[1][2] 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 long-term 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.
[citation needed] 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.
[citation needed] Extracorporeal life support (ECLS) systems differ from 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.
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.
This is based on the assertion that the rapid application of ECPR can temporarily support patients with cardiovascular collapse, whilst permitting an assessment of potential options to maximise long-term survival.
The guidelines qualify this by advising that the patient should have had only a brief period without blood flow and that the condition resulting in the arrest be amenable to reversal i.e. hypothermia, intoxication or acute coronary insufficiency.
The risk associated with the initial process of connecting a patient to an extracorporeal life support device is potentially exacerbated by the emergent nature of ECMO CPR.
[15][16][17][18] The complications included: The following protocol is an example of the site specific regime used as the basis of the CHEER trial[19] based at the Alfred Hospital (Melbourne, Victoria).
Patients are also reviewed for the presence of contraindication such as pre-existing neurological impairment or significant limitation in ability to undertake activities of daily living.
[19] Once the patient is stabilised on the ECMO circuit, they are transferred for further management of causal pathology, for example to the cardiac catheterisation laboratory for coronary angiogram or to radiology for thrombectomy.
[27] When it comes to the consideration of the withdrawal of ECMO, unlike in adult populations parents are encouraged to make the final decision with guidance from the treating physicians.