Is the proabability of a fatal infection from
bacteria and other contamination in a
BCD bladder as high as PADI claims?" |
A Rare Case of Lung Infection
In fact, a British diver developed a deadly fungal infection in his lungs in 2009 that was caused by a contaminated BCD. "The culprit," according to the British magazine DIVER, "was Aspergillus fumigatus, a micro-organism that exists within all our bodies and in the air, but usually safely contained by our immune systems."
Michael Firth, an active 58-year-old technical diver, became seriously ill after taking two deep breaths from his wing BCD's manual inflator to be sure it was working. He had noted a moldy taste at the time, and tests after he fell ill established that the fungus had taken hold in the wing bladder. His condition steadily deteriorated, and he passed away in December 2009 while awaiting a lung transplant.
But is the probability of such a fatal infection as high as PADI claims? David Denning, a professor of mycology at the University of Manchester in the U.K. and director of the National Aspergillosis Centre, told DIVER that Firth's is the only diving-related case he has come across, and that more research is needed into why his body reacted as it did. "His lung reaction was clearly very unusual, and you wouldn't normally expect such a very extreme clinical reaction in someone who's fit enough to dive."
Dive medicine doctor Ian Sibley-Calder added: "Invasive pulmonary aspergillosis is extremely unusual in people with no other history of lung problems or altered immune system - - diabetes, steroids, chemotherapy, HIV etc. Consider the number of divers over the world and the fact that inhaling from a buoyancy device is relatively common - - to extract air to collapse a wing, for instance, which I've done many times.
"While this case is tragic, and it's a fair point that we should all take care of our kit, I don't think we should be overly alarmist. If you need to breathe out of a buoyancy device because you've run out of air, do it. Be careful, but don't panic."
BCDs can be disinfected with solutions readily available in dive shops (see the sidebar "Disinfecting Your BCD"). Or you can use benzalkonium chloride, which is available at drug stores under the brand name Zephiran chloride. Besides, why should you be concerned about a lung infection in an out-of-air emergency? With the exception of Mike Firth's case, there are a lot more cures for respiratory infections than there are for drowning.
The second biggest objection made by training agencies is that divers will need to master new skills and perhaps to overlearn some old ones. For instance, you must be able to clear the ounce or so of water from your inflator hose mouthpiece without choking. Other skills required vary depending on whether your first stage is still supplying air. Additional objections include difficulties with buoyancy control, such as ascending too fast or the possibility of arriving on the surface with no lift in the BCD.
The consensus seems to be that keeping things simple reduces the chance of panic. Retired UCLA professor Glenn Egstrom cited a phenomenon called "peripheral narrowing," which is the tendency to lose track of one's options under stress, thereby subverting the reflexive nature of trained responses. While that may be a valid consideration, does it make sense for those charged with the safety of others (e.g., Rescue, Divemaster, or Instructor levels) to not even be exposed to this proven technique for handling out-of-air situations or equipment malfunctions?
Training Agency Options
A few years ago, PADI spelled out the recommended options for low/out of air situations, in order of priority:- Make a normal ascent, if your tank isn't completely empty.
- Ascend using an alternate air source (redundant supply or buddy's octopus).
- Execute a controlled emergency swimming ascent.
- Buddy-breathe with a single regulator supplied by another diver.
- Make a buoyant emergency ascent.
Steve Lewis, director of marketing and corporate communications and an instructor at TDI/SDI, told Undercurrent he knows of nobody in either agency teaching BCD breathing. At TDI, which offers technical diving certifications, emphasis is on the rule of thirds, with students trained to manage their dives so that one third of their breathing supply is always held in reserve. While acknowledging that BCD breathing might be used by an experienced sport diver to avoid an emergency ascent, he said, "It'll be a cold day on the equator before I'd teach it."
Insisting that BCD breathing was "not a viable option," NAUI Training Manager Randy Shaw confirmed that his agency does not teach it at any level of certification. Watson DeVore, director of education for Scuba Schools International agrees with Shaw, adding, "That skill isn't taught because we teach students not to run out of air."
Of course, that turns a blind eye to the great number of divers who do run out of air - - SSI divers included - - and run into serious consequences. However, frequent Undercurrent contributor Bret Gilliam says the technique may not be viable for the average diver due to the danger of inhaling water on the first breath from a BCD inflator hose. That could cause a laryngeal spasm, which could lead to diver panic. He urges that experience and practice are crucial to master this technique (see our sidebar "How to Breathe from a BCD").
When faced with a life or death situation, should one give second thought to the small chance of a lung infection? Isn't being able to state a controlled emergency ascent or a buoyant emergency ascent safer if you have a few breaths of air from your BCD? Knowing you've got at least one more ace up your sleeve might help keep you cool as you weigh your options. Hopefully, you'll get things under control before you ever need to use your BCD as an alternate air source. But it's there if you need it.
http://www.undercurrent.org/
My personal option still choose to safely ascent when my buddy or me reach 50bar(depend on depth)
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