Common reasons for replacing the ECMO circuit include the buildup of blood clots, with or without an increase in Delta P. This condition can be linked to the activation of the coagulation process and inflammation, such as a rise in D-Dimer levels and a decrease in fibrinogen levels (less than 2). Although rare, the oxygenator may also malfunction and fail to adequately oxygenate the blood. In such cases, a post oxygenator PaO2 level below 300mmHg should be scrutinized and if it falls below 200mmHg (with a FiO2 of 1.0), a circuit replacement should be considered. Additionally, inefficient clearance of CO2 can inhibit gas exchange. It’s important to note that the age of the circuit is not a reliable indicator, as a need for replacement can occur early in its use or after 2-3 weeks.
Read the full procedure here: https://ecmo.icu/procedures-ecmo-circuit-change/#:~:text=Circuit%20priming-,ECMO%20circuit%20change,-LV%20vent