Cardiac Tamponade

Definition

Intrathoracic bleeding resulting in cardiac compression with potentially severely reduced ECMO circuit blood flow secondary to access insufficiency that is not explained otherwise.

Effects

There will be loss of arterial pulsatility and potentially access insufficiency. The mean arterial pressure will commonly fall and CVP may rise.

Causes

Postoperative bleeding following cardiac surgery (generally within the first 24 hours) is the most common cause.

Diagnosis

Recognition of cardiac tamponade may be impaired, due to a running circuit and blood delivery via the ECMO circuit may in fact not be impaired. Access insufficiency is NOT reliably demonstrated partly because the main drainage holes are commonly extracardiac (e.g. in the IVC).

TOE/TTE may demonstrate cardiac compression. It is important to note that all the classic echocardiographic features of tamponade may not be present. There may be regional compression of a cardiac chamber which can cause tamponade physiology in these patients which TTE might miss. Hence, TOE should be considered if clinical suspicion is high in these patients.

Example of cardiac tamponade in VA ECMO with substantial RV collapse. This patient though remained supported by the ECMO circuit without access insufficiency.

Response

• Manage the access insufficiency and reduce ECMO speed setting (RPM) till access insufficiency settles
• Call for help – ICU consultant, ECMO consultant and ECLS coordinator (in hours)
• Contact cardiothoracic surgeon and registrar
• In postoperative patients, a resternotomy should be performed before blood pressure and circuit flow become critical in ICU