Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jul 2007
Propofol and remifentanil effect-site concentrations estimated by pharmacokinetic simulation and bispectral index monitoring during craniotomy with intraoperative awakening for brain tumor resection.
Different anesthetic techniques have been suggested for craniotomy with intraoperative awakening. We describe an asleep-awake-asleep technique with propofol and remifentanil infusions, with pharmacokinetic simulation to predict the effect-site concentrations and to modulate the infusion rates of both drugs, and bispectral index (BIS) monitoring. Five critical moments were defined: first loss of consciousness (LOC1), first recovery of consciousness (ROC1), final of neurologic testing (NT), second loss of consciousness (LOC2), and second recovery of consciousness (ROC2). ⋯ At ROC2, predicted effect-site concentrations of propofol and remifentanil were, respectively, 1.2+/-0.5 microg/mL and 1.4+/-0.2 etag/mL (data are mean+/-SE). A significative correlation was found between BIS and predicted effect-site concentrations of propofol (r=0.547, P<0.001) and remifentanil (r=0.533, P<0.001). Multiple regression analysis between BIS and propofol and remifentanil predicted effect-site concentrations at the different critical steps of the procedure was done and found also significative (r=0.7341, P<0.001).
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J Neurosurg Anesthesiol · Jul 2007
Randomized Controlled TrialQuantification of burst suppression and bispectral index with 2 different bolus doses of thiopentone sodium.
Metabolic suppression caused by barbiturates is a major mechanism responsible for their cerebral protective potential. Maximal cerebral metabolic suppression is believed to coincide with electroencephalographic burst suppression. However, many neurosurgical procedures associated with cerebral ischemic threat are still performed in the absence of electroencephalogram monitoring, especially in developing nations. ⋯ We conclude that thiopentone in a bolus dose of 3 to 5 mg/kg produces only a short duration of incomplete burst suppression. Also, in this dose range, burst suppression does not occur consistently in all patients. The present data suggest that bolus doses of thiopentone in the range of 3 to 5 mg/kg may have very limited value in providing significant metabolic suppression required for intraoperative cerebral protection during temporary ischemic episodes.
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J Neurosurg Anesthesiol · Jul 2007
Management of the airway in patients undergoing cervical spine surgery.
The perioperative management of the airway in patients with cervical spine disease requires careful consideration. In an observational prospective cohort study, we assessed the preoperative factors that may have influenced the anesthesiologists' choice for the technique of intubation and the incidence of postoperative airway complications. We recorded information from 327 patients: mean (+/-SD) age 51+/-15 year, 138 females and 189 males, for anterior surgical approach (n=195) and posterior (n=132). ⋯ There was no association between method of intubation and postoperative airway complications. Acute postoperative airway obstruction occurred in 4 (1.2%) patients requiring reintubation. The technique of management of the airway for cervical spine surgery varied considerably among the anesthesiologists, although the choice was not associated with postoperative airway complications.
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J Neurosurg Anesthesiol · Jul 2007
Quantitative evaluation of the neuroprotective effects of thiopental sodium, propofol, and halothane on brain ischemia in the gerbil: effects of the anesthetics on ischemic depolarization and extracellular glutamate concentration.
Although propofol and thiopental are commonly used as neuroprotective agents, it has not been determined which is more neuroprotective. This study was designed to quantitatively evaluate the neuroprotective effects of thiopental, propofol, and halothane on brain ischemia by determining P50, ischemic time necessary for causing 50% neuronal damage. Gerbils were anesthetized with thiopental, propofol, or halothane and underwent 2-vessel occlusion (0, 3, 5 or 10 min). ⋯ By using P50, we found that the neuroprotective effect of thiopental was greater than that of propofol. Although duration of ischemic depolarization was equally reduced in thiopental and propofol groups, thiopental has a greater suppressive effect on neuronal injury during identical duration of ischemic depolarization than propofol does. Glutamate concentration during brain ischemia tended to be attenuated more by thiopental than by propofol, but it was not statistically significant.