Diving Risks -- real information

[pufferfish]

I agree with Rick in that with regards to recreational diving our sport is very safe (also relative to other sports) and there is a tendency to make it seem more dangerous than it really is. I have noticed this in conversations amongst divers and moreso amongst non-divers who often see diving as dangerous. Probably those involved in treating injured divers have an even more skewed view towards attributing a higher risk to our sport than it really does have. Talk to any cop in Toronto who still does night shift and he or she would have you believe, "it is a war zone out there" when in fact we have about one murder per week in a city of three million, a very low incidence.

That being said we do need more Abacus type projects in different dive locals and with different types of diving activities. Cozumel should be an easy place to do such a study as the catchment area is an island, it appears most of tank fills come from a few large suppliers, and we have a true recreational population with "people who dive" and "divers". My guess is the incidence of DCI and fatalities given the number of dives done is still very very low. Diving is a pretty forgiving sport when one looks at all the things people do out there and get away with it.

In this month's DAN Alert Diver there is a nice article, "Dive Injuries and Fatalities Are Down" page 26 where they have looked at the prospective data for DCI from the PDE (Project Dive Exploration). This is a data base where both the numerator and denominator is known. Here they looked at incidence and found that DCI on liveaboards is almost unheard of, less than .01%. There were though several groups with much higher risk profiles. The cold water wreck group (deep square profiles) had an incidence for DCI of .37 % which is quite significant.

I suspect as more prospective data becomes available over time and the risks can be stratified we will see the following incidence evolve

Low risk: Liveaboards and Carribean recreational diving like Coz
Medium risk: Cold water square profile diving
Higher risk : ??Tech diving

Now about risk in Toronto there DocV. Let me see, in August our West Nile epidemic should be peaking, SARS will likely still be here, and there still might be a few mad cows around. You might be better off instead on Maracaibo Deep in Cozumel that risking yourself here in TO

 

[Walter]

Rick,

Good point. OTOH, many of these folks who were prevented from killing themselves are blissfully unaware. I saw an excellent example recently. The guy is clueless that he almost killed himself. He had no accident, yet he's not safe by any stretch of the imagination. He'll be lucky if all his dives are with alert buddies who can safe his butt. If not, this guy will kill himself sooner or later.

By telling everyone diving is very safe, we encourage them to not be as concerned for safety. We need to tell the majority they need a baby sitter to keep them safe.

I think it would be a wiser course of action to give them adequate training to start.

 

[pufferfish]

I may be wrong but I believe I read/heard on course that the incidence of DCS Type II injuries has remained unchanged despite better gear, ?better instruction, and the introduction of computers into recreational diving.

As Walter says DCS rates will drop when ascent rates are slowed down consistently AND for those deep cold square profiles we start making deep stops to allow the fast CNS tissues more time to offgas.

What I have noticed on air is that in the Carribean I can dive to 130 feet look around and then over the next thirty or forty minutes make my way slowly back to the surface puttering at sixty feet, thirty feet and then make my safety stop with no pathological fatigue.

In Tobermory ( on air) in cold water I dive down to a hundred feet swim around on a wreck for fifteen minutes and then spend three minutes ascending to the safety stop for an additional three to five minutes. Seventeen minutes filling up CNS tissues and eight minutes offgassing doesn't look too wise. Usually about one to two hours later, moreso if I am imobilized in a car driving home, an uncontrollabe sleepiness or fatigue descends over me. I have had to pull over and have fallen asleep (out cold) for up to an hour. I am sure this is sub-clinical DCS or some manifestation of those deep square profiles.

Yes I know you are all saying I should be on Nitrox for this reason and that, but I am going to experiment this summer before I do that. First I am going to add a fifty foot three to five minute stop (gas allowing) as well as a the five minute safety stop. That will lengthen my ascent time to thirteen minutes. Secondly before jumping in my car and driving home for three hours I am going to go for a one hour walk. Thirdly I will slow my ascent to 10 ft/minute in that last fifteen feet. That higher DAN incidence for DCI on the cold water wreck group is likely from not spending enough time on a deep stop (say half of the deepest depth) so as to allow the CNS tissues to offgas. So throw in a deep stop on these square profiles, slow ascent rates, and I'd imagine the incidence will fall back towards .02- .03%. I'll let you know about my experimental outcome later.

 

[Saturation]

The Abacus study is often misquoted and I too made the error of equating risk per dives to risk per divers. They are not, although they are looking at the same phenomenon from different perspectives.

Dr. Bennett is quick to point out numerous times that stats on diving safety have been relatively 'stable' for over 20 years, i.e., DCI incidence and deaths.

In Carl Edmonds' current 2003 textbook, he overviews stats spanning decades. While 1/10K versus 3/10K could be seen as a 3 fold increase, at issue is really the accuracy of the numerator and the denominator. As these annual rates are in a state of flux, its probably more useful to compare values as a trend than to compare them against each other, as methodological issues can not be eliminated as a source of these fluxes.

However, what is probably most useful is whether diving is a safe sport. What does safe mean? What does risk mean?

To concretize the abstract notion of risk, it maybe most useful to compare diving against a standard activity as baseline to which safety is defined below the line and danger, above the line.

Since there is no such standard, I've arbitrarily chosen driving in the USA.

http://www.dive-med.org/


There is a practical issue of concern to all. Because the safety of diving is either purposely misfed, confused or misunderstood by the general non-diving public, life and disability insurance policies may add hefty premiums to scuba divers, yet no data supports the daredevil risk the public considers diving to be, particular in relation to a baseline risk activity, such as car driving.

Misrepresentation of a truth of diving's risk will be paid for in real dollars by everyone in the sport and only few companies, one being DAN, understand and charge for the risks appropriately.

