Little Jack Hayes has had more than his fair share of hospital visits.

Born with one small lung, one enlarged lung and “floppy” airways, his start in life was spent inside the walls of the Royal Children’s Hospital.

But watching him now, aged 4 ½, mum Elanor Hayes bursts with pride.

She will never forget how the doctors, surgeons and staff at the hospital refused to give up on her son — the son who can now ride up to 7km on his bike.

“The amount of times that we thought he was going to die or be really severely disabled … things were really touch and go for him,” Hayes says.

“(But) they were always willing to give something else a try.”

When Jack was less than a year old, a team of innovative surgeons used a 3D printer to design a makeshift stent which would “hold open” his airways.

But because Jack’s body was still developing, the stent had to be dissolvable so it wouldn’t get stuck in his airways.

“There were a few complications,” Hayes says.

“They had to give him transplant medication to try and reduce the amount of (tissue) scarring.

“Which was good but it meant he had no immune system for quite a long time.”

And about six months later, at just 14 months old, doctors made the decision to put his tiny body in an induced coma to help heal the airways and reduce any swelling and further scarring.

“But what they did during that time was they held their ground and waited and let his airways settle down.

“He’s had his challenges since then but he’s amazing. He climbs, he runs, he does everything any other 4-year-old would do.

“He’s a really happy, normal, little kid and we’re really proud of him.”