Extra Corporeal Membrane Oxygenation (ECMO): The Machine We Love to Hate

Editorial

ECMO is an increasingly used tool in the arsenal of organ support. It still remains a challenge when to start ECMO therapy due to the variably amounts of patients’ cardiovascular reserve. There are many delays to initiate ECMO that continue to haunt the clinicians: How invasive to get? Will organs recover? Will the patient tolerate transfer? Can the patient be anti–coagulated? Are we willing to relinquish control of case to other doctors? All these questions are important, but perseverating on them can delay possible intervention. All of the deliberation can be rounded into five very important considerations that should be considered before embarking on the ECMO pathway. This editorial will try to address each one of these issues.

1. Is my patient sick enough to get ECMO?

2. Will ECMO provide an opportunity to heal so my patient returns to a good quality of life?

3. Logistically can I do ECMO in my center or is the patient transferable to an ECMO site?

4. How and who manages patients on ECMO.

5. How do we stop ECMO once we start (for either better or worse).

There are conflicting reports of the benefits of ECMO, and unfortunately have resulted in ECMO being reserved for the sickest of patients [1,2]. It is very clear that the literature is confounded by selection bias, variable rescue therapies, and a need for well done, NIH sponsored studies [3]. Every study presents different patients, disease etiologies as well as various interpretations of the data [4]. Our clinical experience has been to consider ECMO early. Patients started on ECMO prior to vasopressor and multiorgan failure do better. But even without the vasopressor being considered, patients started on ECMO early did better which is supported by the literature. 2

The ability of the body to recover after severe organ injury, especially ARDS is impressive [5]. Using tools to predict survival have also been attempted but still not comprehensive enough to determine survival with high sensitivity or specificity (poor ROC curve) [6]. Doing pre–hospitalization functional status has been helpful in case by case basis, but unfortunately there are no tools to help the clinicians. Our team excludes patients with chronic, illness that is not amenable to treatments such as advanced malignancy or nonreversible diseases like IPF if transplant is not an option. Reversibility is key. We have had numerous cardiac failures that have been supported by ECMO to recovery. The diagnosis of peripartum, viral, Takotsubo, postoperative, embolic, steroid, and even sepsis induced cardiomyopathy have been successfully treated with ECMO. Historically balloonpumps were used to support these patients, but current literature is suggesting that balloon–pumps may be less effective than previous thought [7]. Although the literature is lagging behind the absolute indications, our institution has embraced the idea of a “trial of ECMO”, in settings were acute organ failure occurs that is caused by reversible etiologies.

In the most recent, randomized control study on ECMO, Peck et al. showed that transfer of critically ill patients to a centralized ECMO site improves outcomes in ARDS patients [8]. The 2009, Australian⁄ New Zealand H₁N₁ experience described by the JAMA paper, supports the idea that early intervention improves outcomes [9]. Although it is an extrapolation to apply improved outcomes in ARDS to respiratory failure from cardiovascular collapse, it is worth some pondering. There are many logistical issues involved in transporting respiratory cases which are acidotic and hypoxic, and planning in advance can minimize the delay and errors that are prone to happen. Although our group has shown that organ recovery can occur on ECMO, we attempt to initiate ECMO prior to multi–organ failure or lactic acidosis [10]. There are simple algorithms to facilitate transfer of these patients into tertiary ICU’s, staffed by Intensivists with an interest and dedication to an ECMO service. The multidisciplinary team of cardiology, pulmonary and ECMO trained Intensivists works best to ensure a successful outcome.

Management strategies are defined by numerous societies around the world. Expert opinion focuses on three major issues [xi]. Reduce barotrauma, minimize a telectatrauma, and avoid hyperinflation. These are very similar recommendations that stemmed from the pivotal ARDS net trial of 2000 [11]. Although the opinion is that minimizing lung strain is ideal, this cannot always be accomplished. Initiating ECMO is a multidisciplinary approach that clinicians, both pulmonary and surgeon must understand; initiation of ECMO emergently can result in more difficult cannulation. A planned procedure with echocardiography or fluoroscopy improves flows by optimizing cannula placement and reduces catheter manipulation. Choice of ventilator settings is large influenced on flows defined by the ECMO circuitry. For example, if a VA ecmo circuit fails to empty the right atrium and ventricle, the ventilator is obliged to oxygenate the non–ecmo blood. If not, shunt physiology occurs. Understanding the heart, lung, ventilator, circuit interaction can only be addressed by dedicated CT surgery Intensivists working in tight collaboration with medical Intensivists.

