You're right! It is rare! I think I have seen it one-two times when in the ICU but with patients that were there to begin with, not because they developed it in the course of another treatment. Might I suggest, since it is a rare occurrence that you seek guidance and help from one of the larger medical centers ie Mayo, Cleveland Clinic, John Hopkins, Duke. These institutions will more than likely have more experience in the management of her condition. I wish you and your sister well in seeking medical assistance.