Delayed immune dysfunction following hemorrhagic shock and resuscitation

Immune system function is thought to be depressed after hemorrhagic shock. We evaluated the delayed effect of hemorrhagic shock on the immune system in rats with and without spleens and investigated the effect of the colloid hetastarch on reticuloendothelial system (RES) function. There were six groups: controls (N = 30, no shock), two groups of shocked animals resuscitated with either hetastarch (HES, N = 13) or lactated Ringer's (LR, N = 13); the remaining three groups were identical except that splenectomy had been performed (N = 16, N = 14, and N = 16, respectively). One week after shock and resuscitation, all groups were challenged with intravenous Streptococcus pneumoniae; quantitative blood and tissue (liver, lung, and spleen) cultures were then obtained. There were no differences between the HES and LR groups. In nonsplenectomized animals, colony counts in the blood, liver, lung, and spleen were significantly higher in shocked animals when compared with controls. Splenectomized rats had no significant differences between shocked groups and controls. These data demonstrate that delayed immune function is depressed in nonsplenectomized rats. Splenectomy causes more severe immune dysfunction than does shock. Also, in similar animals without splenectomy, hetastarch does not appear to alter delayed RES function.