Soon to start CPAP - Question on dehydration

[Sleeprider]

Aerophagiamis not the cause of OA, except to the extent your sleep is disrupted and an arousal OA occurs. I don't think that accounts for most of your events. Let's be clear, OA is made worse by
1. higher pressure, and
2. higher EPR or pressure support.

We are using EPR to reduce flow limitation and hypopnea. Since you have flow limitation your automatic pressure always rises fairly quickly to the maximum, so if I suggest a pressure of 7 to 10, that is hardly any different from 8 to 10. Either way, you end up at 10 most of the night. We have learned that your aerophagia trigger ks somewhere between 10 and 11, and we know that you are not having significant OA at 10 cm, so that becomes your best maximum pressure, and you might tolerate a lower maximum pressure. Higher pressure is not going to reduce your CA event rate.

I think we should try a pressure of 10 for a while and keep an open mind to a maximum pressure of 9.0 if CA or aerophagia remain high.

[picante]

Aerophagiamis not the cause of OA, except to the extent your sleep is disrupted and an arousal OA occurs.  I don't think that accounts for most of your events.  Let's be clear, OA is made worse by
1. higher pressure, and
2. higher EPR or pressure support.

Do I understand this right?: 
1. OA is treated by raising pressure temporarily. What you're saying is that we get more/worse OAs at an ongoing higher pressure? And because of my flow limitation, the machine gives me ongoing max pressure.
2. The EPR of 3 is to reduce flow limitation, but it increases OAs as well?

We have learned that your aerophagia trigger ks somewhere between 10 and 11, and we know that you are not having significant OA at 10 cm, so that becomes your best maximum pressure, and you might tolerate a lower maximum pressure. Higher pressure is not going to reduce your CA event rate. 

Yes, we've definitely learned that, LOL.  And I already know higher pressure doesn't reduce CA events. What I've seen on my graphs is the exact opposite: a big increase in CA events. I was just wondering about causality. Since a higher ongoing pressure increases my aerophagia, would that be a trigger for CA events? Because of CO2/O2 imbalance from aerophagia?

I think we should try a pressure of 10 for a while and keep an open mind to a maximum pressure of 9.0 if CA or aerophagia remain high.

Okey dokey, I'll give it a try.

Thank you, dear Sleeprider. I'm trying to toss out the wrong information I've acquired, and learn the subtleties of treatment for my situation, and I would be lost without this forum. The doc is incommunicado, but then ... maybe that's actually a blessing for the moment. He might be reluctant to consider what you're suggesting.

Hats off to @Hydrangea and @Fats Drywaller as well.

[Sleeprider]

Aerophagiamis not the cause of OA, except to the extent your sleep is disrupted and an arousal OA occurs.  I don't think that accounts for most of your events.  Let's be clear, OA is made worse by
1. higher pressure, and
2. higher EPR or pressure support.

Do I understand this right?: 
1. OA is treated by raising pressure temporarily. What you're saying is that we get more/worse OAs at an ongoing higher pressure? And because of my flow limitation, the machine gives me ongoing max pressure.
2. The EPR of 3 is to reduce flow limitation, but it increases OAs as well?

I'm working with a broken keyboard and using an on-screen keyboard, so there are errors, in fact that quote was a disaster.  Try this:
Aerophagia is not the cause of CA, but some CA may be recorded with aerophagia due to sleep disturbance.  CA is made worse by higher pressure and higher EPR. EPR reduces flow limitations, but may increase CA.

We have learned that your aerophagia trigger ks somewhere between 10 and 11, and we know that you are not having significant OA at 10 cm, so that becomes your best maximum pressure, and you might tolerate a lower maximum pressure. Higher pressure is not going to reduce your CA event rate. [\quote]

Yes, we've definitely learned that, LOL.  And I already know higher pressure doesn't reduce CA events. What I've seen on my graphs is the exact opposite: a big increase in CA events. I was just wondering about causality. Since a higher ongoing pressure increases my aerophagia, would that be a trigger for CA events? Because of CO2/O2 imbalance from aerophagia?

I think we should try a pressure of 10 for a while and keep an open mind to a maximum pressure of 9.0 if CA or aerophagia remain high.

Okey dokey, I'll give it a try.

Thank you, dear Sleeprider. I'm trying to toss out the wrong information I've acquired, and learn the subtleties of treatment for my situation, and I would be lost without this forum. The doc is incommunicado, but then ... maybe that's actually a blessing for the moment. He might be reluctant to consider what you're suggesting.

Hats off to @Hydrangea and @Fats Drywaller as well.

Sorry about the confusion in the last post.  I should have reread it closer.

