StillAnotherGuest wrote: ↑Tue Oct 16, 2007 4:08 am
6PtStar wrote:I thought I had it all figured out but I got Pro Analyzer and I am confused again. Can someone explain what Variable Breahing is and what effect it has on your condition. Breathing in and out seems to be variable but why do I care as long as I get enough air?
It may make more sense to view Variable Breathing (VB) as not necessarily related to variable breathing per se, but rather the machine has entered a different mode, and the algorithm has been taken over by the Variable Breathing Control Layer. But let's call it Variable Breathing Mode (VBM). It has seen some erratic breathing and has
suspended titration mode.
Right, there's not a lot of clinical data about it, but I imagine you could have either some normal variation (REM sleep, normal wake periods) and/or abnormal variation (insomnia, repeated wake/1 transitions, arousals from non-respiratory events).
There are times, however, when seemingly "variable breathing" per se will not cause the machine to enter VBM (the algorithm hierarchy seems to say that if there are leaks, snores, or apnea/hypopnea, you can't enter VBM). Without this hierarchy, anyone with untreated SBD would undoubtedly be in VBM all night long.
The basic goal of VBM seems to move the patients back to the setting that was in effect before the onset of erratic breathing. In both APAP and AutoBiPAP, this is accomplished slowly, at a rate of 0.5 cmH2O/minute, up to 2.0 cmH2O (using IPAP in AutoBiPAP, affecting EPAP only if an IPAP change would necessitate an EPAP change because of PS restrictions). Also, pressure changes are tempered based on the presence or absence of snoring prior to the initiation of VBM.
Being able to analyze a patient's VB Mode more closely, like when it actually occurs, would be extremely helpful (but right now, you can't).
REM sleep in adults is generally pretty stable, at least stable enough that if you see 25% VB you shouldn't think it's all REM. I mean, there may be a little variation, but I think the point of considering VB in REM is that you don't want to poke at it
at all with unnecessary pressure changes.
I would look for poor sleep architecture as the most likely culprit of abnormally high percentages of VBM.
In an edit of the VB algorithm:
Variable Breathing Pressure Control
Once the variable breathing controller has been granted control of the pressure support system, it takes some initial action based on the action the auto-CPAP controller is taking. After this initial action, it performs an independent pressure control operation.
A prior pressure that is flat will cause the pressure delivered to the patient to remain at that level.
A prior pressure that is increasing will cause the variable breathing controller to initially decrease the pressure delivered to the patient at a rate of 0.5 cmH2O per minute. The magnitude of the decrease is dependent on the magnitude of the increase in prior pressure. The pressure decrease is intended to erase the prior pressure increase that possibly caused the variable breathing. However, the total decrease in pressure drop is limited to 2 cmH2O. After pressure decrease, the variable breathing controller holds the pressure steady.
A prior pressure that is decreasing will cause the variable breathing controller to initially increase the pressure delivered to the patient at a rate of 0.5 cmH2O per minute. The magnitude of the increase is dependent on the magnitude of the decrease in prior pressure. The pressure increase is intended to erase the prior pressure decrease that may have caused the variable breathing. However, the total increase in pressure is limited to 2 cmH2O. After pressure increase, variable breathing controller holds the pressure steady.
The pressure curve is provided for 5 minutes or until the variable breathing condition clears. Thereafter, the pressure is controlled according to the following:
The pressure is either maintained at a constant value, or it follows a decrease and hold pattern. The decision to hold the pressure or to decrease the pressure is made by comparing the current pressure with the snore treatment pressure. It is to be understood, however, that this duration can be varied over a range of durations.
If there is no snore treatment pressure stored in the system, which will be the case if the snore controller has not been activated, the pressure is held constant. If there is a snore treatment pressure, and if the current pressure is more than a predetermined amount above this snore treatment pressure, such as more than 2 cmH2O above the snore treatment pressure, the variable breathing controller decreases the pressure to a level that is a predetermined amount higher than the snore treatment pressure and holds the pressure at the lower level. The pressure decreases to the snore treatment pressure +1 cmH2O.
The duration during which pressure is provided according to the paradigms discussed above for region is set to 15 minutes or until the variable breathing condition clears. It is to be understood, however, that this 15 minute duration can be varied over a range of durations.
SAG
My anxiety has been getting the better of me lately, especially trying to get my therapy figured out. Thank you
I'm only on two meds at the moment.