Extracorporeal cardiopulmonary resuscitation

Extracorporeal cardiopulmonary resuscitation (commonly known as ECPR) is a method of cardiopulmonary resuscitation (CPR) that passes the patient's blood through a machine in a process to oxygenate the blood supply. A portable extracorporeal membrane oxygenation (ECMO) device is used as an adjunct to standard CPR. A patient who is deemed to be in cardiac arrest refractory to CPR has percutaneous catheters inserted into the femoral vein and artery. Theoretically, the application of ECPR allows for the return of cerebral perfusion in a more sustainable manner than with external compressions alone. By attaching an ECMO device to a person who has acutely undergone cardiovascular collapse, practitioners can maintain end-organ perfusion whilst assessing the potential reversal of causal pathology, with the goal of improving longterm survival and neurological outcomes. Similar to the concept of elective cardiopulmonary bypass, used in open heart surgery, oxygenation and perfusion can be maintained with an ECMO device in patients undergoing cardiovascular collapse. In the setting of cardiac arrest, ECPR involves percutaneous cannulation of a femoral vein and artery, followed by the activation of the device, which subsequently maintains circulation until an appropriate recovery is made. The theory behind this invasive approach is that the artificial restoration of oxygenation and end-organ perfusion allows treating physicians more time to mitigate and reverse pathology which contributes to cardiac arrest and refractory shock. It has been well documented that the likelihood of return of spontaneous circulation and furthermore eventual discharge from hospital, after ten minutes of CPR falls significantly. Once circulation is established, the patient is able to be transferred, for further investigation and intervention, to facilities such as a cardiac cath lab and an intensive care unit. Extracorporeal life support (ECLS) systems differ to traditional, theatre based, cardiac bypass machines in that they are portable and utilise percutaneous access as opposed to catheters which are surgically inserted into an open chest. The first access enters the femoral vein at the groin and is extended superiorly to the right atrium. The second line enters the ipsilateral or contralateral femoral artery and advanced to the distal aorta. Deoxygenated blood is removed from the right atrium prior to being pumped through the ECLS device where it is oxygenated and returned as retrograde flow to the distal aorta.