After the trial, Dr. Eric D. Manheimer, former medical director of Bellevue Hospital Center in Manhattan, where he oversaw one of the busiest and most highly regarded emergency rooms in the country, reviewed Ms. Seelig’s chart at the request of The Times and concluded that she had not been properly monitored.

As a precaution, doctors should have put a tube in her airway to keep her from breathing her own vomit and stomach acid and to provide oxygen, he said. And they should have moved her to intensive care. Her low salt could have been an additional “metabolic cause of stupor and coma,” he said.

“It’s not rocket science,” Dr. Manheimer said. “Once your mental status is going down, you don’t know when the person is going to stop breathing.”

Ms. Seelig’s parents are left with a July 2007 letter of condolence from Dr. Thomas R. Frieden, then New York City’s health commissioner, whose office turned over the Poison Control recording.

“I wept after hearing the recording,” Dr. Frieden, now head of the Centers for Disease Control and Prevention, wrote.

“As a parent, physician and fellow human being, I was deeply disturbed by the interaction of the Poison Control Center with your daughter,” he wrote. Dr. Frieden said that the person who took the call “no longer works for the Poison Control Center,” and that he was working on better coordination with 911.

For Mr. Seelig and Ms. Gibson, the letter serves as evidence that their daughter’s death did matter to someone, and made some difference.

Asked what lesson might be taught by Sabrina’s death, Ms. Gibson said there was one. “No one should go to a hospital without someone with you — no one,” she said. “Don’t go unless somebody at least knows you’re there.”