Surge from ASV makes it difficult to get back to sleep

[Heartman]

I recently started ASV therapy about 1 month ago, with current settings of

EPAP 9.6 - 15
PS 4
PS maximum 15
　
I usually fall asleep fairly soon after getting into bed and have been getting good readings in OSCAR. I typically awaken at least once or twice during the night and then have trouble getting back to sleep because the surge of the ASV is uncomfortable. I get anxious trying to regulate my breathing to satisfy the ASV algorithm in order to avoid the surge, which is not conducive to getting back to sleep.

I was considering raising my EPAP to about 12 and reducing the PS maximum to 4-6, to make the surges easier to tolerate and make me less anxious and more relaxed trying to get back to sleep. I guess I'll have to see how my results in Oscar look on these settings, but does this sound reasonable?

[SarcasticDave94]

I'm not certain of this surge you're referring to, but if it is where you're in transitions from waking to sleeping and the ASV gives a nasty jolt of air then you can forcefully "blow back" through the mask to get the ASV to back off. I think if you change the PS to a low range like that it's going to handcuff the ASVs ability to deal with CA and not a good idea IMO.

[Heartman]

Dave,

Yes, I saw you recommended that in a previous post and I've tried it. It makes the ASV "back off," but for me, only temporarily. I know the ASV algorithm compares your current minute ventilation to ventilation from the previous 5 minutes and I find myself trying to regulate my breathing to maintain a relatively constant minute ventilation to avoid more "surges" (high pressure breaths).  This is not relaxing for me when I'm trying to get back to sleep.  Some mornings I feel really tired even when my Oscar scores are great because I was up so much in the middle of the night fighting the ASV.

[kevrx]

I have been on ASV for a couple of months now.  I wouldn't change the epap settings. You could lower the max ps by a couple of points and see if that prevents the problem without increasing your ahi or you could turn the machine off and back on to reset it or even set a 5 min ramp so when you  turn the machine off and back on it won't change the pressures till you have fallen back to sleep.

[ardenum]

I totally get what you mean. Surges are extremely disruptive to me too. I guess best case is you(and/or us) taking a look at the data to see how much ps you're hitting on average and then maybe try a setting lower by 1-2 from the average. Might get a few more apneas/h more but might be worth it for the overall therapy.

As for the automatic algorithm, It never really worked for me. I'd get better results in the first day and then get worse each day from there.

[Sleeprider]

I’m not a fan of ramp with ASV but I’d do that instead of the changes you outlined. Your current settings work well and what changing PS max to 6.0 will not treat central apnea for most people. We could look at some charts and print figure out what your peak demand is for PS.

I think this comes down to anxiety and your anticipation of the “surge”. You have to let that go and not think about your respiration. That invariably is going to make you breathe more deeply and slowly than tour sleep respiration and cause the surge you fear. The problem is not the machine or settings, it is simple anxiety and that is what needs to be treated. Maybe discuss this with your doctor and consider some behavioral modification or medication until you get over it.

Learning or unlearning a habit is not easy. You have learned to be anxious while falling to sleep in anticipation of a “surge” that really should not be so overwhelming. This is right up there with anxiety over work, relationships and similar sources of stress. Recognize it for what it is and change your focus or treat it. Do not try to control breathing as you fall asleep, as you know this will fail.

[Heartman]

I totally get what you mean. Surges are extremely disruptive to me too. I guess best case is you(and/or us) taking a look at the data to see how much ps you're hitting on average and then maybe try a setting lower by 1-2 from the average. Might get a few more apneas/h more but might be worth it for the overall therapy.

As for the automatic algorithm, It never really worked for me. I'd get better results in the first day and then get worse each day from there.

Thanks for the advice - the PS goes up to about 12-13 when the algorithm cuts in; I have the maximum PS set at 15, so maybe I'll decrease it to about 10-12 and see what happens. I  agree - as long as central apneas are not too prolonged, I would rather get a more restful sleep than have a perfect score.

[kevrx]

I have also found that in my case, lowering the min PS will allow the machine to control the hyperpnea/hypopnea cycle at lower max pressures.  I found than a min ps no less than 2.4 allows me to breath in easier against congestion though.

[Heartman]

I’m not a fan of ramp with ASV but I’d do that instead of the changes you outlined. Your current settings work well and what changing PS max to 6.0 will not treat central apnea for most people. We could look at some charts and print figure out what your peak demand is for PS.  

I think this comes down to anxiety and your anticipation of the “surge”. You have to let that go and not think about your respiration. That invariably is going to make you breathe more deeply and slowly than tour sleep respiration and cause the surge you fear. The problem is not the machine or settings, it is simple anxiety and that is what needs to be treated. Maybe discuss this with your doctor and consider some behavioral modification or medication until you get over it.

Learning or unlearning a habit is not easy. You have learned to be anxious while falling to sleep in anticipation of a “surge” that really should not be so overwhelming.  This is right up there with anxiety over work, relationships and similar sources of stress. Recognize it for what it is and change your focus or treat it.  Do not try to control breathing as you fall asleep, as you know this will fail.

You're right, I have been anxious about the "surge."  I think the reason is because I'm afraid my mask will start leaking at the high pressure.  Before switching to ASV, I was on APAP with settings of 13 -20.  Most nights the pressure would go up to 19-20 and stay there for most of the night.  The F 30 mask I use would invariably leak at this pressure, requiring me to get up, go into the bathroom, turn on the light, take the mask off, and reposition it again from scratch.  Sometimes I had to do this 2 or even 3 times per night, obviously not a good night's sleep.

One of the things I most liked about changing to ASV was that the average pressure was significantly lower and the mass did not leak.  When the surges occur, I would tend to hold the mask in place with one of my hands to make sure it wouldn't start leaking like it did with APAP.

Last night I lowered the PS max from 14 down to 9, and it seemed to work OK. There was no significant change in the AHI and the mask didn't leak during the surge, even without holding it with my hand.  So hopefully this will be the solution going forward.
Thanks all for your advice! 

[Sleeprider]

Most people need a max PS range between 8 and 12 to be therapeutically effective.  You found 9.0 works for you.  This is a good example of problem solving that can help you to resolve the anxiety of mask leaks while keeping you more comfortable...well done!  If UA or hypopnea increases, you can titrate the max PS upward within your comfort zone.  Since this solves the problem that kept you from falling asleep easily, it will soon disappear as a factor in your therapy.