Cardioplegia administration system and method

Claim 2

A cardioplegia administration system for mixing and administering cardioplegia and/or blood to a patient's heart during cardiopulmonary bypass surgery, the system comprising: (a) a tubing set comprising: a cardioplegia supply tube having upstream and downstream ends, the upstream end of the cardioplegia supply tube being adapted to connect the cardioplegia supply tube to a source of cardioplegia medication; a blood supply tube having upstream and downstream ends, the upstream end of the blood supply tube being adapted to connect the blood supply tube to a source of blood or blood substitute; and a cardioplegia administration tube connected to the downstream ends of the cardioplegia and blood supply tubes, the cardioplegia administration tube being adapted to supply cardioplegia solution to the patient's heart; (b) a positive displacement pump for pumping fluid through the cardioplegia administration tube; and (c) a mixing system for controlling the ratio of cardioplegia medication and blood or blood substitute in the cardioplegia solution in the cardioplegia administration tube, the mixing system comprising: mixing valves for alternately continually closing and opening the cardioplegia and blood supply tubes such that only one of the cardioplegia and blood supply tubes is open at a time; and control means for controlling the intervals during which the mixing valves are open with respect to each of the cardioplegia and blood supply tubes to control the ratio of the cardioplegia and blood or blood substitute administered through the cardioplegia administration tube; the system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the cardioplegia administration tube on opposite sides of the positive displacement pump, and an overpressure valve along the recirculation tube which is normally closed to close the recirculation tube to fluid flow but which openable in response to an increase in pressure in the cardioplegia administration tube for allowing recirculation of fluid through the recirculation tube.

Claim 3

A cardioplegia administration system according to claim 1 wherein the control means includes means, operably responsive to the overpressure valve, for actuating the mixing valves to close both of the cardioplegia and blood supply tubes when the overpressure valve is opened.

Claim 4

A cardioplegia administration system according to claim 1 wherein the mixing valves and overpressure valve comprise pinch valves that each pinch a respective one of the cardioplegia supply tube, blood supply tube and recirculation tube to close such respective tube to fluid flow.

Claim 5

A cardioplegia administration system for mixing and administering cardioplegia and/or blood to a patient's heart during cardiopulmonary bypass surgery, the system comprising: a tubing set comprising: a cardioplegia supply tube having upstream and downstream ends, the upstream end of the cardioplegia supply tube being adapted to connect the cardioplegia supply tube to a source of cardioplegia medication; a blood supply tube having upstream and downstream ends, the upstream end of the blood supply tube being adapted to connect the blood supply tube to a source of blood or blood substitute; and a cardioplegia administration tube connected to the downstream ends of the cardioplegia and blood supply tubes, the cardioplegia administration tube being adapted to supply cardioplegia solution to the patient's heart: (b) a positive displacement pump for pumping fluid through the cardioplegia administration tube; and (c) mixing system for controlling the ratio of cardioplegia medication and blood or blood substitute in the cardioplegia solution in the cardioplegia administration tube, the mixing system comprising: pinch valves for alternately-continually pinching the cardioplegia and blood supply tubes to close and open the cardioplegia and blood supply tubes such that only one of the cardioplegia and blood supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the cardioplegia and blood supply tubes to control the ratio of the cardioplegia and blood or blood substitute administered through the cardioplegia administration tube; the system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the cardioplegia administration tube on opposite sides of the positive displacement pump, and a non-invasive overpressure valve acting on the recirculation tube which is normally closed to close the recirculation tube to fluid flow but which is openable in response to an increase in pressure in the cardioplegia administration tube for allowing recirculation of fluid through the recirculation tube, the control means including means operably responsive to the overpressure valve, for actuating the pinch valves to close both of the cardioplegia and blood supply tubes when the overpressure valve is opened.

