The flow chart is the most detailed picture of your night. Your machine measures the air moving in and out of your mask many times a second, and CPAPGeeks draws every breath. Once you know what to look for, you can see exactly what happened at each event.
Normal breathing
Each breath is a wave. The line goes above zero as you breathe in and below zero as you breathe out. Relaxed sleep looks like a steady, even row of rounded waves, about 12 to 20 a minute.
When you first open a night, CPAPGeeks shows 5 minutes so you can see individual breaths. Use ‹ ›to step through the night, drag across a chart to zoom in, or choose Show whole night. Seen across a whole night, the waves blur into a solid band; that's normal.
What events look like
Apnea: the waves stop
During an apnea the line goes almost flat for 10 seconds or more, because air has stopped moving. It usually ends with one or two big recovery breaths. Choose an event in the list under the charts and CPAPGeeks zooms straight to it.
Hypopnea: the waves shrink
During a hypopnea the waves keep going but get noticeably smaller for 10 seconds or more. You're still breathing, just shallowly.
Flow limitation: flattened tops
Sometimes the top of each breath looks flattened or bumpy instead of round. This means the airway is partly narrowed as you breathe in. A little is common; a lot of it, night after night, is worth mentioning to your clinician.
Leak and mask-off moments
A sudden jump in the leak chart, sometimes with messy flow, usually means the mask shifted. Flow that disappears completely, followed by a gap, usually means the mask came off or the machine was paused.
Reading the charts together
- Pressure often rises just after events if your machine adjusts itself (AutoSet, APAP).
- Leak that jumps at the same moment as a cluster of events suggests the leak caused them.
- Breathing rate and, if you use an oximeter, blood oxygen add context around each event.
The flow chart is great for understanding your nights and for showing your clinician exactly what happened. It isn't a diagnosis: if something looks worrying, bring it to your sleep clinician.