Lower risk of DCS with conservative profiles in divers w/ & w/o R->L shunt.

[afdgf]

Recommendation is one thing, was the advice followed or not? What actual change in behavior occurred?

Actually, with this kind of a design of the study, it is not as crucial to know what and how much behavior change occurred. It only matters that the recommendation was given. This is known as "intention to treat." The actual behavior change that occurred is known as "on treatment." if we assume the "treatment" was the behavior change. If however, we assume that the "treatment" was the recommendation, then all participants in this group received the treatment. The major problem with the study is that they are comparing to historical controls rather than having a randomly assigned control group. If they had had a randomly assigned control group and one group got the recommendation (assuming recommendation is the treatment) and the other did not and they had findings that were this dramatic, then that would mean an extremely powerful effect of recommendation, whether or not behavior change occurred.

 

[RJP]

C'mon... are you really suggesting that the "recommendation itself" can be "powerful" even in the absence of behavior change.

PS - medical ethics would prohibit conducting a "placebo" controlled study that deprived one group of divers of a specific recommendation to dive more conservatively post-DCS.

 

[Duke Dive Medicine]

I'm working on getting the full text of the study. The reference to minimization of Valsalva maneuvers must be post-dive. In that context, it probably means bearing down or straining as if to lift a heavy weight. Valsalva on descent would have little if anything to do with DCS.

Best regards,
DDM

 

[tridacna]

Not surprising results - more conservative profile results in less DCS - but this study did not address whether there was a decreased incidence of DCS as a result of PFO closure

 

[afdgf]

C'mon... are you really suggesting that the "recommendation itself" can be "powerful" even in the absence of behavior change.

PS - medical ethics would prohibit conducting a "placebo" controlled study that deprived one group of divers of a specific recommendation to dive more conservatively post-DCS.

Just because behavior change was not measured and included in the design does not mean that it did not occur. And yes if the recommendation was the "treatment" then there could have been behavior change other than what was in the design. For instance, the design might have been to measure one behavior, but a different kind of behavior actually may have caused the change.
Also yes, there are ethics issues with withholding potentially lifesaving treatment in clinical trial designs. but there are design modifications that take that into account. For instance, they have been used in designing trials with HIV/AIDS interventions. From this study, we do not have confirmatory evidence that the intervention actually "caused" anything. Witholding this recommendation from a control group, would probably make it past the ethics committee if there were appropriate modifications to the design (which are somewhat complicated to describe). It is definitely contrary to ethics to even do a study if the answer to the question were already known. But in this case, we do not know that the treatment of making recommendations even has an effect. So the answer to the question of an effect of recommendation is not known and so a trial might be considered ethical because it is not known whether recommendation has an effect.

 

[DocVikingo]

I'm confused. In these recommendations, what exactly is meant by "minimization of Valsalva maneuvers "?

Hey Chilly,

It was not further specified.

Cheers,

DocVikingo

 

[Rich Keller]

I'm sure if they recommended no diving whatsoever there would have been a 100% absence of DCS. The recommended profiles are ridiculous. I'll wait for the DAN study that is being done now with Doug Ebersole.


iPhone. iTypo. iApologize.

This study just confirms what common sense should already be telling you. But don't let little things like facts keep you from doing what you want to do. If you don't like the DAN study just ignore that one too. If ignorance is bliss then you must be shooting for ecstatic.