US Patent 11305041 Oxygenator antithrombotic coating and method of manufacture

Hollow fiber membranes in an oxygenator for an extracorporeal blood circulator are coated with an antithrombotic polymeric material. The porous hollow fiber membranes for gas exchange have outer surfaces, inner surfaces forming lumens, opening portions through which the outer surfaces communicate with the inner surfaces in a housing. A blood flow path is outside of the hollow fiber membrane bundle in the housing, between a blood inlet port and a blood outlet port. The coating is obtained by filling the blood flow path with a colloidal solution containing an antithrombotic polymeric compound, and moving the colloid solution between the blood inlet port and the blood outlet port for a time that coats a predetermined amount of antithrombotic polymeric compound on the outer surfaces of the hollow fiber membranes. Other surfaces within the oxygenator contacting the blood flow likewise receive the coating.