- Anesthetized rats were assigned to sham; brain injury (BI); controlled hemorrhagic shock (CHS); BI combined with CHS (combined injury [CI]); and CI groups resuscitated with 2.5 mL/kg Ringer's lactate solution (RL-2.5), 10 mL/kg RL (RL-10), or 40 mL/kg RL (RL-40). Brain injury was induced by applying 400 millibar negative pressure for 10 s through a hollow screw inserted into a 4.5-mm burr hole drilled into the left parietal region of the skull. Five minutes after BI, 30% of circulating blood volume was withdrawn for 10 min to induce CHS. One hour of fluid resuscitation commenced 20 min posthemorrhage. MAP, lactate, and base excess levels were significantly improved in the RL-40 group compared with all other hemorrhaged groups. The hematocrit level 1 h after resuscitation began was significantly lower in the RL-40 group (27.6% +/- 0.57%) than in all other groups. The RL-40 group had the worst neurological severity score 24 h postsurgery. MAP, lactate, and base excess levels were not significantly improved in the RL-2.5 group, however, the number of surviving neuronal cells in the perilesional brain region was significantly higher than in the CI or RL-40 groups. MAP, lactate, and base excess levels were significantly improved in the RL-10 group (P < 0.05). Mobility and the number of surviving neurons in the perilesional region of the brain were significantly better in the RL-10 group than in the CI or RL-40 groups (P < 0.05). Although massive fluid resuscitation yields preferable hemodynamic and metabolic outcomes, neurological outcomes are better after moderate fluid resuscitation for BI combined with controlled hemorrhagic shock.