Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2002
Therapeutic aspects of brain tissue pO2 monitoring after subarachnoid hemorrhage.
Prolonged phases of brain tissue hypoxia (ptiO2 < 10 mmHg) lead to cerebral infarction. Therefore, the present study investigates the role of ptiO2--monitoring to guide hypervolemic hypertensive therapy in patients suffering from severe subarachnoid hemorrhage (SAH). Besides transcranial doppler, neuromonitoring of ICP/CPP was supplemented by ptiO2 monitoring. ⋯ In the infarction group, 13 patients showed transient phases of hypoxia which normalized under induced hypervolemic hypertension and 5 patients developed persistent hypoxia. In the non-infarction group 6 patients showed transient hypoxia and in 5 patients no hypoxic values could be found. In conclusion, monitoring of ptiO2 provides an additional independent parameter to detect hypoxic events and to guide therapy.
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To investigate asymmetry of cerebra autoregulation in head-injured patients with lateral brain contusions. ⋯ Side-to-side difference in cerebral hemodynamic reserve of injured brain is a predictor of fatal outcome following head injury and correlates with the side of contusion or brain expansion.
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Acta Neurochir. Suppl. · Jan 2002
New methods for monitoring cerebral oxygenation and hemodynamics in patients with subarachnoid hemorrhage.
Radiographic cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) do not reflect cerebral hemodynamics and oxygenation and may occur in the absence of clinical deficit and vice-versa. This report is to describe preliminary findings in further development of a non invasive method to estimate regional cerebral oxygenation and perfusion. Measurements were performed with a technique combining near infrared spectroscopy (NIRS) and indocyaningreen (ICG) dye dilution. ⋯ The influence of extracerebral bone and surface tissue on cerebral NIRS signal has not been clarified yet. Therefore a new subdural NIRS probe has been developed, which gives the opportunity to measure directly the concentration of the chromophores in the brain without the influence of extracerebral contamination. In future comparative measurements with conventional NIRS probes on the scalp will allow to quantify and eliminate extracerebral contamination from the NIRS signal.
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Acta Neurochir. Suppl. · Jan 2002
ICP and CBF regulation: a new hypothesis to explain the "windkessel" phenomenon.
The brain tamponade represents the final condition of a progressive intracranial pressure (ICP) increase up to values close to arterial blood pressure (BP) producing a reverberating flow pattern in the cerebral arteries with no net flow. This finding implies intracranial volume changes, therefore a full application of the Monro-Kellie doctrine is impossible. To resolve this contradiction, in eight pigs a reversible condition of brain tamponade was produced by infusing saline into a cerebral ventricle. ⋯ When ICP approached carotid BP values, reverberating BFV waves both at ICA and SS site were simultaneously observed. The arterial and venous reverberating waves appeared to be almost exactly superimposable, with a delay of about 40 msec. This synchronism between the pulsatile arterial and venous BFV indicates that the residual pulsation, still occurring at the arterial proximal level, is compensated by a passive compression-distension of the SS with no blood volume (that is net flow) crossing the intracranial vasculature.
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Acta Neurochir. Suppl. · Jan 2002
Clinical manifestations, character of aneurysms, and surgical results for unruptured cerebral aneurysms presenting with ophthalmic symptoms.
Cases with unruptured cerebral aneurysms presenting with visual symptoms were investigated about their site, size, symptom, operative methods and results. ⋯ These results suggest that in cases with unruptured large or giant aneurysms presenting with ophthalmic symptoms, especially in IC cavernous or IC ophthalmic aneurysms, parent artery occlusion + EC/IC bypass is the safest operative procedure.