Claim 6

A cardioplegia administration system for mixing and administering cardioplegia and/or blood to a patient's heart during cardiopulmonary bypass surgery, the system comprising: a tubing set comprising: a cardioplegia supply tube having upstream and downstream ends, the upstream end of the cardioplegia supply tube being adapted to connect the cardioplegia supply tube to a source of cardioplegia medication; a blood supply tube having upstream and downstream ends, the upstream end of the blood supply tube being adapted to connect the blood supply tube to a source of blood or blood substitute; and a cardioplegia administration tube connected to the downstream ends of the cardioplegia and blood supply tubes, the cardioplegia administration tube being adapted to supply cardioplegia solution to the patient's heart: (b) a positive displacement pump for pumping fluid through the cardioplegia administration tube; and (c) mixing system for controlling the ratio of cardioplegia medication and blood or blood substitute in the cardioplegia solution in the cardioplegia administration tube, the mixing system comprising: pinch valves for alternately-continually pinching the cardioplegia and blood supply tubes to close and open the cardioplegia and blood supply tubes such that only one of the cardioplegia and blood supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the cardioplegia and blood supply tubes to control the ratio of the cardioplegia and blood or blood substitute administered through the cardioplegia administration tube; the system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the cardioplegia administration tube on opposite sides of the positive displacement pump, and a non-invasive overpressure valve acting on the recirculation tube which is normally closed to close the recirculation tube to fluid flow but which is openable in response to an increase in pressure in the cardioplegia administration tube for allowing recirculation of fluid through the recirculation tube, the control means including means operably responsive to the overpressure valve, for actuating the pinch valves to close both of the cardioplegia and blood supply tubes when the overpressure valve is opened.

Claim 7

The cardioplegia administration system according to claim 3 wherein the pinch valves comprise a single double-acting solenoid valve that simultaneously allows one of the cardioplegia and blood supply tubes to open as it closes the other of the cardioplegia and blood supply tubes.

Claim 8

A cardioplegia administration system according to claim 4 wherein the pinch valves comprise first and second solenoid valves for opening and closing the cardioplegia and blood supply tubes, respectively, and wherein the overpressure valve is a pinch valve, comprising a third solenoid valve for opening and closing the recirculation tube.

Claim 9

The cardioplegia administration system according to claim 6, wherein the tubing set comprises a cassette holding portions of at least the cardioplegia and blood supply tubes, and wherein the controller comprises a socket for receiving the cassette, and holding the cassette in position where the pinch valves can contact the cardioplegia and blood supply tubes, to open and close these tubes.

Claim 10

The cardioplegia administration system according to claim 4 wherein the pinch valves comprise a single, double-acting, metering solenoid valve that simultaneously allows one of the cardioplegia and blood supply tubes to open as it closes the other of the cardioplegia and blood supply tubes, and wherein the overpressure valve comprises a second, double-acting, overpressure solenoid valve that simultaneously closes one of the cardioplegia and blood supply tubes when it allows the recirculation tube to open, the control means including means for actuating the metering solenoid valve to close the other of the cardioplegia and blood supply tubes when the recirculation tube is allowed to open.

Claim 11

The cardioplegia administration system according to claim 4 wherein the tubing set comprises a cassette holding portions of the cardioplegia and blood supply tubes, and wherein the controller comprises a socket for receiving the cassette, and holding the cassette in position where the pinch valves can contact the tubes and selectively open and close these tubes.

Claim 12

The cardioplegia administration system according to claim 4 further comprising a pressure transducer for monitoring the pressure in the cardioplegia administration tube, and wherein the controller opens the pinch valve on the recirculation tube, and closes the pinch valves on the cardioplegia and blood supply tubes in response to a predetermined pressure in the cardioplegia administration tube.

Claim 13

A cardioplegia administration system for mixing and administering cardioplegia and/or blood to a patient's heart during cardiopulmonary bypass surgery, the system comprising: (a) a tubing set comprising: a cardioplegia supply tube having upstream and downstream ends, the upstream end of the cardioplegia supply tube being adapted to connect the cardioplegia supply tube to a source of cardioplegia medication; a blood supply tube having upstream and downstream ends, the upstream end of the blood supply tube being adapted to connect the blood supply tube to a source of blood or blood substitute: and a cardioplegia administration tube connected to the downstream ends of the cardioplegia and blood supply tubes, the cardioplegia administration tube being adapted to supply cardioplegia solution to the patient's heart; (b) a positive displacement pump for pumping fluid through the cardioplegia administration tube: and (c) a mixing system for controlling the ratio of cardioplegia medication and blood or blood substitute in the cardioplegia solution in the cardioplegia administration tube, the mixing system comprising: pinch valves for alternately-continually pinching the cardioplegia and blood supply tubes to close and open the cardioplegia and blood supply tubes such that only one of the cardioplegia and blood supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the cardioplegia and blood supply tubes to control the ratio of the cardioplegia and blood or blood substitute administered through the cardioplegia administration tube; the system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the cardioplegia administration tube on opposite sides of the positive displacement pump, and a recirculation valve acting on the recirculation tube which is normally closed to close the recirculation tube to fluid flow, but which is selectively openable to allow recirculation of fluid through the recirculation tube, the control means including means for actuating the pinch valves to close both of the cardioplegia and blood supply tubes when the recirculation valve is opened.

