Teaching contradictions: differing dive training philosophies

[boulderjohn]

My understanding is that BSAC has decided to emphasize redundant air sources to the degree that they have decided that no one should ever be in the position to do a CESA. UTD has a similar belief in that they teach the buddy system to such an extreme that their policy is that if the diver is separated from a buddy to the extent that an air share is not possible, then the diver should be gong to the surface already and should nor run out of air.

 

[BDSC]

perhaps PADI feels that its graduates will be more likely to need a CESA (kidding - I am a PADI graduate)

Same here. I was certified in 1991 and I remember doing both "buddy breathing" and the CESA. ( I still think they should teach bb ). When we did the pool skills we practiced doing a horizontal CESA and I remember our instructor telling folks who were running out of breath doing it that way not to worry because they would have plenty of air when we did it in our open water dives. There was a part of me that was skeptical. I remember when it was my turn to do it I took a deep breath and was thinking that I can't imagine that when I reach the surface I'm not going to be gasping for air. To my surprise it was just like the instructor had told us. I was able to blow a small but steady stream of air and when I reached the surface I still had plenty of breath left.

I just can't see how doing it in a pool in a horizontal fashion can come close to what you actually experience when you do it from depth. It was night and day for me.

 

[Thalassamania]

My understanding is that BSAC has decided to emphasize redundant air sources to the degree that they have decided that no one should ever be in the position to do a CESA. UTD has a similar belief in that they teach the buddy system to such an extreme that their policy is that if the diver is separated from a buddy to the extent that an air share is not possible, then the diver should be gong to the surface already and should nor run out of air.

While I think it is a reasonable topic for discussion, at this stage I see that recommendation as the classic, "equipment solution to a skills problem." I'd look at it differently if I actually believed that any of this was driven by what was best for the student rather than what was fastest and cheapest for the shops and would could be accomplished, at the lowest level of risk by an increasingly unskilled instructor pool.

While I agree with a goodly part of UTD's approach, it falls short, in my view, in two ways: despite the most careful of diving procedures buddy separation, especially in low visibility remains a real possibility; and, CESA practice and mastery goes way beyond being a simplistic solution to the single problem of being OOA. A diver knowing that he can, at a low level of risk, make it to the surface with reasonable comfort, is important. In fact, I'd describe that as the dividing line between recreational and technical diving. The technical diving solutions, which are basically solo diving backups that are backstopped by intense buddy diving skills (or the other way round, if you prefer) are clearly not what NASE or BSAC or other other similar groups are aiming at.

 

[DCBC]

Although I continue to teach Emergency Swimming Ascent (CESA), there is evidence that if improperly taught, it can be harmful to the Student. One particular study was published in the Aviation and Space Environmental Medicine Journal (2009;80:371–5) by Drs. AFÈRE, ERMONPRÉ and ALESTRA 'Pulmonary barotrauma in divers during emergency free ascent training: review of 124 cases'. It is available on-line at http://c.ymcdn.com/sites/uhms.site-...ournal_watch/laf_re_umo_pulmonary_barotra.pdf

To quote this report:: "Results: A total of 124 divers were treated, of whom 34 (27.4%) were diagnosed with PBT. Of those, 20 divers (58.8%) had symptoms of AGE. In 16 of those, EFA training exercise was deemed responsible for the injury. The association between EFA training and PBT proved to be very signifi cant, with an odds ratio of 11.33 (95% confidence interval: 2.186 to 58.758). It was possible to calculate that a training dive (0.456 to 1.36/10,000) carries a 100 to 400 times higher risk, and an ascent training dive (1.82 to 5.46/10,000 dives) a 500 to 1500 times higher risk for PBT than a non-training dive (0.0041 to 0.0043/10,000 dives).

Discussion: This study confirms a significant association between EFA training dives and the occurrence of PBT."

Recreational training agencies have to weight the risk to the student and the likelihood that a particular skill will be needed. Over the years, there have been many changes to Diver Training Standards and this is something that all agencies continue to struggle with and refine. Given the shortness of the Instructor training process and the time donated to a particular candidate to demonstrate and teach a deep water emergency ascent, perhaps this is something that will eventually be removed from the training requirements of all agencies for recreational divers.

 

[dbulmer]

In BSAC's case I think they weighed the risks to the trainee primarily and chose to drop the skill.

Bear in mind that the vast majority of BSAC instructors are not paid (for those not aware of this )unless they are attached to a BSAC commercial outfit which tend to be outside the UK.

Since club training often takes place over the winter months there is not the time pressure that instructors of other agencies would have.

 

[Thalassamania]

DCBC, I think that they're drawing the wrong conclusions.

The article states: "Experience from treating diving accidents indicates that a large proportion of divers suffering from pulmonary barotraumas (PBT) or arterial gas embolism (AGE) were engaged in training dives, specifically emergency free ascent (EFA)."

This study relied on, "the average number of dives performed and the proportion of in-water skills training dives (that) were obtained from the major Belgian dive associations." Unless the system in Belgium is radically different from elsewhere in the world, I find it open to serious question.

