Why not BBL under local anesthesia to better prevent embolism?

You do not necessarily need general anesthesia, but I do think it is a better patient experience.   I have performed many of these procedures with local and sedation, but it is certainly not for everyone and risk benefit analysis must be performed for each patient. Fat embolus may be avoided by epinephrine injection into the area to be augmented as well as the use of the use of blunt cannulae.
Kenneth Hughes, MD, Board Certified Plastic SurgeonLos Angeles, CA

A Brazilian Butt Lift is an involved procedure.  Attempting this under local anesthesia will likely result in a suboptimal result and increases the risk of lidocaine toxicity.  Make sure to understand exactly why your surgeon wants no anesthesia and make sure they are properly board certified.

Hi and thanks for the question. It isn't the anaesthetic technique that gives rise to fat embolism but the depth at which the injection takes place, deep to muscle is the problem. If you are sedated orally and the operator is slow and gentle it can be done reasonably comfortably. Make sure the surgeon is board certified and experienced in the techniques and you should be fine. Good Luck! 

I have performed them under local, but the  majority I perform are under general. The patients do tolerate it pretty well.  Each patient is different and evaluating a patient in person is essential.

Being awake will not prevent an embolism.  Being awake will let you know when the muscle is being injected which will be painful.  The will help you avoid the embolism.  BBL can be done under local for smaller areas and reshaping.