+- Apnea Board Forum - CPAP | Sleep Apnea (https://www.apneaboard.com/forums)
+-- Forum: Public Area (https://www.apneaboard.com/forums/Forum-Public-Area)
+--- Forum: Main Apnea Board Forum (https://www.apneaboard.com/forums/Forum-Main-Apnea-Board-Forum)
+--- Thread: help with max pressure setting (/Thread-help-with-max-pressure-setting)
Pages:
1
2
help with max pressure setting - cberistain - 03-09-2022
my sleep study showed mild apnea ..11.5 events/hr (40 OA's , 80 Hypopneas) , snoring 47%, sp02 below 88% for 7.2% of the time, sp02 below 80% for 1.6% of the time.
I seem to be very sensitive to even small leaks.. they wake me up or make me restless. My deep sleep is sometimes less than 15 minutes per 8 hours of sleep. REM time has increased from 1 hour to 1.5 hours (based my my fitbit )
I've tried many different masks.. full face and nasal.. currently using the P10 with chin strap and cervical collar. I'm a side sleeper but still spend some time on my back.
many nights I have zero events .. a bad night would be 0.3 AHI's.
seems no matter where I set the max pressure .. the machine will try to come close to it sometime during the night.. and that increases the mask leaks. AHI's stay the same regardless of pressure.
So, my current settings are: no ramp 8.6 start, 9.6 max with EPR = 3.
with those settings my median pressure is 9.56, 95% is 9.6
with that as background, have I pushed my luck with lowering the max pressure? should I increase it?
RE: help with max pressure setting - Sleeprider - 03-09-2022
With pressures from 8.6 to 9.6 and EPR 3 your pressure seeks the maximum set pressure due to flow limitations. Your AHI is zero, so you clearly don't need more pressure and if you would be more comfortable with lower pressure, just set the minimum and maximum pressure the same. There is nothing in your chart that suggests your current pressure is inadequate. I'm sure if you set a higher maximum pressure the machine would go there because the algorithm is designed to respond to flow limitation this way. The higher pressure has no benefits and makes you uncomfortable, so you did the right thing and could probably go lower if desired.
RE: help with max pressure setting - cberistain - 03-09-2022
(03-09-2022, 04:28 PM)Sleeprider Wrote: With pressures from 8.6 to 9.6 and EPR 3 your pressure seeks the maximum set pressure due to flow limitations. Your AHI is zero, so you clearly don't need more pressure and if you would be more comfortable with lower pressure, just set the minimum and maximum pressure the same. There is nothing in your chart that suggests your current pressure is inadequate. I'm sure if you set a higher maximum pressure the machine would go there because the algorithm is designed to respond to flow limitation this way. The higher pressure has no benefits and makes you uncomfortable, so you did the right thing and could probably go lower if desired.thanks for the quick and imformative response.
can you explain how to read the flow limitation chart so I understand where I'm flow limited?
many thanks
RE: help with max pressure setting - SarcasticDave94 - 03-09-2022
I look at flow limits charts this way, scale it as a percentage 0-100 with 100% equaling 1 in the chart. Your left panel states your FL had a .22 or 22% of the 99.5% level. This means you had 22% FL or less that session.
Now what you do then is look at the actual flow limits chart. Those black trace lines are about 25% up in scale and span your whole sleep session. That line trace states you're flow limited all night.
RE: help with max pressure setting - Sleeprider - 03-09-2022
To help you with this, I'll refer you back to your own chart. Zoom in on the flow-rate chart so you can see the individual wave-forms. The tops of the waves are probably flattened, showing that the rate of flow is limited. You don't have a severe problem, but it's there, and if you had a more pressure support, it would probably be a lot better. Read this wiki http://www.apneaboard.com/wiki/index.php/Flow_limitation
Flow limitation means that your airway restricts or limits the maximum amount of airflow (mL/second) that can pass. It's like a partial kink in a water-hose. If the airway was fully open and compliant, that wave-form would be nicely rounded. You probably would need a Resmed VPAP (bilevel) machine with more than 3 cm of pressure support to fully overcome your flow limitation. EPR works just like bilevel pressure support and this concept is illustrated in the wiki by showing mask pressure and how it affects the flow rate chart. Pressure support comes in to assist your inspiratory respiration effort with the mechanical work of pressure allowing a more normal breath.
RE: help with max pressure setting - cberistain - 03-10-2022
(03-09-2022, 04:58 PM)SarcasticDave94 Wrote: I look at flow limits charts this way, scale it as a percentage 0-100 with 100% equaling 1 in the chart. Your left panel states your FL had a .22 or 22% of the 99.5% level. This means you had 22% FL or less that session.
Now what you do then is look at the actual flow limits chart. Those black trace lines are about 25% up in scale and span your whole sleep session. That line trace states you're flow limited all night.
so increasing the max pressure will reduce the flow limit i'm currently seeing on my charts?
RE: help with max pressure setting - SarcasticDave94 - 03-10-2022
Sometimes that's what you need to resort to, but a better way is with EPR or pressure support to give a differential between exhale and inhale pressures.
RE: help with max pressure setting - cberistain - 03-10-2022
(03-10-2022, 09:00 AM)SarcasticDave94 Wrote: Sometimes that's what you need to resort to, but a better way is with EPR or pressure support to give a differential between exhale and inhale pressures.mine is set at EPR = 3 and has been almost from the beginning
RE: help with max pressure setting - Gideon - 03-10-2022
For a lot of users the max is irrelevant in that actual pressure never reaches it and never causes a significant rise in pressure. You are not one of these.
I am totally with Sleep rider on this, you have no need to increase your max pressure at all. The only complaint you have registered is that your pressure goes to your max. In fact you could lower your pressure as by the numbers you are extremely well treated. Ignore these number, but pay attention to how you feel. Do keep on your AHI solely as an indicator to take a deeper look say if you consistently hit AHI 2.5 - 3.0+
RE: help with max pressure setting - cberistain - 03-10-2022
(03-10-2022, 11:07 AM)Gideon Wrote: For a lot of users the max is irrelevant in that actual pressure never reaches it and never causes a significant rise in pressure. You are not one of these.
I am totally with Sleep rider on this, you have no need to increase your max pressure at all. The only complaint you have registered is that your pressure goes to your max. In fact you could lower your pressure as by the numbers you are extremely well treated. Ignore these number, but pay attention to how you feel. Do keep on your AHI solely as an indicator to take a deeper look say if you consistently hit AHI 2.5 - 3.0+
appreciate all the help ... very reassuring
fortunately I've never had an AHI over 0.7 (and that only once and had very large leaks) since I started 4 months ago. AHI 0.0 - 0.3 seems to be my range.
again, thanks to all for the help