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Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
#11
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
(02-01-2022, 01:32 PM)Geer1 Wrote: Trigger from very high to low is a big change. Higher trigger sometimes helps with centrals so my guess is that low is too low hence the increase in centrals. The centrals are a warning that you have manipulated the settings out of a comfortable range.

Low trigger and high cycle are both trying to force a short inhale but the reality is your spontaneous breathing will drive respiration and fight the machine (with centrals and all sorts of stuff) if you use settings that put the pressure out of sync with spontaneous breathing. You want to use the timing controls to try and match spontaneous breathing not force your spontaneous breathing to change. Trying to force breathing is never the goal unless you have a neuromuscular or hypoventilation issue which I assume you don't.

When working on these timing control settings two graphs are important, flow rate and mask pressure. For trigger sensitivity what you want to see is that pressure increases are being initiated when you take main inhalation and not prematurely during the end of your exhalation. If trigger is too high you will start seeing pressure increase before exhalation has finished and it will often start appearing as two pressure waves per breath (one falsely triggered early and then a second one triggered at inhale). My recommendation is to check if your old very high trigger was causing this and if so slowly adjust it down until that stops happening (in other words try high then normal, don't jump straight to low).

Cycle doesn't seem to clearly cause issues in the same way although many people find it uncomfortable on higher settings because it stops early trying to force you to stop inhaling. I believe it is mostly a comfort setting but if you are seeing pressure drop and flow rate continuing on it is an indicator your cycle sensitivity is too high. Most prefer normal or low rather than the high you are trying to use to force you to exhale.  

Similarly you shouldn't need Timin or Timax unless you have medical issues that require it. 0.3 Timin and 2 Timax are fine and shouldn't ever really come into play (most inhalations are 1-1.5 seconds).

I appreciate your feedback as it's helping me learn more about my xPAP therapy.

Last night I left Cycle at HIGH but lifted the Trigger from LOW to Medium and this seems to have had a positive effect. If it carries on this way I might drop Cycle to medium as well but I'll give it a few days. I'll post some charts then and if you don't mind having a look and providing feedback (especially in regards to where  the pressure is changing and how that syncs to my spontaneous breathing) it would be appreciated. SevereApnea has already helped me to add to my knowledge base and your post has done the same thing which I am very grateful for.
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#12
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
@holden4th

Slowly slowly catchee monkey! 
One thing I have learned is to make small changes, one at a time, and stick with them. It tests my patience! I want a quick fix, but there 'aint none!
Often when I would make a change, night 1 feels good, night 2 feels ok, night 3, 4 and 5 felt ok and then things went pear-shaped.
Tough to figure out why. Trial and error, paying attention to how it all felt.

My notes from last year indicate that it feels better when TS is higher than CS.
ie TS can be High and CS medium or Low
or TS can be Very High and CS Medium.

But when I had them reversed, ie TS Low and CS High it felt terrible and I couldn't maintain that. I think Geer1's comment allude to why this may be the case but I will have to digest this information a bit more.

Extract from my notes of 22 April 2021, still chopping and changing between settings (bad idea to change settings during the course of a night, but that's another story)

Another messy night.
#1. Vauto 6 – 11 (4) TS Lo, CS High. Starting Vauto with Lo/Hi is a mistake.
#2. Vauto 6 -11 (4) TS M, CS M.
#3. S-mode 6.6 – 10.6 M/M PS = 4
#4. S-mode 5.6 – 10 M/M PS = 4.4 too much

Sleep Pattern
:


#1: 3.4 hours. 10.9/6.0 – 4L – 1.4/2.6 (bad ratios) 540/12/6.8
Feels wrong TS CS are the wrong way around. I feel rushed into breathing out.
Starting to get a headache. Needed time to recover.
SE: HEADACHE. 

#2: Vauto 6 -11 (4) TS M, CS M.
ended 03:35. Feels off. I need to breathe in longer. So more PS or CS to low.

Good Stuff: 1. I slept. 2. I learnt to avoid Lo/Hi. 3. I learnt that PS 4.4 with M/M is bad. 4. I learnt that even with many CA I can have headache and a different kind of palpitation. 


Bad Stuff: did not feel too bad on waking but the rest of the day was bad. Some headache and bad heart palpitations.

Thoughts
: Looking through my data since January the TS should always be higher than CS. High/Low is good. Medium/Low is ok. Low/High is BAD.


Possible you have overdone it and gone the other way?

Looking forward to your progress and joining your learning curve.
@Geer1: thanks heaps for chipping in and adding your valuable insight here. Thanks

You said:
"When working on these timing control settings two graphs are important, flow rate and mask pressure."
I have not found a way to understand the mask pressure graph, but will search the board for more information, perhaps there may be a dedicated thread on that.
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#13
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
(02-02-2022, 03:03 AM)SevereApnea Wrote: But when I had them reversed, ie TS Low and CS High it felt terrible and I couldn't maintain that. I think Geer1's comment allude to why this may be the case but I will have to digest this information a bit more.

