Table 3.

Comparison of various filters available for use in COVID-19 patients requiring KRT.

Characteristics	Filters
	CytoSorb (Cytosorbents)	oXiris (Baxter)
Membrane composition	Polystyrene divinylbenzene co-polymer microporous beads (coated with polyvinylpyrrolidone)	AN69 copolymer covered with polyethyleneimine and unfractionated heparin
Sterilization type	Gamma irradiation	Ethylene oxide
Capability of adsorption	Cytokines	Endotoxin and cytokines
Adsorption mode	Hydrophobic interactions	Ionic interactions-cytokines due to sulfonate groups.-endotoxins due to high PEI concentration on inner part of membrane.
Heparin-covered inner surface	No	Yes

Adapted from Karkar and Ronco (29).

AN69, acrylonitrile and methalylsulfonate.