Kaylee, her six-week-old baby, had just undergone emergency surgery for congenital heart disease.

Everything was unfamiliar and scary.  

In that moment, her five-year-old son put his arms around her and whispered – 'don't worry Mummy, I will fight all of the monsters'. 

It was the support she needed, but it wasn't something she expected from a five-year-old.

Ms Guest, her husband John and their six other children have been "fighting the monsters" ever since Kaylee was born with Tetralogy of Fallot – a condition where four heart malformations present together. 

Kaylee was also born with Cornelia de Lange syndrome – a rare genetic disorder that affects development in about one in 40,000 people. 

Her wider diagnosis means Kaylee lives with developmental delays, but Ms Guest said her daughter's heart condition had always been at the centre of her care. 

"We found out about her heart condition after she was born and then we flew over to Melbourne. We didn't come home for two months," she said. 

"Hearts are binary things, they are either working or they are not. If they don't, it's pretty major straight away. Kaylee might outlive me, or she might not, and I honestly don't know which one is scarier because she is exceptionally vulnerable."

One of the leading causes of death in children under one, every day eight Australian babies are born with CHD and four lives are lost to the disease. 

Kaylee underwent her first surgery for a cardiac shunt when she was six weeks old, followed by a full repair at six months. 

Now seven, Ms Guest said her daughter was stable, but her condition ongoing. 

"If you imagine a plate broken and then put back together. It is still not 100 per cent. That's how of I think of a full repair surgery," she said.

"Her pulmonary valve, which stops the blood from the lungs going back into the heart, it's only half there. At the moment she is doing great. 

"However, it does mean that when she is a teenager, we are probably going to need to have that valve replaced. You can't predict 100 per cent what is going to happen."

Improvements in surgical outcomes means that more children born with CHD are surviving into adulthood, with about 30,000 Australian adults estimated to be living with the condition. 

However, issues relating to mental health and access to care affecting patients and their families at different stages of life, are only just starting to be understood. 

A national survey conducted by the Congenital Heart Disease Alliance of Australia and New Zealand and HeartKids has highlighted the impact of CHD, based on the personal experiences of people living with or caring for those affected by the condition.

Of the 1709 participants, including 588 adult Australians living with CHD and 1121 carers, more than 70 per cent were found to be living with symptoms of anxiety or depressive thoughts. 

About 40 per cent of respondents said they travelled more than 200 kilometres to access vital cardiac treatment, resulting in significant time away from work and increased expenses. 

The Guest family recently relocated from Mole Creek to West Launceston, in order to be closer to Kaylee's support network. It was also a decision based on finances, with Mr Guest re-purposing his business to better accommodate for Kaylee's needs. 

Ms Guest said post traumatic stress disorder was something the entire family had experienced. 

"All the kids have seen Kaylee go blue. It is like you were sitting on a boat, and then you had a heart kid and you dived over the side into the reef. You know its all around there, but until you have lived it you don't really understand it," she said. 

"Usually you can say 'the monsters aren't under the bed'. But the monsters are under the bed and rather than pretend they're not we say – 'yes, it is possible that Kaylee will get sick again'."

Ms Guest said it was only a question of when Kaylee would require further cardiac surgery. 

"Three weeks after Kaylee's heart surgery, a friend of mine's daughter died. She was three years post-transplant and went into emergency and died on the table. I had to recailbrate what I saw as success," she said.

"I thought living a long life is not what I can go for here, because it is not what I can control.

"What I need to go for is loving her every single minute, completely and fully and supporting her in what she wants to achieve."