Its all about matching what is comfortable to you/body.

This view shows normal trigger and cycle. If you increase trigger or cycle it shifts the start/stop of pressure wave left (trigger affects start point, cycle the stop point). 

     

If you lower TS and increase CS then it compresses the period of inspiration. Your guys ideas earlier was that this would support exhalation, the problem is that it supports exhalation by fighting to minimize inhalation. Your body doesn't like that so the best you can do is find the settings that avoid premature triggering and that allow for comfortable exhale.
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#14
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
   
           
(02-02-2022, 12:17 PM)Geer1 Wrote: Its all about matching what is comfortable to you/body.

This view shows normal trigger and cycle. If you increase trigger or cycle it shifts the start/stop of pressure wave left (trigger affects start point, cycle the stop point). 

 

If you lower TS and increase CS then it compresses the period of inspiration. Your guys ideas earlier was that this would support exhalation, the problem is that it supports exhalation by fighting to minimize inhalation. Your body doesn't like that so the best you can do is find the settings that avoid premature triggering and that allow for comfortable exhale.

Here are last two nights charts. AHI has improved then but is still well north of where I want it. Last night with the 5+ AHI I didn't feel too bad when I gotr up and only 2 breaks of sleep.

The previous night wasn't good even though the AHI was lower

Settings for 1 Feb for TS and Cycle were Low for TS and high for Cycle. There were no CAs
I made just one change for Feb 2 and that was to raise the TS to medium and you can see the increase in OAs, Hyps and especially CAs. I had no feelings of breathlessness which was good.

So currently these are my settings:

Max IPAP 25.0
Min Epap 10.0
PS 3.0
TS MED
Cycle High
Insp Max time 2.9 and .03 for MIN

In my previous post I wondered if maybe I should have lowered my Cycle instead of raising my trigger. These are the only things that have changed and they have made a difference. They do  appear to be the two main factors at the moment. From here I've decided to go MOR and use the medium setting for both Trigger and Cycle. I know that this won't necessarily be ideal but it should give an indication if it's exhalation or inhalation is the issue and I can start to make changes from there. Please have a look at the charts for the two nights and tell me what you think. Last night was the first in a while where I didn't wake feeling breathless.

Once again, many thanks for your input and hopefully it can help someone else further down the road. The p*** off for me was that for a long while my therapy was close to the sweet spot but now it's gone.
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#15
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
I would change CS to med or low, that is what others usually find comfortable.

Have you compared flow rate to mask pressure for past results and found any cases of premature pressure increases using very high trigger or anything like that?

What were you using for settings when results were good?
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#16
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
OK, dumbass here forgot to replace the SD card in the machine but AHI was down to 2.7 and an OK nights sleep. I posted my settings when it was going well but can't seem to find them. So my next move is to leave the trigger at MED and lower the CS to LOW. At least I feel that I'm making progress and am certainly in a far better position than a week ago. Looking at previous posts I had my trigger higher than my cycle. The SD card is back in the machine. I've not had the breathlessness feeling for a few nights now, if it returns I know I've gone too far.
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#17
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
My guess is your trigger was too high and triggering prematurely. Trigger of H or M and cycle of M or L are probably best and that seems to be the case for most users.
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#18
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
OK, last night only 5 hours sleep but the figures are already better. AHI of 2.25, 3 CAs, 5 OAs and 2 Hypopneas. I've now set the machine with a trigger at H and Cycle at L which means that both have at least one more notch which hopefully I won't have to use. Again no breathlessness. I can't remember what my original settings were. I know that they were at either end of the scale and it's likely that trigger was VH and Cycle VL.

I've had a look at mask pressure and flow rate. Highest mask pressure was 17.41 and lowest was 10.3. The tidal volume graphs showed that what I recorded for inhalation was matched by exhalation as the pattern was basically symmetrical.

Tomorrow I'll post tonight's charts for you to look at. What I like is that I seem to be making progress and I have the two of you to thank.
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#19
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
"OK, dumbass here forgot to replace the SD card in the machine"

Heh, heh, annoying? I hate it when I do that.

Hoping things start to feel better for you soon in terms of comfort.

Then it will be time to look at the number of OSA vs number of CA and hopefully find settings that will reduce your AHI and Flow limitations.

It's a process! I am still tweaking after 2 years.

(My ageing grey cells are still trying to understand the Mask pressure chart and comments made by Geer1.
Project for tomorrow.)
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#20
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
You can go back to previous OSCAR charts and you will find your previous settings logged. The statistics page also has them.
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