RERA: should I be concerned?

[ittiandro]

I've been suggested to make a new thread on this topic because I had posted yesterday on an older thread.
Basically, I wanted to know if I should be concerned about an increased frequency of RERA’ s after I adjusted the pressure settings upwards to 13cmH2O-18.6cmH2O a few months ago from the original ones prescribed by my doctor in 2020 ( 10cmH2O-15cmH2O). These RERA’s seem to occur now every 2nd day, keeping between 0.15-0.60 +/-, whatever it means. I was also reporting that lately I am feeling a bit more sleepy and sluggish at wake-up, until late morning, early afternoon.
You tell me that the settings shown on the screenshot are too low. I don’t know why, because they are much higher than the original ones prescribed by my doctor.
Anyway, after I posted yesterday I adjusted them back to 10cmH2O-15cmH2O to see if if there is a change in the RERA pattern. It is too early to say, but, for one thing , the 1st reading shows an unusually high AHI score of 1.63 ( usually they are around 0.60 median value) .As to the RERA, it is still there and it is also unusually high. I don’t know what to make of it.
I enclose screenshots of the OSCAR reports for both the lower and higher pressure settings.
Any comments?

[Pugsy]

These RERA’s seem to occur now every 2nd day, keeping between 0.15-0.60 +/-, whatever it means.

CAa, OAs, Hyponeas and RERAs numbers that you see on the bar graphs on the left are a per hour average over the time the machine was on.
Take the total number over the entire night's machine usage and divide by the number of flagged events to get that per hour average.

Your RERA numbers....not really enough to worry about as long as you are sleeping good and feeling good during the day.

As for your pressures being too low...maybe the maximum is too low because you are hitting it quite often along with your Flow Limitation graph is pretty ugly. The flow limitations are probably what is driving the pressure up.
FLs could potentially grow up to be OAs/hyponeas...and they can potentially cause awakenings and disrupt sleep.

Your minimum pressure is your most critical setting.
If you are sleeping great and feeling good then I don't know that I would worry about the FLs but if you aren't then probably you need more minimum as well as maximum just to see if your sleep quality improves if the FLs are better dealt with.

If you are having a lot of nasal congestion then your ugly FL graph could be from nasal congestion and not airway issues and we can't deal with FLs from nasal congestion with more pressure. Instead you have to deal with the nasal congestion in the more traditional ways of dealing with congestion.....sprays, rinses, meds, etc.

[ittiandro]

Thanks for the input.
Indeed, I have chronic nasal congestion and this may explain my RERA’s.
As to the FL graphic being “ ugly” perhaps you can elaborate why..in short, simple words.
As to the minimum pressure settings needing an upward adjustment are you referring to the 10-15 cmH2O screen shot or to the other one ( 13-18 cmH2O) ?
Regarding the minimum pressure being critically too low, if I understand correctly you mean that this low settings is not sufficient to trigger enough pressure to counter a restriction in the air flow picked up by the machine . This may not be severe enough to be recorded as an H or an OA, but it is classified as a RERA resulting in a disruption of sleep. Do I understand correctly? Perhaps you can suggest a pressure range higher than 10-15 cmH2O.
I should mention that when I first had my polysomnography, the doctor said that my airways are unusually narrow. When I am awake, this does not bother me. In fact I run regularly and I am never out of breath, except when I push, which I don’t do very often because I am 80. On the other hand it may become an issue when asleep.
I
Thanks

Ittiandro

[Jlfinkels]

Flow limits are an impairment to the flow-rate through the respiratory tract. Nasal congestion is a typical contributor. Flow limits can occur both on inspiration and expiration.

Your flow limits are driving up your pressure. Look closely at the flow limit graph and then look at the pressure graph, you will see how the pressure increases when the flow limits increase. You may want to consider increasing your pressure from 10-15 to 12-20 as a way to test where the real max pressure needs to be and also to see how it affects your flow limits.

[Pugsy]

As to the FL graphic being “ ugly” perhaps you can elaborate why..in short, simple words.

You look at the overall activity. The more you see the worse it is.

Compare your FL graph to mine.

