Can high loop gain be changed?

[NoddingHacker]

I'm looking at all of these papers about loop gain, but nobody bothers to mention if it's genetic and if it can be changed. Is loop gain like a chronotype (i.e. you cannot change it, its how you work) or is it like insulin sensitivity (i.e. there is a big margin of potential improvement for most people).

[Sleeprider]

We know that therapy onset of CSA will generally improve or fully resolve in most new users of CPAP, so there appears to be an adaptation mechanism that plays a role for most individuals that are sensitive to a loop gain in pCO2. "CPAP-emergent CSA occurs during the initial nights of CPAP in up to 15% of patients with OSA, with near complete abolition after 2 to 3 months of CPAP". https://www.apneaboard.com/wiki/index.ph...entilation

We know that certain disease pathways such as heart failure greatly increases the occurrence for CSA and CSR, and that these individuals are also more prone to loop gain in CPAP or spontaneous bilevel therapies. It is easily observed that there is an individual response to CPAP and spontaneous bilevel pressure, and differences in the tolerance to pressure and pressure support before loop gain (aka apneic threshold) becomes apparent. Environmental conditions such as high altitude also significantly increase the liklihood of loop gain. I don't know that we can rule out a genetic factor, because there is a great deal of individual variation in how people react to pressure and pressure support as well as general health, altitude and other factors. I am not aware of research into genetics as a root cause.

Beyond the adaptation to lower PCO2 that seems to occur for most individuals, the symptoms of loop gain can be treated or mitigated by using therapy that prevents onset of the hyperventilation - hypoventilation cycle that seems to characteristic. ASV is specifically designed to mitigate loop gain and is effective in treating CSA that would normally occur when these respiratory cycles are out of control.

[CPAPfriend]

Look into buteyko breathing. I haven't reviewed that actual scientific literature on it, but they claim you can change your loop gain.

[bh1332]

Appreciate your post sleeprider. I was just told this morning by my doc that he thinks I have high loop gain, and am having ASV titration tonight. I grew up at an altitude of around 600 feet, but have lived the last decade at 4500 ft or so and was diagnosed with sleep apnea this year. I have continued to struggle throughout treatment  the last 5 months bc of central sleep apnea events. Hopefully ASV will be the answer. I have noticed a decrease in AHI the last week or so though on my bipap, so I almost wonder if I should give bipap more time (been doing a couple of months now). Regardless, I have felt awful even though my AHI has decreased some recently (all attributable to centrals).

[ChadBSr]

Buteyko breathing will teach you to breathe with a very slight air hunger which will train your chemoreceptors to be less sensitive.

In the meantime all you need is less IPR, more EPR. Vcom is good for this.

[bh1332]

Thanks. I’ll have to look into that.

[ChadBSr]

Sorry, I meant to say less IPAP more EPAP ?

[staceyburke]

We have found that raising the trigger to high or very high has helped many people on an Aircurve..  Have you tried that to reduce centrals?

[bh1332]

I did try that on my Aircurve 11 vAuto. It helped some, and over the last couple of weeks my AHi did begin to come down. I actually started on ASV two nights ago. First night was the best night sleep in many years with AHI of 0.0/hour. Last night was 0.1/hour. My initial Aircurve 11 VAuto bipap is what I have been on the last couple of months, but my DME gave me an Aircurve 10 ASV. I’ll get into the clinical menu and see if there’s a setting to change the trigger to high. I do feel better on ASV so far. I think I had OSA for many years and didn’t know it, but just thought I was stressed out with work and raising kids. My respiratory cycles are likely just way out of whack with the high loop gain so hopefully over time that will improve now that I am receiving treatment for OSA and CSA. The additional 4000’ of altitude compared to where I was born and raised probably made it all worse, so sleep apnea kind of snuck up on me and I was in bad shape by the time my doctors figured it out. Thanks to everyone for their expertise and hope you all had a Happy Thanksgiving.