Apparatus and method for providing enhanced heat transfer from a body

Abstract

Methods and apparatuses for temperature modification of a patient, or selected regions thereof, including an induced state of hypothermia. The temperature modification is accomplished using an in-dwelling heat exchange catheter within which a fluid heat exchange medium circulates. A heat exchange cassette is attached to the circulatory conduits of the catheter, the heat exchange cassette being sized to engage a cavity within a control unit. The control unit includes a heater/cooler device for providing heated or cooled fluid to a heat exchanger in thermal communication with the fluid heat exchange medium circulating to the heat exchange catheter, a user input device, and a processor connected to receive input from various sensors around the body and the system. A temperature control scheme for ramping the body temperature up or down without overshoot is provided.

1 . (canceled) 
     
     
         2 . A patient temperature management system for adjusting the temperature of a patient, the system comprising:
 a heat exchanger configured to change a body temperature of the patient, the heat exchanger comprising heating or cooling device that is placed externally on the patient;   a primary fluid circuit comprising a device for heating or cooling fluid of the primary fluid circuit;   a secondary fluid circuit in fluid communication with the heat exchanger and in thermal communication with the fluid of the primary fluid circuit;   a temperature sensor configured to provide a signal representative of the body temperature of the patient; and   a controller configured to receive the signals from the temperature sensor to control the heat exchanger, the controller configured to perform operations comprising:
 obtaining a user input indicative of a target temperature for the patient; 
 obtaining an upper temperature threshold relative to the target temperature for the patient; 
 obtaining a lower temperature threshold relative to the target temperature for the patient; 
 obtaining, based on the signal from the temperature sensor, temperature data representing the body temperature of the patient; 
 based on the user input, determining a mode of operation for the heat exchanger, the mode of operation being for at least heating the patient, at least cooling the patient, or neither heating or cooling the patient by the primary fluid loop, the mode of operation being a first mode of operation selected from a plurality of modes, each mode of operation corresponding to a portion of a heat exchange therapy; 
 based on the first mode of operation, causing the heat exchanger to add or remove heat from the patient to reduce a difference between the body temperature and the target temperature; 
 determining that the patient temperature is between the upper temperature threshold and the lower temperature threshold responsive to causing the heat exchanger to add or remove heat from the patient; and 
 in response to determining that the patient temperature is between the upper temperature threshold and the lower temperature threshold, updating the first mode of operation to a second mode of operation that is a next portion of the heat exchange therapy. 
   
     
     
         3 . The system of  claim 2 , wherein the heating or cooling device that is placed externally on the patient comprises a pad. 
     
     
         4 . The system of  claim 2 , wherein the heating or cooling device that is placed externally on the patient comprises a blanket. 
     
     
         5 . The system of  claim 2 , further comprising a user interface configured to display the target temperature. 
     
     
         6 . The system of  claim 2 , further comprising a user interface configured to display the body temperature. 
     
     
         7 . The system of  claim 2 , further comprising a user interface configured to display a cooling or warming rate. 
     
     
         8 . The system of  claim 2 , further comprising a control panel that enables modification of the target temperature. 
     
     
         9 . The system of  claim 2 , further comprising a control panel having at least one alarm button. 
     
     
         10 . The system of  claim 2 , the operations further comprising receiving the signal representing the body temperature from the temperature sensor, and causing an alarm to be sounded. 
     
     
         11 . The system of  claim 2 , further comprising a cassette receiver which includes an internal cavity to receive a heat exchange cassette. 
     
     
         12 . The system of  claim 2 , further comprising a fluid circuit including at least one valve, wherein the controller is configured to open or close the at least one valve to control fluid flow in the fluid circuit. 
     
     
         13 . The system of  claim 12 , wherein the valve comprises one of a quick connect valve or a quick shut-off valve. 
     
     
         14 . The system of  claim 2 , further comprising a reservoir in fluid communication with the primary loop, the reservoir configured to store heat exchange fluid that is heated or cooled to the target temperature for the patient. 
     
     
         15 . A method for adjusting a temperature of a patient, the method comprising:
 obtaining, by a controller, a user input indicative of a target temperature for the patient, the controller being configured to receive signals from a temperature sensor and control a heat exchanger in a secondary fluid loop that is in thermal communication with the primary fluid loop, the heat exchanger being configured to change a body temperature of the patient, the heat exchanger comprising a heating or cooling device that is placed externally on the patient;   based on the user input, determining, by the controller, a mode of operation for the heat exchanger, the mode of operation being for at least heating the patient, at least cooling the patient, or neither heating or cooling the patient by the secondary fluid loop, the mode of operation being a first mode of operation selected from a plurality of modes, each mode of operation corresponding to a portion of a heat exchange therapy;   based on the first mode of operation, causing the heat exchanger to add or remove heat from the patient to reduce a difference between the body temperature and the target temperature;   determining that the patient temperature is between an upper temperature threshold and a lower temperature threshold responsive to causing the heat exchanger to add or remove heat from the patient; and   in response to determining that the patient temperature is between the upper temperature threshold and the lower temperature threshold, updating the first mode of operation to a second mode of operation that is a next portion of the heat exchange therapy.   
     
     
         16 . The method of  claim 15 , wherein the heating or cooling device that is placed externally on the patient comprises a pad. 
     
     
         17 . The method of  claim 15 , wherein the heating or cooling device that is placed externally on the patient comprises a blanket. 
     
     
         18 . The method of  claim 15 , further comprising receiving, by the controller, a signal representing the body temperature of the patient from the temperature sensor; and
 causing, by the controller in response to the receiving the signal, an alarm to be sounded.   
     
     
         19 . The method of  claim 15 , further comprising receiving, at a cassette receiver, a heat exchange cassette in an internal cavity of the cassette receiver, the heat exchange cassette being connected the heat exchanger. 
     
     
         20 . The method of  claim 15 , further comprising controlling, by the controller, a fluid circuit including at least one valve by opening or closing the at least one valve to control fluid flow in the fluid circuit. 
     
     
         21 . The method of  claim 15 , wherein a reservoir is in fluid communication with the primary loop, the method comprising storing, in the reservoir, heat exchange fluid that is heated or cooled to the target temperature for the patient.