Apnea to hypopnea RATIO?

[JHZR2]

Hi,

Curious, I see very little anywhere, including academic literature about the Apnea to hypopnea ratio. Why?

It seems like it would be good.

Isnt it the case that treatment is trying to convert apneas to hypopneas, and in reality, knowing the ratio perhaps is more important than anything, because it gives an indication of efficacy. Then, with ahi the information can be more meaningful

[Lizistired]

Not sure what you are asking. The treatment is intended to eliminate both. My machine gives a breakdown of hypopneas, Oa's and CA's on the machine and in the software data.

[Mary Z]

Hi,

Curious, I see very little anywhere, including academic literature about the Apnea to hypopnea ratio. Why?

It seems like it would be good.

Isnt it the case that treatment is trying to convert apneas to hypopneas, and in reality, knowing the ratio perhaps is more important than anything, because it gives an indication of efficacy. Then, with ahi the information can be more meaningful

Perhaps you don't see anything because it is meaningless. The goal of treatment is to eliminate apneas and hypopneas. Use a little basic math and the info from the machine and figure out the ratio yourself.

[pap4life]

Converting apneas to hypopneas is only getting 50% of the job done. Your body will still struggle (however) lightly, if the hypopneas are reducing your intake of O2 thats needed. The perfect (if only in our dreams) solution is complete irradication of apneas, hypopneas and a clear airway.

[DoriC]

When my husband first started using cpap, the expert helping me said he would have liked to see the reverse with more Hypops than Apneas on my husband's reports, but that never happened, then or now. He has very few Hypops but more sudden onset apneas with no preceding indicators that don't last very long. His AHI is usually between 1.5-2.5, sleeps 9hrs, and feels well. I don't worry about the ratio.

[JHZR2]

Not sure what you are asking. The treatment is intended to eliminate both. My machine gives a breakdown of hypopneas, Oa's and CA's on the machine and in the software data.

Of course it is. Obviously the optimal state would be free-breathing for the entire night, making O2-related issues irrelevant.

In an imperfect world, this is not possible.

In my view, the ratio of Apneas to Hypopneas is absolutely an important metric. Yes, sure, the math is beyond easy. But it just seems that folks dont consider it.

Im considering it because Im new to this. The reality seems to be this: it is better to have a hypopnea than an apnea, and it is better to breathe freely than to have a hypopnea.

In reviewing my data, some nights I have more apneas than hypopneas, some nights I have more hypopneas than apneas. The ratio is about a factor of two in either direction, and generally I see more hyponeas than apneas.

An AHI is often reported, but is fairly useless in that we dont know which we got. Lower is better overall, but is an AHI of 5 with all apneas the same as an AHI of 5 with all hypopneas?

Thus my point, the ratio to me seems important to see how treatment is progressing. If were getting more of one than the other, it would be useful to know which direction we are going.

Because at the end of the day, in a changing biological system, things may not be consistent, and it would be good to know if things are going in the right direction (more hypos than apneas), or the wrong direction. Seeing that ratio along with AHI gives a better picture.

[Pugsy]

Im considering it because Im new to this. The reality seems to be this: it is better to have a hypopnea than an apnea, and it is better to breathe freely than to have a hypopnea.

With things being equal (like event duration) in theory a hyponea might be more desirable than an apnea
(partial collapse vs full or near full collapse of the airway).

Event duration is a variable that would need to be considered because the longer the duration of the event then the greater the chance of oxygen levels dropping below optimal levels.

Which would be (in theory) harder on your body? 2 apneas lasting 15 seconds each within a time frame or 4 hyponeas lasting 30 seconds each within same time frame? Or 30 hyponeas in same time frame?

Another variable would be how close together do they happen to occur? Back to back or in clusters followed by periods of zero events of any kind? Or a single event spaced randomly throughout the night?

While I see your point about ratio, for me a simple ratio wouldn't tell me enough about what was happening because I know that there are other factors affecting the possible damage to my body beyond the simple definition of hyponea or apnea. For me it would be a ratio of apples to oranges.

[Lizistired]

What Pugsy said. My AHI is just a general trend. It doesn't tell be how many times I stop breathing for <10 seconds, which I do quite often. My apneas didn't transition to hypopneas, they just went away. I seldom have hypopneas.
It's why we look at our detailed data. Hell, I had an AHI of 0.0 this morning and I still looked at my detailed data!

[idamtnboy]

Because at the end of the day, in a changing biological system, things may not be consistent,

That's your best answer, right there. There are so many variables in the mechanisms that create an apnea condition, and so many variables in the treatment parameters, that the only somewhat meaningful measure is the 5 or less number for AHI. That number ignores both the ratio of A to H, and the duration of the events. The number of events can bounce up and down so much from night to night there is no way to slice and dice the data into chunks smaller than one week and have it be meaningful. I can go 2 or 3 nights with only 1, 2, or 3, events total, and then I'll have an AHI of ~2, which means I had 10 to 20 events, and then back to 1, then 10, then 5, 5, 5, 1, 20, and so on. It's kind of like trying to count clouds. By the time you've counted from the east to west horizon, some of the clouds in the east have disappeared, others have combined, and others have moved on. It really can be that nebulous.

Think about this. Really flabby airway tissues are going to be the ones that most easily close and cause an apnea. But if they close easy, then doesn't it stand to reason that you can push them open easily? It very well could be that in a particular person the transition from apnea to open is so easily achieved that a hypop just won't happen. An A to H ratio for him/her wouldn't tell you much at all.

For an A to H ratio to be meaningful the entire mechanism of apneas and treatment would have to somewhat analog, i.e., transitions from open to close would have to occur over a range. I suspect though, that the mechanism is more binary, i.e., the airway is either open or closed, with very few occurrences of in-between conditions.

I don't know if any of this makes sense or not. I'm finding it hard to articulate my thinking at midnight!!

[whitesee1]

I have been looking for this topic for a long time, thank you so much

[Mary Z]

Hi,

Curious, I see very little anywhere, including academic literature about the Apnea to hypopnea ratio. Why?

It seems like it would be good.

Isnt it the case that treatment is trying to convert apneas to hypopneas, and in reality, knowing the ratio perhaps is more important than anything, because it gives an indication of efficacy. Then, with ahi the information can be more meaningful

Why don't you start calculating your ratios every morning and see if you note any if there are any correlations, or special information to be gained. Would you do that? Keep us posted. Somebody has to start the research. It could be you.

[DoriC]

Because at the end of the day, in a changing biological system, things may not be consistent,

Think about this. Really flabby airway tissues are going to be the ones that most easily close and cause an apnea. But if they close easy, then doesn't it stand to reason that you can push them open easily? It very well could be that in a particular person the transition from apnea to open is so easily achieved that a hypop just won't happen. An A to H ratio for him/her wouldn't tell you much at all.
I don't know if any of this makes sense or not. I'm finding it hard to articulate my thinking at midnight!!

I think I can understand that. I'm in the unique position of being able to observe my husband during sleep and I notice that I really have to listen to hear him having an apnea because they happen quickly and quietly and he resumes breathing easily with no movements. His events happen without any preceding snores,hypops or flow changes, just a quick "frank" apnea. Of course this was not the case when he first started, he would scare me to death with all the long silences, gasping and thrashing. So can I be describing someone with flabby tissues that close and open easily? This is a very interesting thread!