WHAT IS ECMO and ECPR?
Extracorporeal membrane oxygenation (ECMO) is a means of cardiopulmonary support for respiratory and circulatory failure. ECMO support therapy can be applied in cases where the lungs cannot provide enough oxygen to the body under oxygen therapy, the lungs cannot get rid of the carbon dioxide load even with the help of a mechanical ventilator, the heart cannot pump enough blood to the body, or in patients awaiting heart-lung organ transplantation. The ECMO device is designed as smaller, closed and portable compared to standard cardiopulmonary bypass systems and has specially designed cannulas. The ECMO device is connected to the patient with these cannulas. Cannulas are inserted into large veins or arteries in the leg, neck, or chest, a process called cannulation. The ECMO machine pumps the blood in the patient's body to an artificial lung (oxygenator) that oxygenates and removes carbon dioxide, then returns the blood to the patient through a pump of the same strength as the heart. There are two main types of ECMO. These are veno-venous (VV) and veno-arterial (VA) ECMO. While veno-venous ECMO is mostly used to correct hypoxia and hypercarbia, veno-arterial ECMO provides circulation and cardiac support in addition to oxygenation.
Extracorporeal life support was first developed by John Gibbon in the 1950s. In several reports published in the late 1970s, ECMO over the conventional bypass method was found to be successful for the treatment of cardiopulmonary failure outside the operating room (1,2). ECMO practices and studies entered a stagnant period in the 80s and 90s, when a high mortality rate was reported as a result of a randomized controlled study in patients with acute respiratory failure syndrome (ARDS), published in 1979. In a randomized trial (CESAR) comparing conventional ventilation with ECMO in patients with severe ARDS, and during the H1N1 pandemic, survival rates were shown to increase in patients with ARDS supported by ECMO (3,4). Recently, studies on ECMO, which have been increasing gradually, have started to reveal ECMO indications, contraindications, how patient selection should be made, and how the procedure should be performed with clearer boundaries. However, studies in which ECMO was applied to well-selected patients showed significant differences in its effect on survival.
Acute respiratory failure syndrome, post cardiac arrest, weaning from cardiopulmonary bypass after cardiac surgery, reversible acute respiratory failure, cardiogenic shock, resistant hypotension, pneumonia, acute myocarditis, bridge in heart transplantation, failed lung transplant graft, trauma, resistant arrhythmias, pulmonary embolism, pulmonary hypertension, poisonings VV or VA are clinical indications for ECMO (5).
Extracorporeal cardiopulmonary resuscitation (ECPR) is the application of ECMO in patients in whom conventional cardiopulmonary resuscitation (CCPR) is insufficient and continuous spontaneous circulation does not return during post cardiac arrest, which is one of the ECMO indications. The purpose of ECPR is to provide time to reach the root of the problem and solution in the cardiac arrest patient. With ECPR, circulation and gas exchange continue, so the perfusion of the organs is tried to be preserved. During this period, necessary diagnostic procedures and treatment procedures such as percutaneous coronary intervention, pulmonary thrombectomy, toxin clearance are performed for the root of the problem.
Timing is important in extracorporeal cardiopulmonary resuscitation and it is an intervention that should be performed with a team of well-trained and experienced healthcare professionals. ECPR can be applied in-hospital cardiac arrests as well as out-of-hospital cardiac arrests. However, since the ECMO procedure is a complex procedure and there is no definitive data comparing the ECPR application at the scene with the post-transfer ECPR application in the out-of-hospital cardiac arrest patient, it is recommended that the out-of-hospital ECPR application be performed by highly specialized teams. Extracorporeal cardiopulmonary resuscitation has a time-consuming process in preparation and organization. For this reason, in patients whose spontaneous circulation does not return continuously with 10-15 minutes of conventional cardiopulmonary resuscitation, the decision and action phase for ECPR should be started. The importance of time to ECMO is associated with neurological outcomes (6,7).
