The present invention relates to a portable apparatus for warmingbiocompatible fluids for use in the treatment ofinjured patients and a method of heating a biocompatible fluid to treat apatient experiencing hypothermia. The present inventionmay be used to warm intravenous fluids for trauma resuscitation or to warm airfrom a ventilator circuit. The portable nature of thepresent invention makes it highly suitable for field applications, such as aforward surgical hospital near a combat zone.