Claim 14

A cardioplegia administration system for mixing and administering cardioplegia and/or blood to a patient's heart during cardiopulmonary bypass surgery, the system comprising: (a) a tubing set comprising: a cardioplegia supply tube having upstream and downstream ends, the upstream end of the cardioplegia supply tube being adapted to connect the cardioplegia supply tube to a source of cardioplegia medication; a blood supply tube having upstream and downstream ends, the upstream end of the blood supply tube being adapted to connect the blood supply tube to a source of blood or blood substitute: and a cardioplegia administration tube connected to the downstream ends of the cardioplegia and blood supply tubes, the cardioplegia administration tube being adapted to supply cardioplegia solution to the patient's heart; (b) a positive displacement pump for pumping fluid through the cardioplegia administration tube: and (c) a mixing system for controlling the ratio of cardioplegia medication and blood or blood substitute in the cardioplegia solution in the cardioplegia administration tube, the mixing system comprising: pinch valves for alternately-continually pinching the cardioplegia and blood supply tubes to close and open the cardioplegia and blood supply tubes such that only one of the cardioplegia and blood supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the cardioplegia and blood supply tubes to control the ratio of the cardioplegia and blood or blood substitute administered through the cardioplegia administration tube; the system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the cardioplegia administration tube on opposite sides of the positive displacement pump, and a recirculation valve acting on the recirculation tube which is normally closed to close the recirculation tube to fluid flow, but which is selectively openable to allow recirculation of fluid through the recirculation tube, the control means including means for actuating the pinch valves to close both of the cardioplegia and blood supply tubes when the recirculation valve is opened.

Claim 15

The cardioplegia administration system according to claim 11 wherein the pinch valves comprise a single double-acting solenoid valve that simultaneously allows one of the cardioplegia and blood supply tubes to open as it closes the other of the cardioplegia and blood supply tubes.

Claim 16

The cardioplegia administration system according to claim 12 wherein the single double-acting solenoid valve constitutes a first, double-acting solenoid valve, and the recirculation valve comprises a second, double-acting, solenoid valve that simultaneously closes one of the cardioplegia and blood supply tubes when it allows the recirculation tube to open, the control means including means for actuating the first solenoid valve to close the other of the cardioplegia and blood supply tubes when the recirculation tube is allowed to open.

Claim 17

A cardioplegia administration system according to claim 11 wherein the pinch valves comprise first and second solenoid valves for opening and closing the cardioplegia and blood supply tubes, respectively, and wherein the recirculation valve is a pinch valve, comprising a third solenoid valve for opening and closing the recirculation tube.

Claim 18

The cardioplegia administration system according to claim 11 wherein the tubing set comprises a cassette holding portions of the cardioplegia and blood supply tubes, and wherein the controller comprises a socket for receiving the cassette, and holding the cassette in position where the pinch valves can contact the tubes and selectively open and close these tubes.

Claim 19

A mixing system for mixing two or more biological or medical fluids, the system comprising: (a) a tubing set comprising: a first supply tube having upstream and downstream ends, the upstream end of the first supply tube being adapted to connect the first supply tube to a source of a first biological or medical fluid; a second supply tube having upstream and downstream ends, the upstream end of the second supply tube being adapted to connect the second supply tube to a source of a second biological or medical fluid; and a mixing tube having an upstream end connected to the downstream ends of the first and second supply tubes, and a downstream end for supplying a mixed fluid comprising a preselected composition of the first and second fluids, the mixing tube having a lumen, in which the first and second fluids are mixed, and an exterior surface separated from the lumen by a tube wall; (b) a positive displacement pump in pumping engagement with the exterior surface of the mixing tube for pumping fluid through the mixing tube; and (c) a mixer for controlling the ratio of the first fluid and the second fluid in the mixed fluid, the mixer comprising: mixing valves for alternately-continually closing and opening the first and second supply tubes such that only one of the first and second supply tubes is open at a time; and a controller for controlling the intervals during which the mixing valves are open with respect to each of the first and second supply tubes to control the ratio of the first and second fluids in the mixed fluid supplied through the mixing tube; the mixing system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the mixing tube on opposite sides of the positive displacement pump, and a recirculation valve along the recirculation tube which is normally closed to close the recirculation tube to fluid flow but which is selectively openable to allow recirculation of fluid through the recirculation tube.

