Just another question (since you said you have broken ribs during chest compression). Wouldn't/couldn't implants rupture during strong compression? Not a cause of death...but I would guess complicate the CPR process.
Was her implants Silicone or Saline? The saline will rupture more easily than the silicone, but they do rupture as well, especially if the bags are getting older. If silicone, it could stay encapsulated in the breast tissue.
They can rupture but wouldnt interfere..at least when I do it. I just keep going no matter what til the code is called.