Journal of neurosurgery
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Journal of neurosurgery · Oct 1977
The effect of norepinephrine on the spinal cord circulation and its possible implications in the pathogenesis of acute spinal trauma.
The effect of intra-arterially administered norepinephrine (NE) upon spinal cord blood flow (SCBF), before and after disruption of the blood-cord barrier was studied in dogs. Barrier disruption was accomplished with an intra-arterial bolus injection of 2.5 M urea. Multiple ligations of branches of the posterior aorta and cannula placements ensured that the urea was directed to the lumbar and sacral segments of the cord. ⋯ However, if the blood-cord barrier had been previously disrupted with hypertonic urea, both concentrations of NE resulted in large reductions in SCBF. No such reductions in SCBF were seen with blood-cord barrier disruption and NE if the animals had been pre-treated with the alpha-blocker, phenoxybenzamine (1.5 mg/kg). Some aspects of the possible involvement of NE in the pathophysiology of acute spinal injury are discussed.
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Six patients with a rapidly progressive myelopathy of the Brown-Séquard type are presented (two in detail). Their clinical history, results of laboratory investigations, and surgical exploration revealed cervical spondylosis as the sole cause of this syndrome. We believe that a rapidly progressive myelopathy of Brown-Séquard type even in younger individuals, is often a presenting clinical feature of cervical spondylosis.
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The authors conducted quantitative analysis of computerized tomography (CT) scans to measure tumor size, cerebral edema, and regional blood volume in man. Mass lesions without edema caused a local reduction in blood volume. ⋯ Consideration of the electrolyte changes and water shifts in white-matter edema suggested that the decrease in absorption coefficient seen in CT scans was due to the increase in water content. Thus, in cerebral edema separation of blood vessels as well as increased interstitial pressure decrease blood volume, and the regional differences in turn reflect pressure gradients within the brain.
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Mongrel dogs with experimental spinal cord injury were treated with the carotenoid compound crocetin. It has been shown that crocetin increases the diffusion speed of oxygen through plasma, and should provide a net increase in oxygen at the level of the capillary endothelial cell. The treated animals showed a significant improvement in recovery rates as compared to controls.
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Journal of neurosurgery · Feb 1977
Effect of positive end expiratory pressure ventilation on intracranial pressure in man.
THsi study was designed to define the effect of positive end expiratory pressure (PEEP) ventilation on intracranial pressure (ICP). In 25 patients with severe head trauma with and without associated pulmonary injury the following parameters were simultaneously monitored under mechanical ventilation with and without PEEP:ICP, arterial blood pressure, central venous pressure, arterial blood gases, and cardiac rate. In addition, the volume-pressure response (VPR) was evaluted in each patient to assess cerebral elastance. ⋯ Half of this latter group manifested impairment of cerebral perfusion pressure to levels less than 60 mm Hg. Return to baseline CIP levels was observed with termination of PEEP. No significantly consistent changes in other parameters were noted.