Even less reported in the literature is how to come off ECMO. As the multidisciplinary team approaches family with the idea of ECMO, the idea of stopping ECMO for futility is also introduced. Families understand that ECMO may be withdrawn for intracranial hemorrhage or refractory shock. Fortunately this rarely happens. Typically Cardiac Ecmo is withdrawn by trials of ecmo wean with echocardiogram confirming improvement of and maintenance of cardiac output with low pump [12,13]. Looking at compliance and radiologic markers are also very helpful in determining wean for respiratory ECMO [14]. Our system is getting better with our increased volumes.

Our ten year experience with ECMO has shown that planning administratively, organizing the network, and bedside communication has improved our effectiveness with ECMO. A multidisciplinary approach ECMO and collaboration improves our preparedness to support theses critically ill patients. ECMO is here to stay, supporting these critically ill patients as the literature defines exact roles.

References

1. Pham T, Combes A, Rozé H, Chevret S, Mercat A, Roch A, et al. “Extracorporeal Membrane Oxygenation for Pandemic Inluenza A(H1N1)- induced Acute Respiratory Distress Syndrome: A Cohort Study and Propensity-matched Analysis.” Am J RespirCrit Care Med. 2013; 187: 276- 285.
2. Beiderlinden M, Eikermann M, Boes T, Breitfeld C, Peters J. Treatment of severe acute respiratory distress syndrome: role of extracorporeal gas exchange. Intensive Care Med. 2006; 32: 1627-1631.
3. Bartlett RH. Extracorporeal life support: history and new directions. ASAIO J. 2005; 51: 487-489.
4. Park PK, Napolitano LM, Bartlett RH. Extracorporeal membrane oxygenation in adult acute respiratory distress syndrome. Crit Care Clin. 2011; 27: 627- 646.
5. Herridge MS. Recovery and long-term outcome in acute respiratory distress syndrome. Crit Care Clin. 2011; 27: 685-704.
6. Schmidt M, Zogheib E, Rozé H, Repesse X, Lebreton G, Luyt CE et al. The PRESERVE mortality risk score and analysis of long-term outcomes after extracorporeal membrane oxygenation for severe acute respiratory distress syndrome. Intensive Care Med. 2013; 39: 1704-1713.
7. Thiele H, Schuler G, Neumann FJ, Hausleiter J, Olbrich HG, Schwarz B, et al. Intraaortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock: design and rationale of the Intraaortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II) trial. Am Heart J. 2012; 163: 938-945.
8. Giles J. Peek, Miranda Mugford, Ravindranath Tiruvoipati, Andrew Wilson, Elizabeth Allen,Mariamma M. Thalanany, Clare L. “Eficacy and economic assessment of conventional ventilatory support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multicenter randomized controlled trial.” Lancet. 2009; 374: 1351-1363.
9. Australia and New Zealand Extracorporeal Membrane Oxygenation (ANZ ECMO) Inluenza Investigators, Davies A, Jones D, Bailey M, Beca J, Bellomo R et al. Extracorporeal Membrane Oxygenation for 2009 Inluenza A (H1N1) Acute Respiratory Distress Syndrome. JAMA. 2009; 302: 1888-1895.
10. Joshua Wong, Vei Shaun Siow, Harrison Pitcher, Matthew V DeCaro, Michael Baram, Hitoshi Hirose, et al. End Organ Recovery and Survival with the QuadroxD Oxygenator in Adults on Extracorporeal Membrane Oxygenation. World Journal of Cardiovascular Surgery (WJCS). 2012; 2: 73-80.
11. Matthieu Schmidt, Vincent Pellegrino, Alain Combes, Carlos Scheinkestel, D Jamie Cooper C. Hodgson.”Mechanical ventilation during extracorporealmembrane oxygenation.”Critical Care.2014 18: 203.
12. [No authors listed] Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network. N Engl J Med. 2000; 342: 1301-1308.
13. Cavarocchi NC, Pitcher HT, Yang Q, Karbowski P, Miessau J, Hastings HM, et al. Weaning of extracorporeal membrane oxygenation using continuous hemodynamic transesophageal echocardiography. J ThoracCardiovasc Surg. 2013; 146: 1474-1479.
14. Courtney Stull, Michael Baram, Harrison Pitcher, Hitoshi Hirose, Kumar Gaurav, Nicholas Cavarocchi. Predictors of a Successful wean from Extracorporeal Membrane (ECMO) For Acute Respiratory Failure Syndrome (ARDS). Critical care. 2013; 41 PA356-A374.