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Sierra

Sierra
Joined Jul 2018
Bio

CPAP: AirSense 10 AutoSet

Set to CPAP Fixed Mode

Pressure 11 cm

Ramp: Auto

Ramp Start: 9 cm

EPR: 2, Full Time

Mask: ResMed AirFit P10 Nasal Pillow

Canada

Sierra
Joined Jul 2018
Bio

CPAP: AirSense 10 AutoSet

Set to CPAP Fixed Mode

Pressure 11 cm

Ramp: Auto

Ramp Start: 9 cm

EPR: 2, Full Time

Mask: ResMed AirFit P10 Nasal Pillow

Canada

The things I have done to help let me sleep on my side with a nasal pillow mask are:

  • Use a down alternative pillow. This pillow type gives easily to your mask and does not push back so much. They are fairly inexpensive at Costco, and are designed to mimic the feel of a real down pillow.
  • Instead of using a standard pillow case, I use a satin pillow protector which zips up. The zipper keeps it on the pillow because the protector is slippery. I feel this lets my head move on the pillow easier and is less likely to pull the mask away from my nose.
  • I try to sleep on the corner of the pillow with my mask out over the end of the pillow. Again to try and not disturb the mask position.

Yes, in theory if you turn flex off it would make it harder to exhale. However, in actual fact especially with the DreamStation you are likely not to notice or if you do easily adapt. Tests have shown that while the ResMed machines with EPR do make a significant reduction in pressure on exhale roughly equal to the EPR setting, DreamStation does not reduce the pressure as much, and mainly changes the shape of the switch over from inhale to exhale. That said your pressures with the nasal mask are quite low, and I suspect you will not notice or adapt easily. I have used a fixed 12 cm pressure with no EPR and have no difficulty at all exhaling against that pressure.

The issue with reducing pressure on exhale is that the reduced pressure can increase apnea frequency. The machine reacts to that by increasing pressure. So, you have gone full circle and it is a bit a zero sum game. My expectation would be that if you turn Flex off, your Inhale pressure (red trace) will actually reduce.

If it were me, I would shut off Flex first, see what it does. In theory the red line could drop down to to where the green line is now. That won't happen though because the green line is not really the effective pressure on exhale. Then next start to increase the minimum pressure to see if you can reduce the incidence of hypopnea events. You do have some central events, but not a lot now that you have pressures lower. DreamStation machines have a characteristic that some have described as hunt and peck (like a chicken!). It periodically spikes pressure up and apparently then checks to see if that helped with flow resistance or not. It it decides no, then is reduces pressure just as fast as it went up. If your minimum pressure is too low then while the pressure is in the low state of hunting and pecking, it can cause an event. Increasing minimum pressure can take some of that hunt and peck out of the machine, and probably improve AHI.

It would be really helpful to know what manufacturer and model of a machine you have. To my knowledge PAP machines may report RERA events, but they do not respond to them with increased pressure. And of course when you increase minimum pressure you are taking manual action which in turn should prevent RERA events from happening. That said I do see RERA flags in my SleepyHead graphs and I am now using a fixed pressure. They can still happen with higher pressures. If you have a DreamStation I believe there may be an option in it to change the sensitivity.

You may be interested in a ResMed article on their For Her algorithm specially developed for what they believe are the different needs of a woman compared to a man. The differences between the For Her algorithm and the standard version are highlighted in the table at the bottom of page 5. Both versions report RERA, but the For Her version is more sensitive to upper airway resistance and flow limitation. It uses single breath data to initiate a change while the standard version uses a 3 breath average and will be slower to react. The For Her version ratchets up pressure in response to apnea in close succession and holds it to a minim for the sleep session. It is more responsive to flow limitation and snoring, and less to apnea. Apnea alone will not increase pressure beyond 12 cm. It raises and lowers pressure at a slower rate. This feature may in fact be an option in the standard machine too, as there is a Response setting which can be set to Soft or Standard. The idea is to prevent arousals. As I understand it the difference between a flow limitation and a RERA is that an arousal is associated with the flow limitation.

The For Her algorithm is included as an option in the specific For Her AirSense 10 AutoSet machine. They sell at the same price, and they can be changed with the Mode setting to the standard algorithm. They can of course be used by men too, if the nature of the apnea they have is more of upper airway resistance and less of the obstructive apnea. The good part is that you can simply try it, and if it works it works. If not you go back to the standard algorithm.

Hope that helps some. Post back with your specific machine and I may be able to add a bit more...