Relationships between heat production, heat loss, and body temperature for rats with burn injuries between 26% and 63% of the body surface area

Burn injury in man is characterized by increased body temperature proportional to burn wound size and may represent fever and/or hyperthermia. A nonseptic animal model used to study this phenomena has not been described. To test the hypothesis that large burn injuries in rats would produce increased body temperature, the rectal, skin, and body temperatures were sequentially measured and were calculated for rats in the control group and rats with burn injuries covering 26% to 63% of the body surface area [< or = 35%, 36% to 45%, and > or = 46% body surface area]. The group with burns covering > or = 46% of the body surface area had significantly higher rectal temperatures than did at least one other group on postburn days 7, 9, 11, 13, 18, and 20. On postburn days 7 and 11 this increase was significantly higher than that of all burn and control groups. Animals did not demonstrate any overt evidence of wound infection. These data do not establish a cause for increased body temperature after burn injury but suggest that a reproducible animal model may be possible for the study of the cause of increased body temperature after burn injury.