Lung infections

[Sarah]

I know that to avoid nasty lung infections, it is recommended to disinfect the inside of your BCD with Milton or the like, but I would like to know just how fast a lung problem can set in if contaminated air is breathed in.

I am looking at rebreathers as part of a university project and they have the same problem with the counter-lungs. As a diver can stay down a number of hours on a rebreather, is it possible for microbes in counter-lungs that haven't been cared for properly, to be able to cause a problem for the diver whilst he/she is actually submerged?

Any help would be greatly appreciated.

Thanks.

[large_diver]

THat's an interesting question. Having come down with some nasty cols recently after diving, I've been wondering the same thing. In each case, I used a rentla regulator, so who knows what kind of nasty stuff may have been "brewing" in the regulator I was using. Same question about tank air....

[John Reinertson]

Perhaps one of the Navy Diving docs can help with more extensive rebreather experience.
The circuit in rebreathers is physiologically very similar to that used for closed-circuit anesthesia. There are two potential problems with inadequate servicing.
One would be bacterial or viral contamination of the surfaces and resultant inhalation of the microbes, producing an infection.

This would have to incubate for some time, at least a few hours, to produce serious infection.

Also possible would be an acute asthma or allergic reaction to bacterial or fungal toxins or antigens, which could produce an immediate impairment at depth.
I know of no studies documenting that in rebreathers, but certainly contaminated gear is nothing to mess around with.
(Closed circuit anesthesia gear is most commonly disposable or disinfected between uses)
Dive Safe
John Reinertson

[detroit diver]

Dr. John,

This was the reason that I decided to purchase a reg for myself and my son. One has no idea what is contained within the second stage, or what care has been taken by the rental shop to disinfect the reg. Now if I get sick, it must have been me!

[scubadoc]

Although certainly possible in closed circuit rebreathers, bacterial or fungal pneumonia is not one of the major dangers of rebreather diving (hypoxia, O2 toxicity, hypercapnia and 'caustic cocktail' with burns). It certainly would have little chance of occurring during a dive but if it did happen, would come on several hours later.

Probably closer early attention has to be paid to cleansing the rebreather than scuba due to the closed nature of the breathing loop. (NOAA)

Possibly of greater concern insofar as causing pneumonitis or breathing problems occurring early after a dive -or even during the latter phases of a dive is the clinical picture of "salt-water aspiration pneumonitis" as described by Carl Edmonds. (Diving and Subaquatic Medicine, Third Edition).

Caused by micronized saltwater droplets from a faulty regulator, this clinical picture is described at http://www.scuba-doc.com/saltwasp.html .

[fooks]

Should a person be useing some sort of disinfectant every once and awhile so that no bacteria builds up in your reg? I usually just soak my regs in luke warm water after every dive for about an hour.

[Sarah]

Thanks very much to both John and scubadoc, your replies are most helpful. I shall follow up on all the info that you very kindly provided.

Cheers

Sarah

[DocVikingo]

Hi fooks,

It's probably not a bad idea to disinfect your reg every once in a while. Do be aware, however, that while soaking it in luke warm water maybe good for salt removal it will not disinfect anything.

Soak the reg in a diluted household bleach solution. The CDC recommends one-quarter cup of bleach to one gallon of water and a soaking time of up to 10 minutes, followed by thorough rinsing. Other disinfectants safe if used as directed include Wescodyne, Santimine & Timsen.

When you soak, you want to make sure the disinfectant solution does not work its way back into the first stage. Therefore, keep the reg on a tank with the lines pressurized. If this is not convenient, make sure the first stage remains above the level of the soak.

Dive healthy.

DocVikingo