Logged apnea without pressure pulse

I was looking at my data in SleepyHead, and noticed something I didn't expect. It showed an event logged as an obstructive apnea, but with no accompanying pressure pulse. I thought my machine needed to use those pulses to determine which category to log an event in. I can see about tacking on a screenshot tomorrow, if anyone is interested.

tetragon wrote:I was looking at my data in SleepyHead, and noticed something I didn't expect. It showed an event logged as an obstructive apnea, but with no accompanying pressure pulse. I thought my machine needed to use those pulses to determine which category to log an event in. I can see about tacking on a screenshot tomorrow, if anyone is interested.

It should only do a pressure pulse if the line is flat during an apnea. If it's an obstructive event that still lets through a small amount of flow it doesn't bother..

The point of the pressure pulse(prs1)/ripple(s9) is a full Obstruction will cause the sent burst of pressure to "bounce" back, and the sensor can detect the airway is closed. In a ClearAirway/Central event the airway is open, and the burst will just inflate the lungs, and not be able to be read back with the same intensity.

If the line really is flat, it could be the PRS1 was busy calculating other stuff and just missed one..

This is a one time event?

I have only noticed this once. Usually my data is spackled with pressure pulses, with at least one or two right by the logged apnea. In the area surrounding this event, the line is mostly flat: there is a little wibble in the line every five seconds, which is slower than the rate that I had been breathing before and after.

Anyway, here are some screenshots. I have already received a PM that has made some incorrect assumptions about the data, ones that this should clarify.

Full night:



Around the logged event:

OA doesn't imply total blockage.. It can be counted with up to a certain percentage limitation in flow. (10%?)

The pressure pulse algorithm only kicks in when it sees NO evidence of respiratory effort in the flow waveform. (probably more like 1% to counter for noisy waveforms)

The OA in this case still showed signs of respiratory effort when a breath was expected.

The pressure pulse on the end peaked a fraction lower than the threshold, which is why it got flagged.