Method and apparatus for removal of gas bubbles from blood

A method for removing gas bubbles from blood to be returned to a patient from a cardiopulmonary bypass circuit comprising the steps of:

• moving blood from a patient into a cardiopulmonary bypass circuit;
• filtering particulates from the blood flowing within the cardiopulmonary bypass circuit;
• operably connecting the cardiopulmonary bypass circuit to the venous system of the patient with a venous cannula;
• and
• removing gas bubbles from the blood passing through the bypass circuit, the step of removing the gas bubbles from the blood comprising:
• providing an axially elongate cylindrical shell defining a chamber;
• disposing an impeller within the chamber, wherein the impeller is a smooth-walled cylinder configured to rotate a volume of blood within the chamber about the central axis of the chamber thus forcing air bubbles within the volume of blood to migrate radially inward in response to centrifugal forces imparted on the volume of blood by the rotation of said blood;
• causing blood to flow into the chamber through a blood inlet port in the shell, the blood inlet port being in fluid communication with a venous cannula, wherein the blood inlet port is located near the circumferential periphery of the shell;
• rotating the impeller with a motor;
• venting gas from the central axis of the chamber;
• and
• receiving blood flowing out of the chamber through a blood outlet port in the shell, the blood outlet port being in fluid communication with the chamber and an arterial cannula and a blood pump configured to pump blood into the patient, wherein the blood outlet port is located near the circumferential periphery of the shell and wherein said arterial cannula is in fluid connection with the arterial system of the patient.