What’s the Difference Between ECLS and ECMO?

ECLS (Extracorporeal Life Support) and ECMO (Extracorporeal Membrane Oxygenation) are terms often used interchangeably in clinical settings—but they’re not exactly the same. ECMO is the most common form of ECLS, providing temporary heart and lung support through membrane oxygenation. This blog breaks down the history, terminology, and configurations behind both terms, helping clinicians, educators, and program leaders understand how they fit into modern critical care. We also clarify how ECLS/ECMO differs from ECPR and why it matters for training and protocol development.
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What’s the Difference Between ECLS and ECMO?

If you’ve encountered the terms Extracorporeal Life Support (ECLS) and Extracorporeal Membrane Oxygenation (ECMO) in critical care literature or hospital settings, you might wonder whether they refer to different technologies or treatments. While often used interchangeably, ECLS is technically the broader category of extracorporeal support, with ECMO being the most common and well-known form. 

Understanding why both terms exist and how they’re used can help clarify communication in clinical settings and provide insight into this critical care technology.

ECLS vs. ECMO: The Hierarchy

ECLS encompasses various forms of temporary mechanical support that assist or replace the function of failing organs outside the body. ECMO is the most widely used form of ECLS, specifically providing heart and lung support through membrane oxygenation technology.

In clinical practice, the terms are often used interchangeably because ECMO represents the vast majority of ECLS cases. However, ECLS technically includes other extracorporeal therapies such as short and long-term right and left Ventricular Assist Devices (VAD’s) and other specialized support systems.

Why Two Names Exist

The terminology reflects the evolution from general to specific naming conventions. ECLS technology began in laboratory studies in the 1960s, with the first clinical use for heart and lung failure occurring in the 1970s. In the early 1980s, following successful randomized trials in neonates that demonstrated much higher survival rates, the more specific term “ECMO” was coined to describe this specific application of ECLS technology.

Professional and Regional Preferences

Different medical organizations, geographic regions, and clinical specialties have adopted varying terminology preferences:

  • ECMO remains the more commonly used term in clinical practice, medical literature, and patient communication
  • ECLS is often preferred in formal medical societies and research contexts
  • Some institutions use the terms interchangeably, while others maintain consistent preferences

Today, while ECLS remains the technically broader category encompassing various extracorporeal support modalities, ECMO has become so dominant that the two terms are used interchangeably in most clinical settings.

The Technology Behind Both Terms

Regardless of which term is used, the technology can be configured to provide various types of support:

Ventricular Assist Devices (VAD): These devices may be placed percutaneously for short periods of decision/recovery or surgically with direct connection to the ventricle for long term or destination therapy.Typically these devices are used for single organ support support and potentially for single sided ventricular support. 

Respiratory Support (Veno-Venous ECMO): The system provides lung function by removing carbon dioxide from the blood and adding oxygen through the artificial lung (oxygenator), while the patient’s heart continues to pump blood through their body. This is used for severe respiratory failure conditions like ARDS when the lungs cannot adequately oxygenate blood.

Circulatory and Respiratory Support (Veno-Arterial ECMO): The system takes over both heart and lung function, pumping oxygenated blood throughout the body when both cardiac and respiratory function are compromised. This is used for conditions like cardiogenic shock, when both the heart and lungs are failing.

Don’t Confuse ECLS/ECMO with ECPR

While ECLS and ECMO are simply two names for the similar technology, ECPR (Extracorporeal Cardiopulmonary Resuscitation) represents a distinctly different application. ECPR refers to the specific use of ECMO technology during cardiac arrest to provide immediate circulatory and respiratory support while attempting resuscitation. 

Unlike conventional ECMO, which is typically initiated in patients with failing but still functioning hearts or lungs, ECPR is deployed emergently during active CPR when traditional resuscitation efforts are failing. While the underlying technology may be the same, ECPR involves much more urgent deployment, different patient selection criteria, and specialized protocols designed for the unique challenges of cardiac arrest scenarios. 

The Extracorporeal Takeaway

Whether you encounter the term ECLS or ECMO in medical literature, hospital protocols, or clinical discussions, it’s likely you’re reading about ECMO. Although the terms are generally used interchangeably, ECLS represents the broader category of extracorporeal support. The terminology choice generally reflects institutional preference rather than technological differences. 

Overall, what matters most is not which name is used, but ensuring that patients who need this critical therapy have access to experienced teams and robust clinical expertise.

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Does your team know the difference between ECLS and ECMO? Integration Health offers comprehensive ECMO education and continuing education programs to ensure your staff stays current. Contact us to learn more. 

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