Patient temperature regulation method and apparatus

Abstract

A device and method for providing body cooling. The cooling device applies cooling to blood flowing in a vena cavae that is then distributed throughout the body. The cooling can be assisted by use of thermoregulatory drugs or warming devices to prevent shivering and vasoconstriction.

We claim:  
     
         1 . A cooling system for cooling a patient's body intravascularly, comprising: 
 a flexible catheter insertable into a vena cavae;    a flexible metallic cooling element attached to a distal end of the flexible catheter, the flexible metallic cooling element including a plurality of heat transfer segments connected by flexible joints; and    a heating blanket for applying heat to a selected portion of the patient's body.    
     
     
         2 . The system of    claim 1   , wherein the heat transfer segments further comprise a plurality of exterior surface irregularities, the surface irregularities being shaped and arranged to create mixing in surrounding fluid.  
     
     
         3 . The system of    claim 1   , wherein the heating blanket employs a warm-air blower and includes air channels for evenly distributing warm air to the surface area of the selected portion of the patient.  
     
     
         4 . The system of    claim 1   , wherein the heating blanket includes an electrical resistance heater.  
     
     
         5 . The system of    claim 1   , wherein the flexible joint includes a bellows.  
     
     
         6 . The system of    claim 1   , wherein the flexible joint includes a flexible tube.  
     
     
         7 . The system of    claim 2   , wherein: 
 the surface irregularities comprise a helical ridge and a helical groove formed on each heat transfer segment; and    the helical ridge on each heat transfer segment has an opposite helical twist to the helical ridges on adjacent heat transfer segments.    
     
     
         8 . The system of    claim 1   , further comprising a plurality of interior surface irregularities in the cooling element, the interior surface irregularities being shaped and arranged to create mixing in fluid within the cooling element.  
     
     
         9 . A method for cooling a patient's body intravascularly, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element having mixing-inducing surface features thereon;    inserting the catheter through the vascular system of the patient to place the cooling element in a vein that drains into the heart of a patient;    circulating fluid through the cooling element; and    transferring heat from the blood in the vein to the cooling element.    
     
     
         10 . The method of    claim 9   , further comprising applying heat via a warming device to a substantial portion of the surface area of the patient.  
     
     
         11 . The method of    claim 9   , further comprising applying cooling via a cooling device to a substantial portion of the surface area of the patient.  
     
     
         12 . The method of    claim 9   , further comprising administering a vasoconstrictive drug to the patient.  
     
     
         13 . The method of    claim 10   , wherein the warming device is a heating blanket.  
     
     
         14 . The method of    claim 11   , wherein the cooling device is a cooling blanket.  
     
     
         15 . The method of    claim 9   , further comprising inducing mixing in the blood of the vascular system of the patient.  
     
     
         16 . The method of    claim 9   , further comprising administering a thermoregulatory drug to the patient.  
     
     
         17 . The method of    claim 10   , further comprising administering a thermoregulatory drug to the patient.  
     
     
         18 . The method of    claim 17   , wherein the thermoregulatory drug is selected from the group consisting of clonidine, meperidine, propofol, magnesium, dexmedetomidine, and combinations thereof.  
     
     
         19 . The method of    claim 9   , wherein the cooling element is disposed in a vein selected from the group consisting of the superior vena cava, the inferior vena cava, or both.  
     
     
         20 . A method for substantially reducing platelet aggregation in a blood vessel in which blood is flowing, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element employing surface features and thereby inducing mixing in the blood;    inserting the catheter through the vascular system of the patient to place the cooling element in a blood vessel in which blood is flowing;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood is cooled and platelet aggregation is substantially reduced.    
     
     
         21 . A method for substantially reducing dependence on drug therapies in treating insults or injuries resulting in ischemia, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element employing mixing-inducing surface features;    inserting the catheter through the vascular system of the patient to place the cooling element in a blood vessel in which blood is flowing;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood is cooled.    
     
