Acta neurochirurgica. Supplement
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Acta Neurochir. Suppl. · Jan 2002
The evaluation of brain CBF and mitochondrial function by a fiber optic tissue spectroscope in neurosurgical patients.
The brain of neurosurgical patients are exposed to various manipulations in the ICU or during surgery. Under such conditions brain O2 balance may become negative and as a result brain vitality and function will deteriorate. In order to evaluate brain vitality in real time it is important to measure more than one parameter. ⋯ Our monitoring device was able to evaluate the efficacy of the STA-MCA anastomosis during aneurysm surgery. 3. A significant correlation was recorded between CBF and NADH redox state during changes in blood pressure, papaverine injection, spontaneous drop in blood supply to the brain or during releasing of high ICP levels. We conclude that in order to evaluate the metabolic state of the brain during neurosurgical procedures it is necessary to monitor both CBF and mitochondrial NADH by using the tissue spectroscope.
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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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Induced blood pressure elevation has become a popular treatment for intracranial hypertension. However, there remains a concern that in some patients blood pressure elevation will further elevate ICP. This study was conducted to test the hypothesis that increasing MAP decreases ICP. ⋯ In patients with lower GCS and high SjvO2 an increase in MAP resulted in an increase in ICP. We concluded that in the majority of studies increasing MAP was followed by an increase in ICP. CPP therapy has a selective indication in patients with high GCS, low SjvO2 and increased ICP.
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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
Continuous cerebral compliance monitoring in severe head injury: its relationship with intracranial pressure and cerebral perfusion pressure.
Cerebral Compliance describes the ability of cranial content to accommodate volume variations. Intracranial vascular compartment is thought to be one of the most important determinants of Compliance. Cerebral perfusion pressure (CPP) has a significant influence upon the calibre of cerebral vessels and consequently, upon blood volume. ⋯ At CPP > or = 60 mmHg Compliance decreased with CPP (R2 = 0.83). In the range of low CPP vasoparalysis is impending. However, when ICP is pathological, at high CPP our results may express vasodilatation instead of expected vasoconstriction from normal autoregulation.