Brain edema and neurological status with rapid infusion of lactated Ringer's or 5% dextrose solution following head trauma

Rapid infusion of 0.25 ml/g of 0.9% saline over 30 minutes has been shown to have no effect on electrolyte balance, neurological severity score (NSS), or brain edema, following closed head trauma (CHT). Rapid infusion of the same volume of 5% dextrose solution decreased blood sodium concentration, increased edema, and decreased NSS following CHT. In the present study the authors examined the effect of rapid infusion (30 minutes) of smaller volumes of 5% dextrose (0.08 ml/g and 0.16 ml/g) and of 0.25 ml/g lactated Ringer's solution on blood electrolyte concentrations, plasma osmolality, brain edema, and NSS. The purposes of this study were to determine whether rapid infusion of a large volume of lactated Ringer's solution could be given after CHT without increasing mortality or brain edema or producing electrolyte disturbances, and whether small volumes of 5% dextrose could be infused with few or none of the deleterious effects expected from large volumes of 5% dextrose. One hundred eighteen rats, which survived halothane anesthesia and CHT, were randomly assigned to one of 15 experimental groups. Fluids were administered beginning 1 hour after scalp incision or CHT. The NSS, extent of edema, blood electrolyte concentrations, and plasma osmolality in the groups treated with lactated Ringer's solution were not significantly different from those values in the nontreated groups. In addition, the mortality rate after CHT was not increased by administration of lactated Ringer's solution. The groups treated with 5% dextrose solution showed a significantly higher mortality rate, but the NSSs of the surviving rats were not different from controls. None of the groups treated with 0.16 ml/g 5% dextrose solution survived 24 hours. Although blood glucose concentration increased to 1126 ± 102 g% (mean ± standard deviation) and 1568 ± 283 g% and blood sodium concentration decreased to 110.4 ± 4.6 mEq/L and 92.0 ± 5.2 mEq/L in the groups treated with 0.08 ml/g and 0.16 ml/g of 5% dextrose solution, respectively, plasma osmolality was normal and no significant difference could be found between the brain tissue specific gravity of animals in the nontreated and 5% dextrose treatment groups. It is concluded that in the CHT model used in this study, the large volume of lactated Ringer's solution did not affect blood electrolyte concentration, neurological outcome, or formation of brain edema, whereas smaller volumes of 5% dextrose solution increased blood glucose and decreased blood sodium concentrations, did not affect plasma osmolality, and had a deleterious effect on neurological outcome.