Claim 20

A mixing system for mixing two or more biological or medical fluids, the system comprising: (a) a tubing set comprising: a first supply tube having upstream and downstream ends, the upstream end of the first supply tube being adapted to connect the first supply tube to a source of a first biological or medical fluid; a second supply tube having upstream and downstream ends, the upstream end of the second supply tube being adapted to connect the second supply tube to a source of a second biological or medical fluid; and a mixing tube having an upstream end connected to the downstream ends of the first and second supply tubes, and a downstream end for supplying a mixed fluid comprising a preselected composition of the first and second fluids, the mixing tube having a lumen, in which the first and second fluids are mixed, and an exterior surface separated from the lumen by a tube wall; (b) a positive displacement pump in pumping engagement with the exterior surface of the mixing tube for pumping fluid through the mixing tube; and (c) a mixer for controlling the ratio of the first fluid and the second fluid in the mixed fluid, the mixer comprising: mixing valves for alternately-continually closing and opening the first and second supply tubes such that only one of the first and second supply tubes is open at a time; and a controller for controlling the intervals during which the mixing valves are open with respect to each of the first and second supply tubes to control the ratio of the first and second fluids in the mixed fluid supplied through the mixing tube; the mixing system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the mixing tube on opposite sides of the positive displacement pump, and a recirculation valve along the recirculation tube which is normally closed to close the recirculation tube to fluid flow but which is selectively openable to allow recirculation of fluid through the recirculation tube.

Claim 21

A mixing system according to claim 16 wherein the controller includes means, operably responsive to the recirculation valve, for actuating the mixing valves to close both of the cardioplegia and blood supply tubes when the recirculation valve is opened.

Claim 22

A mixing system according to claim 16 wherein the mixing valves and recirculation valve comprise pinch valves that each pinch a respective one of the cardioplegia supply tube, blood supply tube and recirculation tube to close such respective tube to fluid flow.

Claim 23

The mixing system for mixing two or more biological or medical fluids, the system comprising: (a) a tubing set comprising: a first supply tube having upstream and downstream ends, the upstream end of the first supply tube being adapted to connect the first supply tube to a source of a first biological or medical fluid: a second supply tube having upstream and downstream ends, the upstream and of the second supply tube being adapted to connect the second supply tube to a source of a second biological or medical fluid; and a mixing tube having an upstream end connected to the downstream ends of the first and second supply tubes, and a downstream end for supplying a mixed fluid comprising a preselected composition of the first and second fluids, the mixing tube having a lumen, in which the first and second fluids are mixed, and an exterior surface separated from the lumen by a tube wall; (b) a positive displacement pump in pumping engagement with the exterior surface of the mixing tube for pumping fluid through the mixing tube; and (c) a mixer for controlling the ratio of the first fluid add the second fluid in the mixed fluid, the mixer comprising; pinch valves for alternately-continually pinching the first and second supply tubes to close and open the first and Second supply tubes such that only one of the first and second supply tubes is open at a time: and a controller for controlling the intervals during which the pinch valves are open with respect to each of the first and second supply tube to control the ratio of the first and second fluids in the mixed fluid supplied through the mixing tube; the mixing system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the mixing tube on opposite sides of the positive displacement pump, and a non-invasive overpressure valve means acting on the recirculation tube which is normally closed to close the recirculation tube to fluid flow but which is openable in response to an increase in pressure in the mixing tube for allowing recirculation of fluid through the recirculation tube, the controller including means, operably responsive to the overpressure valve means, for actuating the pinch valves to close both of the first and second supply tubes when the overpressure valve means is opened.

