They arrived at the airport at 8:05 am. However, the duty manager refused to let them board the flight, as the check-in had closed.

"If they had helped us, we could have got on the flight," Chen posted on his Sina Weibo account.

However, he received help from another airline, and the doctors boarded a flight to Wuxi at 9:50 am.

At 12:40 pm, about nine hours after the lungs were collected, the doctors finally reached the operating room. Some four hours later, the transplant was completed and the recipient's life was saved.

In 2015, Chen told ThePaper, a news outlet based in Shanghai, that in the first half of that year, at least 300 lung donations were made in China. However, only 60 lung transplants were carried out, as many of the donated organs could not be accepted due to long transfer time.

In view of this situation, the authorities asked Chen for his views on setting up a green channel to facilitate organ transfers. They also carried out related research. On May 6,2016, Chinese authorities set up the Green Channel of Human Organ Transport system, specifying that in the event of flight delays, departure priority will be given to flights transporting donor organs, unless there are unavoidable factors such as weather conditions. "That was epoch-making progress," Chen said.

However, time continues to be a restrictive factor in live organ transfers. Chen said there are some ways to extend the "golden time" and create more favorable conditions for organ donations and transplants.

"Organs can be put into a fluid that closely resembles those in the human body. In addition, they can be placed in a machine to simulate conditions in the human body. In such a situation, the organs can theoretically last for one to two days," he said.

"Meanwhile, a new generation of transfer boxes has been developed. An embedded chip enables doctors to monitor the location of a box and its interior temperature via smartphone. This means we don't have to call doctors accompanying the organ."