(05-15-2015, 10:00 AM)storywizard Wrote: I am feeling better in some ways, but the pressure spikes are nasty, I have to say.
I am thinking of lowering max PS, to 10. I get the air blowing out my mouth and waking me up when the spikes hit.
Any idea if that would work??
Yes, for a person with healthy lungs a Max PS of 10 will likely be high enough to do all the work of breathing during what would have been a central apnea. This information had been posted on the ResMed website before it was re-designed to be more sales-oriented but less informative.
I suggest permanently lowering Max PS to 10 unless you have a lung condition like COPD.
If you have a lung condition then I would suggest consulting your doctor but lowering Max PS to 10 at least temporarily, and occasionally wearing at night a recording pulse oximeter to verify your SpO2 is not dipping below 90% during the times the machine is treating central apneas.
If the Flow waveform (Flow is the estimated the rate of airflow into and out of our lungs) is zero during a pressure peak, this was an obstructive arpnea, which is most commonly caused by having rolled flat onto our back.
If the Flow is start/stop intermittent this is caused by intermittent obstruction.
If during a hypopnea the Flow waveform is steady, with smooth inhalation and exhalation - but the Minute Volume (the amount of air breathed per minute) is too small (is significantly lower than your recent Minute Volume) even though PS has become maxed out - this is when the ASV machine has managed to change a central apnea into something we might call a central hypopnea, and a higher setting for Max PS might have been able to treat the hypopnea more completely.
To see these details in the Flow waveform one has to zoom in until 5 or 10 minutes fills the screen. Also, the vertical scale on the flow needs to be zoomed in, to show only about -75 Liter per minute to about +75 L/m.
Raising the Min PS setting will tend to raise your average SpO2.
I think an ideal setting for Min PS is one which will help keep the average SpO2 staying between 94% and 96%. (Just paying attention to the average SpO2 during each hour or so, not paying attention to momentary dips.). I think averaging 98% and above for most of the night may cause problems like interfering with prescription medicines; it creates higher oxidative stress on the body, which long term would be bad for our health.