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+--- Thread: Are these flow limits my problem? (/Thread-Are-these-flow-limits-my-problem)
RE: Are these flow limits my problem? - Sleeprider - 01-14-2024
The lower maximum pressure looks good. You arouse and discontinue therapy when pressure is above 15, so you're doing all the preventive things, and when those don't work, the higher pressure is not helping. There will be varying results, but the trend looks to be in the right direction. I don't know that there is much more you can do other than have more good nights than bad ones. It seems to be a good move to avoid higher pressures by using lower pressures in combination with sleep aids to prevent positional obstruction as best you can.
RE: Are these flow limits my problem? - SingleH - 01-14-2024
Hi PeaceLoveAndPizza,
When you say flow limits are high what figure are you looking at.
I'm a bit confused by this, if the median is 0.01 out 1.0 is that not a low number of flow limitations? I suspect I may have been misinterpreting how to read this figure as to what quantifies low or high flow limitations?
Also does flow limits tracking increasing pressure reflect some kind of specific issue as I've observed the same.
RE: Are these flow limits my problem? - k888 - 01-14-2024
Hi SingleH, The flow limits vary. Last night was .05 - .46. The night before was .11-.29. Definitely better than before the Vauto, but still making for more sleepiness than nights when it is lower. k888
RE: Are these flow limits my problem? - SingleH - 01-14-2024
Hi K888,
Ok, in your first email you listed two figure ranges for flow limitations example .20-.33 .
Are they your med to 99%, or med to 95%, or 95%-99%?
RE: Are these flow limits my problem? - k888 - 01-14-2024
95%-99%
RE: Are these flow limits my problem? - SingleH - 01-14-2024
ok so you dont use the median figure, the your figures are not much different to what I am seeing in Oscar.
Do you know what figure is considered ok or acceptable based on the 95-98%?
RE: Are these flow limits my problem? - PeaceLoveAndPizza - 01-14-2024
There is currently no medical standard for flow limitations. What we have learned is that having a 95% < 0.05 works well for most.
There are extenuating circumstances for some where higher FL's are acceptable as long as they do not affect sleep quality too badly.
https://www.apneaboard.com/wiki/index.php?title=Optimizing_therapy#TroubleShooting_Therapy
RE: Are these flow limits my problem? - k888 - 01-14-2024
Thanks for your comments Sleeprider and PeaceLoveandPizza,
The reason I wonder about higher pressure is that when I look at a good night like Jan. 9 (posted here), I see some individual spikes from about 5:15-6:00 am that were handled by that pressure. And I did sleep through that night well.
[attachment=58402]
And even during the bad night of Jan 10 posted above, there were individual spikes handled by higher pressure during that 3:15-5:15 am run of events, not just the long run of apparently positional apnea. I guess the obvious way to test is to set max IPAP at 20 and see what happens, but I have to have a few good nights under my belt first. I am thinking the best thing is to approach from the other direction and raise PS in the hope that this will reduce flow limits and thereby reduce events and need for pressure. I have not wanted to do that too fast and cause centrals. What is a reasonable rate to increase PS, and should I increase minimum EPAP at the same time?
And why are there more events/need for pressure in the early morning? Or is that just me? k888
RE: Are these flow limits my problem? - SingleH - 01-14-2024
Thanks for sharing that useful guideline figure PeaceLoveAndPizza.
0.05-0.15 is on average the best figures Im seeing on Oscar
Very useful link in that link you sent:
>>The check for whether flow limitation is upper airway or a result of ventilation is to look at pressure support when it occurs. If the flow limitation mostly occurs during higher pressure support, it is pulmonary. If the flow limitation occurs during minimum or low pressure support, it may be upper respiratory, and a higher minimum pressure support or higher minimum EPAP may help.<<
This does conflict with what I am seeing though:
Flow limitations are reduced with higher pressure support, so it should not be pulmonary
Flow limitations incease as minimum EPAP increases, the lowest EPAP settings result in the best Flow limit figures, which suggests its may not be upper respiratory either?
High EPAP + High PS produces worse flow limitations than low EPAP + High PS
RE: Are these flow limits my problem? - SingleH - 01-14-2024
I would try increasing PS very slowly, 0.2 at a time. I discovered that making large PS changes has negative effect on CA's that seems to linger on for days or weeks even before they start to drop down. I had got CA's totally under control in the past, then made a large change, and actually not been able to get back to that point.
I dont believe there is an issue raising EPAP in larger amounts, or at least I've not ready anything to the contrary so far on this forum, but perhaps not more than 1.0 at a time as I think the body doesnt like too many big changes.