(12-14-2013 06:45 PM)pdeli Wrote: I have a Respironics Bi-pap Auto Bi-flex with 6-16 pressure settings. The Bi-flex setting is 3. In looking at my Sleepyhead data, I can see that my inhale Pressure is sometimes as high as 10 while my exhale is always a constant 6.
Some clarification is needed here.
It's clear that your minimum EPAP = 6
and your maximum IPAP = 16
. There are one or two other settings that we need to know about in order to fully understand how your machine is going to behave during the night.
On bi-level machines, the pressure support (PS)
is defined to be the difference between IPAP and the EPAP. In other words, PS = IPAP - EPAP
. On the PR System One BiPAPs, the PS is allowed to vary based on the PS settings that are set inside the clinical set up menu.
If you have a newer PR Series 60 System One BiPAP Auto, we need to know what your minimum PS and maximum PS settings are.
These settings control how far apart the IPAP and EPAP can be from each other.
If you have the older PR Series 50 System One BiPAP Auto, there won't be a minimum PS setting, but there will be a PS
setting. The minimum PS = 2 on the Series 50 machines and the PS setting gives the maximum PS setting.
Some things to keep in mind about the PR BiPAP Auto machines: The PR BiPAP Auto algorithm is split between the things that affect the IPAP pressure and the EPAP pressure. The short version of how things work on the PR BiPAPs is this:
EPAP is increased only when the machine detects
- a clusters of two or more OAs (A cluster of events are two or more events that occur within about 5 minutes of each other.)
- a cluster of events made up of both OAs and Hs.
- the IPAP needs to be increased and the current PS = maximum PS setting.
IPAP is increased when the machine detects
- a cluster of two or more Flow Limitations
- a cluster of two or more RERAs
- a cluster of two or more H's
- the proactive "search" algorithm's test increase of IPAP pressure results in an improvement in the shape of the inhalations in the wave flow
- the EPAP needs to be increased and the current PS = minimum PS setting.
NOTE: The Auto algorithm on the Resmed S9 VPAP Auto is very different. On the Resmed VPAP Auto, the IPAP and EPAP pressures are increased by the same amount in response to any event that triggers a pressure increase. In other words, the PS = IPAP - EPAP is a fixed number and does not vary on S9 VPAP. The PS is set in the clinical menu, but once it's set, at any point during the night, IPAP = EPAP + PS.
Quote:I may be getting too picky here, since I would very much like to more fully understand the treatment, but I can only seem to grasp a somewhat vague, fragmented, understanding of all this. I do notice that when I begin each night, it seems that my inhale pressure is inadequate. Not enough to keep me awake, but it still seems that I am sucking in air, and that doesn't seem right.
Do you know what your starting IPAP pressure is???
Since your min EPAP = 6
, your starting IPAP should be equal to 6+minPS. If you are using a Series 60 System One BiPAP, the minPS is probably set to something between 0cm and 4cm. You can increase the starting IPAP pressure by increasing the minPS setting. But if you are using the Series 50 BiPAP Auto, your starting IPAP will be 6+2 = 8cm, and the only way to increase the starting IPAP is to increase the min EPAP.
Quote:On the exhale side of things, I notice that in the last two weeks (new equipment) most of my inhale pressures are graphically "spiked" 15 minute periods, and there has been only one period of sustained (2+ hours) higher exhale pressure. Not a problem, I suppose, but puzzling.
If the machine is NOT scoring a lot of snoring and the recorded OAs are isolated---i.e. pretty far away from other OAs and Hs, then that EPAP line is going to sit at your min EPAP regardless of what the IPAP graph is doing---unless you happen to reach a point where IPAP - EPAP = maxPS and IPAP needs to be increased. If you post the wave flow, event, and pressure curves that show the period of sustained higher exhale pressure along with the 15-20 minutes before the EPAP pressure was increased, I'll be happy to look at it and see if I can tell what triggered the EPAP increase and why it stayed elevated as long as it did.
But on the inhalation side of things, IPAP curve is going to have some real variation in it even if there are very few events recorded because of the PR proactive "search" algorithm that is applied only to the IPAP pressure in the System One BiPAP Auto algorithm. Even if absolutely NOTHING is going on in your breathing, the "search" algorithm will periodically kick in and you'll see a test increase of 2cm in IPAP pressure followed by a decrease back down to the current "baseline" IPAP pressure. In other words, the IPAP curve will have a sawtooth appearance to it when there's no evidence of sleep disordered breathing going on in the wave flow. And from your description, that may be what you are noticing in your IPAP curve. Again, if you post a picture of your typical IPAP data, I'll be happy to look at it and determine whether the "spikes" are just the test pressure increases in the "search" algorithm being applied to the IPAP pressure.
Quote:I also notice that the pattern of Event Breakdown Statistics varies greatly from day to day.
Our sleep is not the same each night and our (untreated) OSA varies from night to night. Hence there are going to be some nights where the machine's Auto algorithm may have a more difficult time prenting almost all events. And then there's the fact that on some nights we have more wake after sleep onset (WASO)
time and whenever there's a lot of WASO, there's the possibility that the AHI will be different (possibly very different) from a night where you sleep soundly. The reason why is that wake breathing
is very different from sleep breathing
and there are patterns in normal wake breathing
that can fool a machine into scoring "false" events.