At first glance, the manuscript “Extracorporeal Life Support Organization (ELSO) Registry International Report 2022:100,000 Survivors” is simply one more update of the massive ELSO registry by Tonna and 19 colleagues in the ELSO leadership. But no, this is actually a celebration of 45 years of critical care evolution, carefully documented in the American Society of Artificial Internal Organs (ASAIO) society meetings and Journal as each step of extracorporeal membrane oxygenation (ECMO) development unfolded. This report conveniently starts from 2009, which the authors deem the modern era. Probably appropriate, because this timeline is when multiple advances in ECMO technology occurred. But to those who witnessed or participated in the last 45 years of ECMO, this report summarizes the current acceptance of ECMO into the management of the critically ill patient ranging from neonates to adults. The incremental progress from homemade roller pump circuits, guarded by a spring-loaded plunger against a “bladder” to regulate flow, to the portable complete circuits of today has been one incremental risk/benefit field assessment, at a time.

The earliest attempts at ECMO resulted from a painstaking decade of R&D, bench and large animal research orchestrated by Robert (Bob) H. Bartlett.1 Bob’s colleagues included legendary pioneers in the development of ECMO components; Phil Drinker (silicone membrane gas exchange), Alan Gazzaniga (physiology and hematology), J. Donald Hill (adult application), and Ted Kolobow (cannula and oxygenator); all legendary in the archives of ASAIO.2–5 A successful first trauma application prematurely encouraged a disastrous National Institutes of Health (NIH) sponsored adult acute respiratory distress syndrome (ARDS) trial where standard ventilator management and ECMO yielded equally poor outcomes (91% mortality) that almost doomed ECMO at the onset.6,7 Although Robert Bartlett is often credited with inventing ECMO, his true insight was the recognition of neonates struggling for survival from only a single insult, including persistent fetal circulation or meconium aspiration, in the mid 1970s.8 At that time, these newborns were medically managed to restore normal blood gases using contemporary endotracheal ventilation, however, positive pressure ventilation often resulted in worsening gas exchange or pneumothorax with progressive deterioration and death. Placing these delicate patients on veno-arterial ECMO with large bore cannulas in the internal jugular vein for drainage and the common carotid artery for oxygenated blood return allowed “lung rest” with recovery, often within a few days. The courage and dedication of dozens (now thousands) of neonatologists, nurses, residents, respiratory therapists, and administrators who braved the unknown to generate the precious first survivors, gave rise to more centers attempting this new aggressive therapy.

The rest is history starting with the educational seminars in the large animal labs of University of Michigan, to the open gatherings of early adapters who would present case successes and, most importantly, failures to allow colleagues to openly learn and criticize each other in robust debate.9 The landmark first prospective randomized trial to show safety and efficacy in neonates, resulted in groundbreaking “play-the-winner” statistical design that is used even today when the ethics of a negative outcome cannot be justified by a 50/50 randomization.10 To be sure the outcome (11 ECMO survivors versus one conventional management death) was unexpected and controversial, but foreshadowed the outcomes seen in this registry report almost 4 decades later. Several clinical trials, notably the Pearl O’Rourke led “Boston Study,” validated these early findings.11,12 To avoid the feared stroke consequences of carotid artery ligation, the development of two cannula veno-venous (VV) ECMO techniques, then single cannula double lumen VV ECMO soon followed.13 Veno-venous techniques still play a major role in the treatment of severe respiratory failure including children and adults.14 The first ECMO registry report was presented at ASAIO.15 Dedicated yearly Neonatal ECMO meetings (notably at ski resorts) became the focus of several days of detailed multidisciplinary exchange and collegiality. Entry criteria for ECMO were proposed and validated. Then, one day when the snow was too deep to ski, a brainstorming session resulted in the creation of the ELSO collaborative (see figure 1 of manuscript).

As results from multiple centers were faithfully reported at yearly ELSO and ASAIO meetings, ECMO was boldly applied to children and adults with cardiac or respiratory failure with ever increasing frequency, with survival in multiple deteriorating circumstances. Improvements in pumps, oxygenators, cannulas, and surface modifications to decrease the blood surface interactions ensued, explaining the focus of this ELSO report starting from 2009. Management of anticoagulation was, and still is, hotly debated to optimize circuit longevity against clotting yet prevent bleeding complications. Different diseases presented different challenges and opportunities. As the authors describe, H1N1 (swine flu) prompted a sharp increase in the application of VV ECMO in adults, with a notable increase in survival! (see figures 2–5 of manuscript) The British adult randomized controlled trials alerted all critical care physicians to the safety/efficacy and risk/benefit of ECMO as a critical care tool.16,17 Soon thereafter, came the huge increased use of ECMO for acute cardiac support, championed by postheart and lung transplant support and the embracing of acute cardiac support by the interventional cardiologists. Positive results from the cardiac cath lab, as presented at the ASAIO and Cardiology meetings, evolved into routine application for acute events including extracorporeal cardiopulmonary resuscitation (ECPR) (figures 5, 6 of manuscript). Mobile ECMO teams, transport on ECMO, and transfer to major ECMO centers (initially pioneered in neonates) became increasingly common in adults. Then came bridge to transplant (or recovery) for both cardiac and lung transplantation. When the unexpected pandemic coronavirus disease of 2019 (COVID-19) spread rapidly around the globe, hundreds of ECMO centers responded with doubling and tripling the capacity of ECMO to treat patients who failed ventilator management.18 The real challenge as COVID peaked several times was—how do we manage the intensive care unit (ICU) space, personnel, and circuits to maximum advantage? Unfortunately, during COVID, demand exceeded resources and expertise limiting access to ECMO as life-saving treatment.

Read this report carefully, not for the raw survival numbers, but for the advancements necessary to achieve the survivors who otherwise would have languished under optimal medical management of the day. Likewise, large multicenter voluntary registries only capture data in retrospect and do not reflect critical decision-making. I must recall the original ECMO criteria that Bob Bartlett used in the Michigan seminars decades ago “ECMO should be considered for acute, severe, cardiac or pulmonary failure unresponsive to optimal management, with recovery potential in 2–4 weeks, months, or when an acceptable organ is available for transplant.”19 So read this manuscript with the eyes of 45 years of critical care progress created through the crucible of the ASAIO meetings plus Journal, and enjoy.

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