ECMO Explained: How It Supports the Heart and Lungs in Critical Illness

ECMO Explained: How It Supports the Heart and Lungs in Critical Illness
Date posted:  13-08-2025

Have you ever wondered what happens when even the most advanced ventilators can’t keep someone alive? In those rare, life-threatening moments—when the heart or lungs are too weak to do their job—doctors turn to one of the most extraordinary machines in modern medicine: ECMO (Extracorporeal Membrane Oxygenation).

Often described as a “lifeline outside the body,” ECMO can take over the work of these vital organs, giving them a chance to rest and heal. Whether it’s a severe lung infection, a sudden heart failure, or complications after surgery, this advanced technology has saved countless lives. In this blog, we’ll take you behind the scenes to understand how ECMO works, when it’s used, and why it can mean the difference between life and death.

Understanding ECMO 

In extracorporeal membrane oxygenation (ECMO), blood is pumped outside of the body to a heart-lung machine. Unlike a ventilator, which helps move air in and out of the lungs to improve oxygen levels, an ECMO machine works outside the body, circulating blood to add oxygen and remove carbon dioxide.

The machine removes carbon dioxide and sends oxygen-rich blood back to the body. Blood flows from the right side of the heart to the heart-lung machine. It's then rewarmed and sent back to the body. ECMO lets blood go around the heart and lungs. This allows the heart and lungs to rest and heal. ECMO is a form of extracorporeal life support (ECLS). 

It's used for life-threatening heart and lung conditions. 

Some heart conditions in which ECMO may be used include:

  • Complications from a heart transplant

  • Heart attack, also called acute myocardial infarction

  • Heart muscle disease, also called cardiomyopathy

  • Heart that can't pump enough blood, called cardiogenic shock

  • Low body temperature, called hypothermia

  • Sepsis

  • Swelling and irritation of the heart muscle, called myocarditis

 

Some lung conditions in which ECMO may be used include:

  • Acute respiratory distress syndrome (ARDS)

  • Blood clot that blocks and stops blood flow to an artery in the lung, called pulmonary embolism

  • COVID-19

  • Fetus breathing in waste products in the womb, called meconium aspiration

  • Hantavirus pulmonary syndrome

  • High blood pressure in the lungs, called pulmonary hypertension

  • Hole in the muscle between the chest and the belly area, called congenital diaphragmatic hernia

  • Influenza, also called flu

  • Pneumonia.

  • Respiratory failure.

  • Severe allergic reaction called anaphylaxis

  • Trauma

Types of ECMO 

There are two types of ECMO 

1. Venoarterial ECMO (VA ECMO) : Used for heart and lung support. Venoarterial (VA) ECMO provides support for the patient's heart and lungs by allowing most of a patient's blood to move through the circuit without going through the patient's heart. This type of ECMO takes blood out of a large vein and returns it into a large artery, allowing oxygen-rich blood to circulate through the body even if the heart is too weak to pump it. Therefore, two cannulas must be placed in either the neck or the groin(s).

2. Venovenous ECMO (VV ECMO) : Used exclusively for lung support. Venovenous (VV) ECMO provides lung support only, so the patient's heart must still function well enough to meet the body's needs. Two cannulas are placed into veins in spots close to or inside the heart. With VV ECMO, the surgeon cannulating physician has an option of using a special type of cannula with two lumens (pathways inside the tubing). This allows for blood to leave and return to the body in one place, creating the need for only one entry site instead of two. Blood from the ECMO system returns to the body before the heart, and the patient's own heart pumps the blood throughout the body.

Risks and Complications 

Possible risks and complications of ECMO include:

  • Bleeding

  • Blood clots

  • Clotting disorder, called coagulopathy

  • Infection

  • Loss of blood supply in hands, feet or legs, called limb ischemia

  • Seizures

  • Stroke

ECMO at Believers Hospital 

At Believers Church Medical College Hospital in Thiruvalla, Kerala, patients benefit from the region’s first and finest ECMO centre, offering top-tier extracorporeal life support for severe heart and lung conditions. This state-of-the-art ICU—the largest single-unit facility in Central Travancore—features 42 Level 3 beds, 4 isolation rooms, a 7-bed isolation ICU, and a 26-bed High Dependency Unit (HDU) to ensure smooth transitions during recovery. Our multidisciplinary team of consultant intensivists, respiratory therapists, critical care nurses, and specialists provides personalized, 24/7 monitoring and support. Alongside advanced respiratory assistance, the ICU integrates seamless pain and infection control, rapid diagnostics, and compassionate care to deliver life-saving interventions at the highest level of quality. 

Visit the Believers Hospital Critical Care page to explore how our ECMO services can make a difference.

 

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