Types of Extracorporeal Membrane Oxygenation

Extracorporeal Membrane Oxygenation commonly referred to as ECMO is a life-saving procedure that helps patients suffering from severe lung and heart problems. When traditional treatments are unsuccessful, types of extracorporeal membrane oxygenation acts as an external heart-lung machine that delivers oxygen and nutrients to your body as well as eliminating carbon dioxide permitting the important organs rest, and heal. 

ECMO has revolutionized the intensive care treatment of patients with heart arrest ARDS (Acute Respiratory Distress Syndrome) or those waiting for organ transplants. The kinds of ECMO are based on the condition of the patient, with two main modes – Veno-Arterial (VA) ECMO and Veno-Venous (VV) ECM–and a range of types that are specifically tailored to requirements of the patient.

Why ECMO Is Used in Critical Care

Before exploring the types of extracorporeal membrane oxygenation It is essential to know the reasons behind why ECMO is employed:

• Respiratory failure that is severe (e.g. COVID-19, ARDS, pneumonia complications)
• Cardiac arrest or heart failure
• The bridge to heart or lung transplant
• Support during high-risk cardiac surgery
• Trauma, embolisms or poisoning cases which lead to collapse of the cardiopulmonary system

Let’s look at the most important kinds of ECMO and how they work in various clinical situations.

Veno-Arterial ECMO (VA ECMO)

What Is VA ECMO?

VA ECMO supports both heart and lung function. It takes deoxygenated blood out of the large vein (usually the internal or jugular vein, also known as the femoral) is then passed through an oxygenator, then delivers oxygen-rich blood back to an artery of major importance, most often the subclavian or femoral arterial.

When Is VA ECMO Used?

• Cardiogenic shock
• Heart collapse (as component of ECPR (extracorporeal Cardiopulmonary Reuscitation)
• Myocarditis
• Massive embolisms of the lungs
• Post-cardiotomy assistance

Benefits of VA ECMO

• Complete support for circulation
• Stabilizes critically ill patients in organ failure
• It acts as a bridge to the recovery process or surgical intervention

Veno-Venous ECMO (VV ECMO)

What Is VV ECMO?

VV ECMO provides support exclusively for the lung. The blood is drawn from one large vein, then oxygenated outside of the body, and then returned to a different vein. The heart is still pumping an oxygenated stream of blood around the body.

When Is VV ECMO Used?

• ADS (acute respiratory distress syndrome)
• Severe pneumonia
• COVID-19-related lung failure
• Inhalation of smoke injury
• Lung transplantation support

Benefits of VV ECMO

• Gas exchange is supported when mechanical ventilation is not sufficient.
• Allows lung rest and recovery
• More minimally invasive than VA ECMO

Hybrid ECMO Configurations

In certain medical situations that are complex in some cases, hybrid ECMO techniques are utilized by combining the aspects from both VA as well as VV ECMO. This includes:

Veno-Arteriovenous ECMO (VAV ECMO)

• A mixture with VA VV ECMO and VV ECMO
• Offers respiratory as well as partial support for the heart.
• The blood is returned to the artery and vein
• It is used when patients suffer from trouble with their lung and heart however, they may regain the function of their heart.

Venovenous-Arterial ECMO (VVA ECMO)

• Most commonly for patients whose cardiac function starts to decline in the course of VV ECMO support
• It provides additional oxygenation and circulatory support
• Provides a flexible way to transition when clinical conditions change

Choosing the Right ECMO Type: How Doctors Decide

The selection of ECMO is based on:

• The cause of organ failure is Are you referring to the lungs, the heart, or both?
• The oxygenation and patient stability status
• The diagnosis underpinning and the possibility of reversibility
• Support is needed for a certain amount of time
• Access to experienced ECMO centers and experts in cannulation
  

ECMO Procedure: What to Expect

1. Cannulation: Insertion or insertion of big tube (cannulas) in blood vessels.
2. Circulation: Blood moves by the oxygenator in order to swap gasses
3. Monitoring: Continuous monitoring at the ICU level in heart rate and oxygen levels and the function of organs
4. Weaning: Gradual reduction in ECMO help as the patient gains strength

Risks and Complications

Although ECMO can be life-saving however, it’s not completely safe. Common problems include:

• Infections (due the anticoagulation treatment)
• Infection at cannula sites
• The thromboembolic process (clot formation)
• Failure of mechanical components in ECMO equipment
• Stroke or neurologic injury (rare but very serious)

A close monitoring system and expert assistance within specialized ECMO centers can significantly lower these dangers.

ECMO Outcomes and Recovery

Recovery is contingent on:

• The underlying reason for organ failure is at the root.
• Time frame for ECMO support
• The patient’s age, comorbidities and general health

Patients with ECMO may require further rehabilitation and follow-up. However, survival rates have risen substantially with advances in technology and multidisciplinary medical care.

Conclusion

Extracorporeal Membrane Oxygenation is a highly effective life-saving therapy that is utilized in a variety of demanding situations. Knowing the different types of extracorporeal membrane oxygenation- VA VV and hybrid models can help clinicians and their families make educated decisions in times of medical emergencies. If it’s supporting the lungs, heart or both of them, ECMO provides a second shot for patients with severe illnesses.