Challenges of Brain Death and Apnea Testing in Adult Patients on Extracorporeal Membrane Oxygenation—A Review

EXTRACORPOREAL MEMBRANE oxygenation (ECMO) is a form of extracorporeal life support in which blood is drawn out from the patient via a central vein, passed through a membrane oxygenator where gas exchange occurs, and then returned to the central venous system in venovenous ECMO (VV ECMO) or to the arterial system in venoarterial ECMO (VA ECMO) via a separate return cannula. Venoarterial ECMO has the advantage of providing complete cardiac and respiratory support, whereas VV ECMO only provides respiratory support. Cardiorespiratory support in VA ECMO is dependent on pump speed, composition of the gas mixture, and rate of gas flow through the oxygenator. Extracorporeal membrane oxygenation is used for potentially reversible life-threatening cardiac or respiratory failure for which conventional management strategies have failed or when temporary cardiac support is required. Such situations include hypoxemic or hypercapnic respiratory failure from pneumonias or acute respiratory distress syndrome (ARDS), 1 Davies A. Jones D. Bailey M. et al. Australia and New Zealand Extracorporeal Membrane Oxygenation Influenza InvestigatorsExtracorporeal membrane oxygenation for 2009 influenza A(H1N1) acute respiratory distress syndrome. JAMA. 2009; 302: 1888-1895 Crossref PubMed Scopus (1303) Google Scholar , 2 Peek G.J. Mugford M. Tiruvoipati R. 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: 1351-1363 Abstract Full Text Full Text PDF PubMed Scopus (2391) Google Scholar , 3 Abrams D. Brodie D. Emerging indications for extracorporeal membrane oxygenation in adults with respiratory failure. Ann Am Thorac Soc. 2013; 10: 371-377 Crossref PubMed Scopus (45) Google Scholar , 4 Combes A. Hajage D. Capellier G. et al. Extracorporeal membrane oxygenation for severe acute respiratory distress syndrome. N Engl J Med. 2018; 378: 1965-1975 Crossref PubMed Scopus (1113) Google Scholar cardiogenic shock, 5 Ouweneel D.M. Schotborgh J.V. Limpens J. et al. Extracorporeal life support during cardiac arrest and cardiogenic shock: A systematic review and meta-analysis. Intensive Care Med. 2016; 42: 1922-1934 Crossref PubMed Scopus (306) Google Scholar difficulty weaning off cardiopulmonary bypass owing to low cardiac output syndrome after cardiac surgery, 6 Hsu P.S. Chen J.L. Hong G.J. et al. Extracorporeal membrane oxygenation for refractory cardiogenic shock after cardiac surgery: Predictors of early mortality and outcome from 51 adult patients. Eur J Cardiothorac Surg. 2010; 37: 328-333 PubMed Google Scholar , 7 Lomivorotov V.V. Efremov S.M. Kirov M.Y. et al. Low-cardiac-output syndrome after cardiac surgery. J Cardiothorac Vasc Anesth. 2017; 31: 291-308 Abstract Full Text Full Text PDF PubMed Scopus (155) Google Scholar or as an extracorporeal support for cardiopulmonary resuscitation. 8 Thiagarajan R.R. Brogan T.V. Scheurer M.A. et al. Extracorporeal membrane oxygenation to support cardiopulmonary resuscitation in adults. Ann Thorac Surg. 2009; 87: 778-785 Abstract Full Text Full Text PDF PubMed Scopus (220) Google Scholar , 9 Shin T.G. Choi J.H. Jo I.J. et al. Extracorporeal cardiopulmonary resuscitation in patients with in hospital cardiac arrest: A comparison with conventional cardiopulmonary resuscitation. Crit Care Med. 2011; 39: 1-7 Crossref PubMed Scopus (280) Google Scholar , 10 Stub D. Bernard S. Pellegrino V. et al. Refractory cardiac arrest treated with mechanical CPR, hypothermia, ECMO and early reperfusion (the CHEER trial). Resuscitation. 2015; 86: 88-94 Abstract Full Text Full Text PDF PubMed Scopus (388) Google Scholar , 11 Patel J.K. Schoenfeld E. Parnia S. et al. Venoarterial extracorporeal membrane oxygenation in adults with cardiac arrest. J Intensive Care Med. 2016; 31: 359-368 Crossref PubMed Scopus (5) Google Scholar Although evidence to support the use of ECMO is limited and much debated, its use has increased steadily over the past decade. 12 Karagiannidis C. Brodie D. Strassmann S. et al. Extracorporeal membrane oxygenation: Evolving epidemiology and mortality. Intensive Care Med. 2016; 42: 889-896 Crossref PubMed Scopus (318) Google Scholar