A two-year-old boy has made medical history by becoming the world's youngest person to receive an artificial lung.

Owen Stark seemed a happy and healthy toddler until his collapse during a shopping trip near his home in Missouri, US.

Paramedics struggled to keep the infant alive when his heart ceased beating while he was being rushed to hospital by air ambulance, the Daily Mail reported.

Stark suffered from Pulmonary Artery Hypertension, which shuts down the heart and lungs rapidly. Although common among pensioners, it is rare in children, affecting just one in 100,000.

The infant needed a lung transplant urgently to save his life and was put on a heart-lung bypass machine as the search for a donor began.

More than two weeks on the machine could cause irreversible damage. So doctors at the St. Louis Children's Hospital took Stark off the machine and fitted him with NovaLungs LA, a German-built artificial lung.

The device, placed outside the body, works by stimulating a person's own lungs to take in more oxygen and expel carbon dioxide.

Owen's father Justin, 32, said: 'It's without doubt the worst experience I have ever been through and could ever imagine going through. We thought we were going to lose him for good.'

Doctors predict the toddler, who has now been taken off the transplant list, should live a long and happy life.

Owen's mother Tonya, 29, said: 'His life expectancy has gone from a few days to a few weeks and now years. It's a miracle.'

Mark Grady, a paediatric cardiologist at St. Louis Hospital, said Owen had made a miraculous recovery despite being given little chance of survival without a transplant.

'Now he could be going home within a month which we never ever thought would be possible,' Grady said.

'This potentially opens the way for younger patients and even newborns everywhere to be fitted with artificial lungs,' he added.