Sarah's parents had challenged existing transplant policy that made children under 12 wait for pediatric lungs to become available, or be offered lungs donated by adults after adolescents and adults on the waiting list had been considered.
"We are beyond thrilled," Janet Murnaghan, the girl's mother, told The Associated Press on Wednesday. "Obviously we still need a match."
The ruling applied only to Sarah, who has end-stage cystic fibrosis and has been awaiting a transplant at the Children's Hospital of Philadelphia. An expert has questioned the decision on medical and ethical grounds.
Lung transplants are the most difficult of organ transplants, and children fare worse than adults, which is one reason for the existing policy, said Dr. Arthur Caplan, a bioethicist at New York University Langone Medical Center.
He called it troubling, and perhaps precedent-setting, for a judge to overrule that medical judgment, and predicted a run to the courthouse by patients who don't like their place on the waiting list.
"I'm not sure I want judges or congressmen or bureaucrats trying to decide what to do with organs at the bedside," Caplan said.
Sarah's family, who live Newtown Square in suburban Philadelphia, filed suit Wednesday. The Murnaghans say pediatric lungs are rarely donated, so they believe older children should have equal access to adult donations.
Baylson suspended the age limit in the nation's transplant rules for 10 days for Sarah, who has been at the Philadelphia hospital for three months. A June 14 hearing on the request has been scheduled for a broader injunction.
Nationwide, about 1,700 people are on the waiting list for a lung transplant, including 31 children under age 11, according to the Organ Procurement and Transplantation Network.
Sebelius had declined to become involved in the case earlier this week, despite urgent pleas from several Pennsylvania congressmen.
Sebelius said there were three other children at Children's Hospital alone in the same condition as Sarah. She has called for a review of pediatric transplant policies amid the higher death rates for pediatric patients, but the Murnaghans say Sarah doesn't have time for that.
Sarah's doctors, one of whom testified Wednesday at an emergency hearing before Baylson, believe they can perform a successful transplant on her with adult lungs.
"She definitely understands things have improved quite a bit," the girl's aunt, Sharon Ruddock, said after the ruling.
The Murnaghans' attorney, Steve Harvey, said a committee of the organization that sets transplants policy may meet next week and he hoped it would change the policy.
"I hope that they decide to discontinue it completely for children under 12. I won't be satisfied until Sarah Murnaghan receives a set of lungs," he said. "The risk of her dying until she gets those lungs is high."
Joel Newman, spokesman for the United Network for Organ Sharing that operates the nation's transplant network, said he was unaware of any previous court order that overruled a transplant policy.
While many more adult lungs than children's lungs wind up being donated, the ruling doesn't guarantee Sarah a new set of lungs. The matches are based on blood type, the risk of dying, the chance of surviving a transplant and other medical factors. The donor lungs would also have to be an appropriate size for her chest.
Newman said some lungs donated from deceased adults have been offered for children's transplants over the past two years, although he couldn't give a number. But he said all were turned down by the children's surgeons.
The UNOS system was established to avoid bias in determining who gets organs, thus ensuring that the rich or celebrities, for example, don't have a better chance, Caplan noted. He said it is transparent, with policies open to public comment and scrutiny before they're enacted.
"When a judge steps in and says, 'I don't like these rules, I think they're arbitrary,' they better be very arbitrary or he's undermining the authority of the whole system. Why wouldn't anybody sue?"