattern resumes when the Total Leak Rate graph has gone down to 82.5 L/min. It's still a pretty large leak, but it's a lot smaller than that peak Total Leak Rate of 110 L/min.

I'm hesitant to speculate about the reason all this happened in the first place. But if I had to guess what went on here, this is what I'd come up with:

At 00:30:30 some kind a small-to-medium sized leak started. You had some kind of an arousal/awakening at 00:30:30 that caused the very, very large inhalations and after that second inhalation you started holding your breath for some reason. The machine starts to respond by increasing the IPAP pretty drastically between 00:30:40 and 00:30:50, but that increase in IPAP causes the leak to grow from medium sized to very large, but not quite large enough to be flagged as an Official Large Leak. At 00:31:30 you exhale pretty forcefully to end the event and have a couple of larger than normal inhalations. By this point the leaks have grown large enough that it's possible the machine simply lost track of your breathing. Or you removed the mask. And because of the large leak, the machine starts lowering the "max IPAP level", probably in hopes of fixing the very large leak. But at any rate, by 00:32:45 the machine can track the breathing, which is already looking very similar to sleep breathing. And by 00:33:00 it's clear that the breathing pattern looks like sleep breathing.

As for what caused you to inhale so sharply and deeply for two breaths around 00:30:30 to start the event? I have no idea. The whole pattern of a few big inhalations, followed by a (short) period of not breathing, followed by a big exhalation and a couple more larger than normal inhalations sometimes occurs when people wake up just enough to turn over in bed. But usually those "turn over in bed" events are more in the 10-15 second range, which is much shorter than this one.

Pugsy wrote:Was the large leak blank area when you removed the mask?
Are you referring to the period right before the blank area?
Looks like the machine called that a hyponea...and yeah, it appears to be rather long duration.
Hyponeas are usually some air is flowing but the reduction isn't as much with the OAs but it looks like the machine tried to help you out...see the spikes in the mask pressure line during this time?
Looks like it did it's job but this time you still woke up in a panic.

I believe the blank area at 31:45 is where I tore my mask off and sat in bed for a minute recovering. So if there was a partial airflow restriction, this would likely be an obstructive event, and not a central event?

In general yes...if partial restriction (if that is what happened here) I believe they are usually obstructive in nature.
RobySue also has some good thoughts...I just read what she posted.

Unfortunately the best that we can do with what we are given is come up with some sort of educated guesses.

Robysue, thanks for the extensive reply.

I wear a full face mask and I really don't ever notice any leakage outside the rare occasion where there is a tiny little area where the seal breaks and a little bit of air comes out, which i fix.

One thing that has me thinking, is that I have a deviated septum, and can't always breath well out of my nose at night. It's quite restrictive. I am wondering if I was nose breathing and not getting the volume of 02 that my body wanted, causing this to happen.

Either way, I have a pretty advanced machine. It kind of scares me that the event went on for this long.

If you have a deviated septum discuss that with you doctor. After I had mine fixed and a blocked meatal passage I had considerable improvement. But ask how surgery will affect your current therapy. I had to have packing in my nose for 2 weeks and sleep sitting no less than 45 degrees from upright. And do nothing during that time. You may need an alternate mask for that time frame. That is if surgery is recommended. Mine was was a huge help. I remember breathing through my nose for the first time in 20 years. And smelling! I cannot describe it.

craigojones wrote:If you have a deviated septum discuss that with you doctor. After I had mine fixed and a blocked meatal passage I had considerable improvement. But ask how surgery will affect your current therapy. I had to have packing in my nose for 2 weeks and sleep sitting no less than 45 degrees from upright. And do nothing during that time. You may need an alternate mask for that time frame. That is if surgery is recommended. Mine was was a huge help. I remember breathing through my nose for the first time in 20 years. And smelling! I cannot describe it.

Glad you found relief. My deviated septum is up my left nostril, and is only problematic at night usually. Often times I can't fall asleep with my mouth closed, hence me using a full face mask.