Sterilization of an artificial organ

In a heat sterilized artificial organ comprising:

• a device body filled with an aqueous solution harmless to the human body;
• at least one of blood ports and dialyzate ports in liquid communication with the device body;
• and
• a liquid pressure-buffering tube in liquid communication with at least one of said blood ports and dialyzate ports, and containing such an amount of gas as is capable of quantitatively absorbing the expansion of said aqueous solution during thermal sterilization of the artificial organ, said liquid pressure-buffering tube having two end portions;
• the improvement wherein:
• said liquid pressure-buffering tube being substantially unexpandable during thermal sterilization of the artificial organ, and comprising one end portion near said at least one of said blood and dialyzate ports with which said liquid pressure-buffering tube is in liquid communication, means defining a small orifice in said one end portion of said tube, said small orifice being dimensioned sufficiently small for preventing said gas within said liquid pressure-buffering tube from being replaced by said aqueous solution filled in said device body at normal ambient temperatures and for allowing the passage of said aqueous solution through said small orifice during heating of said artificial organ during sterilization thereof, said small orifice being smaller than the cross-sectional area of said port with which it communicates and smaller than the cross-sectional area of said liquid pressure-buffering tube at least in the vicinity of said port with which it communicates.