Claim 24

The mixing system for mixing two or more biological or medical fluids, the system comprising: (a) a tubing set comprising: a first supply tube having upstream and downstream ends, the upstream end of the first supply tube being adapted to connect the first supply tube to a source of a first biological or medical fluid: a second supply tube having upstream and downstream ends, the upstream and of the second supply tube being adapted to connect the second supply tube to a source of a second biological or medical fluid; and a mixing tube having an upstream end connected to the downstream ends of the first and second supply tubes, and a downstream end for supplying a mixed fluid comprising a preselected composition of the first and second fluids, the mixing tube having a lumen, in which the first and second fluids are mixed, and an exterior surface separated from the lumen by a tube wall; (b) a positive displacement pump in pumping engagement with the exterior surface of the mixing tube for pumping fluid through the mixing tube; and (c) a mixer for controlling the ratio of the first fluid add the second fluid in the mixed fluid, the mixer comprising; pinch valves for alternately-continually pinching the first and second supply tubes to close and open the first and Second supply tubes such that only one of the first and second supply tubes is open at a time: and a controller for controlling the intervals during which the pinch valves are open with respect to each of the first and second supply tube to control the ratio of the first and second fluids in the mixed fluid supplied through the mixing tube; the mixing system further comprising a recirculation tube having upstream and downstream ends in fluid communication with the mixing tube on opposite sides of the positive displacement pump, and a non-invasive overpressure valve means acting on the recirculation tube which is normally closed to close the recirculation tube to fluid flow but which is openable in response to an increase in pressure in the mixing tube for allowing recirculation of fluid through the recirculation tube, the controller including means, operably responsive to the overpressure valve means, for actuating the pinch valves to close both of the first and second supply tubes when the overpressure valve means is opened.

Claim 25

The mixing system according to claim 19 wherein the pinch valves comprise a single double-acting solenoid valve that simultaneously allows one of the first and second supply tubes to open as it closes the other of the first and second supply tubes.

Claim 26

The mixing system according to claim 19 wherein the pinch valves comprise first and second solenoid valves for opening and closing the first and second supply tubes, respectively, and wherein the overpressure valve comprises a third solenoid valve for opening and closing the recirculation tube.

Claim 27

The mixing system according to claim 21, wherein the tubing set comprises a cassette holding portions of at least the first and second supply tubes, and wherein the controller comprises a socket for receiving the cassette, and holding the cassette in position where the pinch valves can contact the first and second supply tubes, to open and close these tubes.

Claim 28

The mixing system according to claim 19 wherein the pinch valves comprise a single, double-acting, metering solenoid valve that simultaneously allows one of the first and second supply tubes to open as it closes the other of the first and second supply tubes, and wherein the overpressure valve comprises a second, double-acting, overpressure solenoid valve that simultaneously closes one of the first and second supply tubes when it allows the recirculation tube to open, the control means including means for actuating the metering solenoid valve to close the other of the first and second supply tubes when the recirculation tube is allowed to open.

Claim 29

The mixing system according to claim 19 wherein the tubing set comprises a cassette holding portions of the first and second supply tubes, and wherein the controller comprises a socket for receiving the cassette, and holding the cassette in position where the pinch valves can contact the tubes and selectively open and close these tubes.

Claim 30

The mixing system according to claim 19 further comprising a pressure transducer for monitoring the pressure in the mixing tube, and wherein the controller opens the pinch valve on the recirculation tube, and closes the pinch valves on the first and second supply tubes in response to a predetermined pressure in the mixing tube.

Claim 33

A method according to claim 26 further comprising the step of actuating the pinch valves to close both of the cardioplegia supply tube and blood supply tube when the overpressure valve is opened.

Claim 34

A cardioplegia administration system for mixing and administering cardioplegia and/or blood to a patient's heart during cardiopulmonary bypass surgery, the system comprising: a replaceable tubing set comprising a cardioplegia supply tube, a blood supply tube, and a cardioplegia administration tube, the cardioplegia supply tube having upstream and downstream ends, the upstream end of the cardioplegia supply tube being adapted to connect the cardioplegia supply tube to a source of cardioplegia medication; and the blood supply tube having Upstream and downstream ends, the upstream end of the blood supply tube being adapted to connect the blood supply tube to a source of blood or blood substitute; and the cardioplegia administration tube being connected to the downstream ends of the cardioplegia and blood supply tubes, and adapted to supply cardioplegia solution to the patient's heart; at least portions of the cardioplegia supply tube and the blood supply tube being contained in a cassette adapted for mounting on a mixer: and a mixer for controlling the ratio of cardioplegia medication and blood or blood substitute in the cardioplegia solution in the cardioplegia administration tube, the mixer adapted to receive the cassette of the replaceable tubing set, and having pinch valves for alternately-continually pinching the portions of the cardioplegia and blood supply tubes in the cassette to close and open the cardioplegia and blood supply tubes such that on by one of the cardioplegia and blood supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the cardioplegia and blood supply tubes to control the ratio of the cardioplegia and blood or blood substitute administered through the cardioplegia administration tube; the system further comprising a positive displacement pump for pumping fluid through the cardioplegia administration tube, the replaceable tubing set further comprising a recirculation tube having upstream and downstream ends in fluid communication with the cardioplegia administration tube on opposite sides of the positive displacement pump, a portion of the recirculation tube being in the cassette; and wherein the mixer comprises a non-invasive overpressure valve that acts on the portion of the recirculation tube in the cassette, the overpressure valve being normally closed but being openable in response to an increase in pressure in the cardioplegia administration tube for allowing recirculation of fluid through the recirculation tube, the control means including means for actuating the pinch valves to close both of the cardioplegia and blood supply tubes when the overpressure valve is opened.

