CPAPtalk.com

with iVAPS tidal volume is secondary, it's Va and MV that are prime. As well as getting the RR dialled right. resscan will show Va chart if you want to see it.

You can set the trigger while you are awake, you don't want it too fine that it will self trigger or give a breath halfway through exhale because you paused a bit. Adjust it so you have to breath a bit to trigger and doesn't feel ahead of you, try different settings and you will see the difference.

"I'm going to try 18 bpm target rate tonight, and adjust the dial so the target Va is around 8ml/kg. Hopefully way less forced breaths tonight."
I dialled in your height and 18RR, Va 4.5-4.6 should be fine then for around 8ml/kg, see what the result is in the morning. You may be able to further reduce the RR. You don't want to over inflate your lung. There is no need to go below 16 as 12-16 is normal, under 20 is good, over 25 is trouble.

"I do need to bust the pulse oximeter out of the closet, I haven't used it in a while."
Yes, if you can get decent o2, I'd call that perfectly fixed. Getting your chest working may also help during the day, though your diaphragm may be doing most of it.

I know you have formed a belief now and it will take a bit to shift it. From the titration guide I linked
" Ti Min ensures adequate time for gas exchange without having to increase the pressure setting. Ti Min may be helpful for patients with restrictive lung disease."

yes, it's to allow for a better mix of gasses in the lung. they don't want inhale too short. As per the guide, down to 0.3 seconds is enough time for normal lungs. Restrictive is down to 0.8 for RR18-20. You don't want to have the min Ti high enough to impact on a normal breath of 0.9 or more, in the RR range of 18-20. Which was the issue when you had ti min: 1.5s and may still be an issue with 1.2s.

Having too long an inhale and not enough time to exhale with backup breathing, is breath stacking. Also not a good thing and worth reading about. It's more scary than gas mixing. Unless there is a good, sound reason to move from default, it's best not to guess at it and to put it past a good doctor when you get one.

Have another look at the ResMed TiControl: Ti Min and Ti Max Calculation Guide chart on page 41. It will give you the max and min times for a RR
https://www.resmed.com/us/dam/documents ... er_eng.pdf

I will try less aggressive trigger/cycle, and lower Ti min tonight and see what happens.

I'd set the trigger while you are awake, go through the different settings and see which feels right.

Last night with Ti min .8 seconds, Ti Max 2.2 seconds, the median Ti was .88 seconds. While awake it did show the Ti max being reached for a while. My median respiratory rate showed as 20 on both resscan and sleepyhead. I had plugged in a target of 16bpm, so I guess I will see what happens tonight when I set it to 20bpm.

Were you were getting your target Va?
you need time to exhale, or you could type of breath stack. .88 median was enough time to get the required amount of air in. It is not a negative and is above the min setting. So it would indicate to me that you aren't reliant on the min or max to get your targets. Your 95% would have been higher. I would also use the max suggested times and move to 1.5 for RR20 a bit at a time
are you putting a chart up? what were the spontaneous breath %

I would follow your natural RR and not set it too low. You need to take as many breaths as you need to get to the Va. You don't want to overdrive the tidal volume and put strain on your chest and lungs. In saying that, you were titrated at 20cm and on your last chart. you have a possible max of 28 with your max used of 24cm and 95% 22. So the machine doesn't need the max available to achieve your target.

I would follow the RR and not predetermine it, on your last chart you had set 19 and was your natural RR at 20/4
At 19 your results showed you didn't need it that high and your median was 18, on that charts and settings, I would then move my RR target to 18. If the next night showed 17, then I would set it to 17. If it was going up from 19 to 20 I would then set 20.

Don't try to out think the machine. You set the Va target and the machine will make sure you get that amount of air per minute. you will get Va 4.6 litres of air a minute, whether it's 10 breaths or 25 breaths per minute. whether it's .88 or 2 seconds insp time.

ajack wrote: ↑

Mon Apr 09, 2018 12:59 pm

Were you were getting your target Va?
you need time to exhale, or you could type of breath stack. .88 median was enough time to get the required amount of air in. It is not a negative and is above the min setting. So it would indicate to me that you aren't reliant on the min or max to get your targets. Your 95% would have been higher. I would also use the max suggested times and move to 1.5 for RR20 a bit at a time
are you putting a chart up? what were the spontaneous breath %

I would follow your natural RR and not set it too low. You need to take as many breaths as you need to get to the Va. You don't want to overdrive the tidal volume and put strain on your chest and lungs. In saying that, you were titrated at 20cm and on your last chart. you have a possible max of 28 with your max used of 24cm and 95% 22. So the machine doesn't need the max available to achieve your target.

I would follow the RR and not predetermine it, on your last chart you had set 19 and was your natural RR at 20/4
At 19 your results showed you didn't need it that high and your median was 18, on that charts and settings, I would then move my RR target to 18. If the next night showed 17, then I would set it to 17. If it was going up from 19 to 20 I would then set 20.

Don't try to out think the machine. You set the Va target and the machine will make sure you get that amount of air per minute. you will get Va 4.6 litres of air a minute, whether it's 10 breaths or 25 breaths per minute. whether it's .88 or 2 seconds insp time.

I did reach the target va. the 95% was like 1.58 seconds. i haven't had time to screen shot and upload charts yet, my cat has been sick so i had to take off work and then take her to the vet . It's been a crappy day.

I did relax the trigger/cycle, down to high/low, which felt pretty much the same while awake. I did notice it cut the inhale a few times but overall it felt fine. Probably settling down as I breathe different using the machine.

I may try a "learn period" that is mentioned in the titration guide, with the normal ti min and ti max, to try and see what it captures as a good target rr. Just out of curiousity, to see if it seems in the ballpark of ideal.

Last night my I:E ratio was more like 1:2, with 50% of the breaths spontaneously cycled, and 91% spontaneously triggered. My median leak value was zero! For whatever reason, my median IPAP was only 13, so maybe that is a good sign that the faster rr is good for me.

You will get there. As you know the I:E ratio 1:2 is very normal. 95% 1.58, sounds good. Make that your max Ti for a while. If you would rather that than the default 1.5, it's close enough. The machine may cut your breath off, a few times as you fall asleep. You still get the target Va and the machine works it out. You will get use to falling asleep with a shorter breath. As you saw, it lets you breathe out.

The learn mode only takes a half hour and it gives another data set. It may help, it may not. Either way it's interesting. Did you dig out the cms50 and f20?
The faster RR will need less pressure, but it's more work to breathe. You can work with your RR later. There's some stuff you can do, It's a balance. When 20/4 gives RR19, there may not be much room to work with. I know you were told some settings by palerider, that resmed wouldn't suggest. That may have also impacted.

How is your cat? when you are ready, How did the learn mode go?, now that the Ti is in range, you can see what the epap, rise time and min PS settings are doing. I use these for my tidal volume and RR, I have my my epap till the UA are sorted and min PS to just under my median PS for my obstructive, I use a rise time of 150. You might like to keep epap 4 and raise the min PS to just under you median. it gives a floor for the machine to work from. At the moment, yours is epap 4 min ps 6 and rise 300, I would look at the min PS first.