Comparisons of Outcomes between Patients with Direct and Indirect Acute Respiratory Distress Syndrome Receiving Extracorporeal Membrane Oxygenation

Abstract

Acute respiratory distress syndrome (ARDS) is a heterogeneous syndrome caused by direct (local damage to lung parenchyma) or indirect lung injury (insults from extrapulmonary sites with acute systemic inflammatory response), the clinical and biological complexity can have a profound effect on clinical outcomes. We performed a retrospective analysis of 152 severe ARDS patients receiving extracorporeal membrane oxygenation (ECMO). Our objective was to assess the differences in clinical characteristics and outcomes of direct and indirect ARDS patients receiving ECMO. Overall hospital mortality was 53.3%. A total of 118 patients were assigned to the direct ARDS group, and 34 patients were assigned to the indirect ARDS group. The 28-, 60-, and 90-day hospital mortality rates were significantly higher among indirect ARDS patients (all p < 0.05). Cox regression models demonstrated that among direct ARDS patients, diabetes mellitus, immunocompromised status, ARDS duration before ECMO, and SOFA score during the first 3 days of ECMO were independently associated with mortality. In indirect ARDS patients, SOFA score and dynamic compliance during the first 3 days of ECMO were independently associated with mortality. Our findings revealed that among patients receiving ECMO, direct and indirect subphenotypes of ARDS have distinct clinical outcomes and different predictors for mortality.

Venovenous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome Due to Severe Fever With Thrombocytopenia Syndrome

“…However, to the best of our knowledge, no studies have shown the effectiveness of ECMO in patients with ARDS due to SFTS. As previous studies have shown that ARDS caused by factors other than viral pneumonia and ARDS caused by insults from extrapulmonary sites (like our case) are associated with higher mortality rates than those caused by viral pneumonia or pulmonary insults among patients treated with ECMO [10,11], it is difficult to extrapolate the abovementioned results from H1N1 influenza or COVID-19 to SFTS that has a clearly distinct pathology. H1N1 influenza and COVID-19 mainly affect the lungs as viral pneumonia, whereas SFTS often affects multiple organs.…”

Association and predictive value of soluble thrombomodulin with mortality in patients with acute respiratory distress syndrome: systematic review and meta-analysis

“…Direct and indirect lung injuries are two distinct subphenotypes of ARDS. The former features alveolar epithelial injury and local alveolar inflammation, whereas the latter is characterized by inflammatory mediatorinduced systemic vascular endothelial damage (32). Existing evidence has demonstrated that patients with indirect ARDS have more significantly elevated sTM levels than do those with direct ARDS (13), suggesting that circulating sTM cannot reflect the severity of lung injury in direct ARDS.…”