Every hospital maintains an elaborate disaster plan, but after Hurricane Sandy, the fact that many health care facilities are in low-lying areas proved to be something of an Achilles' heel. The city?s health commissioner, Dr. Thomas Farley, defended the decision not to require evacuations of Bellevue, Coney Island and NYU Langone hospitals before the storm, which he said had been made in consultation with the state health commissioner, Dr. Nirav Shah.