(08-30-2014 04:40 PM)vsheline Wrote:
(08-30-2014 11:36 AM)Robert6 Wrote: Maybe if I tried the ASV Auto mode on my machine, it [forced oscillation technique (FOT)] might be there because the machine may then need the FOT to find the EPAP automatically.
Yes, that would be an interesting experiment. Perhaps you could change to ASVauto mode with Min EPAP of 9.0 and Max EPAP only slightly higher, like perhaps 9.2 or so.
I tried the ASVauto mode and I had two short apneas, both indicated with red flags, which is supposed to mean obstructive apnea events. In the ASV (not ASVauto) mode that I had always used, the flags were always red, i.e. supposedly obstructive apnea events. Note that my sleep study before I got the ResMed machine indicated predominantly central events (or maybe all, just going by my memory here).
I then tried to look at the corresponding detailed data graphs of flow and pressure near the time of one of the apneas and wasn't able to see the oscillations of the FOT. That might be from not setting the graph scales for best viewing or limitations of the ResScan software or computer that I have. Not sure what's going on.
Examples of the FOT in action are shown on pages 41 and 42 at ww.apneaboard.com/ResScan_Interpretation-Guide.pdf . Note in those examples that the tiny oscillations aren't always present but kick in after 4 seconds of an apnea.
(08-30-2014 04:40 PM)vsheline Wrote: By the way, your Min PS setting is maxed out as high as your machine allows (6). That may be a little too high. I suggest wearing a recording Pulse Oximeter ocassionally while sleeping, to verify your average saturation percentage of oxygen (SpO2) is not higher than around 96% or so. 94-96 is considered ideal, and 90-93 is probably fine, too. Less than 89 is considered low. Less than 75% is considered severely low. An average of 97% or higher (not counting the occasional short dips caused by apneas), if lasting for hours on end, may be unhealthful and can lead to dangerous conditions.
Hyperoxia is something I hadn't considered so I'll look into it. So far I have seen the range 94–96% mentioned as you suggested, but I'm not sure about that. For example, at the Mayo Clinic website the pulse oximeter normal range is given as 95–100%. See ww.mayoclinic.org/symptoms/hypoxemia/basics/definition/sym-20050930
"An approximate blood oxygen level can also be estimated using a pulse oximeter — a small device that clips on your finger. Though the pulse oximeter actually measures the saturation of oxygen in your blood, the results are often used as an estimate of blood oxygen levels. Normal pulse oximeter readings range from 95 to 100 percent, under most circumstances."
I checked my levels with a non-recording pulse oximeter a few times while in bed last night and got 96–98%. I also checked it while writing this message and I got 98%. So for me, the pulse oximeter reading being at or above 96% may be normal, which is consistent with the Mayo Clinic article.
P.S. I left out a "w" in each of the two urls in my message because of this board's rules for new members. If this was improper, please make appropriate modifications. Thanks.