Does a sleep study HAVE to show AHI greater than 5 to warrant cpap use?

[Respirator99]

I thought when he said "There are lots of tools in the box", they were actually "in the box".

I was actually referring to other indicators apart from AHI, which you had (correctly) described as "a hammer". Clinicians should be looking beyond just AHI in diagnosing sleep problems, that's all.

[kteague]

I was one who showed no events in my first lab sleep study back in 1998. Only a few in my 2nd study. But I was an outlier due to having limb movements. My general practitioner was sure I had OSA. An ENT was sure I had OSA. I was sure I had OSA. My symptoms were classic. But we couldn't get confirmation until my legs were somewhat quieted in 2005. They did a study to see how the medication for my legs was working and lo and behold I had OSA. Back then nobody was talking about having more than one sleep disorder can have a masking effect, and nobody put the puzzle pieces together that on the nights my legs weren't too bad I was having hellacious apneas.

The last sleep doctor I had over 10 years ago was always careful to hedge her bets. When my night's sleep in the lab didn't have enough REM stage or REM while supine she termed the study "technically suboptimal" thus allowing room that it might not be fully revelatory.

So, based on my experience only, an AHI of 5 or less may well be a starting point of discovery, not automatically a conclusion.

Like Pugsy said, good to see you Morbius!

[chunkyfrog]

You need a lot of education to be a physician--then you have to take an oath.
Neither is required of insurance company, DME, or HMO executives.
When any of the latter work for our best interests, they may be violating a contract.

[Morbius]

Like Pugsy said, good to see you Morbius!

A pleasure to be back (albeit briefly), and hope you're doing well!

[SleepyCPAP]

…Any other thoughts as to the original question???
Which was just how critical is that medical profession line in the sand of 5.0 AHI????
Is it set in stone from a symptomatic point of view along with the diagnosis criteria meeting thing....or is it a gray line in the sand where people really need to take a look at the much bigger overall picture before making black and white statements?
…

There have been studies suggesting other than <5 AHI. I’m digging around for the one that said health risks increased starting at 0.1 AHI, that one really caught my attention and I’ve somehow saved it in a safe place on my hard drive. I don’t know if it is the same as the study that said risk of stroke increases for every 1 AHI. Don’t worry, I’ll keep looking.

The shape of the breath curves has been focused on as well. Here is one study about flow limitations being better than AHI/Snore:

Respiratory Medicine (2006) 100, 813–817 “Physiological consequences of prolonged periods of flow limitation in patients with sleep apnea hypopnea syndrome” by Gabriel Calero, Ramon Farre, Eugeni Ballester, Lourdes Hernandez, Navajas Daniel, Josep M. Montserrat Canal

…In the light of our findings, and of other authors, it should be pointed out that the usual criterion for considering an optimal CPAP—suppression of apnea/hypopnea and snoring—may not be the most suitable approach. We suggest that high pleural pressure swings occurring in PPFL [Prolonged Periods of Flow Limitation] should be considered and normalized by achieving a rounded flow contour shape...

- SleepyCPAP

[Morbius]

Here is one study about flow limitations being better than AHI/Snore:

Respiratory Medicine (2006) 100, 813–817 “Physiological consequences of prolonged periods of flow limitation in patients with sleep apnea hypopnea syndrome” by Gabriel Calero, Ramon Farre, Eugeni Ballester, Lourdes Hernandez, Navajas Daniel, Josep M. Montserrat Canal

…In the light of our findings, and of other authors, it should be pointed out that the usual criterion for considering an optimal CPAP—suppression of apnea/hypopnea and snoring—may not be the most suitable approach. We suggest that high pleural pressure swings occurring in PPFL [Prolonged Periods of Flow Limitation] should be considered and normalized by achieving a rounded flow contour shape...

Yeah, well also note that

Given the high pleural pressure swings occurring in these periods, it is conceivable that a hemodynamic workload is produced along with brief disruptions in cortical activity that could contribute to some clinical symptoms.

