Updated 9:20 PM ET
(CBS News) Sarah Murnaghan cheered last week when a judge ruled she could be considered for adult lungs. With weeks to live, her health continued to decline. Four days ago, she went into a coma. Then last night, Sarah's mother, Janet, got the call.
"It was a very exciting moment but also a little bit cautious moment because this is our fourth time being told that," Janet said. "This morning, really only about 15 minutes before they took her into surgery did we have the guarantee that it was a go."
Sarah's new lungs arrived Wednesday afternoon at the Children's Hospital of Philadelphia. Her mother said she had no details about the donor but that the lungs came from someone over the age of 12.
Watch: Experts say it's time to fix transplant rules, below.
There are two ways to make an adult lung fit into a child. The simplest way is to trim off pieces of the lung, reshaping it to fit the child. When the adult is much larger than the child, just a portion of the adult lung - called a lobe - is transplanted into the recipient.
"Lung transplant is the most challenging transplant of all the organs," said Dr. Joshua Sonett, who specializes in lung transplantation. "If she makes it through the transplant and makes it through the first year, she's going to have a 50 to 70 percent chance of making it over five years and perhaps a 50 percent chance of making it 10 years."
There's no chance the cystic fibrosis will recur in the lungs, but since it's a genetic disease, it could affect other organs.
Update: Early Tuesday evening, the Murnaghan family issued a statement saying that Sarah was out of surgery: "Her doctors are very pleased with both her progress during the procedure and her prognosis for recovery...the surgery went smoothly and Sarah did extremely well."