Selective organ hypothermia method and apparatus
a technology of organs and hypothermia, applied in the field of organ selection and hypothermia, can solve the problems of placing and achieve the effect of significant demands on the size and flexibility of the catheter
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second embodiment
[0040] the heat transfer element is shown in FIG. 2. This embodiment can be constructed of a tubular material such as nitinol, which has a temperature dependent shape memory. The heat transfer element 28 can be originally shaped like the flexible tube 24 shown in FIG. 1, at room temperature, but trained to take on the coiled tubular shape shown in FIG. 2 at a lower temperature. This allows easier insertion of the catheter assembly 10 through the vascular system of the patient, with the essentially straight but flexible tubular shape, similar to the flexible tube 24. Then, when the heat transfer element is at the desired location in the feeding artery, such as the internal carotid artery, refrigerant flow is commenced. As the expanding refrigerant, such as a 50 / 50 mixture of pentafluoroethane and 1,1,1 trifluoroethane or a 50 / 50 mixture of difluoromethane and pentafluoroethane, cools the heat transfer element down, the heat transfer element takes on the shape of the heat transfer coi...
third embodiment
[0041] the expansion element and the heat transfer element is shown in FIG. 3. This embodiment of the expansion element is an orifice 30, shown at the distal end of the refrigerant supply conduit 20. The outlet of the orifice 30 discharges into an expansion chamber 32. In this embodiment, the heat transfer element is a plurality of hollow tubes 34 leading from the expansion chamber 32 to the refrigerant return lumen 19 of the catheter body 18. This embodiment of the heat transfer element 34 can be constructed of a tubular material such as nitinol, which has a temperature dependent shape memory, or some other tubular material having a permanent bias toward a curved shape. The heat transfer element tubes 34 can be essentially straight, originally, at room temperature, but trained to take on the outwardly flexed “basket” shape shown in FIG. 3 at a lower temperature. This allows easier insertion of the catheter assembly 10 through the vascular system of the patient, with the essentially...
fourth embodiment
[0042] the heat transfer element is shown in FIG. 4. This embodiment can be constructed of a material such as nitinol. The heat transfer element 36 can be originally shaped as a long loop extending from the distal end of the catheter body 18, at room temperature, but trained to take on the coiled tubular shape shown in FIG. 4 at a lower temperature, with the heat transfer element 36 coiled around the capillary tube 22. This allows easier insertion of the catheter assembly 10 through the vascular system of the patient, with the essentially straight but flexible tubular loop shape. Then, when the heat transfer element 36 is at the desired location in the feeding artery, such as the internal carotid artery, refrigerant flow is commenced. As the expanding refrigerant cools the heat transfer element down, the heat transfer element takes on the shape of the coil 36 shown in FIG. 4. This enhances the heat transfer capacity, while limiting the length of the heat transfer element 36. FIG. 4 ...
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