Extracorporeal blood heating and cooling system and method of operating and maintaining same

A method of purging an extracorporeal blood heating and cooling system that is connectable to an oxygenator of a cardiopulmonary bypass system, the heating and cooling system comprising:

• a heater-cooler unit;
• a coolant flow circuit that is configured to pass temperature-controlled coolant through the heater-cooler unit and an oxygenator;
• and a cardioplegia coolant circuit that is configured to pass temperature-controlled coolant through the heater-cooler unit and a cardioplegia heat exchanger;
• wherein the oxygenator comprises a first plurality of coolant conduits that form part of the coolant flow circuit when the oxygenator is connected to the heating and cooling system, and wherein when the heating and cooling system is in a coolant mode, blood passing through a first extracorporeal blood circuit contacts an exterior surface of the first plurality of coolant conduits;
• and wherein the cardioplegia heat exchanger comprises a second plurality of coolant conduits that are part of the cardioplegia coolant circuit, and wherein when the heating and cooling system is in the coolant mode, blood passing through a second extracorporeal blood circuit contacts an exterior surface of the second plurality of coolant conduits;
• the method comprising the steps of:
• adding temperature-controlled coolant to at least one of the coolant flow circuit or the cardioplegia coolant circuit, wherein the temperature-controlled coolant has a trisodium phosphate concentration of about 1-35 millimole/liter;
• and
• subsequently flowing the temperature-controlled coolant within the at least one of the coolant flow circuit or the cardioplegia coolant circuit in a manner that at least inhibits growth of microbes within the at least one of the coolant flow circuit or the cardioplegia coolant circuit;
• wherein the first and second plurality of coolant conduits are capable of maintaining a trisodium phosphate concentration ratio across the wall of each coolant conduit of at least 100:1, from the interior to the exterior of each coolant conduit.

A method of operating an extracorporeal blood heating and cooling system, wherein the heating and cooling system is connectable to an oxygenator of a cardiopulmonary bypass system, the heating and cooling system comprising:

• a heater-cooler unit;
• a coolant flow circuit that is configured to pass temperature-controlled coolant through the heater-cooler unit and the oxygenator;
• and a cardioplegia coolant circuit that is configured to pass temperature-controlled coolant through the heater-cooler unit and a cardioplegia heat exchanger;
• wherein the oxygenator comprises a first plurality of coolant conduits that form part of the coolant flow circuit when the heating and cooling system is connected to the oxygenator, and wherein when the heating and cooling system is operating in a coolant mode, blood passing through a first extracorporeal blood circuit contacts an exterior surface of the first plurality of coolant conduits;
• and wherein the cardioplegia heat exchanger comprises a second plurality of coolant conduits that are part of the cardioplegia coolant circuit, and wherein when the heating and cooling system is operating in the coolant mode, blood passing through a second extracorporeal blood circuit contacts an exterior surface of the second plurality of coolant conduits;
• the method comprising the steps of:
• adding temperature-controlled coolant to the coolant flow circuit and the cardioplegia coolant circuit, wherein the temperature-controlled coolant is water-based and has a trisodium phosphate concentration of 1-10 millimole/liter and a pH of 10-13;
• and
• subsequently flowing the temperature-controlled coolant through the coolant flow circuit and the cardioplegia circuit in order to at least inhibit growth of microbes within the coolant flow circuit and the cardioplegia circuit;
• wherein the first and second plurality of coolant conduits are capable of maintaining a trisodium phosphate concentration ratio across the wall of each coolant conduit of at least 100:1, from the interior to the exterior of each coolant conduit.