palerider wrote:archangle wrote:igdoc wrote:Could be a blockage of the flow sensor.
Look at the leak rate. It stays pretty much the same throughout the event. That strongly suggests:
The flow rate sensor is not plugged and is functioning normally.
The average pressure in the mask was the same before and during the event.
The hose is not plugged or kinked, unless it's plugged or kinked between the exhaust port and your lungs.
There's not some sort of leak event causing the problem.
The exhaust vent isn't blocked.
could you please explain your logic? you start out saying that the *flow* sensor can't be clogged and then cite examples from the chart that are from the *pressure* sensor.
I agree, the *pressure* sensor, and the leak rate derived from it, indicate that the vent isn't blocked, there's no kink in the hose. mask *pressure* spikes with the ASV pulses. but there's no concomitant *FLOW* recorded from the *flow* sensor.
your soapboxing about what resmed does notwithstanding, the flow sensor doesn't sense pressure, so what's all the pressure readings have to do with it?
It's not 100% proof, just reasonable assumptions, but here's the idea. I can expound if necessary.
Short version - The constant value of the leak rate strongly suggests the machine is correctly measuring the raw flow rate. The constant leak rate suggests the pressure at the elbow is constant. The constant pressure at the elbow suggests the machine is correctly sensing the pressure.
Medium version.
The respiratory flow rate graphs, minute vent, tidal volume drop by a factor of 4:1 or sor.
The leak rate doesn't change very much.
The leak rate graph peaks and dips roughly in proportion to the EPAP graph.
- The leak rate display is correct.
- Since the leak rate doesn't jump, there's not a big leak somewhere causing the event.
The leak rate is calculated as a time average of the hose air flow rate.
- The machine's hose flow rate calculation is correct.
The leak rate doesn't spike a lot like mask or mouth leaks tend to do. No sudden jumps
- The leak rate is mostly the leak through the exhaust vent.
- Since the exhaust vent rate is constant, the airflow is not blocked between the elbow and the blower.
- The exhaust vent isn't blocked.
The exhaust vent leak rate is proportional to mask pressure at the elbow where the vent is located.
-The average mask pressure is constant. (Constant as in not varying 4:1 during the event.)
-The machine's pressure regulation is working correctly.
-The pressure readings are correct.