Guinea pigs with large burns are consistently hypermetabolic without an associated increment in rectal temperature

This study was conducted to examine the guinea pig as a suitable model for the study of the postburn hypermetabolic response and the febrile response that accompanies burn injury in man. Thirty animals were randomly assigned to four groups: > 50% body surface area burn (n = 6); 45% to 50% body surface area burn (n = 10); < 45% body surface area burn (n = 6); and controls (n = 8). On postburn days 3, 7, 11, 13, and 15, sequential temperature measurements were made. On postburn days 7 to 15, the randomly selected burn group (n = 12) and the control group (n = 8) had calorimetry studies performed. Sequential rectal temperature data demonstrate that the guinea pig does not mount a prolonged or consistent febrile response after burn injury (p > 0.05 for burn group vs control group on postburn days 7 to 13; p < 0.05 for postburn days 3 and 15 only). However, the burned guinea pig is significantly hypermetabolic after burn injury, with significant increases in dry and evaporative heat loss. The hypermetabolic response was proportional to burn wound size. Guinea pigs are not an ideal model for the study of the postburn febrile response; however, this is an excellent model for the study of postburn hypermetabolism.