Update in the field of upper airway physiology

Just got back from a three day meeting with some of the leading experts in the field of upper airway physiology. As always, special guest Prof. David White (sleep research guru and Chief Medical Officer of Respironics) made the trip from the US to take part in the meeting.

The meeting was again of a high standard with some exciting research in the field of upper airway physiology, with special emphasis on the pathophysiology behind OSA.

Here's a brief summary of what was discussed:

OSA phenotypes: An ex colleague of mine (now working in Boston) talked about a study which looks at different OSA phenotypes; airway anatomy, airway muscle activity, arousalibility, ventilatory instability.

Regional fat distribution and OSA: While neck circumference has been shown to be a good predictor of OSA, the amount of fat (in grams) in the neck seems to be a better predictor. However, an increased waist-to-hip ratio also predicted OSA severity.

Slow-wave sleep and OSA: OSA severity generally decreases in slow-wave sleep. Some possible mechanisms include reduced arousability, increased respiratory drive leading to increased genioglossus activity.

The effect of stretching the airway: stretching the airway in rabbits leads to increased upper airway size

My talk: I'm now looking at lung volume changes at sleep onset in obese OSA patients compared to healthy-weight individuals. A lower lung volume results in the airway becoming more collapsible. Perhaps obese OSA patients experience a greater fall in lung volume at sleep onset compared to healthy-weight individuals. This greater decrease, if present, would likely contribute to apneic events.

Snoring and atheroscelrosis: A very interesting talk! Increased vibration (from snoring) on the carotid artery in rabbits led to carotid artery endothelial injury and dysfunction. The vibrations from snoring may break off plaques from the artery wall.

Mandibular Splints: Imaging studies of the upper airway during wakefulness may predict whether an OSA patient is likely to succeed with a splint.

The genioglossus muscle: Appears to be very complex and is modified by CO2 and airway resistance/negative pressure. Different areas of muscles are active during different times of the respiratory cycle.

Lots of great data! I look forward to hearing from these groups next year

Thanks for sharing, Split-City! The slow-wave sleep, and especially the stretching the airway and snoring's possible effect on the carotid artery and plaque, as well as the possible effect of lower lung volume (I'm not overweight but do have COPD) were especially interesting. You seem to have condensed the subjects covered very well.

Thanks for the summary - appreciate your sharing it. Like Slinky my eye caught this bit

"The effect of stretching the airway: stretching the airway in rabbits leads to increased upper airway size "

Now for some people to try it on

Cheers DSM

PS Wife was in Adelaide 3 weeks back to collect an art show award. Said it was hot & dry (just as I always remember it). But Sydney has had the wettest & coldest summer in 16 years.

Thanks split-city.

So maybe an op to stretch the airway - maybe by shortening it and then fastening it back into it's original position - will be the go sometime in the future?

I hope your talk was a big success and you got lots of intelligent feedback and questions!

di

Moby wrote:Thanks split-city.

So maybe an op to stretch the airway - maybe by shortening it and then fastening it back into it's original position - will be the go sometime in the future?

Certainly might be an alternative to simply cutting tissue out.

Moby wrote:I hope your talk was a big success and you got lots of intelligent feedback and questions!

Yeah it went well thanks. I had a tough task as the previous speakers had very fascinating images/videos of the upper airway.

Prof. David White did a little talk at the end of the meeting in which he discussed "gaps in our understanding of OSA." He mentioned that lung volume is an important area of research that we should be looking at. He quoted my talk.

That was quite a compliment for Prof White to refer to and quote from your presentation, SplitCity! Congratulations.