Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jul 2002
Clinical TrialVasoactive modulators during and after craniotomy: relation to postoperative hypertension.
Hypertension after craniotomy is frequent. To establish an association between vasoactive modulators and postoperative hypertension, we followed the arterial blood pressure and plasma concentrations of selected substances in patients undergoing craniotomy. Twelve consecutive patients scheduled for operation of a supratentorial brain tumor were anesthetized with thiopental, fentanyl, isoflurane, and pancuronium. ⋯ Only renin levels were higher intraoperatively in group H when compared to group N. However, postoperative levels of catecholamines, aldosterone, renin, and endothelin levels were higher in group H patients. The results suggest that in addition to an increased discharge of the sympathetic system, activation of the renin-angiotensin aldosterone system may also play an important role in the development of postoperative hypertension after craniotomy.
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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.