Claim 35

A cardioplegia administration system for mixing and administering cardioplegia and/or blood to a patient's heart during cardiopulmonary bypass surgery, the system comprising: a replaceable tubing set comprising a cardioplegia supply tube, a blood supply tube, and a cardioplegia administration tube, the cardioplegia supply tube having upstream and downstream ends, the upstream end of the cardioplegia supply tube being adapted to connect the cardioplegia supply tube to a source of cardioplegia medication; and the blood supply tube having Upstream and downstream ends, the upstream end of the blood supply tube being adapted to connect the blood supply tube to a source of blood or blood substitute; and the cardioplegia administration tube being connected to the downstream ends of the cardioplegia and blood supply tubes, and adapted to supply cardioplegia solution to the patient's heart; at least portions of the cardioplegia supply tube and the blood supply tube being contained in a cassette adapted for mounting on a mixer: and a mixer for controlling the ratio of cardioplegia medication and blood or blood substitute in the cardioplegia solution in the cardioplegia administration tube, the mixer adapted to receive the cassette of the replaceable tubing set, and having pinch valves for alternately-continually pinching the portions of the cardioplegia and blood supply tubes in the cassette to close and open the cardioplegia and blood supply tubes such that on by one of the cardioplegia and blood supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the cardioplegia and blood supply tubes to control the ratio of the cardioplegia and blood or blood substitute administered through the cardioplegia administration tube; the system further comprising a positive displacement pump for pumping fluid through the cardioplegia administration tube, the replaceable tubing set further comprising a recirculation tube having upstream and downstream ends in fluid communication with the cardioplegia administration tube on opposite sides of the positive displacement pump, a portion of the recirculation tube being in the cassette; and wherein the mixer comprises a non-invasive overpressure valve that acts on the portion of the recirculation tube in the cassette, the overpressure valve being normally closed but being openable in response to an increase in pressure in the cardioplegia administration tube for allowing recirculation of fluid through the recirculation tube, the control means including means for actuating the pinch valves to close both of the cardioplegia and blood supply tubes when the overpressure valve is opened.

Claim 36

The cardioplegia administration system according to claim 28 wherein the pinch valves comprise a single double-acting solenoid valve that simultaneously allows one of the cardioplegia and blood supply tubes to open as it closes the other of the cardioplegia and blood supply tubes.

Claim 37

A cardioplegia administration system according to claim 28 wherein the pinch valves comprise first and second solenoid valves for opening and closing the cardioplegia and blood supply tubes, respectively, and wherein the overpressure valve comprises a third solenoid valve for opening and closing the recirculation tube.

Claim 38

The cardioplegia administration system according to claim 28 wherein the pinch valves comprise a single, double-acting, metering solenoid valve that simultaneously allows one of the cardioplegia and blood supply tubes to open as it closes the other of the cardioplegia and blood supply tubes, and wherein the overpressure valve comprises a second, double-acting, overpressure solenoid valve that simultaneously closes one of the cardioplegia and blood supply tubes when it allows the recirculation tube to open, the control means including means for actuating the metering solenoid valve to close the other of the cardioplegia and blood supply tubes when the recirculation tube is allowed to open.

Claim 39

The cardioplegia administration system according to claim 28 wherein the mixer further comprises a pressure transducer for monitoring the pressure in the cardioplegia administration tube, and wherein the controller opens the pinch valve on the recirculation tube, and closes the pinch valves on the cardioplegia and blood supply tubes in response to a predetermined pressure in the cardioplegia administration tube.