Additionally, even if one is to grant all the assumptions and simplifications made, the bottom line is that study is only meaningful if you stay inside the box of the course(s) sampled. While I have no doubt that some exercises pose more danger than others, I suggest that this can be dealt with with care and attention to detail. I point to the science community's experience with Scripps Model courses where, during entry level training, each and every student performs between 50 and 100 buoyant free ascents as part of the training exercises. There has never been a single accident during such training. I advance two explanations for this: the first is staff quality as evidenced by the Local Dive Shop operated course in the Auburn University pool that resulted in fatality some years ago using precisely the same exercise without staff supervision; and the second: the many, many repetitions of the skill, starting in a free diving mode and then progressing much later to scuba.

 

[boulderjohn]

]While I agree with a goodly part of UTD's approach, it falls short, in my view, in two ways: despite the most careful of diving procedures buddy separation, especially in low visibility remains a real possibility; and, CESA practice and mastery goes way beyond being a simplistic solution to the single problem of being OOA. A diver knowing that he can, at a low level of risk, make it to the surface with reasonable comfort, is important. In fact, I'd describe that as the dividing line between recreational and technical diving. The technical diving solutions, which are basically solo diving backups that are backstopped by intense buddy diving skills (or the other way round, if you prefer) are clearly not what NASE or BSAC or other other similar groups are aiming at.

For the record, I agree with you and believe CESA should be an important part of OW training.

Although I continue to teach Emergency Swimming Ascent (CESA), there is evidence that if improperly taught, it can be harmful to the Student. One particular study was published in the Aviation and Space Environmental Medicine Journal (2009;80:371–5) by Drs. AFÈRE, ERMONPRÉ and ALESTRA 'Pulmonary barotrauma in divers during emergency free ascent training: review of 124 cases'. It is available on-line at http://c.ymcdn.com/sites/uhms.site-...ournal_watch/laf_re_umo_pulmonary_barotra.pdf

I found the report troubling for several reasons. First, let's look at a key paragraph:

Back in 1977, during a UHMS workshop, it was
concluded that training in such a skill should be maintained,
but the training agencies (PADI, NAUI, SSI,
YMCA) committed themselves to improving education
techniques to lower the risks associated with the training
procedures, and to give preference to the safest
ascent procedure ( 16 ). Propositions from this workshop
included abandoning rapid ascent training while exhaling
without regulator, e.g., emergency free ascent (EFA),
and limiting the depth of rapid ascent training to the
7-15 msw (20-40 fsw) zone. Despite these propositions,
some diving certification agencies in Belgium
still require many ascent skills, especially EFA, performed
from a depth of 10 msw, 30 msw, and 40 msw.
This skill is actually taught in Belgium without a
regulator inserted in the mouth in an approach meant
to mimic as closely as possible an emergency “ out of
air ” situation.​

In other words, in response to research showing the dangers of CESA instruction in 1977, all the major agencies in the world decided to use approaches that minimized the risk, but in Belgium, they decided to maintain the risky approaches that were abandoned as too dangerous elsewhere. Divers in this study were not taught CESA in the way it is taught in the rest of the world.

Most importantly, the paper goes on to emphasize the part about CESAs in Belgium being taught with the regulator out of the mouth. This is close to obscene in my opinion. Doing it that way very much encourages the ascending student who has exhaled too quickly to hold the breath the rest of the way up. In the rest of the world keeping the regulator in the mouth is emphasized for that reason. More importantly, in a real world CESA situation, the regulator should be in the mouth because as ambient pressure decreases on ascent, the diver will be able to get a desired breath of air if the diver inhales. If the diver inhales with the regulator out, the diver drowns. The Belgian procedure is not only unsafe, it teaches the student to do something different from what should be done in an actual emergency.

The report makes me glad that my children and grandchildren will not learn to dive in Belgium.

---------- Post added November 30th, 2012 at 04:00 PM ----------

Unless the system in Belgium is radically different from elsewhere in the world, I find it open to serious question.

Apparently it is.

 

[Thalassamania]

"Despite these propositions, some diving certification agencies in Belgium still require many ascent skills, especially EFA, performed from a depth of 10 msw, 30 msw, and 40 msw."

I know of no entry level ascent training that is conducted from 30 or 40 msw. Do you?

 

[boulderjohn]

"Despite these propositions, some diving certification agencies in Belgium still require many ascent skills, especially EFA, performed from a depth of 10 msw, 30 msw, and 40 msw."

I know of no entry level ascent training that is conducted from 30 or 40 msw. Do you?

According to the article, it is common practice in Belgium. Never having seen a scuba class in Belgium, I have no basis to disagree.

 

[The Chairman]

I do remember my vertical CESA exercise during training in 1994.

You also clearly remember your instructor doing those seven bounce dives. What kind of example is that setting for you? Not a very good one. Do you now view bounce dives as being OK?

How was your trim and buoyancy after the class? Was it excellent? I would suggest that excellent trim and buoyancy would do more for your confidence AND your competence than a single GUIDED ascent. I mean really, how accurate could it be with your instructor holding on to you?

I'd estimate that a student in my class completes on the order of 50 to 100 ascents,

I wonder what your students FIRST reaction is to a problem then? Simply bolt for the surface? Yeah, I don't like that precedent.

Only one of most anything, incuding a horizontal CESA is, IMHO, a waste of time. Why would you do only one?

That's what's being done and many times, they do their first one in OW. In a pool, my students can do several easily and ultimately, it builds confidence.

My students should have no need for instruction on skills by the time we hit OW. I want to see how competent they are at this point. Do they know when to use the skill and can they accomplish it with ease?