A system for managing the temperature of a person using an intravascular heat exchanger inserted into the lumen of a body vessel of a patient, comprising: a refrigeration circuit comprising: a condenser, an expansion valve, a heat exchange block, and a compressor for circulating and compressing a first heat exchange fluid through the condenser, expansion valve 260) and heat exchange block; a heating/cooling element mounted in thermal communication with the heat exchange block; an intravascular fluid circuit comprising: an intravascular heat exchanger (205, 208) having a fluid inlet and a fluid outlet; a first heat exchanger having an inlet port and an outlet port; a first fluid line (215, 815) and a second fluid line; and a pump for circulating a second heat exchange fluid through the intravascular fluid circuit, wherein the pump is configured to pump the second heat exchange fluid through the intravascular heat exchanger (205, 208) and the first heat exchanger, wherein the inlet port of the first heat exchanger is configured to receive the second heat exchange fluid from the fluid output of the intravascular heat exchanger through the first fluid line, and the outlet port of the first heat exchanger is configured to provide the second heat exchange fluid to the fluid input of the intravascular heat exchanger through a second fluid line, wherein the intravascular fluid circuit is separate from and not in fluid communication with the refrigeration circuit and wherein the heat exchange block (230, 830) is placed in thermal contact with first heat exchanger; and a controller (50, 270) having a processor configured by software commands to receive temperature indications related to the temperature of a patient and to control operation of the refrigeration circuit and the heating/cooling element in accordance with a target temperature, to heat or cool the heat exchange block as necessary to maintain the patient's temperature at the target temperature. a refrigeration circuit comprising: a condenser, an expansion valve, a heat exchange block, and a compressor for circulating and compressing a first heat exchange fluid through the condenser, expansion valve 260) and a condenser, an expansion valve, a heat exchange block, and a compressor for circulating and compressing a first heat exchange fluid through the condenser, expansion valve 260) and heat exchange block; a heating/cooling element mounted in thermal communication with the heat exchange block; an intravascular fluid circuit comprising: an intravascular heat exchanger (205, 208) having a fluid inlet and a fluid outlet; a first heat exchanger having an inlet port and an outlet port; a first fluid line (215, 815) and a second fluid line; and a pump for circulating a second heat exchange fluid through the intravascular fluid circuit, wherein the pump is configured to pump the second heat exchange fluid through the intravascular heat exchanger (205, 208) and the first heat exchanger, wherein the inlet port of the first heat exchanger is configured to receive the second heat exchange fluid from the fluid output of the intravascular heat exchanger through the first fluid line, and the outlet port of the first heat exchanger is configured to provide the second heat exchange fluid to the fluid input of the intravascular heat exchanger through a second fluid line, an intravascular heat exchanger (205, 208) having a fluid inlet and a fluid outlet; a first heat exchanger having an inlet port and an outlet port; a first fluid line (215, 815) and a second fluid line; and a pump for circulating a second heat exchange fluid through the intravascular fluid circuit, wherein the pump is configured to pump the second heat exchange fluid through the intravascular heat exchanger (205, 208) and the first heat exchanger, wherein the inlet port of the first heat exchanger is configured to receive the second heat exchange fluid from the fluid output of the intravascular heat exchanger through the first fluid line, and the outlet port of the first heat exchanger is configured to provide the second heat exchange fluid to the fluid input of the intravascular heat exchanger through a second fluid line, wherein the intravascular fluid circuit is separate from and not in fluid communication with the refrigeration circuit and wherein the heat exchange block (230, 830) is placed in thermal contact with first heat exchanger; and a controller (50, 270) having a processor configured by software commands to receive temperature indications related to the temperature of a patient and to control operation of the refrigeration circuit and the heating/cooling element in accordance with a target temperature, to heat or cool the heat exchange block as necessary to maintain the patient's temperature at the target temperature.