It is also possible that the anesthesia used and the administration of it was proper and she had an unexpected allergic reaction to it which caused cardiac arrest. Just a theory ..
Yes, that’s a perfectly reasonable possibility as well. She was 81. Surgery is risky in many ways for 81-year-olds.
It’s appropriate for New York authorities to be investigating the death. If an avoidable error was made, and especially if there was a deliberate violation of safe practices for the procedure, the public should know about it.