I've read and heard different accounts about this incident. If the reports are correct (if) the staff at the home did not abandon the residents, which was one of my first concerns when I heard the story. The deaths actually happened after the storm had passed, but the air conditioning failed and was not able to be repaired. Requests for assistance were made, to include calls to 911, but in the aftermath of the storm they "were not heard" and mixed in with the hundreds if not thousands of other calls.
What I fault the operators of the home for is "waiting for the emergency response system" to respond. Sometimes you have to go outside of the system to get help. Since there was a hospital very close by (some describe it as being across the street), I would have gone there and asked for medical assistance. Getting just one doctor or nurse to come over to the facility would have gotten the attention they needed.
This is also when elected officials can be of assistance. They are not busy responding, and a call, if a call was possible — and it sounds like it was — would have also gotten attention. In these circumstances, they are looking for opportunities to help their constituents.
All of this is in retrospect. Perhaps someone will learn something from these deaths, but then as noted in the linked story above, it has been 12 years since Katrina and new regulations are just now coming into play. As always, there are those who oppose the regulations due to costs. This is why here in Washington state there have been no requirements for our care facilities when it comes to emergency power. I recall one nursing home being evacuated due to a lack of electrical power and no heat during a winter storm event. It is not an easy thing to do!