Letter re: Extracorporeal Membrane Oxygenation: Rescuing the Resuscitative Thoracotomy

I read with great interest the recently published work by Owattanapanich et al ¹ that looked at extracorporeal membrane oxygenation (ECMO) as an adjunctive therapy to a resuscitative thoracotomy (RT). This was a 11-year (2007-2017) retrospective review of the National Trauma Data Bank (NTDB). The study included patients who underwent a RT and excluded those who died within the first hour, had a delay in ECMO initiation, or had missing data. Patients were divided into those who underwent a RT alone or those who had ECMO immediately initiated. The premise was that ECMO may serve as a rescue therapy for traumatically injured patients undergoing a RT. Although the numbers are too small to reach a statistically significant conclusion in terms of mortality, the authors found that there was a higher rate of return of spontaneous circulation (ROSC) in those whose RT was augmented by ECMO.

Extracorporeal membrane oxygenation in traumatically injured patients is not a novel concept and it has been widely used as an adjunct in correctable causes of cardiac and/or respiratory organ failure. In 1972, the first traumatically injured patient was placed on ECMO after being struck by an automobile. ² While ECMO, in the traumatically injured patient has been traditionally reserved for those with acute respiratory distress syndrome (ARDS), with advancements in technology there has been increasing use of venous-arterial ECMO by allowing the circuit to run with little or no anticoagulation. ³ This includes the use of extracorporeal life support (ECLS) in the trauma population to augment RT with open cardiac massage. ⁴ With advancements in technology, there needs to be a refinement in patient selection. Addressing this knowledge gap is key, as ECMO is not without expense, both in financial cost and in personal cost.

Although this was an interesting read, it was not without limitations-most notably the patient population selected and the outcomes measured. It is not unsurprising that the immediate ECMO cohort only had 23 patients. However, with a paucity of patients, it is uncertain if the patient populations are comparable. As such, the RT with immediate ECMO cohort had a higher proportion of stab wounds (43.5% vs 16.8%). Typically, those who undergo a RT from a stab wound, have an overall higher rate of survival. Meanwhile, it is interesting to note that the 36.5% was the survival rate in those undergoing RT alone-especially given that 81.1% of the cohort’s mechanism was from a gunshot wound, a motor vehicle collision, or a fall. This is higher than expected given the underline mechanism. Lastly, the authors selected the achievements of ROSC and overall mortality as their primary outcomes. While the patients placed immediately on ECMO were more likely to achieve ROSC, overall mortality rates were similar. Meanwhile, neurological outcomes, such as, the modified Rankin Scale at 3-month, could not be ascertained.

Despite these limitations, Owattanapanich et al ¹ addressed a critically important area of research that may help to increase the use of ECMO in traumatically injured patients. This is a patient population that is potentially salvageable and ECMO may have a survival benefit with further research. Larger studies would address some of the limitations of the authors’ work, as ECMO is not without ramifications, both in cost and in expertise. I appreciate that the authors produced their great work. I applaud both the authors and the American Surgeon for increasing awareness of ECMO as an adjunctive therapy in RT patients. And I hope to see future publications regarding traumatically injured patients being placed on ECMO.