EDITORIAL VIEWS 528 APRIL 2019 ANESTHESIOLOGY, V 130 • NO 4 “[Beyond survival]…there are few long-term follow-up data, including functional outcomes, in patients who received extracorporeal membrane oxygenation for [acute respiratory distress syndrome].” Comparing Apples to Oranges? Carol L. Hodgson, Ph.D., F.A.C.P., Daniel Brodie, M.D. E xtracorporeal membrane oxy- genation is a lifesaving inter- vention used for patients with severe forms of the acute respira- tory distress syndrome (ARDS), often when clinicians believe that other less invasive therapies have failed to improve severe hypox- emia. 1,2 While the use of extra- corporeal membrane oxygenation has rapidly increased around the world in recent years, 3,4 the focus has been on survival as the pri- mary outcome of interest. Despite the enthusiasm in the critical care community for studying long- term outcomes after critical illness, there are few long-term follow-up data, including functional out- comes, in patients who received extracorporeal membrane oxygen- ation for ARDS. 5 In this issue, Grasselli et al. report the long-term outcomes of survivors of extracorporeal mem- brane oxygenation at 1 yr after discharge from a single center. 6 Over a 3-yr period they measured patient outcomes, including lung function, 6-min walk distance, and health-related quality of life. They compared the outcomes of 34 patients who received extracorporeal membrane oxygenation for ARDS with 50 non–extra- corporeal membrane oxygenation–treated patients with ARDS. At baseline, there were notable differences between the groups. Extracorporeal membrane oxygenation patients were more severely hypoxemic, with worse respiratory sys- tem compliance, although with fewer major comorbidities. This may be like comparing apples to oranges, as extracor- poreal membrane oxygenation is likely to be considered for use in patients with severe forms of ARDS refractory to other therapies. In addition, major comorbidities are usu- ally exclusion criteria for consideration of extracorporeal membrane oxygenation. Despite the baseline differences between the groups, survival, lung func- tion, chest computed tomography, and 6-min walk distance were reasonably comparable between the groups at 1 yr. Of note, the authors report that lung function was nearly normal at 1 yr, while reporting numerous abnormali- ties, particularly in the chest com- puter tomography in both groups. Nonetheless, patients in both groups appeared to have had a rea- sonable recovery at one year from a pulmonary perspective. Patients who received extra- corporeal membrane oxygenation had better health-related quality of life and lower risk of post- traumatic stress at 1 yr, despite having worse ARDS. This is dif- ferent from previous reports of health-related quality of life after extracorporeal membrane oxy- genation, and clinicians should be cautious interpreting these results. 7 There are several limita- tions to comparing extracorporeal membrane oxygen- ation and non–extracorporeal membrane oxygenation ARDS patients who were not matched at baseline and who were not randomly allocated. First, major comorbid- ities have an effect on the trajectory of recovery. 8 As the non–extracorporeal membrane oxygenation group had significantly more comorbidities at baseline compared with the extracorporeal membrane oxygenation group, it is unsurprising that their quality of life was also lower at 1 yr. Second, there was no baseline measure of health-related quality of life in either group, so it is unclear if the differ- ences at 1 yr reflect baseline differences.This is an ongoing limitation in evaluating outcomes of critically ill patients admitted in an emergency. In such cases, the options to Accepted for publication January 9, 2019. From the Australian and New Zealand Intensive Care Research Centre (ANZIC-RC), Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia (C.L.H.); and the Center for Acute Respiratory Failure, Columbia University College of Physicians and Surgeons/New York-Presbyterian Hospital, New York, New York (D.B.). Copyright © 2019, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. All Rights Reserved. Anesthesiology 2019; 130:528–9 Image: J. P. Rathmell. Corresponding article on page 572. Copyright © 2019, the American Society of Anesthesiologists, Inc. Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/130/4/528/388148/20190400_0-00009.pdf by guest on 27 November 2023