Claim 40

A mixing system for mixing two or more biological or medical fluids, the system comprising: a replaceable tubing set comprising: a first supply tube, a second supply tube, and a mixing tube, the first supply tube having upstream and downstream ends, the upstream end of the first supply tube being adapted to connect the first supply tube to a source of a first biological or medical fluid; the second supply tube having upstream and downstream ends, the .upstream end of the second supply tube being adapted to connect the second supply tube to a source of a second biological or medical fluid; and the mixing tube having an upstream end connected to the downstream ends of the first and second supply tubes, and a downstream end for supplying a mixed fluid comprising a preselected composition of the first and second fluids, the mixing tube having a lumen in which the first and second fluids are mixed, and an exterior surface separated from the lumen by a tube wall; at least portions of the first and second supply tubes being contained in a cassette that is adapted to be mounted on a mixer; and a mixer for controlling the ratio of the first fluid and the second fluid in the mixed fluid, the mixer adapted mount the cassette of the tubing set, the mixer having pinch values for alternately-continually pinching the portions of the first and second supply tubes in the cassette to close and open the first and second supply tubes such that only one of the first and second supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the first and second supply tubes to control the ratio of the first and second fluids in the mixed fluid supplied through the mixing tube; the tubing set further comprising a recirculation tube having upstream and downstream ends in fluid communication with the mixing tube, a portion of the recirculation tube being in the cassette, and wherein the mixer further comprises a non-invasive overpressure valve means acting on the portion of the recirculation tube in the cassette, the overpressure valve being normally closed to close the recirculation tube to fluid flow but which is openable in response to an increase in pressure in the mixing tube for allowing recirculation of fluid through the recirculation tube, the control means including means for actuating the pinch valves to close both of the first and second supply tubes when the overpressure valve is opened.

Claim 41

A mixing system for mixing two or more biological or medical fluids, the system comprising: a replaceable tubing set comprising: a first supply tube, a second supply tube, and a mixing tube, the first supply tube having upstream and downstream ends, the upstream end of the first supply tube being adapted to connect the first supply tube to a source of a first biological or medical fluid; the second supply tube having upstream and downstream ends, the .upstream end of the second supply tube being adapted to connect the second supply tube to a source of a second biological or medical fluid; and the mixing tube having an upstream end connected to the downstream ends of the first and second supply tubes, and a downstream end for supplying a mixed fluid comprising a preselected composition of the first and second fluids, the mixing tube having a lumen in which the first and second fluids are mixed, and an exterior surface separated from the lumen by a tube wall; at least portions of the first and second supply tubes being contained in a cassette that is adapted to be mounted on a mixer; and a mixer for controlling the ratio of the first fluid and the second fluid in the mixed fluid, the mixer adapted mount the cassette of the tubing set, the mixer having pinch values for alternately-continually pinching the portions of the first and second supply tubes in the cassette to close and open the first and second supply tubes such that only one of the first and second supply tubes is open at a time; and control means for controlling the intervals during which the pinch valves are open with respect to each of the first and second supply tubes to control the ratio of the first and second fluids in the mixed fluid supplied through the mixing tube; the tubing set further comprising a recirculation tube having upstream and downstream ends in fluid communication with the mixing tube, a portion of the recirculation tube being in the cassette, and wherein the mixer further comprises a non-invasive overpressure valve means acting on the portion of the recirculation tube in the cassette, the overpressure valve being normally closed to close the recirculation tube to fluid flow but which is openable in response to an increase in pressure in the mixing tube for allowing recirculation of fluid through the recirculation tube, the control means including means for actuating the pinch valves to close both of the first and second supply tubes when the overpressure valve is opened.

Claim 42

The mixing system according to claim 33 wherein the pinch valves comprise a single double-acting solenoid valve that simultaneously allows one of the first and second supply tubes to open as it closes the other of the first and second supply tubes.

Claim 43

The mixing system according to claim 33 wherein the pinch valves comprise first and second solenoid valves for opening and closing the first and second supply tubes, respectively, and wherein the overpressure valve comprises a third solenoid valve for opening and closing the recirculation tube.

Claim 44

The mixing system according to claim 33 wherein the pinch valves comprise a single, double-acting, metering solenoid valve that simultaneously allows one of the first and second supply tubes to open as it closes the other of the first and second supply tubes, and wherein the overpressure valve comprises a second, double-acting, overpressure solenoid valve that simultaneously closes one of the first and second supply tubes when it allows the recirculation tube to open, the control means including means for actuating the metering solenoid valve to close the other of the first and second supply tubes when the recirculation tube is allowed to open.