Inflammatory Response Assessment in Patients with COVID-19 Under Extracorporeal Membrane Oxygenation Support

Extracorporeal membrane oxygenation (ECMO), could be extremely helpful in the management of COVID-19 patients with refractory hypoxemic respiratory failure; however, to date, evidence on the true effecttiveness of ECMO in the COVID19 setting still hangs in the balance.

This was a prospective cohort study of 39 COVID-19 patients admitted to the intensive care unit (ICU) in an experienced ECMO center at a tertiary hospital during March/April 2020. Among the recruited participants, 10 (25.6%) required ECMO (ICU-ECMO group) and 29 (74.4%) did not have ECMO support (ICU group). Immunological parameters were assessed both at ICU admission and on a daily basis for 7 consecutive days.

The absolute lymphocyte count increased significantly in the ICU-ECMO group compared to the ICU group in which it remained relatively stable: β for the time variable was 127.1 [95% CI 68.9 - 185.3], p < 0.001 and for the interaction term -141.36 [-208.95 - -73.77], p < 0.001. On the other hand, globally, no significant differences were observed over time for the lymphocyte percentage, although it was higher in the ICU patients. Neutrophil counts were overall higher in the ICU-ECMO group (β -4,275.38 [-6,845.21 - 1,705.55], p = 0.001). In regard to neutrophil percentage, a significant decrease over time was reported (β -1.76 [-3.16 - -0.36], p = 0.014), namely in the ICU-ECMO group (β for the interaction 2.09 [0.45 - 3.73], p = 0.013).

Herein, we found ECMO support seems to provide a less aggressive immune response in COVID-19 patients with severe and refractory respiratory dysfunction.