     
         22 . A method for substantially reducing cell damage during and after a myocardial infarction, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element employing mixing-inducing surface features;    inserting the catheter through the vascular system of the patient to place the cooling element in a vein selected from the group consisting of the superior vena cava, the inferior vena cava, or both;    circulating fluid through the cooling element; and    transferring heat from the blood in the vein to the cooling element,    whereby at least one of platelet aggregation, oxygen demands, or the metabolic rate of the heart is reduced or bradycardia is induced.    
     
     
         23 . The method of    claim 22   , further comprising administering a drug to lower blood pressure.  
     
     
         24 . A method for substantially reducing stenoses recurring following angioplasty, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element employing mixing-inducing surface features;    performing an angioplasty or stenting operation on a blood vessel of the patient;    inserting the catheter through the vascular system of the patient to place the cooling element in the blood vessel;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood and the blood vessel wall is cooled.    
     
     
         25 . A method for substantially reducing reperfusion injury following reflow, comprising: 
 performing a catheter having a cooling element attached to a distal end thereof, the cooling element employing mixing inducing surface features;    performing an reflow operation on a blood vessel of the patient;    inserting the catheter through the vascular system of the patient to place the cooling element in the blood vessel;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood in the vessel is cooled.    
     
     
         26 . A method for cooling a patient's body intravascularly, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element having mixing-inducing surface features thereon;    inserting the catheter through the vascular system of the patient to place the cooling element in the inferior vena cava of a patient;    circulating fluid through the cooling element; and    transferring heat from the blood in the inferior vena cava to the cooling element.    
     
     
         27 . A method for cooling a patient's body intravascularly, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element having mixing-inducing surface features thereon;    inserting the catheter through the vascular system of the patient to place the cooling element in the iliac vein of a patient;    circulating fluid through the cooling element; and    transferring heat from the blood in the iliac vein to the cooling element.    
     
     
         28 . A method for cooling a patient's body intravascularly, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof, the cooling element having mixing-inducing surface features thereon;    inserting the catheter through the vascular system of the patient to place the cooling element in the femoral vein of a patient;    circulating fluid through the cooling element; and    transferring heat from the blood in the femoral vein to the cooling element.    
     
     
         29 . A method of treating a human body, comprising: 
 inserting a flexible conductive heat transfer element into a vein from a distal location; and    circulating a working fluid through the flexible conductive heat transfer element to modify the temperature of the blood in the vein, thereby modifying the temperature of the body.    
     
     
         30 . A method of treating a human body, comprising: 
 inserting a flexible heat transfer element into a vein from a distal location, the flexible heat transfer element having mixing-inducing surface features on the exterior thereof; and    circulating a working fluid through the flexible heat transfer element to modify the temperature of the blood in the vein, thereby modifying the temperature of the body.    
     
     
         31 . A method of treating a human body, comprising: 
 inserting a flexible heat transfer element into a vein from a distal location, the flexible heat transfer element having mixing-inducing surface features on the interior thereof; and    circulating a working fluid through the flexible heat transfer element to modify the temperature of the blood in the vein, thereby modifying the temperature of the body.    
     
     
         32 . A method of treating a human body, comprising: 
 inserting a flexible heat transfer element into a vein from a distal location, the flexible heat transfer element having mixing-inducing features on the surface thereof;    circulating a working fluid through the flexible heat transfer element to modify the temperature of the blood in the vein, thereby modifying the temperature of the body; and    modifying the temperature of at least a portion of the surface of the human body by a surface heater or cooler.    
     
     
         33 . A method of modifying the temperature of a human body, comprising: 
 inserting a heat transfer element into a portion of the vasculature from a distal location, the heat transfer element having mixing-inducing features;    circulating a working fluid through the heat transfer element to modify the temperature of the blood in the vasculature, thereby modifying the temperature of the body.    
     
     
         34 . The method of    claim 33   , wherein said mixing inducing features create a turbulence intensity of at least about 0.05.  
     
     
         35 . The method of    claim 34   , wherein said mixing-inducing features include at least one helical invagination.  
     
