Journal of neurotrauma
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Journal of neurotrauma · Jan 1996
Thresholds for cerebral ischemia after severe head injury: relationship with late CT findings and outcome.
Cerebral ischemic insults in at least 30% of severely head injured patients at a very early stage following trauma and are associated with early death. To date, the threshold for ischemia of 18 mL/100g/min used in human head injury studies has been adopted from animal studies (by temporary occlusion of the middle cerebral artery). Since the traumatized brain becomes more susceptible to irreversible damage if accompanied by ischemia one may question whether the threshold for ischemic vulnerability is higher than 18 mL/100 g/min. ⋯ The difference in the proportions was significant at p < 0.001 (chi-square test). We conclude that a measure of atrophy does not correlate with ultra-early CBF. However, based on the clear distinction between survivors and nonsurvivors, we suggest the threshold for ischemia after head injury be redefined as a CBF of 20 mL/100 g/min.
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Journal of neurotrauma · Jan 1996
Comparative StudyMild pre- and posttraumatic hypothermia attenuates blood-brain barrier damage following controlled cortical impact injury in the rat.
Recent studies have demonstrated a neuroprotective effect of mild/moderate hypothermia in models of cerebral trauma and ischemia. In contrast, hypotension is known to exacerbate CNS injury. To better understand the mechanisms whereby hypothermia and hypotension influence secondary neural injury, the present study assessed the effects of these two variables upon blood-brain barrier (BBB) permeability following controlled cortical impact injury. ⋯ Previous results, using this same model, have shown that the progressive posttraumatic increase in BBB permeability is preceded by an increase in cortical. OH and lipid hydroperoxides at the site of injury and is attenuated by the lipid peroxidation inhibitor tirilazad mesylate. Thus, the present results are discussed in terms of the role of free radical-induced lipid peroxidation in the genesis of posttraumatic BBB damage and the possible effects of hypothermia upon this injury process.