SINGAPORE: "The most difficult part was the decision to let her go. But in the end, we had to let her leave with dignity," Mr Keller Wong said, his voice cracking with emotion.
"Towards the end, you could tell she was very sick. She was on life support. Her face was yellowish, there were blood clots in her brain and red spots were appearing on her body because of internal bleeding."
Tears welled up in the 43-year-old's eyes as he spoke and he paused frequently to gather himself. His wife, a calm, reassuring presence, shook her head gently at him. She flashed me a slight, wry smile.
From the moment she was born, Wong ZiQin had to fight for her life. A normal heart has one major artery allowing blood to flow out from each of its two ventricles on the left and right. But because of a rare congenital abnormality known as Taussig-Bing syndrome, both of these arteries were connected to her right ventricle.
Mr Wong's wife – who only wanted to be known as Mrs Wong – was five months pregnant when they learned of their expected daughter's condition.
Abortion was an option, but they decided to keep their first child, who was conceived through in vitro fertilisation. "We wanted to give her a chance," Mr Wong said.
ZiQin was always weak, according to Mrs Wong. Her lips would turn purplish because of blood circulation issues, and she would get bloated or vomit easily. She couldn't walk.
One night when she was two years old, the toddler had a persistent fever. Thinking it was just the flu, her parents returned home after checking her into KK Women's and Children's Hospital (KKH) for treatment.
Hours later, the hospital called: ZiQin's heart had collapsed and she was in a coma. Doctors performed CPR on her for more than half an hour but she did not come around. Her parents never saw her conscious again.
Even as toxins filled the child's body, her father posted a hopeful message on Facebook. "She is showing positive signs of recovering and fortunately, the blood clots formed in her head is (sic) not found on vital parts of the brain. She tried to move her hands and open her eyes when we talked to her today," he wrote.
"We hope she will recover from this ordeal so she can be transferred onto Berlin Heart machine to buy time for a heart transplant."
The Berlin Heart is an air-driven pump that takes over the work of one or both sides of a child's heart. It is the only long-term ventricular assist device available for infants and smaller children and is usually used as a temporary solution while the patient waits for a donor heart for a transplant.
Doctors told the Wongs the Berlin Heart was not available in Singapore but could be flown in for the procedure. It would take about a week.
The device would buy some time, but also carried a higher threat of causing blood clots the longer the child relied on it while waiting for a donor heart. Singapore does not have a paediatric heart transplant programme and they would have to look overseas for a hospital able to perform the procedure – a process that could take anything from months to a year or longer.
Faced with diminishing options and ZiQin's worsening condition, the couple agonised over what to do. On Jul 8 last year, about two weeks after she fell into a coma, they decided to pull the plug.
"It was harder for my wife because even during the period that ZiQin was in a coma, she had a lot of hope that she would recover," he told me. "Then we had to let her go."
And Mrs Wong started to cry too.
The world's first paediatric heart transplant was performed by an American cardiac surgeon in 1967. The procedure has since been established as a standard of care for infants and children with end-stage heart disease, according to an article by KKH in 2015.
"Singapore with its well-equipped healthcare infrastructure is well-poised to develop a paediatric heart transplant programme in order to provide the best possible care to our children with end-stage heart disease who hitherto have limited options for survival and quality of life," KKH said in the article on healthcare group Singapore Health Services' website, adding that public campaigns would be an initial step in creating awareness and promotion of organ donation.
Transplants are available in countries like the US and the UK, but also closer to home: Malaysia, China, India, Japan and Thailand are among the many countries where paediatric heart transplants have been performed.
Although the surgery carries its own risks such as having the new organ rejected by the recipient's body, survival rates for children who undergo heart transplants are encouraging.
A 2014 study by experts from Loma Linda University Health in California found that of 337 paediatric heart transplant patients who underwent the procedure between 1985 and 1998, more than half lived at least 15 years with reasonable cardiac function and quality of life. (The study noted that the average adult survival rate following heart transplantation was 10 years.)
In Singapore, the main barrier to starting a paediatric heart transplant programme is the lack of donor hearts, according to the chairman of the National University Hospital's medical board.
Associate Professor Quek Swee Chye, who also heads the hospital's division of paediatric cardiology, said the size of the heart was roughly the same as the patient's fist.
"For kids, there are different ages and sizes from newborns, infants, to toddlers, children, adolescents. You have to have a heart that is of fairly similar size. That's a major difficulty compared to the adult population."
In countries with a successful paediatric heart transplant programme, there is usually a large population, a considerably bigger donor pool and a "very well-integrated network", according to Dr Quek.
For example, if an accident happens in California or New York, a hospital could issue a nationwide call for help and arrange for an available heart to be sent over from a different state.
Singapore's Human Organ Transplant Act allows doctors to recover the kidneys, liver, heart and corneas from the bodies of all Singaporean citizens and permanent residents of sound mind and above the age of 21 if they die for any reason, unless they opt out.
Children are not covered under the Act, although family members may volunteer to donate a dead child's organs for transplants, education or research under the Medical (Therapy, Education and Research) Act.
Dr Quek pointed out possible ethical dilemmas for doctors when it came to encouraging family members to donate the organs of their dead children for even the transplant programmes that Singapore currently has.
"In the absence of the ability to give consent, the consent is actually applied to them by their parents. Kids are something that are very close to their parents' hearts. If this is your organ, is somebody able to make that decision of giving it away on your behalf?
"It's a very, very tough situation on the ground even for adults. A lot of times when the person's brain dead, and he's gone, then by right we can take his organs. But the reality is that a lot of families would be very emotional – firstly to accept their death and secondly to accept that now we want to take their organs. So what we face on the ground is challenging. It's more than just the law."
"When the Chinese want to scold someone, they say they hope you si wu chuan shi (die without your whole body). They believe you somehow have a better time in the afterlife if you have everything intact," Mr Wong said.
"But actually, that's all rubbish. When you die, your organs turn to ash."
Mr and Mrs Wong want to prevent future donor organs for children from being wasted by forming a group which they plan to call OTM, short for Organ Transplants for Minors, in the next few months.
They already have some volunteers and want to reach out to other parents in the same situation. Their goal: To raise awareness of the need for child-to-child organ transplants and challenge the stigma surrounding organ donation.
More than six months on since ZiQin's death, the pain of her loss is clearly still raw.
"Honestly, I haven't really recovered. I just try to keep myself busy," Mr Wong, who is self-employed, said.
The couple had wanted to start an awareness campaign for some time but put it off as they grappled with grief, they said.
While friends have suggested they look for other parents who have lost their children and set up a support group to work through their feelings, Mr Wong said this was not their priority as they would rather do something constructive to help others.
"We want to save other parents from the heartbreak. We don't want anyone to feel the way that we do," he said.
Follow Melissa Zhu on Twitter: @MelissaZhuCNA