In observational studies comparing extracorporeal cardiopulmonary resuscitation with patients who have undergone traditional cardiopulmonary resuscitation in the past, survival is within a range of 15-50% and favorable (8,9). The International Extracorporeal Life Support Organization (ELSO) has been collecting data on clinical use and outcomes of extracorporeal life support devices since 1989. According to these data, ECPR practice increased more than ten times between 2003 and 2014, and the survival rate after ECPR was 29% until discharge (10). To date, no large prospective randomized controlled trial has been published comparing extracorporeal cardiopulmonary resuscitation with conventional cardiopulmonary resuscitation.
Extracorporeal life support and extracorporeal cardiopulmonary resuscitation are becoming an important tools in cardiac critical care and cardiac intervention in the world. Studies to date have shown that better survival and neurologic outcome can be expected in in-hospital cardiac arrest cases ECPR compared to CCPR. In our country, due to the complexity of the extracorporeal cardiopulmonary resuscitation procedure, it causes reservations for emergency physicians at the point of application. Better understanding and practice are needed to expand the use of extracorporeal life support devices. Therefore, we think that the use of extracorporeal cardiopulmonary resuscitation in emergency services will become widespread by organizing trainings for emergency physicians.
Assoc. Prof. Dr. Sema CAN
Assistant Dr. Eda YAMAN
References
1. Hill JD, O'Brien TG, Murray JJ, Dontigny L, Bramson ML, Osborn JJ, et al. Prolonged extracorporeal oxygenation for acute post-traumatic respiratory failure (shock-lung syndrome). Use of the Bramson membrane lung. N Engl J Med. 1972;286(12):629–34. doi: 10.1056/NEJM197203232861204.
2. Bartlett RH, Gazzaniga AB, Fong SW, Jefferies MR, Roohk HV, Haiduc N. Extracorporeal membrane oxygenator support for cardiopulmonary failure. Experience in 28 cases. J Thorac Cardiovasc Surg. 1977;73(3):375–86.
3. Peek GJ, Mugford M, Tiruvoipati R, Wilson A, Allen E, Thalanany MM, et al. Efficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicentre randomised controlled trial. Lancet 2009;374:1351-63.
4. Brogan TV, Thiagarajan RR, Rycus PT, Bartlett RH, Bratton SL. Extracorporeal membrane oxygenation in adults with severe respiratory failure: a multi-center database. Intensive Care Med 2009;35:2105-14.
5. Richardson Alexander (Sacha) C, Tonna Joseph E, Nanjayya Vinodh, Nixon Paul, Abrams Darryl C, Raman Lakshimi, et al. Extracorporeal Cardiopulmonary Resuscitation in Adults. Interim Guideline Consensus Statement From the Extracorporeal Life Support Organization, ASAIO Journal: March 2021- Volume 67- Issue 3- p 221-228. doi: 10.1097/MAT.0000000000001344
6. Bougouin W, Dumas F, Lamhaut L, et al. Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest: A registry study. Eur Heart J. 2020; 41:1961–1971
7. Debaty G, Babaz V, Durand M, et al. Prognostic factors for extracorporeal cardiopulmonary resuscitation recipients following out-of-hospital refractory cardiac arrest. A systematic review and meta-analysis. Resuscitation. 2017; 112:1–10
8. Sakamoto T, Morimura N, Nagao K, et al.; SAVE-J Study Group. Extracorporeal cardiopulmonary resuscitation versus conventional cardiopulmonary resuscitation in adults with out-of-hospital cardiac arrest: A prospective observational study. Resuscitation. 2014; 85:762–768
9. Chen Y-S, Lin J-W, Yu H-Y, et al. Cardiopulmonary resuscitation with assisted extracorporeal life-support versus conventional cardiopulmonary resuscitation in adults with in-hospital cardiac arrest: An observational study and propensity analysis. Lancet. 2008; 372:554–561
10. Richardson AS, Schmidt M, Bailey M, Pellegrino VA, Rycus PT, Pilcher DV. ECMO cardio-pulmonary resuscitation (ECPR), trends in survival from an international multicentre cohort study over 12-years. Resuscitation. 2017; 112:34–40
