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Hi snoredog! Where ya been split_city?

split_city wrote: I have looked at the prevelance of OSA during pregnancy. Unfortunately, there have been very few studies looking at this. The ones which have been published are generally case reports and many of these women were overweight/obese to begin with and already had OSA. Nevertheless, there is some evidence that snoring and OSA increases during pregnancy, particularly during the third trimester. There was a recent longnitudinal study which followed a group of women during pregnancy and then postpartum. This group showed that OSA severity increased during pregnancy and decreased one the babies were born. There are a few ressons why the incidence of OSA is rarely reported in pregnant women:

1) Increased levels of estrogen throughout pregnancy helps to protect the upper airway

2) Pregnant women chose not to sleep on their back (common position where OSA increases)

3) Change in sleep architecture changes during pregnancy

All of these may help prevent OSA.

Geez, if I'd known this earlier, I could have gotten knocked up and saved myself a bundle of money.

M.

Hi there,
my theory is that having apnea/hypopnea causes a beer belly. I am serious.

My sleep study said I wake up with 81 hypopneas per hour. Sometimes I wake all of the way up into a full fight or flight panic attack. I assume when I am waking up 81 times and I do not remember them, that I am having small fight or flights - tons of adrenaline - and doesn't that cause a lot of release of cortisone or cortisol or something like that? As far as I know that makes the body store weight in the stomach area. If I have been having an adrenaline release maybe 80 times an hour, 8 hours a night, - roughly 700 times per night - for years - wouldn't that explain why a 1500 calorie diet, and kickboxing 3x a week along with hiking 1/2 a week did not allow me to lose even one pound but to gain?
Just wondering...

thanks!!!

-angi

Yes Fight or Flight responses are accompanied by a release of Cortisol as a result of the stimulation of the Adrenal Glands.

Wow, I didn't expect to see this thread pop up again.

Anyways, I have pretty much finished the data analysis for this study. Spent months sorting out the lung volume changes.

Anyways, here is a summary of this thread and also my main findings:

Background: Our lab believes that increased pressure inside the abdomen, common in overweight/obese males, may contribute to OSA. How you ask? The increased abdominal pressure is likely to force the diphragm and airways upwards towards the head. This movement may reduce the tension or "tug" on the airway, thereby making the airway "floppier," thus more collapsible. There have been a series of studies in animals which have shown that if you reduce the tension on the airway, the airway becomes more collapsible. The reverse is seen if you stretch the airway.

Aim of study: Consequently, we thought to ourselves, what would happen to airway collapsibility if we simply increased pressure inside the abdomen? Would this make the airway floppier and more collapsible?

Study population: Obese (BMI 30-40) male OSA patients already established on CPAP.

Protocol: Allowed patients to go off to sleep on CPAP. Assessed airway collapsibility when there was no abdominal compression and when pressure inside the abdomen was increased via abdominal compression. Airway collapsibility measurements were taken only when subjects were in stage II sleep. Patients remained supine throughtout the study.

Results: 14 successful studies

Abdominal compression increased abdominal (stomach) pressure by ~50%

This led to an increase in airway collapsibility of about 0.6cmH2O (NOTE: Difference between an OSA patient and a non-OSA person is about 4-6cmH2O)

Abdominal volume decreased by ~1L, thoracic volume increased by ~0.5L i.e. abdomen went in while chest went out with abdominal compression. Net change in lung volume was ~0.5L.

Conclusion: This is the first study to show that abdominal compression increases airway collapsibility. These results may (partially) explain why more males have OSA compared to females.

Excellent!

Thank you Split-City

Di

I thought I would bring this thread up again as my study was published in the Journal of Sleep this month. The full article can be accessed by clicking the "view full text" in the following link:

http://www.journalsleep.org/ViewAbstract.aspx?pid=27636

I have also recently submitted my PhD for review. I'm also in the process of setting up another study looking at the effect of abdominal compression on OSA severity. Pretty much follows on from my previous work.

