Waveform Standard Notation

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Are you south of the equator?

Sorry, I honestly don't know. I'm looking at mine right now, and it looks like I do exactly like what you are seeing (negative then positive in Sleepyhead).

Tom W wrote:What it the normal convention of 'airflow' on a waveform graph?

Is positive inhalation or exhalation?

In both Sleepyhead and Encore Pro, when the wave form is ABOVE the 0-line, air is moving INTO the lungs at the rate shown on the vertical axis.

In both Sleepyhead and Encore Pro, when the wave form is BELOW the 0-line, air is moving OUT of the lungs. The rate is the numerical value of the vertical axis after discounting the negative sign.

On the graphical examples for Encore Pro the obstructive apneas normal breathing resumes with 'positive' airflow. My obstructive apneas normal breathing resumes with 'negative' airflow.

Encore Pro's examples are typical OAs that end with the typical recovery breaths (sharp inhales).

I'm wondering if I'm experiencing apneas (can't inhale) or am I holding my breath (Catathrenia)?

Technically an apnea is just the cessation of air movement into/out of the lungs. But I do think that for the vast majority OAs that the vast majority of us experience, the airway collapses during the exhale and so we can't get air in at the start of the next breath---even though on a PSG the belts show that we are still making the effort to breath. But flow limitations are abnormal shapes in the inspiratory part of the wave form and they indicate the airway is compromised---i.e. starting to collaps, and RERAs and hypopneas are prevented by setting the IPAP on a bi-level sufficiently high; so there's more evidence that the airway can be in trouble on the inhalation part of a breath. So it seems reasonable to assume that it is possible for the airway to collapse during/at the end of an inhalation. And when the airway is finally forced open by the arousal, there's already a full lungful of air in the lungs that first must be exhaled before new air can be inhaled. Whether this is what's happening in the data you show, I have no idea. Perhaps -SWS or DeltaDave/Muffy/NotMuffy will stop by and look at your wave form and shed some light on what's going on.

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Tom W wrote:If it true that my airway is in fact closing during/after an inhalation (assuming an obstructive event) then it would almost seem that once my airway is closed that an increase in CPAP pressure will not help and that only an exhalation will open it but an increased pressure might keep it open.

Think of it this way. Your airway is a long, thin balloon. Pressure in the balloon tends to increase the diameter and keep it open. The part of your airway between the obstruction and your nose will tend to inflate with CPAP pressure and help it to open up.

Whether it works that way in real life, I can't say.