My ResMed AirSense 10 AutoSet trial arrived a couple of weeks ago. After setting it up and picking some starting options, the data flowed for roughly two weeks. Nasal pillows weren’t for me: my mouth kept opening, creating the strangest air-pressure sensations. My notes call the ResMed N20 a full-face mask, but the AirFit N20 is a nasal mask. I either wrote the mask type or the model down wrong. 😷

Using the Open Source CPAP Analysis Reporter (OSCAR v1.4.0), we can dig into the data. The missing days were nights when insomnia kept me awake. Not fun. I’ve also put the screenshot exports into an OSCAR ZIP file. Anyway, let’s look at some of the days and event types in more detail.

We’ll start off with longer periods of recorded data. Above is the 17th August. Many nights were only a few hours of data because the mask itself would cause me to wake up. The machine flagged a lot of clear-airway events. I was calling these central apnoeas, but a PAP device flag is not the same thing as a sleep-study diagnosis. If we disregard the earlier data in the night while I was still trying to get to sleep, we can see some of those flags.

The machine flagged a clear-airway event lasting about 21 seconds. Interesting. That duration doesn’t tell me what caused it, or whether I was actually asleep for the whole event.

Here’s the 18th August, and the machine has flagged some obstructive apnoeas (OAs).

How does the machine distinguish between clear-airway and obstructive events though? The AirSense 10 uses small pressure oscillations during an apnoea to estimate whether the airway is open or closed. That is useful machine data, but it still is not the same thing as polysomnography. What’s also interesting is that central events can appear after treatment of obstructive sleep apnoea begins, known as treatment-emergent central sleep apnoea.

Here’s some data from the 19th August. The machine-reported apnoea-hypopnoea index (AHI) was below five on most days and never exceeded eight. It counts flagged events per hour of mask-on therapy, which is not necessarily the same as an hour asleep. I found the numbers reassuring, but they weren’t a diagnosis.

A few more clear-airway flags. I originally assumed the 20+ second ones were automatically more concerning than the 10-second ones, but event duration alone is not enough for me to make that judgement from CPAP data.

Jumping forward a week to the 26th August we have more data. This one has it all! Large leaks (LL), clear-airway flags (CA), obstructive apnoea flags (OA), and hypopnoeas (H). In my recordings, many of the large leaks appeared while I was readjusting the mask.

There’s a hypopnoea. In plain English, that is a partial reduction in breathing rather than a complete apnoea. The machine is inferring these events from its flow and pressure data.

And on the last day of recorded data, the pressure ramped up to 11 cm H2O and I threw the mask off after a few hours.

What have I learnt from this? While my snoring might be an issue to any roommates, I still did not know whether it was clinically important. I varied the settings on the machine night to night, but found that EPR, which reduces pressure during exhalation, made it much easier to sleep.

However, I did not feel more rested. What’s worse is there were at least three days where I woke up sweat drenched. This was one of the things I was trying to solve: night sweats. The CPAP trial did not make them disappear, but that does not tell me what was causing them.

Did APAP or CPAP solve the night sweats during this trial? For me, no. That was the practical question I wanted answered. I still had a proper sleep study in the future, which mattered because this trial could not diagnose or rule out sleep apnoea. With the sweats showing up on only about 3 of 14 nights, I was also worried a single night might not capture that symptom. That does not mean a sleep study could not still find sleep-disordered breathing.

I guess all I can do is keep investigating why I have issues getting to sleep and staying asleep. I’ve tried eliminating caffeine, reducing room temperature and changing sleeping positions, and nothing seems to work. The phantom itches as I’m trying to sleep certainly don’t help either.

I was starting to wonder whether stress and anxiety were part of the picture, but I did not have an answer yet. 😮‍💨

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