Thermodilution injection system including an injectate cooling system

In a thermodilution injection system of the type including means for delivering a measured volume of cooled injectate into a patient's circulatory system through a catheter at predetermined time intervals, the improvement comprising:

• housing means, said housing means being tubular in shape, said housing means have first and second ends, said first and said second ends being open, said housing means defining a cavity;
• non-disposable conduit means, said conduit means being received by and partially filling said housing means cavity, said conduit means having first and second ends, said conduit means defining at least one injectate fluid passageway from said housing means first end to said housing means second end, said conduit means absorbing heat from the injectate, said conduit means having a volume commensurate ate with the measured volume of injectate supplied by the delivering means, said conduit means being sterilizable;
• first cap means, said first cap means being received by and sealing said housing means first end, said first cap means being provided with a fluid port, said first cap means fluid port having first and second ends, said first cap means fluid port defining a fluid passageway for the injectate, said first cap means fluid port first end being in fluid communication with and sealed to said conduit means first end, said first cap means fluid port second end being in fluid communication with the delivering means;
• second cap means, said second cap means being received by and sealing said housing means second end, said second cap means being provided with a fluid port, said second cap means fluid port having first and second ends, said second cap means fluid port defining a fluid passageway for the injectate, said second cap means fluid port first end being in fluid communication with and sealed to said conduit means second end, said second cap means fluid port second end being in direct fluid communication with and sealed to the catheter;
• and
• a liquid filling the remainder of said housing means cavity, the temperature of said liquid being capable of being reduced below the desired temperature of the injectate whereby said liquid will absorb heat from said conduit means and thereby cool the injectate to the desired temperature.