Effects of Infection on Oxygen Consumption and Core Temperature in Experimental Thermal Injury

Oxygen consumption (VO₂) and colonic temperature (T_c) were measured in groups of rats before and after 30% total body surface, full thickness burns. Some wounds were seeded with Pseudomonas aeruginosa or Staphylococcus epidermidis, and some seeded wounds were treated with Sulfamylon^$$ or Silvadene^$$. Three groups became bacteremic (B) during the 2–3 week period of observation. At an ambient temperature (T_a) of 32 C, VO₂ of the B groups rose from 0.83 ± 0.01 to 1.20 ± 0.01 ml/hr/g (mean ± S.E., p < 0.001) versus 0.81 ± 0.01 to 0.99 ± 0.02 for nine nonbacteremic (NB) groups (p < 0.001). T_c increased only in the B groups—from 36.8 ± 0.1 to 37.7 ± 0.1 C (p < 0.001). In the second or third week postinjury, VO₂ of the NB rats was reduced when T_a was increased to 34 C; T_c followed changes in T_a. Sulfamylon lowered VO₂ of P. aeruginosa seeded, NB rats. The metabolic cost of wound contamination appeared to vary with bacterial strain. The metabolic effects of infection appear to be a continuum, beginning with a modest rise in VO₂ and progressing to greater increases in VO₂ and T_c with wound invasion and systemic infection.