EARLY INFLAMMATORY RESPONSE CORRELATES WITH THE SEVERITY OF INJURY

Objective: To determine if the early inflammatory response correlates with the severity of injury in a blunt trauma model in rats, Design: P rospective, randomized, controlled trial, Setting: Research laboratory , Subjects: Male Sprague-Dawley rats, weighing 250 to 400 g, Intervent ions: Twenty-two male Sprague-Dawley rats were divided randomly into s ingle hindlimb fracture, bilateral hindlimb fracture, and no fracture groups, At 90 mins, all animals under-went midline laparotomy and aspi ration of blood from the inferior vena cava, Venous blood gas, plasma lactate, and plasma concentrations of tumor necrosis factor (TNF), pro staglandin F (6-keto-PGF(1 alpha)), and interleukin (IL)-6 were sample d, Statistical analysis was done via one-way analysis of variance and Scheffe post hoc analysis, In a second part of this experiment, the ef fect of hemorrhage on the release of IL-6 was evaluated, Animals in th is group were compared with control and bilateral hindlimb fracture an imals, using the Student's t-test, Measurements and Main Results: Ther e were no significant differences in venous pH or base deficit among t he groups, Oxygen saturation was significantly decreased in the bilate ral hindlimb fracture group when compared with the control group, In t he hemorrhage plus bilateral fracture group, oxygen saturation was sig nificantly decreased when compared with the bilateral fracture group. Lactate concentrations in plasma were increased in both fracture group s as well as the hemorrhaged groups, Plasma TNF concentrations were in creased in the injured groups but there was no significant difference between single and bilateral hindlimb fracture groups, The 6-keto-PGF( 1 alpha) concentrations were increased in both of the fracture groups when compared with the control group and there was a significant diffe rence between single and bilateral hindlimb fracture groups, Similarly , circulating IL-6 concentrations were significantly higher in the bil ateral fracture group than in the single fracture group; both fracture groups were significantly higher than the control group, Hemorrhaged animals had even higher IL-6 concentrations. Conclusions: Plasma lacta te and TNF concentrations were affected by injury, however their conce ntrations did not correlate with degree of injury, IL-6 concentrations were increased early postinjury and correlated with severity of injur y, The 6-keto-PGF(1 alpha) concentrations in plasma also correlated wi th the severity of injury and this phenomenon may represent early endo thelial activation which may be the source of IL-6 release.