How sleeping positions helps AHI numbers

[JimP]

I wanted to throw this out for discussion to see what your experience has been.

I've found that with pillows in certain positions and trying to keep my head from tilting forward, I'm able to drive my AHI numbers down.

I'd speculate that by keeping the airway as straight as possible, it's not closing up and avoiding some of the events I would have otherwise.

Is this coincidence or is there something to it?

[Julie]

Of course you'll do better if your airway is fully open... and one way to help is by wearing a soft cervical collar - keeps your head from falling forward and stops mouth breathing (somewhat). Sleeping on your back is the worst for provoking new apneas, but be careful in general that in trying to keep it all 'straight' you don't end up rigid (and sore in the a.m.)!

[photonic]

I have just recently tried using a cervical collar with my Oracle mouth mask in that I had plateaued off in my AHI improvement over my first 4 months of therapy. It cut my AHI in half instantly and actually allowed me to sleep on my back some which used to wreck havoc on my numbers. I have gotten used to it and actually find that it prevents any kinked neck problems that can occasionally occur in the morning when you have been sleeping on your pillow "wrong".

I tried one other trick as well. My collar has a dip in front for your chin. I turned that upside down because I don't want my chin down. This also improved my numbers. I suspect it is preventing me from having my jaw go slack or dipping my head down while side sleeping and contributing to keeping my airway open. Anyhoo, it seems to be working great and once used to it, I am actually finding it comfortable.

[70sSanO]

+1 on using a collar.

I have found that I am breathing through my nose more (I have a FFM) as I think it keeps my jaw from dropping. My AHI has drastically improved (night and day).

Only issue... you'll be hard pressed to find a sleep doctor to acknowledge the improvements to a collar.

John

[fdw]

Keeping the head straight and not tucked for sure keeps MY airway open, which helps with AHI numbers.

A few weeks ago I purchased a pillow from BB&B that supports the neck, and its done a really good job of helping me keep my head straight.http://www.bedbathandbeyond.com/store/p ... eck+pillow

[arkis26]

This has also been my experience. I was stuck at ahi levels between 7 and 12, and was assessed in lab as having mixed obstructive and central disease. I was placed on auto-sv without improvement until a trial with the collar instantly dropped me to ahi .1-occasional 1. By way of proof as to the collar's effect, one night I forgot it, woke up half way through, recognized the mistake, and finished the night collar on. In the morning, sleepyhead showed an ugly spiked high AHI period and then zero events the rest of the night. This works.

[TyroneShoes]

I wanted to throw this out for discussion to see what your experience has been.

I've found that with pillows in certain positions and trying to keep my head from tilting forward, I'm able to drive my AHI numbers down.

I'd speculate that by keeping the airway as straight as possible, it's not closing up and avoiding some of the events I would have otherwise.

Is this coincidence or is there something to it?

I only have an opinion, but I feel that there is indeed something to it. OSA is most-definitely position-dependent, because, well, gravity works. And your airway will be more or less open/closed from position to position, which is why they say sleeping on your back is not advised. It is also why untreated suffers snore differently in different parts of the night.

But without going too far out on a limb (I have not heard that cracking noise just yet), I think this may also imply that sometimes we need more pressure in certain positions, and that for some, a straight brick CPAP pressure might just not cut it. An APAP is apparently smart enough to vary the pressure dynamically according to your instantaneous needs, so for some patients that is probably a significant improvement to the therapy over the brick. On the other hand, a straight pressure might be best for other patients. In either case, it is a delicate balance to get the IPAP pressure and the EPAP pressure balanced properly (although for some they can be identical), and that is highly personalized for each patient.

Of course "to your instantaneous needs" can refer to differences in the airway due to position, as well as differences in what sleep state you might be in at any particular moment, so an APAP is useful for more than just positional dynamics of the airway. I think.

[split_city]

Not a regular poster these days, but during my more active times on here (about 5-7 years ago) when I did a PhD in sleep research, a lot of my work looked at the effect of posture on OSA severity. There are several studies which have examined the effect of posture and head/neck position on OSA severity and upper airway collapsibility. One of the more important ones was undertaken by a group here in Australia. Here's the abstract:

Influence of Head Extension, Flexion, and Rotation on Collapsibility of the Passive Upper Airway

Abstract
Study Objectives:

To determine the effect of head posture on upper airway collapsibility and site of collapse of the passive human upper airway.
Design:

Pharyngeal critical closing pressure (Pcrit) and site of airway collapse were assessed during head flexion, extension and rotation in individuals undergoing propofol anesthesia.
Setting:

Operating theatre of major teaching hospital.
Participants:

Fifteen healthy volunteers (8 male), including 7 who were undergoing surgery unrelated to the head or neck.
Measurements and Results:

Applied upper airway pressure was progressively decreased to induce variable degrees of inspiratory flow limitation and to define Pcrit. Upper airway and oesophageal pressure transducers identified the site of collapse. Genioglossus muscle activity (EMGgg) was assessed using intramuscular fine wire electrodes inserted percutaneously. Data from 3 subjects were excluded from analysis due to persistent EMGgg. In the neutral posture Pcrit was –0.4 ± 4.4 cm H2O and collapsed most frequently in the velopharyngeal region. Relative to neutral, Pcrit increased to 3.7 ± 2.9 cm H2O (P < 0.01) and decreased to –9.4 ± 3.8 cm H2O (P < 0.01) when the head was flexed and extended, respectively but was unchanged by rotation (–2.6 ± 3.3 cm H2O; n = 10; P = 0.44). The site of collapse varied, in no consistent pattern, with change in head posture in 5 subjects.
Conclusions:

Head posture has a marked effect on the collapsibility and site of collapse of the passive upper airway (measured by EMGgg) indicating that controlling head posture during sleep or recovery from anesthesia may alter the propensity for airway obstruction. Further, manipulating head posture during propofol sedation may assist with identification of pharyngeal regions vulnerable to collapse during sleep and may be useful for guiding surgical intervention.

