Sarah Murnaghan's mother wrote on her Facebook page that after a "tough" day on Sunday, Sarah's condition had become more stable on Monday. She said her daughter's doctors believe the infection was caused by "aspirations from her belly," which is the entry of stomach contents into the lungs.
"We have an amazing team of doctors who go above and beyond but also walk this road with us in such a kind and compassionate way," Murnaghan wrote.
Sarah has been at Children's Hospital of Philadelphia for months with end-stage cystic fibrosis, a chronic genetic disorder that causes sticky mucus to build up in the lungs, pancreas and other organs. The girl from Newtown Square, Pa., a Philadelphia suburb, was a top candidate for organs from a child donor but none was available and her parents sued to change a national transplant policy that put her at the bottom of the adult list for patients 12 and older.
A federal judge intervened and the Organ Procurement and Transplantation Network - the private nonprofit group that manages U.S. organ allocation - added Sarah to the adult list.
Sarah's situation has sparked a national debate and raised questions among some health experts and medical ethicists about how organ donation rules are developed and under what circumstances they might be disregarded.
Sarah received an adult set of lungs on June 12 but they failed within hours. She stayed on a ventilator until a new set became available for a second surgery, which occurred June 15.
Her mother said after Sarah's second lung transplant that those lungs were infected with pneumonia but doctors had removed the infected portion before the transplant and the girl's condition was too dire to wait for another set of lungs to become available. That transplant did prove more successful, and Sarah was able to take a few breaths on her own after doctors removed her breathing tube.
She had to be put back on the ventilator because of diaphragm paralysis, which her mother described as a common complication that prevents the lungs from fully expanding. Sarah underwent surgery to repair her diaphragm July 2.
The typical life expectancy for cystic fibrosis patients is 37 years and continues to rise as new medical advances are developed. Lung transplants do not cure the condition but can extend the patient's life.
Children's Hospital officials have declined to comment on Sarah's case.