 

[pufferfish]

Good point Saturation. Look at the actuarial data or insurance rates over time. My Mastercard for the last decade has included in their medical travel coverage recreational diving with no exclusions as long as one is certified. DAN rates have been pretty stable too over the decade. Now my car insurance has gone up 40% over the last decade but suspect that is more from increased theft than increased liability claims.

Interesting point in that DAN article this month on the PDE data.

Average DCI incidence was...........10/10,0000 and 1.3/100 divers

Cold water wreck group.................37/10,000 and 4/100 divers

Recreational dive professionals......10/10,000 and 9.5/100 divers

This illustrates the problem with statistical interpretation. If one looks at the instructor data without the incidence one might be tempted to say instructors have increased risk of DCI, but they don't. The incidence is the same as the average which just says they are doing more dives and hence as a group we see more DCI. The cold water wreck group on the other hand as a group sees more DCI and the incidence is higher which tell us this is a riskier endeavor than teaching diving or general recreational diving. Add some deep stops to those cold deep wreck dives and that incidence should fall.

In the DAN article they leave us in suspence by saying they are investigating a subset of recreational dive professionals with a higher incidence of DCI but need to validate this. Anybody know who they are looking at? Maybe the backplate/wing instructors vs the rest :boom:

 

[Saturation]

pufferfish once bubbled...
Good point Saturation. Look at the actuarial data or insurance rates over time. My Mastercard for the last decade has included in their medical travel coverage recreational diving with no exclusions as long as one is certified.

That's wonderful, PF.

Health insurance isn't so bad to those who offer it.

As example this company provides $2,000,000 worth of non-US coverage for $300 a month premium. Its $250 without 'hazardous sport' option added, i.e., diving.

"
Hazardous Sports Option (Check for Yes)
Not applicable for Global Medical InsuranceSM or Patriot Executive Travel Medical InsuranceSM
The following named hazardous activities are excluded but may be added by the Optional Sports Rider: Scuba diving, mountain climbing (where ropes or guides normally used), jet, snow and water skiing and snowboarding, sky diving, amateur racing, piloting an aircraft, bungee jumping and spelunking"


OTAH, term life insurance is wicked. Many companies specifically exclude and mention scuba diving. Those that allow diving may have shallow cutoff depths. If you have a draconian insurance company now, your insurance maybe invalid every time you dive.

http://www.budgetlife.com/term_life_insurance_estimate.htm

Try it for yourselves. As example, cheapest premium for maximum coverage from 15 companies for premiums ranging from $3,600-$10000/yr without scuba, and $4600-$11500/yr with scuba, but offered only by 4 companies. The difference are companies that offer no insurance under the conditions you specify. For this example, answer the questions as you would normally then compare the premiums with and without scuba.

 

[pescador775]

Saturation, that was refreshing, thanks. If diving were so safe as purported then DAN would be out of business. Otherwise, diver rate premiums reflect a realistic risk assessment just as for smokers, etc. The subject of diver risk is an emotional one and generates enough long winded speaches so I'm closing for now.
Pesky

 

[Saturation]

pescador775 once bubbled...
Saturation, that was refreshing, thanks. If diving were so safe as purported then DAN would be out of business. Otherwise, diver rate premiums reflect a realistic risk assessment just as for smokers, etc. The subject of diver risk is an emotional one and generates enough long winded speaches so I'm closing for now.
Pesky

Hi P:

Very welcome. Actually, diving is 'safe' enough that's why DAN is in business. Not trying to beat their drum here, but I feel the issue of safety is often misrepresented.

From Jefferson Davis MD's [deceased] idea of a 'decompression alert network,' it wasn't until DAN offered injury insurance did DAN grow really well.

With DAN's knowledge of more 'accurate' accident rates and what divers truly suffer from, DAN offered what initially appears as low rates, but its actually suitable to the real accident rates of diving.

That diving accident insurance can be offered for ~$100/year, when a treatment begins at $10,000 a pop, and typically runs to $100,000 when airlifts and multiple treatments are added, shows that DCI must not occur enough such that 200,000 DAN members paying $100 each provides a steady capital base for DAN to grow as it has.

 

[pufferfish]

Once a year I check to make sure Mastercard has not changed their scuba coverage policy. From the book they provide:

The insurance does not cover participation in professional sports; any speed contest; SCUBA diving, unless the Insured person holds a basic SCUBA designation from a certified school or other licensing body;hang gliding, sky diving, parachuting, bungee jumping, parasailing, spelunking, mountaineering, rock climbing or a flight accident, except as a passenger in a commercially licensed airline.

My life insurance also still covers recreational scuba deaths.

The diving data to date and the actuarial data all indicate recreational scuba diving is safe 'enough'.

One should tell non-divers and divers alike that the sport they practice is safe, however one should still be careful as a diver.

 

[Doppler]

I am not sure that we can state that diving is safe... or safer than <insert sport>. Any statistics associated with our sport are suspect at best and the jury is still out on several studies being undertaken at the moment.

In the context of the original question... I think we have to be honest about the potential risk. Diving takes place in a hostile environment and until we learn to breath water, there is a serious risk of injury or death.

What keeps that risk at a manageable and / or acceptable level is training, mental and physical fitness, knowing the limits of one's training, experience and equipment and staying well within them.

Unfortunately, for years open water training -- especially in North America, but more and more globally -- has skirted the issue of risk management and accident assessment. Diving is more dangerous than bowling, that's why you need training before you can participate.

By the way, I think the risk to a trained and experienced technical diver executing a well-planned staged decompression dive to 250 feet is better managed (and therefore less likely to bite her in the ass) than on many "recreational" dives on a reef to 50 feet.

Thanks