@WetSEAL - Several people have already tried to explain that's it's not the questions you ask, but the way you ask those questions.
The IWR discussion was started a long time ago, and
this was one of the threads in which Simon Mitchell already mentioned the IWR study with David Doolette that has now been published. It's a study, if you want to understand the contents, you have to be able to determine the validity of the results. The questions you ask about the results, indicate that you are drawing your own, not completely correct conclusions.
It's understandable, since loads of others have drawn wrong conclusions from NEDU studies in the past.
I'll address one of your remarks, but keep in mind that Dr. Simon Mitchell is the specialist on this subject, not me.
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Others in this thread have also mentioned patient deterioration as a risk, which confused me because it is known that recompression would immediatley reduce the size of nitrogen bubbles and one would naturally expect this to provide immediate relief of symptoms (a point you noted in your paper as well). You also provide some concrete statistics related to this...In the various studies you've quoted, it seems that in most of them 95-98% of patients treated with O2 IWR have a complete relief of symptoms, and the only examples you mentioned of deteriorating symptoms during IWR were when air was used instead of O2. If there are no documented examples of patient deterioration during O2 IWR, then why is it still considered a serious risk factor?
Recompression indeed reduces the size of any present bubbles. And the moment those bubbles are reduced, the blood flow will no longer be blocked.
Now imagine laying on your own arm, which impairs the circulation. You'll start to feel a tingling sensation, which will turn to a numb feeling and then to no feeling. After a minute you get off your arm and the circulation will no longer be impaired. Pins and needles.
Now
imagine doing the same again for one hour and imagine the pins-and-needles sensation after that hour. It'll hurt bad. You'll feel worse than while your arm was just numb. My personal experience was that it can take way longer than those 20 minutes mentioned in the statistics, while breathing 100% oxygen.
What the study does, is looking at statistics from past cases, categorize them and draw conclusions. The main problem with this approach, is that individual different DCI cases cannot be easily compared with each other. For more valid conclusions and recommendations, the ideal situation would be to have multiple similar DCI cases, all treated with the same protocol and then draw conclusions on the outcome. David Doolette has been working on this.
But when it comes to a real life DCI situation, it will be a whole different ballgame. Every single diver starts a dive with DCI prevention as a goal and the majority of all dives are uneventful. When a diver presents him/herself with DCI, statistics and study results will not help you at that moment.
You'll have to diagnose that specific diver at that specific time, recognize and evaluate the limitations of the situation you're in, and finally decide on a course of action.
My impression is that you're turning the whole thing around, focusing on those actions and questioning them. Knowledge about just the actions will not be enough to handle a DCI/IWR situation.