Oxygenator antithrombotic coating and method of manufacture

A method for manufacturing an oxygenator having a housing retaining a hollow fiber membrane bundle, wherein the hollow fiber membrane bundle comprises a plurality of porous hollow fiber membranes for gas exchange which have outer surfaces, inner surfaces forming lumens, and opening portions through which the outer surfaces communicate with the inner surfaces, wherein the oxygenator defines a blood flow path which is outside of the hollow fiber membranes in the housing between a blood inlet port and a blood outlet port, the method comprising:

• filling the blood flow path with a colloidal solution containing an antithrombotic polymeric compound;
• and
• moving the colloidal solution along the blood flow path 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;
• wherein the lumens of the hollow fiber membranes are used as a gas flow path, and carbon dioxide gas is passed through the gas flow path while moving the colloidal solution between the blood inlet port and the blood outlet port.