[picante]

I'm working with a broken keyboard and using an on-screen keyboard, so there are errors, in fact that quote was a disaster.  Try this:
Aerophagia is not the cause of CA, but some CA may be recorded with aerophagia due to sleep disturbance.  CA is made worse by higher pressure and higher EPR. EPR reduces flow limitations, but may increase CA. 

Now it's making perfectum sensum. It's exactly what my data shows.

Sorry about the confusion in the last post.  I should have reread it closer.

No hay problema. If everyone is else here is in a pinch, you're a busy guy. I've never had to learn anything so fast. With your help, I'll soon be back from the brink of anorexia. Gotta go eat some dinner, hooray!

[picante]

The first two nights after decreasing max pressure. Range is 8-10 both nights. Only one obstructive apnea event each night. Still got plenty of CAs.
So you are right, @Sleeprider, I'm tolerating that range with no increase in obstructive events -- in fact, it's a decrease.
[attachment=9366]                   [attachment=9365]

The sleep doc finally called me yesterday, and we didn't even discuss my tinkering with the Autoset. Apparently his nurse is more uptight about that than he is. He was just really pleased that my numbers have improved drastically with the Airfit F20, and that my "compliance" was 100%.

I told him my No. 1 priority is to reduce aerophagia so I can eat more and gain weight. He had no objections, and I think that's why my pressure experiments don't bother him. 

I'm still not eating very much, just a little more than I was on the other mask. And I've had massive brain fogggg the last two mornings, possibly because I'm ending my therapy around 4:30-6:00 am and then sleeping 2-3 more hours. (That's to try and get the air out of my guts, or at least not make it any worse.) I've also had sinus constriction both nights, getting up to rinse twice.

Time to decrease max pressure again?

[Sleeprider]

I think 6.0 to 8.4 max with EPR reduced to 2. I'm hoping to see improvement in CA with reduced EPR. This could increase flow limitations and hypopnea, and we're seeing some reduction in tidal volume, so something to keep an eye on.

It's starting to look like you should be on a bilevel machine with very low exhale pressure at 4.0, with enough pressure support to overcome flow limitation, but that would probably increase CA and move you back towards ASV. The problem with that is, I don't think you could tolerate ASV pressure support with your aerophagia. Glad you're feeling better.

[picante]

I'm posting last night's graphs in 2 screenshots, one from 23:37 to 03:58, and the other from 06:32 to 08:16, because I was doing an experiment: I've been taking off the mask in the wee hours due to gut-aches, and wanted to find out if those 2-3 hours before I get up are my worst. They are. That's why my morning brain exhaustion has been so severe lately.

[attachment=9373]          [attachment=9374]

All 7 obstructive events are in that little 1h 43 m slice of time, as well as 36 out of 55 central apneas.

Lowering my max pressure from 10 to 9.4 and my EPR from 3 to 2 did not help with CAs. Also, exhalation became more difficult, and I awoke very suddenly at 3:58 feeling airless, and flung off the mask. I don't know why. My sinuses were very constricted, but that happens every night. After my 4-hour break, I did a sinus rinse at 6:15 and I raised EPR back to 3. No more airless waking.

In fact, my brain was better this morning, despite those 41 events, no doubt because it's worse without CPAP! (Oddly, my baseline was 41 AHI.)

So Sleeprider, you're right about my need for a low exhalation pressure. And I only quickly skimmed your last message yesterday; I see now your recommendation was 6.0 - 8.4, but I would not have tried that radical a drop all at once. I had already set the EPR for 2 - must have read your mind.

So far, my lowest CAs were Sunday when my range was still 8.2-11.0. But gut-aches. 
CAs were still OK at range 8.0-10.00 Monday and Tuesday (less gut-aches & more food), 
but last night doubled as a % of total time at range 8.0-9.4. But only because of the 06:32 to 08:16 time slice.

The sleep doc says don't worry about CAs; they'll subside as you get used to CPAP, and for some people they don't even lower O2 saturation. So... is it time to acquire an overnight pulse oximeter?

[picante]

I don't understand flow limitation. Please, can someone direct me to a good article?

[Gideon]

I don't understand flow limitation. Please, can someone direct me to a good article?

Obstructive Apnea, Obstructive Hypopnea, and Flow Limitation are the same thing, the difference is in the impact.  See the below definitions.

• Apnea: 80% to 100% reduction in airflow for >= 10 seconds
  
  
• Hypopnea: 50% to 80% reduction in airflow for >= 10 seconds
  
  
• Flow Limitation: <50% reduction in airflow for >= 10 seconds
  

So an Apnea is a Flow Limitation with 80 to 100% reduction in airflow.

We follow all 3 because the Auto-CPAP algorithms react to all 3.

Fred

[picante]

Bonjour Fred, merci pour l'explication!