Methods and devices for prevention of hypothermia in a mammal during prolonged exposure to extreme cold

Abstract

Methods and devices for preventing a change in the core body temperature of a mammal under cold conditions are provided. In the subject methods, a requirement for thermal energy input in said mammal is first detected. In response to the detection of this requirement for thermal energy input, a surface of a portion of the mammal is contacted with a warm temperature medium under negative pressure conditions for a period of time sufficient to introduce thermal energy into the core body of the mammal. The subject devices include at least a means for detecting a requirement for thermal energy input and a means for contacting a surface of the mammal with a warm temperature medium under negative pressure conditions. The subject methods and devices find use in a variety of applications, and are particularly suited for use in maintaining the core body temperature of a mammal substantially constant under cold conditions for an extended period of time.

What is claimed is: 
     
         1 . A method for preventing a change in the core body temperature of a mammal under cold conditions, said method comprising:
 (a) detecting a requirement for thermal energy input in said mammal; and   (b) contacting a surface of a portion of said mammal in response to the presence of said requirement with a warm temperature medium under negative pressure conditions for a period of time sufficient to introduce thermal energy into the core body of said mammal;   whereby the core body temperature of said mammal is prevented from changing under said cold conditions.   
     
     
         2 . The method according to  claim 1 , wherein said requirement is detected by detecting the presence of a thermoregulatory error in said mammal. 
     
     
         3 . The method according to  claim 1 , wherein said thermoregulatory error is detected by detecting the presence of vasoconstriction in said mammal. 
     
     
         4 . The method according to  claim 1 , wherein said method further comprises enclosing said portion of said mammal in a sealed enclosure to produce an enclosed portion of said mammal. 
     
     
         5 . The method according to  claim 1 , wherein said method is a method of maintaining said core body temperature of said mammal substantially constant for a temporal duration of at least about 60 min and said method comprises performing steps (a) and (b) at least twice during said temporal duration. 
     
     
         6 . The method according to  claim 1 , wherein said portion of said mammal is a limb or a portion thereof. 
     
     
         7 . The method according to  claim 6 , wherein said limb is selected from the group consisting of an arm and a leg. 
     
     
         8 . The method according to  claim 4 , wherein said sealed enclosure has a pressure ranging from about −20 to −80 mm Hg. 
     
     
         9 . The method according to  claim 1 , wherein said warm temperature medium has a temperature ranging from about 44 to 48° C. 
     
     
         10 . The method according to  claim 1 , wherein said period of time ranges from about 1 to 600 min. 
     
     
         11 . The method according to  claim 1 , wherein said mammal is a human. 
     
     
         12 . A method for maintaining the core body temperature of a mammal substantially constant for a temporal duration of at least about 60 min under cold conditions, said method comprising:
 (a) monitoring said mammal during said temporal duration for the presence of a thermoregulatory error; and   (b) contacting a surface of an enclosed portion of said mammal in response to the presence of said thermoregulatory error with a warm temperature medium under negative pressure conditions for a period of time sufficient to introduce thermal energy into the core body of said mammal;   whereby the core body temperature of said mammal is maintained substantially constant during said temporal duration.   
     
     
         13 . The method according to  claim 12 , wherein said thermoregulatory error is detected by detecting the presence of vasoconstriction in said mammal. 
     
     
         14 . The method according to  claim 12 , wherein said method further comprises enclosing said portion of said mammal in a sealed enclosure to produce an enclosed portion of said mammal. 
     
     
         15 . The method according to  claim 12 , wherein said portion of said mammal is a limb or a portion thereof. 
     
     
         16 . The method according to  claim 15 , wherein said limb is selected from the group consisting of an arm and a leg. 
     
     
         17 . The method according to  claim 14 , wherein said sealed enclosure has a pressure ranging from about −20 to −80 mm Hg. 
     
     
         18 . The method according to  claim 12 , wherein said warm temperature medium has a temperature ranging from about 44 to 48° C. 
     
     
         19 . The method according to  claim 12 , wherein said period of time ranges from about 5 to 600 min. 
     
     
         20 . The method according to  claim 12 , wherein said mammal is a human. 
     
     
         21 . A method for maintaining the core body temperature of a human substantially constant for a temporal duration of at least about 60 min under cold conditions, said method comprising:
 (a) monitoring said mammal during said temporal duration for the presence of a vasoconstriction; and   (b) contacting a surface of an enclosed portion of said mammal in response to the presence of said vasoconstriction with a warm temperature medium under negative pressure conditions ranging from about −20 to −80 mm Hg for a period of time ranging from about 1 to 600 min;   whereby the core body temperature of said human is maintained substantially constant during said temporal duration.   
     
     
         22 . A device for introducing thermal energy into the core body of a mammal under cold conditions, said device comprising:
 (a) a means for detecting a requirement for thermal energy input in said mammal;   (b) a sealable enclosure for enclosing a portion of said mammal;   (c) a means for producing negative pressure conditions in said sealable enclosure; and   (d) a warming means for producing a warm temperature medium in said sealable enclosure.   
     
     
         23 . The device according to  claim 22 , wherein said portion of said mammal is a limb or portion thereof. 
     
     
         24 . The device according to  claim 23 , wherein said limb is selected from the group consisting of an arm and a leg. 
     
     
         25 . The device according to  claim 22 , wherein said means for detecting a requirement for thermal energy input in said mammal is a means for detecting a thermoregulatory error in said mammal. 
     
     
         26 . The device according to  claim 25 , wherein said means for detecting a requirement for thermal energy input in said mammal is a vasoconstriction detecting means. 
     
     
         27 . The device according to  claim 22 , wherein said means for producing a negative pressure in said sealable enclosure is capable of producing a negative pressure ranging from about −20 to −80 mm Hg. 
     
     
         28 . The device according to  claim 22 , wherein said mammal is a human. 
     
     
         29 . The device according to  claim 22 , wherein said sealable enclosure has a configuration selected from the group consisting of a sleeve, glove and boot.