Resmed Autosense Issues

[tricati]

So, I have been using the Resmed Autosense 10 for the past week and have noticed a few things which are a bit odd, and wondering if anyone could make sense of it. Before switching over to the Resmed, I was using a Respirionics System One Auto with a autoset pressure of 7-14.. Now I am on a pressure of 8-14.

On the Respironics I was (90% pressure of 8.4, Avg. pressure of 7.5.. Leak rate was 5.72)
With the Resmed the first weeks statistics are ( 90% pressure of 12.70 And Avg Pressure 11.02.. Leak rate 3.6) Not only that, but I reaching the 14cm pressure setting most every night.

This is almost a 4cm increase, with no changes in mask or sleeping habit. Just wondering if there is that much of a difference between algorithms, and if anyone else has experienced this.

Also, With the Resmed, I am waking up most every morning with a dry mouth and a nearly empty humidifier.. I have all of the settings on auto and the heated hose on 85 degrees.. Could it be the weather, but again, not much has changed (Cold & Snow) -- Again, is this something normal with the Autosense?

[TangledHose]

I have four machines at the current time that are all Autos, three different brands, the ResMed S9 and the Airsense Auto both do the same thing. They will climb to substantially higher pressures than either my Transcend or my F&P Auto. When I look at my data in Sleepyhead it appears that the ResMed machines are increasing the pressure primarily based on Flow Limitations. The ResMeds in my personal experience are more sensitive to FL and will raise the pressure more, so I just have come to my own personal conclusion that it is the difference in algorithms between the different brands, but I am surprised there is that much difference.

I was getting some Aerophagia or insulfation and sleep disruptions from the ResMed machines (S9, and AirSense) when they climed up above my prescribed pressure from my sleep study so I set the max pressure about 1.6 cm above my prescribed pressure to limit how high the auto response could go and I monitor things closely in Sleepyhead. My AHI number averages around 1.0 to 1.5 so my numbers and my sleep quality are good even with my capping my upper pressure.

When I have let the ResMed machines go open on the top end not only was I having more sleep disruptions, but I was also picking up more and more Central Apnea events, so I have been successful with limiting my upper pressure range.

As far as humidity is concerned I like lots of moisture in my sinuses so I am running the climate line hose at 83 degrees and manual humidity at 7 (8 is the highest on the Airsense) and I will run the tub out of water if I stay on the hose for more than eight hours.......I have an extra tub that I fill before bed so I can swap out tubs in the middle of the night if I need to. I live in a very dry climate and my average therapy pressure is around 13 cm, I have no mask leak issues.

If you are reporting a dry mouth and using a lot of water I might suspect some mouth breathing in your case, but depending on how dry you environment is it is not unusual to use as much water on the Airsense as you do (the water capacity is 380 ml). You might check the specks on your previous machine to see if it held more water. If you are doing some mouth breathing you will increase your water consumption -- as Pugsy's has pointed out in the past.....the humidification systems on cpap are designed to keep nasal passages moist, but can't keep up with a lot of mouth breathing as the oral cavity is much larger and requires more moisture.

Hope that helps......I don't think what you are reporting is "out of the ordinary".......but I would investigate mouth breathing since you said you had a dry throat.......I don't have that issue with my Airsense.

[InsomniacGuy]

Check that the Airsense humidifier tank is inserted completely.

One night I experienced dry mouth, and in the morning I found condensation inside the machine below the tube gaskets. I then pushed the tank in completely -- no condensation the next morning. Also for the second night, I raised the humidifier to 3 from 1. Seemed to make a difference for improving dry mouth, but I only used the Airsense for four nights: it could have been dumb luck.

[Sleeprider]

The increase in auto pressure support may also be related to the use of EPR. If you are using a EPR of 3.0 you are effectively lowering the EPAP pressure support by 3.0 cm. The Respironics machines do not so drastically change the pressure with A-flex or C-flex.

[archangle]

There's not always one "right" pressure. Also, if you have something like flow limitations, UARS, or RERA, the question of what's "right" is more complicated. I think machines vary quite a bit in their response to such things.

Don't forget that you are in control. You can always select a lower maximum or higher minimum pressure if the machine seems to be going out of what works best for you.

[tricati]

Thanks for the replies.. It looks like there is just intrinsic differences in design. I have decided to lower the humidity hopefully in effort to not empty the tank half way through the night. Hopefully that will work.. we will see..