Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jul 2002
Clinical TrialAmplitudes and intrapatient variability of myogenic motor evoked potentials to transcranial electrical stimulation during ketamine/N2O- and propofol/N2O-based anesthesia.
The aim of the current study was to investigate whether there are differences in amplitudes and intrapatient variability of motor evoked potentials to five pulses of transcranial electrical stimulation between ketamine/N2O- and propofol/N2O-based anesthesia. Patients in the propofol group (n = 13) and the ketamine group (n = 13) were anesthetized with 50% N2O in oxygen, fentanyl, and 4 mg/kg/hr of propofol or 1 mg/kg/hr of ketamine, respectively. The level of neuromuscular blockade was maintained at an M-response amplitude of approximately 50% of control. ⋯ Motor evoked potential amplitudes in the ketamine group were significantly larger than in the propofol group (mean, 10th-90th percentile: 380 microV, 129-953 microV; 135 microV, 38-658 microV, respectively; P <.05). There were no significant differences in motor evoked potential latency (mean +/- standard deviation: 20.9 +/- 2.2 msec and 21.4 +/- 2.2 msec, respectively) and coefficient of variation of amplitudes (median [range]: 32% [22-42%] and 26% [18-41%], respectively) and latencies (mean +/- standard deviation: 2.1 +/- 0.7% and 2.1 +/- 0.7%, respectively) between the ketamine and propofol groups. In conclusion, intrapatient variability of motor evoked potentials to multipulse transcranial stimulation is similar between ketamine/N2O- and propofol/N2O-based anesthesia, although motor evoked potential amplitudes are lower during propofol/N2O-based anesthesia than ketamine/N2O-based anesthesia.
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J Neurosurg Anesthesiol · Jul 2002
Influence of the type and rate of subarachnoid fluid infusion on lethal neurogenic pulmonary edema in rats.
In patients who experience sudden death from spontaneous subarachnoid hemorrhage, more than 90% present with acute pulmonary edema. The underlying pathogenesis of this complication is poorly understood. In addition, the specific role of the extravasated blood products and the associated elevation in intracranial pressure leading to the systemic and pulmonary effects during subarachnoid hemorrhage are not well established. ⋯ These results indicate that the chosen rapid- and slow-injection rates resulted in a similar death rate of 50%. Mortality was similar for blood and albumin administration, pulmonary edema occurred in nonsurvivors in both the rapid- and slow-injection groups, and pulmonary edema is associated with more severe hypertension in the slow-injection group. Furthermore, these results suggest that the development of neurogenic pulmonary edema that is characterized by an acutely increased capillary permeability to proteins is independent of the degree of intracranial pressure increase or the type of fluid administrated.
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J Neurosurg Anesthesiol · Apr 2002
Clinical TrialCombined administration of diltiazem and nicardipine attenuates hypertensive responses to emergence and extubation.
Diltiazem and nicardipine, when injected as a mixture during anesthesia, reduce blood pressure in an additive manner without changing heart rate. The author evaluated the use of this mixture for controlling the blood pressure during emergence from general anesthesia and at extubation. The subjects included 15 preoperative hypertensive (HT) patients who underwent various types of surgery and 18 patients with subarachnoid hemorrhage (SAH) who underwent clipping of a cerebral aneurysm. ⋯ No significant difference (P < .05) in the heart rate was found between the untreated and the treated HT or SAH groups. Two patients in the treated SAH group exhibited tachycardia. The combined administration of diltiazem and nicardipine can help control blood pressure in patients with a possible HT response to emergence from general anesthesia and extubation.
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J Neurosurg Anesthesiol · Apr 2002
Aprotinin and deep hypothermic cardiopulmonary bypass with or without circulatory arrest for craniotomy.
Deep hypothermic cardiopulmonary bypass with or without circulatory arrest has been used to facilitate the surgical repair of complex cerebrovascular lesions. The advantages of deep hypothermia have been tempered by the occurrence of coagulopathy that is associated with substantial morbidity and mortality. This study analyzed retrospectively the records of 13 patients who underwent cerebrovascular neurosurgery using deep hypothermic cardiopulmonary bypass with or without circulatory arrest during the period 1993 through 1999. ⋯ No patients developed postoperative intracranial hemorrhage. There was also no evidence of renal dysfunction, deep venous thrombosis, myocardial infarction, or pulmonary embolism. In conclusion, this study suggests that aprotinin may be beneficial to avoid the coagulopathy that is more likely to occur if deep hypothermic cardiopulmonary bypass with or without circulatory arrest is used for craniotomy without adverse effects on renal function or apparent thrombotic complications.
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J Neurosurg Anesthesiol · Apr 2002
Clinical TrialJugular venous oxygen saturation thresholds in trauma patients may not extrapolate to ischemic stroke patients: lessons from a preliminary study.
The authors' first examinations of 10 patients with severe hemispheric stroke indicate that bedside monitoring of cerebral blood flow (CBF) is of clinical value as a prognostic tool for outcome and as therapy of elevated intracranial pressure (ICP). Jugular venous oximetry, which is easier to handle and provides on-line data, may also be of prognostic value in patients with ischemic stroke. No clinical studies are available on patients with hemispheric infarctions. ⋯ In 8 of 17 pairs of measurements with treated elevated ICP, CMRO2 varied and changes of SjvO2 did not reflect changes in CBF. Jugular bulb oximetry should interpreted with caution in patients with severe hemispheric infarction. Critical thresholds defined in trauma patients may not be extrapolated to ischemic stroke.