Haemostatic changes following ECMO circuit replacement in adult patients with COVID-19: An exploratory retrospective study.

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is an important intervention for severe respiratory failure, yet coagulation abnormalities and circuit thrombosis remain significant challenges. Circuit exchanges are frequently performed to restore oxygenator function and mitigate ECMO-related coagulopathies, but optimal criteria for their indication remain unclear.

METHODS

This retrospective analysis included adult patients with coronavirus disease 2019 associated acute respiratory distress syndrome (ARDS) receiving venovenous (VV) ECMO at a tertiary hospital between January 2020 and April 2023. The primary endpoint was the change in d-dimer level on the third day after a circuit exchange compared to the last value before the circuit exchange. Secondary analyses included parameters such as fibrinogen, platelet count, LDH, post‑oxygenator pO2 and transmembrane pressure. Statistical comparisons were made using Wilcoxon-signed-rank tests and linear mixed models.

RESULTS

Among 48 patients, 37 (77.1 %) underwent at least one coagulation-related circuit exchange, totalling 96 exchanges. D-dimer levels significantly decreased from 19 μg/ml (IQR 11-25) before exchange to 4 μg/ml (IQR 2-7) after exchange (p < 0.001). Platelet counts increased significantly (p = 0.024), while LDH levels decreased (p = 0.001). No significant changes were observed in fibrinogen levels. A sharp increase in d-dimer prior to exchange correlated with subsequent decreases post-exchange (R = -0.66, p < 0.001).

CONCLUSIONS

ECMO circuit exchanges are associated with significant improvements in coagulation parameters, particularly d-dimer reduction, suggesting that d-dimer trends may serve as a key indicator for elective circuit replacement. Future prospective studies should refine exchange criteria to optimize patient outcomes while minimizing unnecessary interventions.