     
         36 . The method of    claim 34   , wherein said mixing-inducing features include at least one protrusion.  
     
     
         37 . The method of    claim 33   , wherein said mixing-inducing features create a mixing characterized by a Nusselt number of at least about 5.  
     
     
         38 . The method of    claim 37   , wherein said mixing-inducing features include at least one helical invagination.  
     
     
         39 . The method of    claim 37   , wherein said mixing-inducing features include at least one protrusion.  
     
     
         40 . A method of modifying the temperature of a human body, comprising: 
 inserting a heat transfer element into a portion of the vasculature from a distal location, the heat transfer element having a mixing-inducing shape;    circulating a working fluid through the heat transfer element to modify the temperature of the blood in the vasculature, thereby modifying the temperature of the body.    
     
     
         41 . The method of    claim 40   , wherein said mixing-inducing shape creates a turbulence intensity of at least about 0.05.  
     
     
         42 . The method of    claim 41   , wherein said mixing-inducing shape is a helix.  
     
     
         43 . The method of    claim 41   , wherein said mixing-inducing shape includes a substantially cylindrical body having protrusions thereon.  
     
     
         44 . The method of    claim 40   , wherein said mixing-inducing shape creates a mixing characterized by a Nusselt number of at least about 5.  
     
     
         45 . The method of    claim 44   , wherein said mixing-inducing shape includes at least one helical invagination.  
     
     
         46 . The method of    claim 44   , wherein said mixing-inducing shape includes at least one protrusion.  
     
     
         47 . A method of modifying the temperature of a human body, comprising: 
 inserting a heat transfer element into a portion of the vasculature from a distal location, the heat transfer element having a segmented shape;    circulating a working fluid through the segmented heat transfer element to modify the temperature of the blood in the vasculature, thereby modifying the temperature of the body.    
     
     
         48 . The method of    claim 47   , wherein the segments of the heat transfer element are separated by flexible joints.  
     
     
         49 . The method of    claim 48   , wherein the joints are bellows.  
     
     
         50 . A cooling system for cooling a patient's body intravascularly, comprising: 
 a flexible catheter insertable into a blood vessel;    a flexible cooling element attached to a distal end of the flexible catheter; and    a heating blanket for applying heat to a selected portion of the patient's body, wherein the heating blanket includes an electrical resistance heater.    
     
     
         51 . A method for changing a patient's body temperature intravascularly while controlling the patient's thermoregulatory setpoint, comprising: 
 providing a catheter having a heat exchange element at a portion thereof;    inserting the catheter through the vascular system of the patient to place the heat exchange element in a blood vessel;    circulating fluid through the heat exchange element;    transferring heat from the blood in the vessel to the heat exchange element; and    administering a thermoregulatory drug to the patient.    
     
     
         52 . The method of    claim 51   , wherein the thermoregulatory drug is selected from the group consisting of clonidine, meperidine, propofol, magnesium, dexmedetomidine, and combinations thereof.  
     
     
         53 . A method for changing a patient's body temperature intravascularly while controlling patient shivering, comprising: 
 providing a catheter having a heat exchange element at a portion thereof;    inserting the catheter through the vascular system of the patient to place the heat exchange element in a blood vessel;    circulating fluid through the heat exchange element;    transferring heat from the blood in the vessel to the heat exchange element; and    administering an antishivering drug to the patient.    
     
     
         54 . The method of    claim 53   , wherein the antishivering drug is selected from the group consisting of clonidine, meperidine, propofol, magnesium, dexmedetomidine, and combinations thereof.  
     
     
         55 . A system for modifying the temperature of a patient's body intravascularly, comprising: 
 a flexible catheter insertable into a blood vessel;    a flexible heat transfer element attached to a distal end of said flexible catheter; and    a heat transfer blanket, wherein said heat transfer blanket includes a heat transfer device adapted to transfer heat between said blanket and a portion of the patient's body.    
     
     
         56 . The system recited in    claim 55   , wherein said heat transfer element comprises a cooling element.  
     
