The incidence of seizures after rehydration of hypernatremic rabbits with intravenous or ad libitum oral fluids.

Hypernatremic dehydration (mean plasma sodium, 184 mEq/L) was produced over a 3-5 d period in 71 rabbits. The dehydrated animals were divided into groups and rehydrated by intravenous (4, 6, and 8 h duration) or oral (4 and 24 h duration) solutions in amounts calculated to return plasma Na to 140 mEq/L. Plasma was obtained serially from each animal for electrolyte and osmolality determinations during dehydration and rehydration. Samples of brain hemisphere and cortex were obtained for chemical analysis from every animal immediately after death. The incidence of seizures was significantly less (P less than 0.025) in rabbits rehydrated orally when compared with rabbits rehydrated by the intravenous route. Brain water content was significantly greater in rabbits rehydrated intravenously when compared with normal rabbits and rabbits rehydrated orally. In addition, the amount of brain water was greater in rabbits with seizures when compared with those which did not have seizure manifestations. The mechanism underlying the significant reduction in seizures when the animals were rehydrated orally may relate to an integration of drinking behavior with rehydration status. Administration of oral fluids may provide an effective method of therapy for some patients with hypernatremic dehydration.