Disposable cassette for intravascular heat exchange catheter
View Patent ↗A heat exchange fluid supply system for supplying a heat exchange fluid to an intravascular heat exchange catheter includes a disposable cassette having a bulkhead and an external heat exchanger, and which is configured to operate in combination with a reusable master control unit. The bulkhead includes a reservoir section and a pump section. The reservoir section is provided with a means to monitor the amount of heat exchange fluid that is in the system. The bulkhead provides the mechanism for priming the system with heat exchange fluid from an external source and for circulating fluid to the catheter in a closed circuit. The pump section is configured to allow for pumping of heat exchange fluid at a constant pressure.
1. A method for providing a temperature regulated source of heat exchange fluid for heat exchange catheters, comprising the steps of:
providing a disposable circuit assembly comprising an external heat exchanger, a heat exchange catheter, and a housing defining a pump section and a reservoir section, the housing having an air vent disposed in a wall of the housing defining the reservoir section, the pump section including a pump head, said external heat exchanger, pump head and reservoir and heat exchange catheter in fluid communication such that fluid pumped by the pump head of the bulkhead is circulated through said heat exchange catheter and said external heat exchanger, and said air vent allows passage of gas in and out of said disposable circuit assembly through said vent but does not allow passage of liquid in and out of said disposable circuit assembly through said air vent;
providing a heat generating or removing unit in heat exchange relationship with said external heat exchanger;
providing an external fluid source in fluid communication with said disposable circuit assembly;
providing a valve between said external fluid source and said disposable circuit assembly, said valve having an open position which permits the flow of heat exchange fluid from said external fluid source into said disposable circuit assembly and a closed position which prevents the flow of heat exchange fluid from said external fluid source to said disposable circuit assembly;
providing a level sensor within said disposable circuit assembly to sense when the fluid level in said disposable circuit assembly is full, said level sensor generating a signal in response to said full fluid level;
initially maintaining said valve in said open position until said sensor senses that the fluid level in said disposable circuit assembly is at an adequately full level; and
operating said valve into said closed position in response to said signal;
circulating heat exchange fluid from said external source through said disposable circuit assembly by means of pumping with said pump head while simultaneously venting any gas contained in said disposable circuit assembly out through said air vent; and
controlling the temperature of said heat exchanger fluid in said disposable circuit assembly by controlling the temperature of said heat generating or removing unit.
2. The method of claim 1 further comprising the step of controlling the pressure of said fluid as said fluid is circulated through said disposable circuit assembly.
3. The method of claim 2 wherein said pressure control comprises a pressure regulator in fluid communication with said disposable circuit assembly.
4. The method of claim 3 wherein said pressure regulator is a pressure damping mechanism.
5. The method of claim 2 wherein said pump head is operated by an electric motor, and said pressure is controlled by maintaining a predetermined current to said electric motor.