     
         57 . The system recited in    claim 55   , wherein said heat transfer element comprises a heating element.  
     
     
         58 . The system recited in    claim 55   , wherein said heat transfer device comprises a heating device adapted to transfer heat from said blanket to the portion of the patient's body.  
     
     
         59 . The system recited in    claim 58   , wherein said heating device comprises an electrical resistance heater.  
     
     
         60 . The system recited in    claim 55   , wherein said heat transfer device comprises a cooling device adapted to transfer heat from the portion of the patient's body to said blanket.  
     
     
         61 . A method for substantially reducing cell damage during angioplasty, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof;    inserting the catheter through the vascular system of the patient to place the cooling element in a first location in a blood vessel, circulating fluid through the cooling element;    transferring heat from the blood in the vein to the cooling element; and    performing angioplasty on the blood vessel at a location proximal of the first location.    
     
     
         62 . A method for cooling a patient's body intravascularly, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof;    inserting the catheter through the vascular system of the patient to place the cooling element in a vein that drains into the heart of a patient;    circulating fluid through the cooling element; and    transferring heat from the blood in the vein to the cooling element.    
     
     
         63 . The method of    claim 62   , further comprising applying heat via a warming device to a substantial portion of the surface area of the patient.  
     
     
         64 . The method of    claim 62   , further comprising applying cooling via a cooling device to a substantial portion of the surface area of the patient.  
     
     
         65 . The method of    claim 62   , further comprising administering a vasoconstrictive drug to the patient.  
     
     
         66 . The method of    claim 63   , wherein the warming device is a heating blanket.  
     
     
         67 . The method of    claim 64   , wherein the cooling device is a cooling blanket.  
     
     
         68 . The method of    claim 62   , further comprising administering a thermoregulatory drug to the patient.  
     
     
         69 . The method of    claim 63   , further comprising administering a thermoregulatory drug to the patient.  
     
     
         70 . The method of    claim 69   , wherein the thermoregulatory drug is selected from the group consisting of clonidine, meperidine, propofol, magnesium, dexmedetomidine, and combinations thereof.  
     
     
         71 . The method of    claim 62   , wherein the cooling element is disposed in a vein selected from the group consisting of the superior vena cava, the inferior vena cava, or both.  
     
     
         72 . A method for substantially reducing platelet aggregation in a blood vessel in which blood is flowing, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof;    inserting the catheter through the vascular system of the patient to place the cooling element in a blood vessel in which blood is flowing;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood is cooled and platelet aggregation is substantially reduced.    
     
     
         73 . A method for substantially reducing dependence on drug therapies in treating insults or injuries resulting in ischemia, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof;    inserting the catheter through the vascular system of the patient to place the cooling element in a blood vessel in which blood is flowing;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood is cooled.    
     
     
         74 . A method for substantially reducing cell damage during and after a myocardial infarction, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof;    inserting the catheter through the vascular system of the patient to place the cooling element in a vein selected from the group consisting of the superior vena cava, the inferior vena cava, or both;    circulating fluid through the cooling element; and    transferring heat from the blood in the vein to the cooling element, whereby at least one of platelet aggregation, oxygen demands, or the metabolic rate of the heart is reduced or bradycardia is induced.    
     
     
         75 . The method of    claim 74   , further comprising administering a drug to lower blood pressure.  
     
     
         76 . A method for substantially reducing stenoses recurring following angioplasty, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof;    performing an angioplasty or stenting operation on a blood vessel of the patient;    inserting the catheter through the vascular system of the patient to place the cooling element in the blood vessel;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood and the blood vessel wall is cooled.    
     
     
         77 . A method for substantially reducing reperfusion injury following reflow, comprising: 
 providing a catheter having a cooling element attached to a distal end thereof;    performing an reflow operation on a blood vessel of the patient;    inserting the catheter through the vascular system of the patient to place the cooling element in the blood vessel;    circulating fluid through the cooling element; and    transferring heat from the blood in the vessel to the cooling element, whereby blood in the vessel is cooled.