Extracorporeal life support provision in COVID-19 patients -An international EuroELSO 2022 update survey

The COVID-19 pandemic overwhelmed healthcare systems globally, with many patients experiencing acute respiratory distress syndrome (ARDS). Extracorporeal life support (ECLS) emerged as a potential bridge to recovery for severely affected individuals. This study aimed to comprehensively understand ECLS usage for both adult and pediatric COVID-19 patients by conducting an international survey. The surge in COVID-19 cases, specifically those developing COVID-19-related ARDS (CARDS), created an unprecedented strain on hospitals and intensive care units worldwide. The severity of CARDS in some patients necessitated the use of ECLS as a life-saving intervention to support respiratory or cardiac function, providing a temporary bridge to facilitate lung recovery. Consequently, the utilization of ECLS increased significantly during the pandemic. This survey sought to enhance our understanding of ECLS implementation in both adult and pediatric populations by providing valuable insights into its application in managing COVID-19 patients.

Several studies have previously investigated the use of ECLS in COVID-19 patients. Prior EuroELSO surveys, such as the one conducted in June 2020, indicated a limited use of ECLS in the early stages of the pandemic due to high resource demands and a lack of understanding of COVID-19 pathophysiology. The Extracorporeal Life Support Organization (ELSO) registry also reported outcomes for a significant number of COVID-19 patients on ECLS, highlighting in-hospital mortality rates. These previous studies formed the basis for comparison with the current survey's findings, allowing for an assessment of the evolving practices and outcomes over time. Specific articles referenced include those from the Lancet, Intensive Care Medicine, Artificial Organs, and the ASAIO Journal, highlighting diverse perspectives on ECLS usage, outcomes, and treatment strategies in the context of the pandemic.

The EuroELSO survey, approved by the Scientific and Steering Committees, was disseminated via various channels, including the organization's website, newsletter, social media, and the 10th EuroELSO Congress in London (May 4th-6th, 2022). Data collection occurred from May 1st to 31st, 2022, using an online platform (SurveyMonkey). The 26-question multiple-choice questionnaire covered various aspects of clinical and organizational practices since December 2019. Questions encompassed geographical location, center characteristics, patient demographics, number of ECLS runs, transport modalities, contraindications, complications, and treatment approaches. Institutional review board review was waived due to anonymity and the lack of individual patient data. Data protection regulations were followed, and results are presented as descriptive statistics. Duplicate responses were merged, and implausible responses were excluded. A total of 69 questionnaires from 62 European and 7 non-European centers were included in the final analysis.

The survey revealed that the majority of COVID-19 patients receiving ECLS support were adults, with respiratory support being the primary indication. A significant proportion (68%) of centers performed 31 or more respiratory ECLS runs since December 2019. While most centers (85.5%) provided both respiratory and cardiac support, respiratory support dominated. Geographical differences in ECLS provision were not observed. Around 67% of retrieval services involved transporting patients on ECLS, while approximately 26% involved retrieval without ECLS followed by cannulation at the referral hospital. The hybrid V-AV ECLS configuration was used in about 23% of cases. Age >65 was frequently considered a relative or absolute contraindication (almost 50% of responders considered it a relative contraindication and nearly 16% considered it an absolute contraindication). Multi-organ failure and prolonged ventilation were also common contraindications. Dexamethasone was widely used as an additive therapy, and therapeutic anticoagulation with heparin was routine. Despite anticoagulation, a higher need for circuit changes due to clotting was observed (63.8% of centers). Practice variability was noted in approaches such as tracheotomy, mobilization, physiotherapy, and awake ECLS. ECLS withdrawal criteria were heterogeneous, with irreversible brain damage being a major factor (92.6% of centers). Pediatric data were limited, reflecting the pandemic's disproportionate impact on adults.

The survey's findings broadly align with existing literature and ELSO guidelines on ECLS indications and contraindications for COVID-19 patients. The increase in ECLS runs compared to previous surveys reflects the growing experience and acceptance of this modality in managing severe COVID-19. The high rate of circuit changes due to clotting highlights the challenges of managing hypercoagulability in COVID-19. The variability in practices regarding physiotherapy, tracheotomy, and awake ECLS suggests a need for further research to optimize these aspects of care. The lack of consistent use of evidence-based treatments warrants further investigation to identify the underlying reasons. The limited pediatric data reflects the pandemic’s heavier impact on adult populations. Long-term outcomes and the impact of long COVID remain uncertain, requiring ongoing research to refine ECLS withdrawal criteria and improve patient outcomes.

This survey highlights the predominantly adult population receiving respiratory ECLS support for COVID-19. Clinical practice broadly aligns with established guidelines; however, the lack of consensus around withdrawal criteria warrants further study, considering the still unknown long-term effects of both the disease and the ECLS treatment itself. Future research should focus on optimizing ECLS protocols, exploring long-term outcomes, and addressing the variability in supportive care practices.

The survey's response rate is unknown as questionnaires were not directly distributed. The data analysis is descriptive and lacks statistical tests to compare across countries or between European and non-European centers. The number of non-European centers is limited, and outcome data were not collected, preventing analysis of survival or ICU discharge rates. Limited pediatric data also restricts the generalizability of findings to this population.