Increased AHI with increased pressure debate

[Carlton]

Like many of you posting on this site I have noticed that encore reports a significant increase in AHI at the top end of my pressure range.

When running a range of 8-12 my highest AHI scores were always at 12. This got me to thinking the cause was pressure induced events as has been suggested here on many occasions or perhaps the machine was only at the higher pressure when I was having a problem?

However when I increase the pressure range to say 10-14 then the AHI scores at pressure 12 returned to the nomal range and the significantly higher results were always at 14. This pattern was followed through what ever pressure ranges I used.

Ok so at this stage I realise that a higher pressure is NOT causing my AHI figure to rise. But it is possible that changing from one pressure to another pressure setting actually causes an increase in events!

So to check this out I look through all my AHi v pressure data and notice that I always spend less time at the higher pressures and it is this that is twisting the data. ie if my highest pressure is 14 and I spend 1 min at that pressure and have one small HI event the software has to round this up to an hour to give an AHI for this pressure ie one small event at pressure 14 that I was only at for one min of the night is recorded as an AHI of 60! for 14 pressure. or if I spent 5 mins at 14 and have 1 event an AHI of 12 is recorded.

So at this point I go back through all my data and only record scores at pressures I have been at for over an hour, work out the average and plot this on a pressure v AHI chart and the results are VERY different from the MY Encore Pressure v AHI chart. It shows that increasing pressures (for me at least) do not as first appeared increase my AHI but that there is very little difference across the pressure ranges and that my AHI ever so slightly seems to decrease with increased pressure.

This leads me to conclude that the MY Encore Pressure v AHI chart displays corrupt data and is not that useful a device when trying to find what your ideal pressure range should be. That the most useful of the charts on My Encore is probably the Time Spent in Apnea. And if we had a time spent in apnea v pressure chart this would be extremely useful.

Would love some feedback/ another opinion on this.Have I missed something?

Carlton