Fix the RERAs.

[Morbius]

So IMO what you need to look at are these PPFL:

This optimal CPAP pressure was maintained for a prolonged period of time (20 min) and then a gradual pressure reduction was applied to obtain PPFL lasting more than 10 min (suboptimal CPAP).

Was it absolutely unbroken (i.e., arousal-free)? Based on their previous comment

brief disruptions in cortical activity

it kinda suggests not, and we'd see some RERAs to fix. You should be able to see their manifestations on flow graph.

Or we can track actual arousals for not a massive expense:

https://shop.openbci.com/collections/fr ... 6379766856

Hey, some people spend 5 times that amount of money on piles of masks, machines and modes during hopeless dial wingin'.

Alternatively, if the PPFL is truly unbroken (as you might see during SWS) one wonder if it's a problem that needs fixing.

[dataq1]

RE:
Respiratory Medicine (2006) 100, 813–817 “Physiological consequences of prolonged periods of flow limitation in patients with sleep apnea hypopnea syndrome” by Gabriel Calero, Ramon Farre, Eugeni Ballester, Lourdes Hernandez, Navajas Daniel, Josep M. Montserrat Canal
- SleepyCPAP

I take note that this study of 14 males with untreated AHIs in the range of 51 to 67 was written in 2006. The paper lays the foundation that further study is warranted.
In the subsequent 16 years has there been any further studies into the effects (and treatment) of prolonged periods of non-rounded flow morphology (aka PPFL)?

I'd suspect that a flow morphology as shown in study as Example #1 is less significant than Example #3. Your thought?



You also mentioned you might have a study/paper correlating AHI that said risk of stroke increases for every 1 AHI. I'd be interested in that paper, and more specifically if that relationship is linear.

[Morbius]

You also mentioned you might have a study/paper correlating AHI that said risk of stroke increases for every 1 AHI. I'd be interested in that paper, and more specifically if that relationship is linear.

6%.

SHHS.

[dataq1]

6%.
SHHS.

??????

[Jlfinkels]

6%.
SHHS.

??????

Sleep Health Heart Study

[dataq1]

6%.
SHHS.

??????

Sleep Health Heart Study

Understood the SHHS, question was 6%.

6% increase in risk of stroke per 1.0 AHI, is that what is claimed?
An 5.0 AHI has 30% risk, 15.0 AHI has 90% risk… etc.
In addition to other stroke risk factors

[zonker]

6%.
SHHS.

??????

Sleep Health Heart Study

thanks for the definition.

google kept giving me high school names.

[Morbius]

I’m digging around for the one that said health risks increased starting at 0.1 AHI, that one really caught my attention and I’ve somehow saved it in a safe place on my hard drive.

It's in the "WSCS" folder.

[Morbius]

So IMO what you need to look at are these PPFL:

This optimal CPAP pressure was maintained for a prolonged period of time (20 min) and then a gradual pressure reduction was applied to obtain PPFL lasting more than 10 min (suboptimal CPAP).

Was it absolutely unbroken (i.e., arousal-free)? Based on their previous comment

brief disruptions in cortical activity

it kinda suggests not, and we'd see some RERAs to fix. You should be able to see their manifestations on flow graph...

Alternatively, if the PPFL is truly unbroken (as you might see during SWS) one wonder if it's a problem that needs fixing.

So let's return to this part:

Was it absolutely unbroken (i.e., arousal-free)?

If it is truly unbroken, then one must ask, is it really an issue?

Tons of people, while in SWS, merrily sleep through FL and are happy as a (insert preferred mollusk here).

So were those kids looking at harmless SWS?

What ho!

However, the fact that PPFL can occur in healthy snoring subjects, e.g. in delta sleep, gives rise to some reservations concerning the need to correct PPFL during sleep.

Sounds like an admission of guilt to me!

Coming up next: monitoring cardiac arousals