Eden's heart didn't beat for two hours. Here's how doctors brought her back to life.

Eden Carlson was just a month short of her second birthday when she drowned.

In February last year, the little girl got through a series of gates and doors and made her way into the swimming pool while her mother, Kristal Carlson, was in the shower.

When Eden was found, she had been in the cold water for as long as 15 minutes.

She wasn’t breathing and had no pulse.

Carlson began cardio-pulmonary resuscitation immediately. Ten minutes later, the paramedics arrived and continued CPR. Eden was taken to hospital in Arkansas, where medics kept working on her.

For nearly two hours, she had no heartbeat. But after non-stop CPR and 17 epishots, her heart began beating again.

“For two hours, Eden was gone,” her family explained in a video made about her story. “She was not here. She passed away. Thanks to the relentless efforts of all the medical staff, she was brought back to us.”

However, because of the amount of time that had passed, the damage to her brain was severe. An MRI showed she had deep grey matter injury and cerebral atrophy with grey and white matter loss.

As the days and weeks passed in hospital, Eden showed some improvements. She couldn’t speak or walk or respond to commands, and she was constantly squirming and shaking her head. She was in a semi-vegetative state. But she could breathe on her own, make eye contact, smile and make noise. After more than a month, she was released from hospital and her parents were told to “wait and see”.

Carlson and husband Chris found hope in a specialist called Dr Paul Harch, the director of hyperbaric medicine at Louisiana State University.

“The neurologist we are working with is the world’s expert in this field and has not had a patient with Eden’s injury this young, this close to the accident, and as responsive and mobile as Eden,” the family explained in the video. “All very positive things!”

Fifty-five days after Eden’s drowning, Dr Harch began treating her brain with pure oxygen. She became more alert and stopped squirming. She started to regain movement and to speak again. After ten sessions of oxygen therapy in a hyperbaric chamber, Carlson said Eden was “near normal”, apart from some of her movement. After 39 sessions, Eden could speak better than she could before the drowning.

An MRI showed only mild residual injury and almost complete reversal of the grey and white matter atrophy.

“The startling regrowth of tissue in this case occurred because we were able to intervene early in a growing child, before long-term tissue degeneration,” Dr Harch said in a statement.

The Carlsons are enormously grateful for the treatment and for the prayers for their daughter.

“The miracles we have witnessed have been humbling.”