Aug. 7, 2013 -- Patrick Bouvier Kennedy, born premature, died after 39 hours of life on Aug. 7, 1963, three months before his father, President John F. Kennedy, was assassinated in Dallas.

Though the baby was a healthy weight, he developed what was known then as hyaline membrane disease, a condition that killed about 25,000 children a year. At the time, the first family had Caroline, 5, and John Jr., 2, but Jacqueline Kennedy had previously had a miscarriage and a stillborn daughter.

The death of the presidential baby a half a century ago today was a critical event, according to historians, one that sparked medical advances that did for the survival of preemies what Sputnik did for the space race.

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That same year, a Canadian doctor had pioneered the controversial use of a ventilator and saved a similarly sick 34-week-old baby, but American doctors couldn't do the same for the Kennedy baby.

"The president was pretty embarrassed about that," said Dr. Jay Greenspan, chief of pediatrics at Thomas Jefferson Medical College and Nemours/A.I. duPont Hospital for Children, where today about 95 percent of all infants diagnosed with what is now known as respiratory distress syndrome survive.

"We have come a long way," said Greenspan. "It was so tragic that the family went though this -- and you wish you could have been there. It was a simple fix. … The baby was really just slightly premature. He would be sort of an afterthought now in the after-care nursery."

Today, respiratory distress syndrome, or RDS, affects more than 16,000 premature infants in the United States each year, according to the March of Dimes. Babies with the condition have immature lungs that lack the protein surfactant that keeps their small air sacs from collapsing.

But it was the presidential spotlight that would ultimately transform the field, giving birth to neonatology and the modern neonatal intensive care unit, or NICU.

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The Kennedy baby's death put a new focus on diseases of the newborn and resulted in increased funding for research by the National Institutes of Health, according to Dr. Suhas M. Nafday, director of Newborn Services at the Children's Hospital at Montefiore Medical Center in New York.

"This event energized the neonatal researchers into action to look for an effective management of RDS," he said.

Millions of babies worldwide have been saved, largely because of the efforts to improve the first infant ventilators and the discovery of surfactant a decade later.

Patrick was born at Otis Air Force Base on Cape Cod at about 37 weeks, weighing 4 pounds, 10½ ounces, according to a recent account in The New York Times. As the infant's respiratory distress worsened, he was airlifted to Children's Hospital in Boston, where he was put in a hyperbaric chamber, used mostly for burn victims and divers with the bends or decompression sickness. At the time, Children's was using it for "blue babies," infants born with congenital heart defects that starve their bodies of oxygen and cause a bluish coloration of the skin.

"[Hyperbaric chambers] allowed for a higher oxygen content in their blood, but their lungs were collapsing," said Greenspan.

And oxygen carried risks, such as blindness. Pop singer Stevie Wonder, born six weeks premature, developed retinopathy while in an incubator because of excess oxygen. "We have now learned to control that," he said.

One of the doctors to receive a call from Patrick Kennedy's doctors was a young pediatrician from Toronto Children's Hospital, Dr. Maria Delivoria-Papadopoulos, who is today considered the "mother of neonatology."

She had used ventilators on child polio victims in her native Greece, but no one had ever adapted them for babies with respiratory illness.

"I couldn't stand the thought of babies dying," she told ABCNews.com.

"They could do a few breaths, but then they were totally exhausted," said Delivoria-Papadopoulos, who is now in her late 70s and head of neonatology at St. Christopher's Hospital at Drexel Medical Center in Philadelphia.

In 1962, she and another Canadian colleague intubated the babies and used a primitive Bird Mark 8 ventilator. "They still didn't have surfactant, but there was hope," she said. "But all my babies died, no matter how much I ventilated them."

Delivoria-Papadopoulos was about to abandon her research, but in January 1963, seven months before the Kennedy baby was born, she used her ventilator on a 34-week preemie who'd suffered cardio-pulmonary arrest. The girl survived, so she presented the case at the Society for Pediatric Research in New Jersey.

"By time Patrick Bouvier had been born, we already had six survivors, because we had been intervening quicker and not waiting until their death bed," she said.

Children's Hospital doctors wanted the Toronto team to bring the ventilator to Boston, an impossibility, she said.

The second breakthrough came from Children's Hospital itself, but was not implemented until decades later.

Dr. Mary Ellen Avery, the first woman to be appointed Children's Hospital physician in chief, made the crucial discovery that these babies lacked a foaming soap-like coating in their lungs -- surfactant, which develops in the lungs around 34 weeks in utero.

Avery, who died in 2012, published 23 papers from 1959 to 1965 on hyaline membrane disease, a condition marked by a gasping inhale and the inability to breathe out. Hyaline refers to the glassy membrane that was found in the lungs of these infants in autopsies.

"Dr. Avery's discovery is still part of the teaching and training here," said Dr. Lawrence Rhein, director of the Center for Healthy Infant Lung Development at Boston Children's Hospital. "She really revolutionized the treatment.

"People initially thought that these babies were dying because of something extra in their lungs," he said. "Her main concern was that something was deficient."

Surfactant is mostly made up of lipid, as in soap, according to Rhein.

"When a baby is in the mother's womb, the lungs are filled with fluid," he explained. "When they take their first breaths, the fluid is absorbed and the lungs fill with air. When the fluid lining of the lung comes in contact with air, a natural force (surface tension) tends to make the lung sacs collapse. But if you have surfactant, the lipid barrier spreads across the surface of the lung sacs and prevents the lung sacs from collapsing down."

Surfactant was not used to treat RDS until 1980, but by 2002, fewer than 1,000 babies a year died of respiratory distress, and some estimate Avery's discovery saved "literally millions of lives," he said.

Today, doctors can save preemies as young as 23 and 24 weeks with the use of surfactant, ventilators and advanced technology known as continuous positive air pressure.

Such was the case with Dexter Brady, born at a little more than 23 weeks, at the University of Iowa Children's Hospital. Today, at 3, he is short for his age, but he doesn't seem to show any developmental abnormalities.

His mother, Tundi Brady, was expecting twins and said, "everything was completely fine" until at 20 weeks she went into premature labor. When bed rest and medication failed to work, she delivered a girl, Beatrix, one day short of 23 weeks. The baby lived for one minute.

"I was saying goodbye to one baby and waiting for the next to be born and say goodbye," said Brady, 45.

But doctors were able to stop her labor with medication, and Dexter, delivered by Cesarean section, held on for another six critical days. He weighed 507 grams – "about the size of a Beanie baby," said Brady.

Doctors jumped into action, according to Brady.

"Off to the side was the neonatology team, and they scooped him up and put him in an incubator and put a breathing tube down his throat," she said. "After a few minutes the doctor came over and said, 'We got him -- he's been resuscitated.' Then he was off to the NICU."

Dexter's parents were told he had a 40 percent chance of surviving, but his father, a doctor himself, didn't believe what the doctors said.

"Nate had gone to med school and did rotations in the NICU 13 years before Dexter was born. At that time, he had not seen any kid make it that young. … When the doctors told us we'd take home a healthy baby, my husband said, 'I couldn't figure out why they were lying to me.'"

But Dexter thrived after being on life support for two months.

Today, Dexter has caught up with all the normal milestones and is attending preschool. "He can pretty much do what any 3-year-old can do," said his mother.

"In our minds, Dexter's survival sits on the backs of years and years of research, and data and trial and error of babies who didn't make it," said Brady. "He was a long shot, but doctors felt confident they could do it."