The parents of a six-month-old boy who died after being misdiagnosed with gastroenteritis is demanding answers about their son's death, saying his condition was treatable and the death preventable.

Key points: Kyran only correctly diagnosed hours after family initially flagged concerns with staff

Kyran only correctly diagnosed hours after family initially flagged concerns with staff Intussusception is a medical condition common in children under two and normally treatable in early stages

Intussusception is a medical condition common in children under two and normally treatable in early stages Helicopter unavailable and the family then left waiting three hours for ambulance

Dr Toby Greenacre, who treated baby Kyran, has been cautioned after being found guilty of unsatisfactory professional conduct.

A Professional Standards Committee found he lacked attention to detail, communicated poorly with nursing staff, had poor time management and failed to prioritise the clinical needs of his patient.

Kyran's parents Naomi and Grant Day gave evidence at a coronial inquiry on Tuesday about what happened with their son.

It all started on October 19, 2013 — the day they noticed something was wrong with Kyran.

"This is normally a happy baby, always with the biggest smile when he saw anyone, and he just wasn't himself, he just wasn't himself at all," Ms Day told 7.30.

"He would go really pale and in pain and he would throw up."

At 4:00pm that afternoon, the concerned parents took Kyran to Shoalhaven Hospital on the NSW south coast. The initial diagnosis was that Kyran had gastroenteritis.

Both of Kyran's grandmothers, Jane Carratt and Pilar Otero, are registered nurses, and Ms Carratt (Grant's mother) suspected something wasn't right.

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"I went over to the nurse and I said 'do you think it could be intussusception, because he hasn't got all the symptoms of gastro', and she said 'no'," Ms Carratt told 7.30.

"She said the doctor doesn't think so and so I accepted that, at the time I accepted that."

Intussusception is a medical condition which leads to bowel obstruction. It is common in children under two, especially boys, and is a treatable condition.

'What I was confronted with still haunts me'

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Kyran continued to be treated for gastro, but instead of improving he got worse. By the next morning, Ms Day was panic-stricken.

"I was crying, saying there is something seriously wrong," she said.

When Ms Carratt arrived at the hospital she was shocked by her grandson's appearance.

"What I was confronted with still haunts me," she said sobbing.

"His whole head just flopped forward, Naomi was trying to hold him, taking him from one shoulder to the other, and his head flopped forward and I couldn't believe what I was seeing.

"His eyes were glassy and he was not responding to anyone in the room, and I said how long has he been like this?

"And she said, the last 90 minutes we've been trying to get the nurse to get the doctor."

Naomi Day says she feels her son Kyran was taken away from her. ( Supplied )

Ms Otero, Ms Day's mother, also knew something was terribly wrong.

"I burst into tears because this looked like a child who was about to have a respiratory arrest," she told 7.30.

"He looked so very sick, he had dark [circles] under the eyes, he just looked terrible and I knew that he was in big trouble."

Kyran didn't have gastro — his grandmother's diagnosis of intussusception had been correct.

Fourteen hours after it was first suggested, Dr Greenacre agreed.

"He said, yes, I think your baby has got a bowel obstruction and he'll have to go to Sydney for surgery, but there wasn't a sense of urgency," Ms Carratt said.

"It was a treatable condition, but it was an emergency situation.

"The reason it was an emergency situation was because it needed to be corrected ASAP, considering it was 30 hours down the track."

What followed was a series of miscommunications and delays.

With no helicopter available to transfer Kyran to Sydney, an ambulance was booked. But it was three hours before Kyran and his mother were finally on their way.

'Baby please wake up, you need to wake up'

In the ambulance on the way to Kyran's condition took a turn for the worse.

"I turned to look at Kyran and I noticed that he had started to go blue in the face and his eyes had rolled in the back of his head," she said.

"And I started yelling at the paramedic, saying something is seriously wrong with Kyran.

"They put a mask over him and the sirens went on."

Instead of heading to Sydney, the ambulance was diverted to Shellharbour Hospital near Wollongong.

Jane Carratt holding her grandson, Kyran, after his birth. ( Supplied )

"I didn't know what was going on and I followed them into the emergency room and they're giving him CPR," Ms Day said.

"He'd had a cardiac arrest in the ambulance."

Kyran was flown by helicopter to the Sydney Children's Hospital in Randwick.

He underwent emergency surgery but never regained consciousness.

"I remember going in and seeing him just laying there and I whispered in his ear and I just said 'baby please wake up, you need to wake up'."

"He was brain dead but he stayed alive ... he kept fighting, and over that period it gave us an opportunity to say goodbye," Mr Day told 7.30.

'I am angry that Kyran was taken away'

Since that day, Kyran's family has been determined to find out what went wrong.

"This was preventable, there has to be a review of the systems and processes to stop this happening again," Ms Carratt said.

"This should never have happened, there were so many moments where his life could have been saved."

The coronial inquiry into Kyran's death is currently underway in Sydney and will hear evidence until the end of next week.

The Day family has since moved from the Shoalhaven area — there are just too many painful memories there.

They have begun a new life on the New South Wales north coast and have another child — a little boy — but they still want answers.

"I am angry. I don't show it a lot but I am angry that Kyran was taken away when he shouldn't have been taken away," Ms Day said.

"We will continue to fight to make sure this doesn't happen to anybody else," Mr Day added.