Congrats, Split City! So, which one of those real names is yours?

Thanks. I'm the first author.

Well this information certainly comes at a very timely moment!

But I have a question. In the case study presented earlier:

viewtopic.php?f=1&t=25185&st=0&sk=t&sd=a

was that patient with the "baseline" Pes of ~20 cmH2O part of the study group? And if so, was that with the abdominal cuff inflated (it looks like you guys were inflating the cuff to ~26.5 cmH2O during your study) or not?

Muffy

Muffy wrote:Well this information certainly comes at a very timely moment!

But I have a question. In the case study presented earlier:

viewtopic.php?f=1&t=25185&st=0&sk=t&sd=a

was that patient with the "baseline" Pes of ~20 cmH2O part of the study group? And if so, was that with the abdominal cuff inflated (it looks like you guys were inflating the cuff to ~26.5 cmH2O during your study) or not?

Muffy

No, the patient in the example you presented was from my second study. No abdominal compression took part in that study.

Well then I guess it was a good idea that you didn't compress him. That would certainly have been a mess.

Eeeewwwwww!

Muffy

split_city wrote:...Conclusion: This is the first study to show that abdominal compression increases airway collapsibility. These results may (partially) explain why more males have OSA compared to females.

Uhh, why men? Women get big guts too as weight increases...yes, usually added first to hips, butt, and thighs but then it starts going everywhere. Or, is the theory that because women add fat to those other places first they are not as quick as men to develop a large gut which increases the tendency for airway narrowing/collapse? This of course only addresses the type of airway narrowing/collapse caused by obesity.

Muse-Inc wrote:

split_city wrote:...Conclusion: This is the first study to show that abdominal compression increases airway collapsibility. These results may (partially) explain why more males have OSA compared to females.

Uhh, why men? Women get big guts too as weight increases...yes, usually added first to hips, butt, and thighs but then it starts going everywhere. Or, is the theory that because women add fat to those other places first they are not as quick as men to develop a large gut which increases the tendency for airway narrowing/collapse? This of course only addresses the type of airway narrowing/collapse caused by obesity.

Thanks for your comments. The highlighted bit is one reason why we specifically targeted obese males. We believed that abdominal compression would have the greatest effect in OSA patients with already raised intra-abdominal pressure. Obese males tend to have greater intra-abdominal pressures versus BMI-matched obese females, again illustrating the difference in fat distribution. It's this raised intra-abdominal pressure which we believe is important.

We certainly could have run this study in obese females but we would have had to take into account the protective role female hormones have on the airway, unless of course we studied post-menopausal women. Another reason why we chose males is that are a bit more tolerable to nasal catheters

I actually did the same experiment in healhy-weight males a few years back. I didn't find any effect of abdominal compression on upper airway collapsibility in this group. The failure to show an effect may be due to the fact this group couldn't really tolerate large amounts of abdominal compression. Gastric pressure levels during compression was still below levels seen in the obese population. Perhaps this group needed a substantial increase in intra-abdominal pressure to have an effect on upper airway function.

Obviously the thinking behind this study relates to the obesity effects on upper airway function and these data cannot be extended to non-obese OSA patients. Several studies have shown that waist circumference and intra-abdominal fat are independent predictors of OSA severity. I believe that the findings of my study are important and may explain why OSA is far more common in obese males. My next study, looking at the effects of abdominal loading on OSA severity will certainly be interesting.

split_city wrote:

Muffy wrote:Well this information certainly comes at a very timely moment!

But I have a question. In the case study presented earlier:

viewtopic.php?f=1&t=25185&st=0&sk=t&sd=a

was that patient with the "baseline" Pes of ~20 cmH2O part of the study group? And if so, was that with the abdominal cuff inflated (it looks like you guys were inflating the cuff to ~26.5 cmH2O during your study) or not?

Muffy

No, the patient in the example you presented was from my second study. No abdominal compression took part in that study.

OK, then I have a follow-up question.

Was that patient on CPAP or ambient presure?

Muffy