[JimP]

Has anyone seen any graphics of head position to minimize AHI?

I'm looking for a head viewed in profile where you can tell how far back of a head tilt is optimal. I find during the night, I'll gradually bring my head forward some and didn't know how far forward is of no consequence.

Also, are the collars pretty much all the same?

Just checked Amazon and there are a lot to pick from. Have any of you tried several and can recommend one of another?

Thanks for your participation in this thread.

[JimP]

This has also been my experience. I was stuck at ahi levels between 7 and 12, and was assessed in lab as having mixed obstructive and central disease. I was placed on auto-sv without improvement until a trial with the collar instantly dropped me to ahi .1-occasional 1. By way of proof as to the collar's effect, one night I forgot it, woke up half way through, recognized the mistake, and finished the night collar on. In the morning, sleepyhead showed an ugly spiked high AHI period and then zero events the rest of the night. This works.

Great results with the collar.

The next question is do you still need the auto-sv or would wearing the collar be enough?

[kteague]

I have found head position makes a difference for me. I have taken measures through the years to be sure my head doesn't tilt either back or forward. These days my Step #1 is pillow selection. My lifetime comfort position is on my side with the tip of my shoulder on the edge of the pillow. Bad habit. This causes the edge of the pillow to collapse, putting the head on a slant and thus vulnerable to either the jaw dropping or head tilting forward/down. In recent months I'm using the buckwheat pillow from Pur-Sleep, and I'm finding if I position my head so that it is flat it doesn't move and I have best results. I feel that pillows that can shift can be problematic for those trying to maintain a preferred position after going to sleep and relaxing. To humor my desire to have my shoulder on the pillow I have a very flat old pillow under the buckwheat pillow with a few inches exposed for my shoulder to lay on. My quirks are satisfied and my neck stays aligned.

[kteague]

Not a regular poster these days, but during my more active times on here (about 5-7 years ago)...

Good to see you and thanks for that information.

[TyroneShoes]

Not a regular poster these days, but during my more active times on here (about 5-7 years ago) when I did a PhD in sleep research, a lot of my work looked at the effect of posture on OSA severity. There are several studies which have examined the effect of posture and head/neck position on OSA severity and upper airway collapsibility. One of the more important ones was undertaken by a group here in Australia. Here's the abstract:

Influence of Head Extension, Flexion, and Rotation on Collapsibility of the Passive Upper Airway

Abstract
Study Objectives:

To determine the effect of head posture on upper airway collapsibility and site of collapse of the passive human upper airway.
Design:

Pharyngeal critical closing pressure (Pcrit) and site of airway collapse were assessed during head flexion, extension and rotation in individuals undergoing propofol anesthesia.
Setting:

Operating theatre of major teaching hospital.
Participants:

Fifteen healthy volunteers (8 male), including 7 who were undergoing surgery unrelated to the head or neck.
Measurements and Results:

Applied upper airway pressure was progressively decreased to induce variable degrees of inspiratory flow limitation and to define Pcrit. Upper airway and oesophageal pressure transducers identified the site of collapse. Genioglossus muscle activity (EMGgg) was assessed using intramuscular fine wire electrodes inserted percutaneously. Data from 3 subjects were excluded from analysis due to persistent EMGgg. In the neutral posture Pcrit was –0.4 ± 4.4 cm H2O and collapsed most frequently in the velopharyngeal region. Relative to neutral, Pcrit increased to 3.7 ± 2.9 cm H2O (P < 0.01) and decreased to –9.4 ± 3.8 cm H2O (P < 0.01) when the head was flexed and extended, respectively but was unchanged by rotation (–2.6 ± 3.3 cm H2O; n = 10; P = 0.44). The site of collapse varied, in no consistent pattern, with change in head posture in 5 subjects.
Conclusions:

Head posture has a marked effect on the collapsibility and site of collapse of the passive upper airway (measured by EMGgg) indicating that controlling head posture during sleep or recovery from anesthesia may alter the propensity for airway obstruction. Further, manipulating head posture during propofol sedation may assist with identification of pharyngeal regions vulnerable to collapse during sleep and may be useful for guiding surgical intervention.

So gravity does work.

[split_city]

Not a regular poster these days, but during my more active times on here (about 5-7 years ago)...

Good to see you and thanks for that information.

Thanks. I did enjoy my time on here all those years ago and had many interesting discussions/debates but life just got very busy. Plus, I changed careers (cardiology) but I still come on here every now and then.

So gravity does work.

Yes, gravity does work but head posture probably has more of an effect on compliance of the airway. If one extends the neck (tilts head backwards), it will tend to stretch the airway and reduce airway compliance, resisting collapse. Vice-versa if you tilt your head forward. Several studies conducted in anesthetized animals clearly show the importance of airway stretch on upper airway patency.

[calusa]

Yes, gravity does work but head posture probably has more of an effect on compliance of the airway. If one extends the neck (tilts head backwards), it will tend to stretch the airway and reduce airway compliance, resisting collapse. Vice-versa if you tilt your head forward.

What does "compliance of the airway" mean?

What might this mean for back-sleepers with OSA -- would this mean a thicker pillow would be better, by keeping the neck tilted forward? Or am I understanding this backwards???