Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Oct 1998
Case ReportsUpper airway obstruction by retropharyngeal hematoma after cervical spine trauma: report of a case treated with percutaneous dilational tracheostomy.
The authors report the case of a patient affected by a cervical spine trauma who developed upper airway obstruction as a result of a retropharyngeal hematoma. An endotracheal intubation with a small-diameter tube was performed, but ventilation and oxygenation were not adequate. An early Percutaneous Dilational Tracheostomy with the Ciaglia technique was then performed. The risk of upper airway obstruction by retropharyngeal hematoma after cervical spine trauma is discussed in this article, as are the feasibility and benefits of using Percutaneous Dilational Tracheostomy in emergency cases of upper airway obstruction.
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J Neurosurg Anesthesiol · Oct 1998
Cerebrovascular effects of high intracranial pressure after moderate hemorrhage.
Patients with head injuries often develop increased intracranial pressure after hemorrhage. The authors studied the effect of moderate hemorrhage followed by elevated intracranial pressure on cerebrovascular variables. Cerebral blood flow in 13 pigs was measured with laser Doppler flowmetry, and cerebral venous blood gases were taken from the sagittal sinus. ⋯ High intracranial pressure after hemorrhage decreased cerebral blood flow to 14% of baseline values. Sagittal sinus oxygen saturation decreased to 22%, cerebral perfusion pressure decreased to 30%, and the cerebrovascular resistance increased by 355%. The moderate hypotension after hemorrhage caused a considerable enhancement of the effects of high intracranial pressure on cerebral hemodynamics.
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J Neurosurg Anesthesiol · Jul 1998
Comparative StudyThe effects of mild hypothermia on thiopental-induced electroencephalogram burst suppression.
Thiopental intravenous injections before temporary clipping and mild hypothermia have protective effects in the setting of cerebral ischemia, and are used clinically in some centers. However, it is not known whether mild hypothermia affects thiopental-induced electroencephalogram (EEG) burst suppression. In this study, the authors compared the onset and duration of EEG suppression by thiopental in normothermic (n=10) and mildly hypothermic (n=10) patients undergoing cerebral aneurysm surgery. ⋯ Onset time was shortened (25.8+/-1.4 versus 43.5+/-5.6 seconds), and duration of suppression (531.0+/-56.6 versus 165.0+/-16.9 seconds) and the maximum duration of isoelectric EEG (47.7+/-5.8 versus 22.8+/-2.0 seconds) were prolonged in the patients with mild hypothermia. In two normothermic patients, the standard dose of thiopental did not produce burst suppression, but only a mild decrease in spectral edge frequency. The authors concluded that the effects of mild hypothermia on thiopental-induced EEG suppression are not simply additive, but synergistic.
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J Neurosurg Anesthesiol · Jul 1998
The effect of sevoflurane on myogenic motor-evoked potentials induced by single and paired transcranial electrical stimulation of the motor cortex during nitrous oxide/ketamine/fentanyl anesthesia.
To overcome anesthetic-induced depression of myogenic motor-evoked potentials (MEPs), several techniques of stimulation using paired pulses or trains of pulses are used. This study investigated the effect of sevoflurane on myogenic MEPs induced by single and paired transcranial electrical stimulation of the motor cortex. Nine patients undergoing elective spinal surgery were anesthetized with fentanyl-N2O-ketamine. ⋯ The success rate of MEP recording during the administration of sevoflurane was greater after paired stimulation than after single stimulation, and percentage MEP amplitude (percentage of the control value after single stimulation but before sevoflurane) after paired stimulation was significantly higher than after single stimulation before and during the administration of 0.25 MAC and 0.5 MAC sevoflurane. The success rate of MEP recording and MEP amplitude after paired stimulation decreased in a dose-dependent manner during the administration of sevoflurane. These results suggest that although facilitation by the second stimulus was considerable, paired stimuli are still not sufficient to overcome the depressant effects of sevoflurane in clinically used concentrations.
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J Neurosurg Anesthesiol · Jul 1998
Randomized Controlled Trial Clinical TrialTranscranial Doppler sonography mean flow velocity during infusion of ultrapurified bovine hemoglobin.
A number of studies have shown that polymerized bovine hemoglobin (HBOC-201) does not cause clinically significant side effects. This has been demonstrated in spite of the fact that a primary increase in oxygen extraction ratio has been associated with an increase in systemic vascular resistance (SVR) and a decrease in cardiac index (CI). The current study investigated the effects of HBOC-201 on cerebral circulation. ⋯ Cardiac indices were significantly lower in Group 1 (1.7-1.8 l/minute x m(-2)) than in Group 2 (2.4-2.7 l/minute x m(-2)) after PM 3. After hemodilution, mean flow velocity showed an insignificant increase in both groups, ranging from 39 to 46 cm/second. Although SVR increased significantly following HBOC-201 -infusion, the results of this study did not reveal changes in cerebral blood flow that establish significant group-to-group differences.