ECMO, short for extracorporeal membrane oxygenation, is a life-support device that takes over the functions of the heart and lungs. It draws blood out of the patient's body, infuses it with oxygen through an external oxygenator, removes carbon dioxide, and returns the blood to the patient.
In the past, patients whose hearts or lungs had nearly stopped functioning — beyond the reach of ventilators or cardiopulmonary resuscitation — had little chance of survival. The development of ECMO, which applies the principles of the heart-lung machine, has since improved survival odds for patients with severe heart or lung failure and those awaiting transplants.
The device can operate at varying levels of support, from partially assisting a weakened heart or lung to fully replacing their function while a patient waits for a transplant. Because of its intensity, ECMO is reserved for only the most critically ill patients with the lowest chances of survival.
In South Korea, ECMO was domestically developed through research by Seoul National University College of Medicine, Asan Medical Center and the Ministry of Health and Welfare. It was first used in December 2019 on a patient with acute respiratory failure who needed a lung transplant, with the device running for three weeks. The domestic production rate has since reached 70%, and is expected to approach 95% once follow-up research is complete. ECMO gained wider public recognition during the COVID-19 pandemic, when news reports frequently covered its use on critically ill patients. Samsung Group Chairman Lee Kun-hee also received ECMO treatment after suffering a heart attack.
Asan Medical Center said recently that two out of every three adult patients who received ECMO treatment at the hospital successfully recovered spontaneous breathing and circulation. The Seoul hospital has now administered ECMO to more than 3,000 adult patients with severe cardiopulmonary failure, the highest total of any institution in South Korea.
Asan Medical Center performed its first ECMO procedure in 2005 and reached 500 cases by 2012, 1,000 by 2015 and 2,000 by 2021. Last year it surpassed 3,000, setting a national record with a cumulative total of 3,123 procedures. In 2019, the hospital formally established a dedicated ECMO team to strengthen the systematic management of severe cardiopulmonary failure. As a result, the hospital's ECMO weaning success rate stood at 65% as of 2025 — meaning 65 out of every 100 patients on ECMO, or roughly two in three, were able to breathe independently and sustain their own heartbeat, allowing the device to be safely removed.
While a patient is on ECMO, the medical team works to treat the underlying cause of the cardiopulmonary failure. As heart and lung function gradually returns, clinicians incrementally reduce the blood flow and oxygen supply provided by the device to assess whether the patient's organs can sustain themselves. Only when the organs are deemed capable of functioning independently is the device safely removed — a process known as weaning.
Patients who are successfully weaned and complete their recovery can ultimately be discharged in good health. Asan Medical Center's survival-to-discharge rate reached 51% as of 2025, a strong result given that ECMO patients are typically among the most critically ill. That more than half were able to leave the device behind and return home healthy reflects the hospital's high standard of ECMO care.
When a patient's organs cannot recover despite continued treatment, ECMO serves as a "bridge to transplant," keeping the patient alive while they wait for a brain-dead organ donor. Asan Medical Center has posted standout results in this role as well, providing a critical lifeline for severely ill patients awaiting organ transplants.
From 2015 to 2025, 452 cases — 20% of all ECMO procedures at the hospital — were conducted for transplant-waiting patients. The transplant rate among bridge patients reached 72%, and the survival-to-discharge rate among those who received a transplant was 82%.
Breaking down the figures, 186 cases involved cardiac bridge treatment — 164 heart transplants and 22 left ventricular assist device (LVAD) implantations — with a post-transplant survival-to-discharge rate of 82%. Lung transplant bridge treatment was performed in 140 cases, with a post-transplant survival-to-discharge rate of 81%.
The hospital has also successfully established an out-of-hospital transfer system that safely brings critically ill patients from other facilities to Asan Medical Center for treatment. A total of 130 such transfers were carried out between 2015 and 2025. Among transferred patients, the ECMO weaning success rate was 70% and the survival-to-discharge rate was 59%.
Particularly notable, 53 of those transferred patients went on to receive transplants — 29 heart transplants, three LVAD implantations and 21 lung transplants — contributing significantly to improved survival rates for severe cardiopulmonary failure patients nationwide.
Lee Je-hwan, vice president of medical affairs at Asan Medical Center, said the milestone reflected the dedication of the medical staff. "Behind the achievement of performing 3,000 adult ECMO cases for the first time in the country lies the noble commitment of our medical team to save every life possible," he said. "It is the result of the ECMO team and all intensive care unit staff giving their all, every moment, in an ICU that never sleeps."
Kang Pil-je, head of the hospital's ECMO team and a professor of cardiovascular and thoracic surgery, said the team would continue working to help patients with severe cardiopulmonary failure recover spontaneous breathing and circulation through treatment of the underlying cause, and ultimately achieve successful weaning and discharge.
Meanwhile, Asan Medical Center held a symposium Friday at the hospital's auditorium to mark the milestone. The event featured academic presentations and exchanges of the latest findings on topics including left ventricular afterload management during veno-arterial ECMO, outcomes and the future of veno-venous ECMO, post-cardiac surgery ECMO at Asan Medical Center, and the role of perfusionists within the ECMO team.
kty@heraldcorp.com
