Hi space45, welcome to the forum!
ResMed selection guide says your machine is their optimal machine for treatment of Obstructive Sleep Apnea.
(03-29-2014, 06:34 PM)space45 Wrote: after my first night with a S9 VPAP auto machine
my resmed machine says my AHI is 4.8 my small wrist o2 recorder says my AHI is 1.42, thing is last night my o2 did go down to 56% when sleeping on my back but averaged 89% one point above the 88% min for the night
An oxygen saturation percentage (SpO2) of 56% is very low, and may indicate it is especially important for you to stay off your back. If it keeps dropping below 88%, be sure to keep your doctor informed.
I have an increased number of obstructive apneas when sleeping in the supine position. I wear a snug teeshirt with a tennis ball in a pocket sewn high on my back, between my shoulder blades. Works really well to keep me off my back.
What was the Pressure Support (PS), the difference between EPAP and IPAP, set to?
Increasing the Pressure Support (PS) will tend to push your average SpO2 higher. But on some people who (like me) tend to get central apneas, too much PS tends to cause excessive central apneas. I think central apneas are not more worrisome than obstructive apneas, especially if short (20 seconds or less), but both central and obstructive apneas or hypopneas will tend to cause arousals leading to poor sleep quality.
I've read that a good target range for SpO2 is about 94 to 96, or a little lower if asleep. If the SpO2 is 97 and above for long periods, this may be too high and may cause health problems.
(03-29-2014, 06:34 PM)space45 Wrote: my wist machine was reporting a AHI from 72 to 87 range over several nights before getting the VPAP machine, so going down to 1.42 is good.
If I may ask, what manufacturer and model of wrist oximeter are you using?
(03-29-2014, 06:34 PM)space45 Wrote: I used most of the default settings of the VPAP, including the high of 25 for max pressure, the data shows the machine pressure going to 21 for a very brief time but hitting close to 19 somewhat often.
If the pressure is going that high, it might have been primarily because you were sleeping on your back, and staying off your back may allow pressure to stay much lower.
Nonetheless, I suggest raising your minimum EPAP from the default value of 4, up to 6 or 8 if not uncomfortable, unless 6 or 8 is very close to your median EPAP pressure.
Actually, a few people find they do best with their Minimum EPAP just a fraction of a cm H2O below their median EPAP pressure, but I think most prefer it at least 1 or 2 cm H2O lower.
If staying off your back allows the EPAP pressure to stay most of the time at the Minimum EPAP setting, then I would suggest the Minimum EPAP setting can be lowered for greater comfort but I suggest not lowering it to less than 2 cm H20 lower than your median EPAP pressure.
Usually not good to set the Minimum EPAP pressure setting a lot lower than your median EPAP pressure. The ResMed AutoSet algorithm treats the Minimum EPAP setting as a target EPAP which it slowly tries to get the EPAP back to (when not having obstructive events). If the Minimum EPAP setting is way too low, the machine will tend drop the pressure too quickly, leading to more obstructive events and lower sleep quality.
By the way, one cm H2O is a very small amount of pressure. It takes about 72 cm H2O to make one pound per square inch (psi) of pressure.
(03-29-2014, 06:34 PM)space45 Wrote: one VPAP event had a obstructive rating of 97, not sure what that means
On ResScan plots, apnea events are labeled with their length in seconds. An apnea event lasting 97 seconds would be very long, indeed. Hopefully keeping off your back while asleep will prevent long events.
(03-29-2014, 06:34 PM)space45 Wrote: so what should I be looking at and what should I be changing for setting on the VPAP?
As mentioned above, you may be able to adjust PS to optimize your SpO2.
Also, it is important to note the Central Apnea Index (CAI), the average number per hour of central apneas or clear airway apneas, compared to the Apnea Hypopnea Index (AHI).
If someone's CAI is higher than 5, and if the CAI is more half of the AHI, I think that person would benefit from an Adaptive Servo Ventilator (ASV) class of CPAP machine. But I think that does not apply in your case, so I think you have the best machine to treat your Obstructive Sleep Apnea.
I use ResScan to zoom in and look closely around the times of my apnea events, looking at the High Rate Pressure plot and (especially) the Flow plot, to verify an actual apnea did happen, and to see its duration. (Interruptions in breathing which do not last at least 10 seconds are not reported and do not count as official apneas.)
It is not unusual for us to require months of treatment before we are able to adapt to therapy well and for excessive daytime sleepiness to no longer be a problem.
ADDED: I see that in my post above I have mixed long term suggestions with short term ones. My only short term suggestion would be to raise the Minimum EPAP if it is obviously way lower than the median EPAP pressure your machine automatically adjusts itself to, and only if raising the Minimum EPAP would not be uncomfortable.
At this point it is most important that the machine settings are comfortable enough that you will be able to use the machine whenever sleeping or napping, and to gather information to form a baseline for future adjustments. Adjusting the Pressure Support would be a long term task, not for the present.
Below, robysue has provided excellent advice, as always.