Articles: brain-injuries.
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J Neurosurg Anesthesiol · Jul 2001
Comparative StudyCould heart rate variability predict outcome in patients with severe head injury? A pilot study.
Despite major improvements in the resuscitation of patients with head injury, the outcome of patients with head trauma often remains poor and difficult to establish. Heart rate variability (HRV) analysis is a noninvasive tool used to measure autonomic nervous system (ANS) activity. The aim of this prospective study was to investigate whether HRV analysis might be a useful adjunct for predicting outcome in patients with severe head injury. ⋯ Referring to the area under the rMSSD ROC curve, HRV might provide useful information in predicting early evolution of patients with severe head trauma. During the awakening period, global HRV and the parasympathetic tone were significantly lower in the worsened neurologic state group. In conclusion, HRV could be helpful as a predictor of imminent brain death and a useful adjunct for predicting the outcome of patients with severe head injury.
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The increased popularity of contact sports worldwide exposes a large number of participants to both acute and chronic traumatic brain injury. Chronic traumatic brain injury (CTBI) represents the cumulative, long-term neurological consequences of repetitive concussive and subconcussive blows to the brain. ⋯ Minimizing the frequency and severity of acute brain injury in sport will be instrumental in accomplishing this goal. The prevention of CTBI will need to be sport specific and will undoubtedly rely on limiting the exposure of high-risk athletes, utilizing of protective equipment, enforcing strict rule adherence, training and supervising athletes, and increasing medical surveillance.
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Intensive care medicine · Jul 2001
Brain energy metabolism during controlled reduction of cerebral perfusion pressure in severe head injuries.
To study cerebral biochemical markers with intracerebral microdialysis and bedside analysis in patients with severe head injuries treated with a controlled reduction of cerebral perfusion pressure (CPP). ⋯ The study shows that pharmacological decrease in CPP according to the "Lund concept" is associated with a normalisation of cerebral metabolism. The study also indicates that intracerebral microdialysis can be used for evaluation of new treatment strategies.
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J. Cereb. Blood Flow Metab. · Jul 2001
Delayed hemorrhagic hypotension exacerbates the hemodynamic and histopathologic consequences of traumatic brain injury in rats.
Alterations in cerebral autoregulation and cerebrovascular reactivity after traumatic brain injury (TBI) may increase the susceptibility of the brain to secondary insults, including arterial hypotension. The purpose of this study was to evaluate the consequences of mild hemorrhagic hypotension on hemodynamic and histopathologic outcome after TBI. Intubated, anesthetized male rats were subjected to moderate (1.94 to 2.18 atm) parasagittal fluid-percussion (FP) brain injury. ⋯ Compared with normotensive TBI rats, hemodynamic depression was significantly greater with induced hypotension in the histopathologically vulnerable (P1) posterior parietal cortex (P < 0.01). Secondary hypotension also increased contusion area at specific bregma levels compared with normotensive TBI rats (P < 0.05), as well as overall contusion volume (0.96 +/- 0.46 mm(3) vs. 2.02 +/- 0.51 mm(3), mean +/- SD, P < 0.05). These findings demonstrate that mild hemorrhagic hypotension after FP injury worsens local histopathologic outcome, possibly through vascular mechanisms.
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J. Cereb. Blood Flow Metab. · Jul 2001
Uncoupling of cerebral blood flow and metabolism after cerebral contusion in the rat.
Positron emission tomography scans of patients with head injuries often show discrete areas of increased 18F-fluorodeoxyglucose uptake ("hot spots") when performed hours to days after the initial ictus. Using quantitative autoradiographic methods, the authors have investigated whether cerebral blood flow and glucose metabolism are uncoupled 2 hours after controlled head injury in an animal model, and whether any "hot spots" are accompanied by changes in cerebral glucose concentration. Experiments were performed on 18 anesthetized, ventilated (1.5% halothane in 2:1 nitrous oxide:oxygen) Sprague-Dawley rats weighing 300 to 330 g. ⋯ In all six rats used for LCGU measurement, there were discrete areas of high metabolism, whereas in all six rats used for LCBF measurement, flow was universally depressed in the boundary zone. Of the six rats used for LCGC determination, there was a discrete area of high signal in only one. The authors conclude that there are discrete areas of uncoupling of cerebral blood flow and metabolism after head injury within 2 hours of cerebral contusion in the rat that cannot be explained by changes in cerebral glucose content in the majority of animals.