Effects of infection on oxygen consumption and core temperature in experimental thermal injury

Oxygen consumption (VO2) and colonic temperature (Tc) 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 (Ta) of 32 C, VO2 of the B group rose from 0.83 +/- 0.01 to 1.20 +/- 0.01 ml/hr/g (mean +/- S.E., p less than 0.001) versus 0.81 +/- 0.01 to 0.99 +/- 0.02 for nine nonbacteremic (NB) groups (p less than 0.001). Tc increased only in the B groups--from 36.8 +/- 0.1 to 37.7 +/- 0.1 C (p less than 0.001). In the second or third week postinjury, VO2 of the NB rats was reduced when Ta was increased to 34 C; Tc followed changes in Ta. 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 Tc with wound invasion and systemic infection.