HYPERTONIC SALINE IMPROVES BRAIN RESUSCITATION IN A PEDIATRIC MODEL OF HEAD-INJURY AND HEMORRHAGIC-SHOCK

Introduction: Blain injury accompanied by hypovolemic shock is a frequ ent cause of death in multiply injured children. Hypertonic saline (HT S) has been shown to return hemodynamics to normal in adult models, wi thout increasing intracranial pressure (ICP) as seen with crystalloids . To assess fluid resuscitation, the authors evaluated HTS versus lact ated Ringer's solution (LR) with respect to hemodynamics and cerebrova scular hemoglobin oxygen saturation (Sco(2)) in anesthetized, head-inj ured, 1-month-old piglets. Methods: Group 1 (n = 6) was studied for 3. 5 hours after a cryogenic brain injury and no shock. Groups 2 and 3 ha d cryogenic blain injury followed by hemorrhagic shock, in which mean arterial pressure (MAP) was reduced to 40 to 50 mm Hg and maintained f or 30 minutes. Group 2 (n = 5) was then resuscitated with 1 mL of 7.5% HTS per 1 mL of blood loss. Group 3 (n = 6) was resuscitated with 3 m L of LR per 1 mL of blood loss. Sco(2) was determined by near-infrared spectroscopy in the injured region of the brain. All data were analyz ed using analysis of variance with repeated measures. Results: MAP, IC P, temperature, serum sodium, and cardiac output (GO) were similar in all groups during baseline and between groups 2 and 3 during shock. Af ter resuscitation, MAP, CO, and core temperature were similar in all t hree groups, and serum sodium was increased in the HTS group (by 29%). Sco(2) increased transiently after cryogenic injury in all groups, th en gradually decreased to below baseline. After shock, Sco(2) decrease d precipitously in groups 2 and 3. After resuscitation, Sco(2) was dif ferent in the two resuscitation groups, increasing in the HTS group, a bove baseline values, but remaining below baseline values in the LR gr oup (P < .002). ICP was lowered by HTS resuscitation and increased by LR resuscitation (P < .002). Conclusion: In our model of head injury a nd shock, resuscitation with either HTS or LR restored MAP and CO to c ontrol levels. However, during shock, the injured brain was severely d eoxygenated, and administration of HTS restored cerebral oxygenation w hereas LR did not, reflecting improved cerebral resuscitation by HTS w ithout elevating ICP. The data suggest that HTS is a better resuscitat ion fluid than LR in head-injured children with hemorrhagic shock. Cop yright (C) 1996 by W.B. Saunders Company