Extracorporeal membrane oxygenation (ECMO) is used in
critical care to manage patients with severe respiratory and
cardiac failure. ECMO brings blood from a
critically ill patient into contact with a non-endothelialized circuit which can cause clotting and
bleeding simultaneously in this population. Continuous systemic anticoagulation is needed during ECMO. The
membrane oxygenator, which is a critical component of the extracorporeal circuit, is prone to significant
thrombus formation due to its large surface area and areas of low, turbulent, and stagnant flow. Various surface coatings, including but not limited to
heparin,
albumin, poly(
ethylene glycol),
phosphorylcholine, and
poly(2-methoxyethyl acrylate), have been developed to reduce
thrombus formation during ECMO. The present work provides an up-to-date overview of anti-thrombogenic surface coatings for ECMO, including both commercial coatings and those under development. The focus is placed on the coatings being developed for
oxygenators. Overall, zwitterionic
polymer coatings,
nitric oxide (NO)-releasing coatings, and
lubricant-infused coatings have attracted more attention than other coatings and showed some improvement in in vitro and in vivo anti-thrombogenic effects. However, most studies lacked standard hemocompatibility assessment and comparison studies with current clinically used coatings, either
heparin coatings or nonheparin coatings. Moreover, this review identifies that further investigation on the thrombo-resistance, stability and durability of coatings under rated flow conditions and the effects of coatings on the function of
oxygenators (pressure drop and gas transfer) are needed. Therefore, extensive further development is required before these new coatings can be used in the clinic.