Dr. Mary Ellen Avery, a pediatrician whose medical discoveries about the underdeveloped lungs of premature babies were credited with saving hundreds of thousands of newborn lives, died Dec. 4. She was 84. (Georgia Litwack/HARVARD MEDICAL LIBRARY IN THE FRANCIS A. COUNTWAY LIBRARY OF MEDICINE)

Mary Ellen Avery, a pediatrician whose groundbreaking research about the underdeveloped lungs of premature babies was credited with saving hundreds of thousands of newborn lives, died Dec. 4. She was 84.

Children’s Hospital Boston, where Dr. Avery was physician in chief from 1974 to 1985, confirmed her death. According to media reports, she died in West Orange, N.J., of complications from Alzheimer’s disease.  She was the first woman to hold the top medical job at the Boston hospital, which is regarded as one of the best pediatric institutions in the country. 

Dr. Avery was a “marquee figure” among women in medicine, said Jessica Sedgwick, an archivist at the Harvard Medical School collection that contains Dr. Avery’s personal papers. More than 50 years ago, Dr. Avery took on and helped solve a medical mystery: the in­trac­table mortality rate among premature babies who struggled to breathe.

In the late 1950s, as a young research fellow at the Harvard School of Public Health, Dr. Avery joined physiologist Jeremiah Mead to study a lung disorder believed to be a leading cause of death among preemies. Before Dr. Avery’s research, the condition was called hyaline membrane disease, taking its name from the glassy, or “hyaline,” film present in the lungs of many premature infants who did not survive. Today it is known as respiratory distress syndrome.

The condition entered the national consciousness in 1963, when first lady Jacqueline Kennedy delivered a baby boy more than five weeks before his due date. Patrick Bouvier Kennedy was diagnosed with hyaline membrane disease and lived two days.

“When medical scientists can solve the mystery of why the membrane forms,” the New York Times reported upon Patrick’s death, “they will have trapped one of the major killers of premature babies.”

During her own previous clinical studies at hospitals, Dr. Avery had watched babies succumb to breathing difficulties. She was spurred to pursue research because of her frustration at not being able to help them.

With Mead, Dr. Avery began examining the lungs of premature babies who did not live more than a few days. She made an unexpected observation: Unlike babies who died for other reasons, apparent victims of hyaline membrane disease had no trace of air in their lungs.

Dr. Avery’s research led her to John Clements, an Army doctor whose study of wartime nerve gases had significantly advanced the study of pulmonology. He showed her a handmade scientific instrument he built to measure surface tension in the lung.

Dr. Avery realized that the concept of surface tension would determine the course of her research. Surface tension, she learned, helps allow lungs to inflate, deflate and reinflate. She further learned that lungs maintain their surface tension with the help of surfactant, a foamy liquid that coats the inside of the organ.

Back at the laboratory, Dr. Avery observed that the underdeveloped lungs of premature babies lacked surfactant. That, she theorized, was why they couldn’t breathe.

In 1959, Dr. Avery and Mead explained their findings in an article published in the American Journal of Diseases of Children. For decades, it went mostly unnoticed, as competing theories about the respiratory ailment continued to circulate. But Dr. Avery persisted, continuing to publish on the topic and standing by her findings.

Over the next two decades, her work “turned the understanding of hyaline membrane disease on its head,” according to an article published by the Federation of American Societies for Experimental Biology.

Ventilators were altered to better aid babies suffering from respiratory distress syndrome. Steroid therapies were developed to quicken the lung development of fetuses at high risk for premature birth. In the late 1970s and early ’80s, building on Dr. Avery’s work, Japanese pediatricians began successfully treating premature babies with replacement surfactants.

Today, the mortality rate from respiratory distress syndrome stands at around 800 per year in the United States, down from 10,000 per year in 1970. In 1991, President George H.W. Bush awarded Dr. Avery the National Medal of Science for her work.

Mary Ellen Avery was born May 6, 1927, in Camden, N.J. Her neighbor, a female pediatrician, encouraged Dr. Avery to pursue medicine and took her to see a premature baby. Dr. Avery said that the experience left a “lasting impression.”

She received a bachelor’s degree in chemistry from Wheaton College in Norton, Mass., in 1948 and earned a medical degree from Johns Hopkins University in Baltimore in 1952.

After finishing medical school, Dr. Avery overcame a bout of tuberculosis. The experience helped crystallize her interest in the lung.

During her career, Dr. Avery was chair of the the pediatrics department at McGill University in Montreal and physician in chief of the Montreal Children’s Hospital. In 2003, she served as president of the American Association for the Advancement of Science.

She had no immediate survivors. Of her patients, she said that she found herself most at ease with the youngest ones.