I read SWS as suggesting that by going back to low pressure for gathering the data & knowing it may raise the AI score is a worthwhile test - this being based on info from a report by Gilmartin Daly & Thomas: "One approach is 'permissive flow limitation' - allowing some obstruction to persist and thus avoiding the worsening of control dysfunction. ".CROWPAT wrote:You two are WAY above my understanding of CSDB, but I appreciate all of your comments and information.
Do either of you have experience with the oximeters at the links above? My previous experience with oximeters was not good - very uncomfortable to have them on my finger. Newer versions use a strip taped to the finger that is much less confining and far more comfortable.
My conclusions from above: Lower pressure that yields more OA and little if any CA may be good and result in better "feeling". It sounds logical and I am more than willing to try anything to get there. I sincerely doubt that supplemental oxygen is necessary in my case as O readings have been good whenever I used an oximater day or night. I am willing to pay for one to help diagnose and remedy my situation, but don't want to buy something that is so inherently uncomfortable that it will further disrupt my sleep. Comments?
The theory as I understand it is that by tolerating a level of 'permissive flow limitation' (let a little bit of obstructive flow take place) the result may well be better daytime well-being and less liklihood of 'worsening control dysfunction'. The worsening control dysfunction includes (as I am reading it) Centrals and erratic/periodic breathing (which in reality is evidence of worrisome respiratory control loss). This is when we see 'control dysfunction' in the form of increased PB + HI + AI scores and an increase in machine triggered breaths vs patient triggered breaths.
Pat, your own feedback highlights that when the machine shows high levels of machine triggered breathing cycles, your daytimes suffer. When you see high levels of patient triggered breaths, you feel better 'to a point'. My reading of your situation thus far is that as pressure is raised (even if just Ipap), you begin to exhibit a respiratory control dysfunction which includes Centrals but goes further and become erratic/periodic breathing. When pressure is lowered to far you start to lose daytime well being. Straight cpap doesn't appear to be adequate & bilevel needs careful tuning OR being implements as Servo Ventilation (where the machine only applies extra Ipap pressure if it sees you won't meet the target (on this model machine) Av peak flow.
I have noticed more & more doctors providing patients with Bipap AutoSV machines set with Epap=IpapMIN (CPAP MODE) & with SV support active(typically with IpapMAX set at 30). I am not completely sure what the logic is behind this but I can't recall seeing too many users who have had their machine set any other way of late. What I think that type of setting means is that the user is essentially on CPAP until their target Av Peak Flow is not being met in the observed 4-min window on the Bipap AutoSV (vs Peak Volume on the Vpap Adapt SV in a 3-min window). I suspect this is because the doctors are viewing a continuous bilevel mode as more likely to cause problems prior to being needed. In Cpap with SV mode active, the extra Ipap pressure is applied very quickly in up to 3 CMs bursts over a range of breaths (IIRC max is 3) . The logic being that if bilevel is applied all the time (every breath) then it may trigger problems such as centrals or periodic patterns of breathing, but if the machine is set to run in CPAP + SV mode and we know a problem is about to occur in a particular breath (target flow is not going to be met) then applying the extra pressure quickly can't make respiration any worse than it is about to get.
By testing you in cpap mode at various pressures, we are building up a set of baseline effects & have the data on RR, AHI & Flow etc:
Then SWS is expecting that from this data + your feedback, the current machine can be optimized to its best settings allowing for the balance required (perhaps by looking for 'permissive flow limitation' vs excessive & debilitating respiratory control dysfunction).
Pls keep asking questions as I am by trawling through what we understand, we can help each other better understand how some of these machines can be best set up & tuned allowing for what respiratory control complications we think are emerging.
DSM
