For patients grappling with severe respiratory or cardiac failure, Extracorporeal Membrane Oxygenation (ECMO) offers a lifeline that was once only a dream. The capability of ECMO to temporarily assume control of both the heart and lungs is a medical marvel that has transformed the landscape of critical care. Before ECMO’s existence, thousands of patients died who would have a fighting chance today. Yet, despite its growing usage and adoption, understanding this remarkable technology can be a challenge.

How was ECMO developed?

In the mid-1900s, physicians realized there was a pressing need to find a way to temporarily divert blood flow from the heart and lungs in order to be able to operate effectively on the heart. Indeed, operations like heart valve repair and congenital defect correction were impossible without this technology. As a result, researchers started to experiment with cardiopulmonary bypass (CPB), which, precisely as the name implies, is a way to temporarily bypass the heart and lungs in order to facilitate complex surgery. In the 1950s, the first patient was successfully put on CPB for open-heart surgery, heralding a transformative breakthrough for cardiac procedures. Surgeons could now assume the job of the heart and lungs and reroute blood away from the heart to conduct vital repairs without apprehension for the well-being of the patient’s entire circulatory system.

Over time, medical professionals realized that CPB held potential beyond the realm of surgery, capable of helping many patients with non-surgical heart or lung conditions. Moreover, they also realized that some patients could benefit from being placed on CPB for longer than just a few hours. So, what initially started as a way to make heart surgery possible evolved into a lifesaving mechanism for patients dealing with conditions such as severe respiratory distress, shock, or heart failure. With modification to the oxygenator, prolonged CPB was possible and became what we now call Extracorporeal Membrane Oxygenation (ECMO).  Being on ECMO allowed the patient’s organs to rest and heal, as well as provided a crucial window for diagnostic investigation and intervention. For respiratory patients, ECMO also prevented lung trauma commonly associated with mechanical ventilation. Thus, ECMO was born—essentially the same technology as CPB but adapted for extended usage.

How does ECMO work?

An ECMO machine can support the heart, lungs, or both, depending on the patient’s condition and the organ that needs support. Essentially, unoxygenated blood is taken from the body and routed through an external machine that removes carbon dioxide, adds oxygen, and then pumps it back into the body. The blood taken from the venous system can be returned to the venous system, leaving the heart to pump normally (termed Veno-Veno ECMO), or the venous blood can be pumped into the arterial system, thereby taking over the work of the heart as well (Veno-Arterial ECMO). 

Indeed, when the acronym for ECMO is broken down, it provides an insightful snapshot of how this therapy works. “Extracorporeal” means ‘outside the body’ and conveys ECMO’s role in functioning as an external heart and lungs. “Membrane” describes the synthetic membrane that removes carbon dioxide and infuses the blood with life-sustaining oxygen. The third component, “Oxygenation,” signifies the core objective—enhancing the blood’s oxygen content to sustain life—a process crucial for patients grappling with severe respiratory or cardiac failure.

In the years since it was first developed, ECMO has been used for conditions like severe acute respiratory distress syndrome (ARDS), cardiogenic shock, and pulmonary embolism. ECMO can be used for several days to several months, although the average is around two to three weeks. ECMO has also proven invaluable for patients awaiting heart or lung transplants, providing a “bridge to transplant” that buys them precious time, a lifeline for those who might have otherwise succumbed while waiting for an organ donor.

How far has ECMO come?

As with any new medical therapy, ECMO encountered its share of early hurdles as researchers and clinicians fine-tuned its techniques and protocols. From refining patient selection criteria to determining the right medications, ECMO has undergone a profound transformation over the years driven by innovative research and clinical trials. A standout example of this evolution is the shift from ECMO patients being sedated and tethered to ventilators to many of them now achieving a level of mobility that was once deemed impossible. In fact, there are awe-inspiring accounts of ECMO patients defying the odds and engaging in physically demanding activities, such as shooting hoops on the hospital basketball court.

Heart and lung issues remain pervasive, and as our understanding of medical conditions deepens, ECMO’s importance continues to grow. With the COVID-19 pandemic, ECMO emerged as an effective therapy for supporting the patient’s lungs as their body battled the virus. Additionally, the outcomes and survival rates for ECMO continue to improve as the technology becomes more advanced and refined. 

ECMO’s journey from a dream to reality is a testament to modern medical innovation. The experiences of ECMO patients have transformed into inspiring tales of resilience and recovery, and its ongoing evolution promises even greater prospects for the future of critical care medicine. Stay tuned for more insights into the future of ECMO in our upcoming blog article, where we’ll delve into the latest advancements and what lies ahead for this life-saving technology.