[ittiandro]

1. Yes, I see that high FL’s correspond to spikes in the pressure, but I still don’t see why the flow limits drive up the pressure. I can always go by trial and error in raising the pressure, for inst. to 12-20 as you suggest, but it would help if I understood .
2. On the screenshot of April 3rd with 1.95 AHI’s there were six RERA events recorded at: 20:26:32, 21:12:32, 21:16:37, 21:34:24, 02:28:12 and 04:31:25. For the first 4 events I was not yet asleep as I suffer from occasional insomnia. I find it odd that the FL value spiked up considerably when I was awake

Thanls

Ittiandro

[Jlfinkels]

1. Yes, I see that high FL’s correspond to spikes in the pressure, but I still don’t see why the flow limits drive up the pressure. I can always go by trial and error in raising the pressure, for inst. to 12-20 as you suggest, but it would help if I understood .
2. On the screenshot of April 3rd with 1.95 AHI’s there were six RERA events recorded at: 20:26:32, 21:12:32, 21:16:37, 21:34:24, 02:28:12 and 04:31:25. For the first 4 events I was not yet asleep as I suffer from occasional insomnia. I find it odd that the FL value spiked up considerably when I was awake

Your machine sees the FL’s as the beginning of an obstructive event, so it raises the pressure to keep your airway open. Starting a bit higher closer to your median means fewer pressure adjustments. When you change the pressure it takes a while (as in days not hours) for your body to adjust, so its best to not do nightly adjustments as you get inconclusive data. We all have a tendency to want to see immediate results, but sadly it doesn’t work that way.

The events that may happen when falling asleep or waking up are sleep-wake junk (SWJ) and are to be ignored.

Once you get things tic-n-tied to a pressure range that works, you should focus on sleep quality.

[Pugsy]

I still don’t see why the flow limits drive up the pressure.

First understand that the machine only measures air flow. It doesn't measure if you are asleep or not. It can't.
Also it can't distinguish between a reduced air flow because of nasal congestion and/or airway collapse.

When in auto adjusting mode the auto algorithm will increase the pressure if certain criteria has happened.
It's main job is to PREVENT the airway from collapsing again.

Since it only measures air flow and since nasal congestion can seriously decrease the air flow ...the machine sees the reduction and subsequent flow limitations as an unwanted precursor to a full grown OA or hyponea.
It can't determine if the reduction in air flow shown by the FL graph is related to the nose congestion or the airway trying to collapse. So it will increase the pressure because that's all it knows to do when there is a flow reduction no matter what the cause.

The auto adjusting algorithm will increase the pressure when it sees enough of these items to meet the criteria.
Flow Limitations
Obstructive Apneas
Hyponeas
Snores.

So that's why the pressure goes up and you may not see many OAs or hyponeas......most likely the flow limitations are what is driving the pressure up.

Flow limitations and/or snores are the earliest warning signs that the airway is trying to collapse and since the machines prime objective is to PREVENT airway collapses it will increase the pressure fairly aggressively because of flow limitations and/or snores. That's its job.
Unfortunately since it can't tell between nose congestion FLs and asleep FLs....sometimes it will increase the pressure in error.

FLs are bad guys that can grow up to be really bad guys and that is why the machine wants to kill them.
PREVENTION of the airway collapse is the main job of the machine.

[Pugsy]

See this video. Maybe it will help explain FLs and why the machine does what it does.

https://www.youtube.com/watch?v=-gie2dhqP2c

[ittiandro]

Getting there. I think I begin to understand. The screenshot for April 1st with the pressure settings at 13-18 shows that the green line on the pressure graph keeps at about 13cmH2O with the red line at about 18cmH2O. If this is what you call the median , then it could help to adjust the pressure a bit closer to it, may be to 12-20 as you suggest. Note that it was already set at 13-18, though.
I understand that it takes some time for my body to adjust. I’ll certainly not play around with the pressure settings needlessly. The reason why I raised this issue is that lately I have been feeling a bit more sleepy than before , while at the same time the RERA’s picked up. ’ll see if I get less sleepy with those.

Thanks for your help

Ittiandro

[Pugsy]

I said nothing at all about the median. Maybe someone else did. I don't get hung up on those statistics numbers because they are too easily skewed as a general rule to the high side by relatively short periods of time at higher numbers.

You are hitting the max of 18 cm at some points during the night. The machine wants to go higher but can't.
Is that maybe part of the reason you aren't feeling as good as you would like??? We can't answer that question but it's a "maybe".

[ittiandro]

I said nothing at all about the median. Maybe someone else did. I don't get hung up on those statistics numbers because they are too easily skewed as a general rule to the high side by relatively short periods of time at higher numbers.

You are hitting the max of 18 cm at some points during the night. The machine wants to go higher but can't.
Is that maybe part of the reason you aren't feeling as good as you would like??? We can't answer that question but it's a "maybe".

