Veno-arterial ECMO (VA ECMO) is a type of life support used for patients whose heart and lungs are failing. It works by taking blood from a large vein, adding oxygen and removing carbon dioxide using an artificial lung (this meaning the ECMO machine itself), and then pumping the blood back into a major artery. This helps both the heart and lungs rest and recover. Similar to VV ECMO, this is done through a series of cannulations, usually in the femoral artery and vein, and the ECMO circuit. 

VA ECMO is different from VV ECMO (veno-venous ECMO), which only supports the lungs. While VV ECMO returns oxygen-rich blood to the veins, VA ECMO sends it directly into the arteries, giving support to the heart as well.

In simple terms, VA ECMO is like a temporary heart-lung machine for people whose heart and lungs can't do their job. It gives doctors time to treat the underlying problem while keeping the body alive and stable.

Cannulation Steps for VA ECMO 

1. Patient Preparation (Usually done in preop for cath lab)

   • The patient is placed under sedation or anesthesia.

   • The skin is cleaned and sterile drapes are applied.

   • Ultrasound and/or fluoroscopy may be used to guide access.

2. Vascular Access

   • Venous cannula is placed (usually in the femoral vein) to drain deoxygenated blood from the body.

   • Arterial cannula is placed (usually in the femoral artery) to return oxygen-rich blood to the body.

   • A small additional catheter (distal perfusion catheter) may be inserted to maintain blood flow to the leg if the femoral artery is used.

3. Heparin Administration

   • Blood-thinning medication (heparin) is given to reduce the risk of clot formation during cannulation and ECMO support. This is usually a drip in the ICU post cannulation to prevent clotting as well. 

4. Cannula Insertion

   • Guidewires are placed into the vessels under imaging guidance.

   • Cannulas are advanced carefully over the guidewires into position.

   • Position is confirmed using imaging (ultrasound, echocardiogram, or X-ray).

5. Connection to ECMO Circuit

   • Cannulas are connected to the ECMO tubing and machine.

   • The ECMO pump is started, and flow is gradually increased to the desired level.

6. Secure Cannulas

   • Cannulas are sutured and secured to the skin to prevent dislodgement.

   • Dressings are applied, and the site is monitored continuously.

7. Monitoring and Adjustments

   • ECMO settings are adjusted based on the patient's needs.

   • Blood pressure, oxygen levels, and heart function are monitored closely.