Journal of neurosurgical anesthesiology
-
J Neurosurg Anesthesiol · Oct 1997
Clinical TrialEffect of sedative and hypnotic doses of propofol on the EEG activity of patients with or without a history of seizure disorders.
Propofol is alleged to possess both pro- and anticonvulsant properties, leading to controversy regarding its use in patients with a history of seizures. Since propofol is administered for both sedation and hypnosis, it is important to understand the effects of low (0.5-1.0 mg/kg) and high (2-2.5 mg/kg) doses of propofol on the electroencephalogram (EEG). In this study, the hemodynamic and EEG effects of cumulative doses of propofol from 0.5 to 2.5 mg/kg i.v. were studied in 30 neurosurgical patients with or without a history of seizure disorders. ⋯ Overall, there were no significant differences in the spectrum of EEG changes between the two patient populations. It is concluded that propofol produces similar dose-dependent effects on EEG activity in patients with or without a history of seizure disorders. While induction of anesthesia with higher doses of propofol (> 1.5 mg/kg) in neurosurgical patients with well controlled seizure disorder is safe, smaller sedative doses should be administered with caution to epileptic patients.
-
J Neurosurg Anesthesiol · Jul 1997
Randomized Controlled Trial Clinical TrialThe use of ketamine or etomidate to supplement sufentanil/N2O anesthesia does not disrupt monitoring of myogenic transcranial motor evoked responses.
Intraoperative monitoring of myogenic transcranial motor evoked responses (tc-MERs) requires an anesthetic technique that minimally depresses response amplitudes. Acceptable results have been obtained during opioid/N2O anesthesia, provided that the concentration of N2O does not exceed 50%. However, this technique may necessitate supplementation with additional agents to achieve adequate depth of anesthesia. ⋯ Administration of ketamine did not significantly change tc-MER amplitudes, whereas etomidate resulted in a transient amplitude depression to 72% of control (p < 0.05) at 2 min after injection. Latency remained unchanged with both drugs. In conclusion, the data suggest that both ketamine (0.5 mg/kg) and etomidate (0.1 mg/kg) can be used to supplement sufentanil/N2O anesthetic without disrupting tc-MER monitoring.
-
J Neurosurg Anesthesiol · Jul 1997
The effect of isoflurane on biochemical changes during and electrophysiological recovery after anoxia in rat hippocampal slices.
It is unclear whether isoflurane protects against neuronal damage. This study examines the extent and mechanism by which isoflurane might affect anoxic neuronal damage. The size of the evoked postsynaptic population spike recorded from the CA 1 pyramidal cell layer of the rat hippocampal slice 60 min after anoxia was compared with its preanoxic, preisoflurane level. ⋯ Isoflurane did not significantly attenuate the changes in these ions during anoxia. In conclusion, isoflurane does not significantly improve recovery of CA 1 pyramidal cells during anoxia nor does it attenuate the anoxic changes in ATP, sodium, and potassium after 4 or 7 min of anoxia. With a more prolonged period of anoxia (10 min) isoflurane reduces the decrease in ATP levels.
-
J Neurosurg Anesthesiol · Jul 1997
Randomized Controlled Trial Comparative Study Clinical TrialConvection versus conduction cooling for induction of mild hypothermia during neurovascular procedures in adults.
Hypothermia for cerebral protection is usually achieved by administration of intravenous fluids at room temperature, cooling ambient air, ice packs, and a temperature-adjustable circulating water mattress. We compared cooling by conduction by using a water mattress to cool by convection by using a forced-air cooling device. Twenty patients were prospectively randomized to two groups: 10 patients cooled by convection (CC) and 10 patients cooled by traditional methods (TC). ⋯ CC, 142 +/- 21 min). One patient had some arrhythmias on cooling in the convective group, but her preoperative condition may have been responsible. In conclusion, cooling by convection appears to be a safe alternative to conduction cooling.
-
J Neurosurg Anesthesiol · Jul 1997
Clinical TrialComputer-controlled infusion of propofol for long neurosurgical procedures.
This study evaluated the performance of a computer-controlled infusion (CCI) system for propofol during long neurosurgical procedures. Anesthesia was induced and maintained in 15 patients using a CCI of propofol. The initial target concentration was set at 3 micrograms/ml, and this was then titrated according to the clinical situation. ⋯ MDPE and MDAPE during the first 20 min after stopping the infusion were -38.7% and 39.0%, respectively. The CCI system did not show significant changes in predictive ability, with time during anesthesia lasting up to 12 h. Changes in the measured blood concentration were in the same direction as changes in the target concentration.