[HSF] Aprotonin

[Tea Acuff]

I just spent the last few days with Nassim Taleb's "Fooled by Randomness" there were several jewels and a lot to think about. I would like to put some form on the exuberant discussion that we have had on aprotonin. I won't say anything new, but as is my wont will try to provide some structure around the meaning of the discussion.
 
Aprotonin reduces bleeding, but so do a lot of things like off pump approach to CAB, or careful technique, etc. Surgical coagulation is a complex process on top of a complex cascade confused by complex patients. However, because we lump everything together in a randomized study we are left with the simple finding that aprotonin causes less bleeding, nothing less and, particularly forgotten, nothing more. 
 
Surgeons however are not primarily interested paying $5000 for a drug that reduces the need for transfusion of a couple of units of blood worth $500. What they are really interested in is the "black swan" event of a patient dying from (near) exsanquination or near exhaustion of the surgeon from reexplorations in prevention of that death.
 
Unfortunately we do not have any way to test for this rare and "random" occurrence. However, in testing for quantitative and manageable bleeding, we approximate a "chaotic" surrogate (like spilling ones tea by adding a large ice cube instead of a drop of water at a time) for the same and "find" other random "consequences" such as renal failure in the analysis.
 
In toto, what has been shown is only that which we do not actually care much about. That is, $5000 dollars of drug can save $500 dollars of blood transfusion. Everything else is, or rationally should be, inferred from this small (relatively) objective point. Everything else statistically speaking is a "random walk" or alternative bet or outcome of our decision from whatever our thinking. Maybe some patients don't die of bleeding or maybe some do die of ATN or clotting. Who can tell?
 
Why do we think what we do? Or why did you feel what you felt?  That is the interesting question.
 
        "...mathematics is tool to meditate, not compute."
                                                   Nassim Taleb

Meditate for a moment my friends. It is a behavior that will help your patients as much as, and perhaps more, than your computations.
 
tea