Understanding Causes of Death in Patients With Acute Respiratory Distress Syndrome: A Narrative Review.

Objectives: To provide a comprehensive summary of the published data on cause of death in patients with acute respiratory distress syndrome (ARDS).

Data Sources: PubMed (January 2015 to April 2024), bibliographies of relevant articles, and ARDS Network and Prevention & Early Treatment of Acute Lung Injury (PETAL) network websites.

Study Selection: Observational studies and clinical trials that reported on cause of death in greater than or equal to 30 patients with ARDS, not obtained from death certificates. Animal studies, case reports, review articles, study protocols, and studies in pediatrics were excluded.

Data Extraction: Causes of death among ARDS patients who died were extracted and tabulated along with other pertinent study characteristics.

Data Synthesis: We identified 15 observational studies (nine non-COVID ARDS, five COVID-related ARDS; one both) and five clinical trials (all non-COVID ARDS). Mutually exclusive prespecified categories were used for recording the cause of death in only eight studies although studies differed in the categories included and their definitions. When multiple organ failure was a predetermined category, it was the most common cause of death recorded (~50% of deaths), followed by respiratory causes with proportions varying from 16% to 42% depending on nomenclature (e.g., refractory hypoxemia, pulmonary causes) and definitions. However, the largest observational study in non-COVID ARDS (964 deaths), did not include multiple organ failure as a predetermined category, and found that pulmonary failure (42%) and cardiac failure (37%) were the most common causes of death. In COVID-related ARDS observational studies, pulmonary reasons were the most reported cause of death (up to 88%).

Conclusions: Few studies have reported cause of death in patients with ARDS. In those that do, cause of death categories and definitions used are heterogeneous. Further research is needed to see whether a more rigorous and unified approach to assigning and reporting cause of death in ARDS would help identify more relevant endpoints for the assessment of targeted treatments in clinical trials.