This analysis examines the use of ECMO in major trauma patients enrolled in the TR-DGU as well as factors associated with ECMO support after trauma. Within the major trauma patient cohort, 1.8% received ECMO resulting in a 46.1% survival and discharge rate. In this cohort, age above 65 years, male gender, massive transfusion, chest trauma, sepsis, and coagulopathy were independently associated with an increased likelihood of receiving ECMO support, while the presence of traumatic brain injuries prevented from ECMO support.

Given the typically younger age and lower comorbidity burden observed in trauma patients compared to those with non-traumatic ARDS, survival outcomes following ECMO support are generally considered more favorable in the trauma population. While recent literature cites survival to discharge rates between 65.9% and 69.1% for major trauma patients supported by ECMO, the cohort analyzed exhibited an overall survival to discharge of 46.1% [14, 23]. Unfortunately we cannot report granular data on ECMO initiation and management, making the comparison of our findings to those mentioned earlier challenging.

Specifically looking at age, it is noted that the mean age of our analysis was remarkebly higher than a meta-analysis conducted by Zhang and colleagues (48 years vs. 36 years) [14]. The higher mean age could be explained by the trend in Germany to provide invasive and specialized care for elderly and high-risk patients. This is consistent for the use of ECMO as well as mechanical ventilation, even for patients above 80 years [24, 25]. In our analysis, mortality in ECMO patients was increased in patients under 18 years and older than 69.

In Germany, mortality of veno-venous ECMO (VV-ECMO) patients decreased from 66 to 53% between 2010 and 2016, while the mortality of veno-arterial ECMO (VA-ECMO) patients increased from 58 to 66%. Although the overall mortality in this analysis is higher compared to international trauma ECMO data, mortality for major trauma patients with ECMO support irrespective of the choice of ECMO is lower than the overall mortality among patients treated with ECMO for non-traumatic organ failure in comparable German settings. As the elderly and high-risk patients are captured both in German health claim data and in our dataset, this comparison appears more reasonable. Moreover, functional outcome after ECMO support for trauma-related organ failure indicated by a GOS above 3 is still limited, yet promising refering to ECMO survivors only. Taken together, this emphasizes the potentially beneficial effect of ECMO in trauma related organ failure.

Survival for patients supported by VA-ECMO following trauma is lower compared to those supported by VV-ECMO [14]. Although we cannot report on the ECMO setup based on our data, we observed a hospital mortality of only 22.8% for ECMO patients with respiratory without circulatory failure and 55.9% for patients with circulatory but no respiratory failure. Assuming that VV-ECMO was primarily used for patients with respiratory, but not circulatory failure, ECMO for isolated respiratory failure after trauma might be beneficial.

For both ECMO and non-ECMO patients, the observed mortality was higher than the predicted mortality based on RISC-II – a score designed to predict survival after major trauma based on e.g., type of injury and initial presentation. Although the grade of injury as assessed by the RISC-II might correlate with organ injury, no definitive parameters of organ failure are included in this model. The study population, comprising patients exhibiting respiratory failure, circulatory failure, or a combination thereof, constituted a highly specific cohort, in which the predicted mortality based on RISC-II was likely to be underscored.

In 2022, Weidemann and colleagues demonstrated improved outcomes for patients with trauma-related ARDS when ECMO was started early [16]. Similar findings have been made for COVID-19- and Influenza-related ARDS as well as VA-ECMO related to cardiogenic shock [26,27,28]. With the number of trauma centers with adequate ECMO experience in Germany appearing limited, referral of patients with refractory organ failure to another trauma center may be required. To streamline patient distribution and resource allocation, timely identification of trauma patients with a potential need for ECMO support seems crucial. Evaluation of factors, which have been associated with ECMO use in this cohort, might contribute to a timely identification of such ECMO candidates, therefore contributing to a timely and physiology based decision process. Rigorous monitoring for early onset of respiratory or circulatory failure in conjunction with early consultation or even referral to a regional ECMO center should be considered.

As ECMO requires systemic anticoagulation, its use in patients with significant TBI was often withheld. However, there is evolving evidence for the use of ECMO after TBI. In 2023, Hatfield and colleagues examined outcomes of 108 patients supported by ECMO after trauma which resulted in a hospital mortality rate of 33.9% [29]. They also identified younger age and male gender as risk factors linked to the requirement of ECMO after trauma. However, in Hatfield’s study, patients undergoing ECMO presented with a reduced trauma load and were generally younger (30 vs. 48 years), potentially contributing to improved survival rates. Consistent Hatfield’s findings, Mader et al. recently provided insights into the use of ECMO in TBI based on the TR-DGU [30]. While this study primarily examines patients which overlap with the present investigation, Mader et al. reported a 51% hospital mortality. Among the survivors, 48% were discharged with a GOS > 3. Concurring with Hatfield, Mader and colleagues, utilization of ECMO might be beneficial for organ failure after trauma after careful consideration of inherent risks against potential benefits. Our cohort, in contrast, associated TBI with a decreased probability of ECMO after trauma. With additional research, Mader’s and Hatfield’s results may contribute to more frequent use of ECMO for TBI patients with refractory organ failure, especially as focused anticoagulation while a patient is on ECMO contributes to risk reduction.

ECMO is associated with both bleeding and thrombembolic complications. Among TR-DGU cases, we observed higher rates of thrombembolic events among ECMO patients, however, there was no difference between ECMO survivors and non-survivors. In a cohort of COVID-19 patients supported with ECMO, an increased risk for ICU mortality has only been seen for cases with bleeding, but not for those with thrombembolic complications [31]. Since, timing of any thrombembolic complication in relation to ECMO therapy is not captured in the TR-DGU, we can only speculate about the role of ECMO contributing to higher frequencies of thromboembolic events in organ support patients as well as its impact on mortality. Interestingly, neither thrombembolic nor bleeding complications ranked among the leading causes of death in either group in our analysis.

A major limitation of this analysis is the lack of data on ECMO setup and performance. The TR-DGU was initially established to guarantee benchmarking in trauma care as well as to facilitate nationwide trauma research throughout the continuum of trauma care. Despite duration of mechanical ventilation and critical care management, general transfusion and fluid regimen, detailed insights into critical care and ECMO procedures (e.g., configuration of ECMO, duration of ECMO, anticoagulation, ECMO-associated complications) are not provided in the data set. While thrombembolic complications are mentioned, it remains unclear, if they occurred during ECMO support or independently. Additionally, the study lacked granular detail regarding the onset of organ failure. Consequently, comparing groups with either isolated respiratory or isolated circulatory failure or combined organ failure was not reasonably possible. However, this study compiles a large set of trauma patients with comprehensively collected health care data. As most of the ECMO cases were submitted by a minority of participating trauma centers, we did not adjust for a potential center effect. Additionally, we did not test for or exclude factors from the multivariate analysis due to collinearity, although some factors such as age and pre-injury health condition might be associated. While detailed conclusions on ECMO management in trauma such as anticoagulation regimen or the ideal start of ECMO cannot be drawn from our study, this analysis allows demographic insights and presents factors associated with the use of ECMO in trauma. However, to further evaluate the effect of ECMO on both survival and functional outcome in major trauma patients, larger randomized controlled trials would be favourable.