Asthma and diving equipment

[DivingDoc]

Paul Thomas wrote:

Quite the opposite as I am sure you must know. Inhalation is caused by the production of a relative vaccuum in the pleural cavity outside the lungs, not in the airways. The lungs passively expand against this due to the pressure supplied by the regulator at the oropharynx. This is why, as you know, in an asthma attack it is the pressure outside the airways that causes them to collapse during forced expiration.[QUOTE\]

OK, but if you produce a vacuum inside the pleural cavity, it must also decrease pressure in the airways, assuming there is resistance to airflow -- in the presant example due to a poorly breathing regulator. A poorly-breathing regulator increases also the external work of breathing, which if asthma is presant, would be additive to the increased internal work of breathing imposed by an asthmatic episode. Airway resistance is already increased in a normal diver due to the greater density of inspired air at depth.

ET

 

[The Iceni]

DivingDoc once bubbled...
Airway resistance is already increased in a normal diver due to the greater density of inspired air at depth.

ET

Another good reason to use Trimix?

 

[SM Diver]

Thanks for that nice note, and for your input Dr. Thomas.

Not sure of all the reasons for the anxiety, but probably a hodge podge of things. All I know right now is slowing down and pacing has made a big improvment. I am in good physical health, but an aerobic workout at 100'+ is not good, probably on several levels.

What do I do with those fish? I eat them! I also give fillets away if to friends and family if I do real well. Just had an outstanding Grouper and Snapper dinner about an hour ago. Still have an amberjack in the smoker that will go for another two hours.

If you were in the States I'd ship you some fillets for your kind advice.

I see myself doing Trimix within a year, as well. Looking forward to it, but not those $90 fills.

Thanks again,

 

[DivingDoc]

Dr Paul Thomas once bubbled...
Another good reason to use Trimix?

Hmmm -- don't know much about Trimix. It's helium-oxygen-nitrogen, right? I would suppose that at any given depth, trimix would be less dense than compressed air due to the lower density of the helium. But of course, at depth, the trimix is still going to be denser than the same trimix is at the surface.

A question for tampascott:

There was a term you used that I am unfamiliar with:

"dropping the jug right on the ledge"

What does that mean??

 

[SM Diver]

DivingDoc: Perhaps it's a vernacular term, but as I am approaching the spot, I'll say "be ready to jug."

"Jugging the ledge" is just dropping the weight over the side of the boat as your over the spot you want to dive. The line is on a reel that pays out and stops when the lead hits the bottom. In other words, it's the same thing as placing a buoy over your dive spot. The term "jug" has become popular because you'll frequently see makeshift buoys made from someone's soda jug, or any other container that will float. Having the ugliest (but highly functional) jug has become kind of a joke on my boat. My current jug is weighted with a trailer ball.

We never anchor, using a "live boat" method. The jug is then the spot to roll the divers off the boat when they're suited up, so they can descend and be right on the ledge or wreck by following the "jug line."

 

[plongere]

Hey Scott..

I am have asthma problems every once in a while as well. However, following up on the Doc's advice check with an Allergist. I found I am allergic to pine and fir and also auto polution.

It is really great when I get to someplace like Hawaii, Bahamas or the Flordia Keys, where there is less traffic and a nice breeze. My allergies / lungs clear up dramtically I can breathe comfortably and my bride tells me I snore a lot less as well.

Few more years and I'll be out of here. Until then, Advair works wonders. jim

 

[The Iceni]

DivingDoc once bubbled...
Hmmm -- don't know much about Trimix. It's helium-oxygen-nitrogen, right? I would suppose that at any given depth, trimix would be less dense than compressed air due to the lower density of the helium. But of course, at depth, the trimix is still going to be denser than the same trimix is at the surface.

Hi again Elaine,

Mol Wt of oxygen = 32
Mol Wt of nitrogen = 28
Mol Wt of helium = 4

I'm not sure of the physical relationship (Poiseuilles law?) but I believe the viscocity of a gas is related to it's molecular weight and helium is about 1/8th the weight of air.

I am informed that when using the same regulator, the work of breathing Trimix at depth is much less than when using it to breath air at the surface;- Transforming a cheap pig of a regulator into an ace piece of kit! Of course hydrogen is even better!

There are considerable additional problems when helium is used, however;

• More decompression penalties
• If is more difficult to blend accurately (Van der Waals)
• If feels cold to breath (but it does not actually cause more heat loss)
• It is not so widely available
• It costs a fortune

Not much help, I know.

 

[The Iceni]

tampascott once bubbled...
If I do six dives over a couple of days, I get bronchitis. My problem is clearly the dryness of the air.

A lot of my diving is 80 - 100 ft. If I exert myself, which I do a lot, it gets real bad.

Anything new on this, or any updated information on that bio-filter thing?

Hi Tampascott,
Is it really the dryness of the air? Surely the water content of your cylinders is going to be pretty small wherever you dive? Pulmonary oxygen toxicity is a well recognised cause of breathing difficulties after prolonged exposure to highish ppO2, which is what you are describing here. I am given to believe any chamber ride leaves the victims with a tight chest.

Just another thought.