Articles: subarachnoid-hemorrhage.
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Acta Neurol. Scand., Suppl.c · Jan 1987
Intracranial pressure: cerebrospinal fluid dynamics and pressure-volume relations.
Continuous measurement of the intracranial pressure (ICP) is routine in todays evaluation of various intracranial diseases and increased ICP is a common therapeutical problem in neurosurgical patients. Still, very little is known about the patho-physiological and biomechanic events that lead to increased ICP. ICP is governed by 1) the resistance to absorption of cerebrospinal fluid (Rout), 2) the production rate of CSF (If) (taken together Rout and If are referred to as the "CSF dynamics"), and 3) the pressure in the Sagittal Sinus (Pss) in accordance with the equation: ICP = If X Rout + Pss. ⋯ The latter was measured by means of the PVI method and in some instances for reasons of comparison with the constant rate infusion technique and "controlled withdrawal". The main conclusions of the studies were: 1) For estimates of PVI the bolus injection technique was applicable. For Rout measurements the method was only safe at relatively low ICP levels.(ABSTRACT TRUNCATED AT 400 WORDS)
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Acta neurochirurgica · Jan 1987
Evaluation of the calcium-antagonist nimodipine for the prevention of vasospasm after aneurysmal subarachnoid haemorrhage. A prospective transcranial Doppler ultrasound study.
70 consecutive patients admitted within four days after the first aneurysmal subarachnoid haemorrhage (SAH) were evaluated by daily transcranial Doppler ultrasound (TCD) measurement of the blood flow velocities (BFVs) of both middle cerebral arteries (MCAs) and by daily recordings of their clinical grade (Hunt and Hess). Patients with no or only little subarachnoid blood in the first CT after admission were classified as low-risk for the development of symptomatic vasospasm (VSP), and patients with big subarachnoid clots or thick layers of subarachnoid blood were graded as high-risk patients for symptomatic VSP. The first series of 33 patients received no nimodipine whereas the second series of 37 patients were treated with nimodipine 2 mg/h intravenously, starting within 24 hours after the SAH in the majority of patients. 7-14 days postoperatively, the intravenous dose was changed to oral nimodipine 60 mg/q4h for one week and then discontinued. ⋯ Nimodipine given within four days after the SAH did not prevent vasospasm evaluated by TCD, but it significantly reduced the severity of the vasoconstriction, especially in high-risk patients. It reduced significantly the incidence of DIND in high-risk patients and improved their functional outcome. Although nimodipine may have a reduced efficacy in preventing vasospasm after early operation of high-risk patients, it probably protects the brain by increasing its tolerance to focal ischaemia.
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Noncontrast computed tomographic (CT) findings in 10 patients with profound brain swelling or a mass effect revealed a high density of the falx and tentorium and thus suggested subarachnoid hemorrhage. Postmortem examinations performed shortly after the CT scans demonstrated no subarachnoid blood. A review of 100 CT scans drawn at random was carried out to assess the frequency of a hyperdense, noncalcified falx in the same population and failed to demonstrate this finding. Therefore, in the presence of profound brain swelling or a mass effect, factors other than subarachnoid hemorrhage may be responsible for increased density of the falx and tentorium on cranial CT head scans.
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The role of lumbar puncture and computed tomography scanning for initial diagnosis of subarachnoid hemorrhage has been evaluated in a retrospective survey of 283 consecutive cases. The material has been divided into early-and late-diagnosed cases with 72 hours after bleeding as the demarcation line between groups. The early-diagnosed cases have been further subdivided into patients exhibiting contraindications for lumbar puncture, patients with a typical history of apoplectic headache, and patients presenting with a diffuse noncharacteristic history. ⋯ If neck stiffness is not considered, 4.68 computed tomography investigations per 100,000 individuals would be performed yearly in falsely suspected cases, a diminishingly small cost corresponding to less than 1% of all cranial computed tomography scans performed in this region. Early-diagnosed patients with a diffuse atypical history constitute a small, low risk group for lumbar puncture. It may be acceptable in such patients to diagnose subarachnoid hemorrhage either by means of computed tomography or lumbar puncture, depending on the availability of local computed tomography resources.