Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 1998
Randomized Controlled Trial Comparative Study Clinical TrialICP during anaesthesia with sevoflurane: a dose-response study. Effect of hypocapnia.
In patients with a supratentorial cerebral tumor, an increase in sevoflurane concentration from 1.5% (0.7 MAC) to 2.5% (1.3 MAC) did not change the intracranial pressure (ICP) significantly (12 to 14 mm Hg (medians)). However, a significant increase in cerebral blood flow (CBF) from 29 to 39 ml/100 g/min (medians) was disclosed. During administration of sevoflurane 1.5% and 2.5%, a significant decrease in ICP (3.5 and 3.0 mm Hg (median) respectively) was found when PaCO2 was decreased by 0.8 kPa.
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Acta Neurochir. Suppl. · Jan 1998
Comparative Study Clinical TrialDual-switch valve: clinical performance of a new hydrocephalus valve.
The Dual-Switch valve (DSV) is the first construction on the market which changes between two different valve-chambers in parallel depending on the posture of the patient. In the lying position the valve acts like a conventional differential pressure valve, in the vertical position the high-pressure chamber only opens, when the pressure exceeds the hydrostatic pressure difference between the formanen of Monro and the peritoneal cavity. The new device has been implanted in 32 adult patients with hydrocephalus of different etiology. ⋯ Contrary to conventional differential-pressure valves, adjustable devices and other hydrostatic constructions like the Anti-Siphon-device (ASD) or Deltavalve, the DSV reliably controls the IVP independently of the posture of the patient, the CSF viscosity or the subcutaneous pressure. In contrast to the Orbis-Sigma-valve (OSV) or the Diamond-valve, the DSV does not control the flow but the physiological IVP avoiding the increased risk of mechanical failure. The results of this study give strong evidence that the shunt-therapy of adult hydrocephalic patients can be significantly improved by the DSV.
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Acta Neurochir. Suppl. · Jan 1998
Comparative StudyAn avoidable methodological failure in intracranial pressure monitoring using fiberoptic or solid state devices.
Failure of intraventricular pressure (IVP) measurement in case of catheter blockage is believed to be eliminated by using intraventricular microtransducers. We report about an avoidable methodological error, which may affect the reliability of IVP measurement with these devices. Intraventricular fiberoptic or solid state devices were implanted in 43 patients considered to be at risk for catheter occlusion. ⋯ In patients treated with Type B devices, no erroneous pressure recording could be identified, irrespective if CSF drainage was performed or not. Transducers, which are simply placed inside the ventriculostomy catheter require fluid coupling. They may fail, either during CSF drainage or when the catheter is blocked or placed within the parenchyma.
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Acta Neurochir. Suppl. · Jan 1998
Comparative StudyUse of vasopressors to raise cerebral perfusion pressure in head injured patients.
Cerebral ischemia due to low cerebral perfusion pressure (CPP) is the most important secondary effect of severe head injury. There is consensus regarding the maintenance of this pressure at levels above 70 mm Hg. One way to elevate CPP is by increasing mean arterial pressure (MAP). ⋯ The results were: a) the increase of MAP effectively increased CPP without changes in intracranial pressure (ICP) and cerebral extraction of oxygen (CEO2); b) noradrenaline at a dose of 0.5 mg to 5 mg/h was effective and safe and might be considered the drug of choice; c) dopamine was not as effective at a high dose of 10 to 42.5 micrograms/kg/min; d) methoxamine given as a bolus was an effective way to control sudden decreases in MAP. It made the patients more responsive to dopamine. No important undesirable reactions occurred during the study.