Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Apr 2009
Randomized Controlled TrialEEG entropy values during isoflurane, sevoflurane and halothane anesthesia with and without nitrous oxide.
We hypothesized that like bispectral index, entropy may be anesthetic agent specific. We carried out a study to assess the entropy values of different anesthetics at equi-minimal alveolar concentrations (MACs) with air and nitrous oxide as carrier gases. Thirty adult patients undergoing spine surgery were randomized to receive halothane, isoflurane, or sevoflurane, in 2 stages, (a) with air/oxygen mixture (2:1) and (b) in nitrous oxide/oxygen (2:1). ⋯ At 1.5 MAC for all agents, after addition of nitrous oxide, there was an insignificant reduction in both RE and SE (P>0.05). Again the values of RE and SE remained high for halothane as compared with isoflurane and sevoflurane. In conclusion, our data suggest a possibility of misinterpretation of anesthetic hypnosis when entropy values increase with addition of nitrous oxide to 1 MAC isoflurane and sevoflurane.
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J Neurosurg Anesthesiol · Apr 2009
Measurement of systolic pressure variation during graded volume loss using simple tools on Datex Ohmeda S/5 monitor.
Direct invasive arterial monitoring is performed routinely for all major neurosurgical procedures. Systolic pressure variation (SPV) used, independently or in combination with central venous pressure (CVP) allows optimal fluid management in hypovolemia and hemorrhage. This study aims to quantify SPV during graded hypovolemia using the simple technique described by Gouvea and Gouvea using Datex Ohmeda S/5, and to compare its reliability relative to other hemodynamic indicators of hypovolemia. ⋯ The area under the curve of receiver operating characteristic analysis was >0.75 for CVP, SPV, and PPV. SPV of 7.5 mm Hg and a change of SPV by 4.5 mm Hg, a PPV of 4.5 and change in PPV by 2.5 mm Hg were the best cut-off values that corresponded to a volume change of 500 mL. This simple method enabled calculation of SPV without the computerized modules, and detected volume loss comparable to CVP.
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Anxiety is common in surgical patients, with an incidence of 60% to 92%. There is little information on the incidence and severity of preoperative anxiety in patients scheduled for neurosurgery. The aim of this study was to measure the level of preoperative anxiety in neurosurgical patients and to assess any influencing factors. ⋯ Questionnaire results showed that the most common anxieties were waiting for surgery, physical/mental harm, and results of the operation. In conclusion, our study showed that neurosurgical patients have high levels of anxiety, with a higher incidence in females. There was a moderately high need for information, particularly in patients with a high level of preoperative anxiety.
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J Neurosurg Anesthesiol · Apr 2009
Propofol and ketamine-induced anesthetic depth-dependent decrease of CaMKII phosphorylation levels in rat hippocampus and cortex.
Ca/calmodulin-dependent protein kinase II (CaMKII) activation through autophosphorylation at threonine 286 was involved in the modulation of neuronal excitability and neurotransmission. Both propofol and ketamine may affect the intracellular Ca levels through N-methyl-D-aspartate receptors or voltage-dependent Ca channels, but they have different mechanisms in general anesthesia. The purpose of this study was to investigate the effects of propofol and ketamine on CaMKII total protein and phosphorylation (p-CaMKII) levels in the brain of rats. ⋯ The maximum reduction of p-CaMKII with both drugs was at 60 minutes, and then restored to control level at 240 minutes. In addition, we confirmed the depression of p-CaMKII in hippocampus and frontal cortex of rats after 100 mg/kg of propofol or ketamine treatment for 60 minutes by using immunostaining. These results suggested that decreased p-CaMKII levels correlate with anesthetic depths achieved by propofol and ketamine, which may be related to the effects of propofol and ketamine on central nervous system function and their clinical effect.