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Why is my Flowrate so spikey?
#1
Why is my Flowrate so spikey?
I have been using APAP for 2-3 weeks now, and my sleep quality has been consistently bad.

I wake up only about 2-4 times during the night, but I'm not sure why my flowrate is so choppy (at any pressure).

Would love to hear any thoughts/feedback, thanks.

[attachment=37218][attachment=37217]
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#2
RE: Why is my Flowrate so spikey?
idk much about pr machines so others may have better replies. you're in early days so things may settle down a bit in time. however, you have too many events and it looks like you're struggling a bit to breathe. some people get treatment onset/pressure induced central apnea which usually abates after 30-90 days. however, if you had much central apnea (ca) in your initial sleep test, you may need a different machine that will treat that. cpap/apap won't. sometimes ca is reduced by limiting the range of pressure, even leaving apap mode for fixed pressure cpap mode. also, from what I read here, most people don't do well with a flex setting of 3. the first thing I'd try is backing that off a notch at a time for a few days each to see what happens. you might also post some closer views of some hypopnea (at, say, a 3 minute view scale, adjusted by the slider at the bottom of the oscar events tab) to see if people that can discern these things can tell if they're obstructive (oa) or central. we need more pressure to treat oa which in turn tends to increase ca so with cpap/apap machines the trick is to tweak pressure looking for the sweet spot of relative frequency of oa and ca at which you feel best.
  Shy   I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  
 
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#3
RE: Why is my Flowrate so spikey?
Thanks for the response! I'll try dialing back the flex setting.

I've taken a home sleep study and was diagnosed with only OSA (AHI 12.5), no mention of central sleep apnea.

However, I've noticed an increase in CA's when the pressure is higher (+10 cmH2O).

I've attached zoomed-in screenshots of flagged events at different pressures below...

[attachment=37222][attachment=37221][attachment=37223]

Could you infer a better optimal pressure range for me?  Thinking-about
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#4
RE: Why is my Flowrate so spikey?
If you take a 2-minute zoom, does it look like this?

http://www.apneaboard.com/forums/attachm...?aid=35934
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#5
RE: Why is my Flowrate so spikey?
in oscar, click on view/reset graphs/standard. turn off (remove check mark) pie chart and calendar. return to daily/details and click on view/screenshot or F12 for a full night chart. then move the cursor to a spot you want to zoom in on and move the slider at the bottom of the events tab to the view scale you want, like 2 or 3 minutes. click on view/screenshot or F12 for a zoomed view. post a full night screenshot and one or two closer views.
  Shy   I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  
 
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#6
RE: Why is my Flowrate so spikey?
Thanks for your patience, I'm still fumbly with the controls.

           
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#7
RE: Why is my Flowrate so spikey?
good job with the charts!

your earlier images are no longer visible so I can't accurately compare to last night's. I'm pretty sure your flow rate looks better, more compact. it might take a couple days to see a trend but reducing flex might be marginally better? feel any different? easier/more difficult to breathe during the night? after a day or so try reducing flex again. you can always bump it back up depending of what you see and how you feel.

still too many events. some of everything. how did you arrive at your current settings. in lab titration or?

others may have better ideas but considering you had only obstructive apnea in your sleep test (assuming they even looked for ca) and your current ca and likely central hypopnea are probably pressure induced, I'd start self titrating the obstructive apnea out. one way is to set the machine on cpap mode with fixed pressure, raising it from your current minimum of 7, one cmw at a time to start, looking for a reduction in oa and monitoring what happens to ca and h. once you've found your best setting against oa, reevaluate depending on what happens to ca and h. your 'best setting' will be the lowest pressure achieving an acceptable level of oa. how you feel is as or more important in making this determination. it's okay to expect and accept a few residual events.

post charts every day or two for a bit and tell us in some detail how you feel after making each settings change.
  Shy   I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  
 
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#8
RE: Why is my Flowrate so spikey?
Thanks a lot for your insight, Sheepless!

I've turned off Flex completely, and my flow rate has been much more uniform. Even though my AHI is much higher, I felt like I've slept well.

   


The following (latest) night, I've started increasing the pressure to treat OA's, and it looks like it's improving. However, this night has been a little uncomfortable (3:00-4:30am), I think I'm not used to high pressure without flex. Maybe my body needs time to adjust. Overall, my sleep wasn't good, nor bad.

   

In hindsight, I should've followed your advice to stick with one single pressure. But judging from the latest night, It seems like I'll need +11cmH2O to better treat OA, though I'm worried about mask leaks.
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#9
RE: Why is my Flowrate so spikey?
good to hear you slept well! goes to show that while ahi is perhaps the most critical measure, it isn't the whole ballgame.

can you re-post a screenshot from your first post? I'd like to your compare settings and pressure waveforms. obviously an ahi of 10.72 on the 17th isn't what we hoped for but better on the 18th, although still too high. ca tends to be highly variable night to night so while it looks like it's coming down, it may be temporary.

meanwhile, I agree you're going to need higher pressure for the oa as you're bumping up against the set max of 11. you're probably going to need to go still higher. once you find the best fixed setting, you can experiment with a range a little below and a little above that which may make breathing a little easier and help minimize leaks. but pressure of 12, 13ish really isn't very high; it might just take some getting used to.

I had suggested you incrementally reduce flex. I'd go back to 2 for a couple nights, then 1 partly for the experience and more importantly flex should be more comfortable exhaling against pressure. now you know what flex at 3 and 0 feels like, after trying 2 and 1 you can pick the setting most comfortable for you. I'm hoping you can tolerate some flex to help you feel more comfortable with pressure. however, it's epap (exhale pressure) that treats oa so with flex you may need your ipap (inhale pressure) to be higher than without flex.

at this point we have to hope the ca and central h diminish in time as you acclimate. again, apap isn't capable of treating ca so we can only try to avoid it. so the first order of business is to reduce oa and obstructive h as much as possible. if ca remains high or goes higher, you might have to reduce pressure and accept a few more oa to bring ca down. that would be your sweet spot.

it's all trial and error even in the sleep lab so don't be discouraged if it takes a while.

btw, few veteran pappers use ramp because the machine provides little to no treatment during that period. if/when you can, best to start reducing ramp time and turn it off as soon as you feel you can fall asleep at set pressures.
  Shy   I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  
 
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#10
RE: Why is my Flowrate so spikey?
Thanks for your detailed feedback! I really appreciate your helpfulness.

Here are some older screenshots (as requested) from the past, I had it on a higher pressure setting. It seemed like the higher pressure combated the OA pretty well. But my quality of sleep was very bad and I falsely blamed it on the higher pressure.

       

But now, given your insight, I'm starting to think the spikey flow rate was caused by either Flex or a wide pressure range.
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