The hospital length of stay and mortality and its risk and protective factors among patients with acute respiratory distress syndrome receiving extracorporeal membrane oxygenation: a systematic review and meta-analysis

Background: Extracorporeal membrane oxygenation (ECMO) has emerged as an advanced therapeutic option for managing acute respiratory distress syndrome (ARDS), especially severe cases of ARDS. However, the mortality remains high among these patients. Therefore, this meta-analysis aims to evaluate the mortality rates and its potential risk and protective factors in ARDS patients receiving ECMO support.

Methods: We systematically searched databases including PubMed, the Cochrane Library, Embase, and Web of Science for relevant studies from their respective inception to April 27, 2024. STATA 16 was used for data analysis. The quality of the included studies was assessed by the Newcastle-Ottawa Scale (NOS).

Results: A total of 70 studies involving 31,666 ARDS patients were included. The overall mortality was 48% in ARDS patients receiving ECMO support, especially high in coronavirus disease 2019 (COVID-19) related ARDS patients (60%), and the average hospital length of stay (LOS) of survivors [standardized mean difference (SMD) =0.84, 95% CI: 0.30–1.38] was significantly longer than non-survivors. Moreover, the results showed that age [odds ratio (OR) =1.02, 95% confidence interval (CI): 1.01–1.03], body mass index (BMI) [hazard ratio (HR) =0.96, 95% CI: 0.9–0.98], Sequential Organ Failure Assessment (SOFA) score (OR =1.05, 95% CI: 1.02–1.08), ECMO driving pressure (OR =1.07, 95% CI: 1.05–1.10), immunocompromised status (OR =1.07, 95% CI: 1.05–1.09), and total respiratory rate from days 1 to 3 on ECMO (OR =1.04, 95% CI: 1.01–1.08) were all significant predictors for mortality.

Conclusions: The current meta-analysis provides valuable insights into the intricate factors influencing mortality rate in ARDS patients on ECMO. The influencing factors for mortality should be further explored in the future, which may help reduce the global burden of ARDS.

Keywords: Extracorporeal membrane oxygenation (ECMO); acute respiratory distress syndrome (ARDS); mortality; risk factors; meta-analysis

 

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Key findings

• This meta-analysis reports a mortality rate of 48% among acute respiratory distress syndrome (ARDS) patients supported by extracorporeal membrane oxygenation (ECMO) and elucidates key factors influencing outcomes, including patient age, body mass index (BMI), Sequential Organ Failure Assessment (SOFA) score, driving pressure, immunocompromised status, and total respiratory rate during the first three days of ECMO support. It represents the first comprehensive meta-analysis to evaluate mortality in ARDS patients on ECMO while accounting for diverse ARDS etiologies (e.g., coronavirus disease 2019, pneumonia, trauma) and variations in ECMO implementation and management protocols across institutions.

What is known and what is new?

• ECMO has been a well-established strategy for supporting ARDS patients and the mortality rate among ARDS patients is high.

• This meta-analysis identifies key modifiable and non-modifiable predictors of mortality in ARDS patients supported by ECMO—including age, BMI, SOFA score, and treatment parameters such as driving pressure and early respiratory mechanics—while highlighting institutional variability in ECMO management.

What is the implication, and what should change now?

• By synthesizing data from heterogeneous patient populations and clinical practices, this study enhances understanding of prognostic determinants and underscores the need for standardized ECMO guidelines tailored to specific ARDS subgroups.


Cite this article as: Zhang J, Pan J, Lu X. The hospital length of stay and mortality and its risk and protective factors among patients with acute respiratory distress syndrome receiving extracorporeal membrane oxygenation: a systematic review and meta-analysis. J Thorac Dis 2025;17(10):7896-7914. doi: 10.21037/jtd-2025-543