human
Where do you work? A lot of EMS protocols around the world are "No ROSC = no transport" except maybe in some extreme cases that can't be treated in the field (ie. PE in some places, or intrapartum cardiac arrest).
gpt
I am so sorry for your loss, it seems you got into a very tough situation but did all you could to help her and gave her and the EMTs the best chances; you're a good friend and person. I would agree with the colle ague that a PE or another clot of some sort (intracranial bleed/occlusion) comes to mind as a plausible possibility, and that waiting on the autopsy results is the best step. A serious underlying reason would also explain why the resuscitation was unsuccessful.
Do you think there will be charges brought against her sister? I could see an Involuntary Manslaughter charge for someone where I live happening.
Sorry to ask, but did the ems people work on her for an hour and half or did they transport her and the docs worked on her for an hour and half?