What is Mask pressure in OSCAR and Query related to EPR in Mask pressure graph.

I have a query related to mask pressure that based on what mask pressure get varied in CPAP device. How EPR can be calculated based on Mask pressure. The EPR Level is different in comparison from pressure to mask pressure. Can anyone please guide me.

As I understand it, the ResMed machine calculates mask pressure based on the pressure measured inside the machine, and considers the flow rate along with the size of hose that goes to the mask. It does not measure the actual mask pressure but calculates it based on pressure, flow, and pressure drop. This compares to the Pressure graph which just shows the pressure demanded. The Red shows IPAP and Green EPAP. The difference should be the EPR setting.

On the mask pressure graph you need to zoom in to the highest level of detail after clicking on a time of interest. Zoom in with the arrow keys. Then you can move the cursor so it sits exactly at the peak of a pressure cycle. The digital display at the very left and above the graph will show the pressure at the cursor point. That will be the IPAP or at least approximately. Then when you move the cursor to the very minimum point it will be the EPAP. The differential will be approximately the EPR, but may not match exactly as the mask pressure is an actual measurement with calculations applied. As you can see it varies with every breath.

You can think of it this way. The Pressure is the desired pressure. The Mask Pressure is the actual pressure. DreamStation machines do not do this calculation and do not display a mask pressure. The ResMed machines are more informative as they give you the actual pressure through the whole breathing cycle.