Does packing hurt lungs?

[picasso]

They say it does. What do you think?

Glossopharyngeal insufflation causes lung injury in trained breath-hold divers.
Chung SC, Seccombe LM, Jenkins CR, Frater CJ, Ridley LJ, Peters MJ.
Department of Thoracic Medicine, Concord Repatriation General Hospital, Concord, Sydney, New South Wales, Australia.
Abstract
ABSTRACT Background and objective: Glossopharyngeal insufflation (GI) is a technique practised by competitive breath-hold divers to enhance their performance. Using the oropharyngeal musculature, air is pumped into the lungs to increase the lung volume above physiological TLC. Experienced breath-hold divers can increase their lung volumes by up to 3 L. Although the potential for lung injury is evident, there is limited information available. The aim of this study was to examine whether there is any evidence of lung injury following GI, independent of diving. Methods: Six male, competitive breath-hold divers were studied. CT of the thorax was performed during breath-holding at supramaximal lung volumes following GI (CT(GI)), and subsequently at baseline TLC (CT(TLC)). CT scans were performed a minimum of 3 days apart. Images were analysed for evidence of pneumomediastinum or pneumothorax by investigators who were blinded to the procedure. Results: None of the subjects showed symptoms or signs of pneumomediastinum. However, in five of six subjects a pneumomediastinum was detected during the CT(GI). In three subjects a pneumomediastinum was detected on the CT(GI), but had resolved by the time of the CT(TLC). In two subjects a pneumomediastinum was seen on both the CT(GI) and the CT(TLC), and these were larger on the day that a maximal GI manoeuvre had been performed. The single subject, in whom a pneumomediastinum was not detected, was demonstrated separately to not be proficient at GI. Conclusions: Barotrauma was observed in breath-hold divers who increased their lung volumes by GI. The long-term effects of this barotrauma are uncertain and longitudinal studies are required to assess cumulative lung damage.
Glossopharyngeal insufflation causes lung injury i... [Respirology. 2010] - PubMed result

 

[hteas]

I think there was a paper (I have no recollection of the auther) that showed only temporary effects of GI.
I recently had a physical, and got to play with pulmonary function. I got 6.3 L with a full breath. With packing (which I don't normally do) I got it up to 7.4 L At the same time my residual volume went up temporearily by 1 L.
So, based on my limited recollection and one pulmonary test, I doubt that most of us will hurt ourselves with GI. Anything carried to too great an extreme will do damage, however, so as always, in moderation (except in competition, in WRs, and for the maniacs among us who can do no less).

 

[stingaree]

http://forums.deeperblue.com/freedi...s-lung-injury-trained-breath-hold-divers.html

 

[picasso]

Thank you guys.

 

[trux]

There are also couple of other studies about packing, showing similar risks:
http://apnea.cz/?documents+packing

The long term effect is still to be determined, but is definitely of a concern.

So, based on my limited recollection and one pulmonary test, I doubt that most of us will hurt ourselves with GI.

Actually the latest study shows the contrary. Well, the sample of the studied subjects was rather small (6 freedivers, where only 5 of them really packed efficiently), so not sufficiently conclusive, but they detected pneumomediastinum in 100% cases of the 5 freedivers packing properly. Of cause, the pneumomediastinum was temporary. The air was then absorbed, but the long-term effect of the leaking alveolar tissue is yet to be studied, so I think it is premature telling that we will or will not hurt ourselves by packing. I'd tell that currently it looks more like we do hurt ourselves, and since this technique is not a traditional one (as far as I know) among any native divers, and used relatively short time among competitive freedivers, it will likely take a while before we will be able to tell better.