In accordance with one embodiment of the present invention, the invention comprises a pliable enclosure containing a Phase Change Material (PCM) that maintains a nearly constant predetermined temperature while transmitting heat during phase change. The predetermined temperature is maintained which the PCM absorbs heat from the body of the patient, thus maintain the patient's body temperature at a nearly constant predetermined temperature for as long as the PCM material is transitioning phase. The pliable enclosure, which in an embodiment forms an enclosed volume, may be comprised of a shell which contains the PCM. The shell may be fabricated from polyethylene, polyurethane, or any other pliable material and may further comprise graphene covering on at least one of its surfaces to provide a tough exterior that is resistant to puncture by, for example, hypodermic needles, suture needles, scalpels, or other sharp instruments.
