Articles: brain-injuries.
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General categories of experimental brain injury models are reviewed regarding their clinical significance, and two new models are presented that use different methodology to produce injury. This report describes and characterizes the pathophysiologic changes produced by a novel fluid percussion (FP) method and a controlled cortical impact (CI) technique, both developed at the General Motors Research Laboratories (GMRL). The new models are compared to prior experimental brain injury techniques in relation to ongoing physical and analytical modeling used in automotive safety research by GMRL. ⋯ These controlled variables enable the amount of deformation and the change in deformation over time to be accurately determined. In addition, the CI model produces graded, reproducible cortical contusion, prolonged functional coma, and extensive axonal injury, unlike the FP technique. The quantifiable nature of the single mechanical input used to produce the injury allows correlations to be made between the amount of deformation and the resultant pathology and functional changes.(ABSTRACT TRUNCATED AT 400 WORDS)
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The effects of resuscitation of traumatic-hemorrhagic shock on the brain are unknown. Traumatic shock in sheep (fracture/crush injury, 2-hr hemorrhage to 40 mm Hg) was followed by resuscitation to baseline mean arterial pressure. Two groups without brain injury were resuscitated with lactated Ringer's (LR1, n = 7) or albumin (ALB1, n = 6). Focal brain injury was added in two further groups (LR2, n = 6; ALB2, n = 6). Hemodynamics, intracranial pressure (ICP), EEG, and colloid osmotic pressure (COP) were followed. Brain water (BW) and cerebral blood volume (CBV) were compared to those of controls (C, n = 7). ⋯ ICP rose in all groups. Animals without brain injury did not have increased brain water. Below are results for brain-injured animals after resuscitation (mean +/- SEM). (table; see text) Maintaining COP during initial resuscitation does not minimize cerebral edema: the effects of LR and ALB were similar in this setting. Focal brain injury causes edema but does not cause large increases in ICP with initial resuscitation.