Sorry, it was JFfinkels who mentioned the median. I'll redirect the reply to him. Your comment about the machine wanting to go higherthan 18, but can't, makes sense and corroborates what was said elsewhere, namely that I raise perhaps the maximum pressure setting to 20.

Thanks

Ittiandro

[ittiandro]

I still don’t see why the flow limits drive up the pressure.

First understand that the machine only measures air flow. It doesn't measure if you are asleep or not. It can't.
Also it can't distinguish between a reduced air flow because of nasal congestion and/or airway collapse.

When in auto adjusting mode the auto algorithm will increase the pressure if certain criteria has happened.
It's main job is to PREVENT the airway from collapsing again.

Since it only measures air flow and since nasal congestion can seriously decrease the air flow ...the machine sees the reduction and subsequent flow limitations as an unwanted precursor to a full grown OA or hyponea.
It can't determine if the reduction in air flow shown by the FL graph is related to the nose congestion or the airway trying to collapse. So it will increase the pressure because that's all it knows to do when there is a flow reduction no matter what the cause.

The auto adjusting algorithm will increase the pressure when it sees enough of these items to meet the criteria.
Flow Limitations
Obstructive Apneas
Hyponeas
Snores.

So that's why the pressure goes up and you may not see many OAs or hyponeas......most likely the flow limitations are what is driving the pressure up.

Flow limitations and/or snores are the earliest warning signs that the airway is trying to collapse and since the machines prime objective is to PREVENT airway collapses it will increase the pressure fairly aggressively because of flow limitations and/or snores. That's its job.
Unfortunately since it can't tell between nose congestion FLs and asleep FLs....sometimes it will increase the pressure in error.

FLs are bad guys that can grow up to be really bad guys and that is why the machine wants to kill them.
PREVENTION of the airway collapse is the main job of the machine.

Excellent explanation. Thanks

Ittiandro

[ittiandro]

1. Yes, I see that high FL’s correspond to spikes in the pressure, but I still don’t see why the flow limits drive up the pressure. I can always go by trial and error in raising the pressure, for inst. to 12-20 as you suggest, but it would help if I understood .
2. On the screenshot of April 3rd with 1.95 AHI’s there were six RERA events recorded at: 20:26:32, 21:12:32, 21:16:37, 21:34:24, 02:28:12 and 04:31:25. For the first 4 events I was not yet asleep as I suffer from occasional insomnia. I find it odd that the FL value spiked up considerably when I was awake

Your machine sees the FL’s as the beginning of an obstructive event, so it raises the pressure to keep your airway open. Starting a bit higher closer to your median means fewer pressure adjustments. When you change the pressure it takes a while (as in days not hours) for your body to adjust, so its best to not do nightly adjustments as you get inconclusive data. We all have a tendency to want to see immediate results, but sadly it doesn’t work that way.

The events that may happen when falling asleep or waking up are sleep-wake junk (SWJ) and are to be ignored.

Once you get things tic-n-tied to a pressure range that works, you should focus on sleep quality.

Getting there. I think I begin to understand. The screenshot for April 1st with the pressure settings at 13-18 shows the green line keeping at about 13cmH2O with the red line at about 18cmH2O. If this is what you call the median , then it could help to adjust the pressure a bit closer to it, may be to 12-20 as you suggest. . Note that it was already set at 13-18, though.
I understand that it takes some time for my body to adjust. I’ll certainly not play around with the pressure settings needlessly. The reason why I raised this issue is that lately I have been feeling a bit more sleepy than before , while at the same time the RERA’s picked up. ’ll see if I get less sleepy with those.

Thanks for your help

Ittiandro

[palerider]

1. Yes, I see that high FL’s correspond to spikes in the pressure, but I still don’t see why the flow limits drive up the pressure. I can always go by trial and error in raising the pressure, for inst. to 12-20 as you suggest, but it would help if I understood .

Because it's programmed to, because flow limitations disturb your sleep (and lead to RERAs, or apneas and hypopneas.

2. On the screenshot of April 3rd with 1.95 AHI’s there were six RERA events recorded at: 20:26:32, 21:12:32, 21:16:37, 21:34:24, 02:28:12 and 04:31:25. For the first 4 events I was not yet asleep as I suffer from occasional insomnia. I find it odd that the FL value spiked up considerably when I was awake

You may have drifted off and not known it, that happens frequently with insomnia. Or, your awake breathing is just irregular.