Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Apr 1997
Comparative StudyFurosemide decreases cerebrospinal fluid formation during desflurane anesthesia in rabbits.
Previous studies suggest that desflurane may increase cerebrospinal fluid (CSF) formation rate (Vf) and volume, particularly during conditions of hypocapnia combined with elevated CSF pressure. The present study was designed to determine whether treatments routinely used in patients during anesthesia for neurological surgery would decrease Vf during desflurane anesthesia in rabbits. Three groups of six rabbits each were examined at four experimental conditions. ⋯ During the combination of desflurane, hypocapnia, and elevated CSF pressure, furosemide decreased Vf to 3.2 +/- 1.7 microliters.min-1, mannitol increased plasma osmolality and decreased plasma sodium concentration, and fentanyl decreased heart rate and increased plasma potassium concentration. Values for Ra and brain water content did not differ between groups. Of the four treatments examined, only furosemide decreased Vf during the combination of desflurane, hypocapnia, and elevated CSF pressure.
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J Neurosurg Anesthesiol · Apr 1997
Intact cerebral blood flow reactivity during remifentanil/nitrous oxide anesthesia.
Remifentanil hydrochloride is a new opioid rapidly metabolized by blood and tissue esterases. The swift degradation accounts for the elimination half-life (t1/2 beta) of < 10 min. An anesthetic agent allowing more rapid postoperative assessment of the neurosurgical patient would be beneficial. ⋯ Electroencephalographic monitoring showed a spectral edge frequency of 26 +/- 1 Hz before induction, 25 +/- 1 Hz during maintenance of the remifentanil/N2O anesthetic (0.32 +/- 0.15 microgram/kg/ min), 24 +/- 1 Hz during hypocapnic CBF determination, and 24 +/- 2 Hz during normocapnic CBF determination. At the completion of the procedure, the patients responded to commands within 3.6 +/- 2.5 min and were extubated 7.2 +/- 4.5 min after the remifentanil/N2O was discontinued. In conclusion, absolute CBF values during remifentanil/N2O are similar to previously reported CBF values during fentanyl/N2O and isoflurane/N2O anesthesia, and cerebrovascular reactivity to CO2 remains intact.
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J Neurosurg Anesthesiol · Apr 1997
Case ReportsCerebral oximetry during circulatory arrest for aneurysm surgery.
A patient underwent surgical clipping of a complex giant intracranial carotid aneurysm with the aid of extracorporeal circulation and complete hypothermic circulatory arrest. During the entire procedure, cerebrovascular oxygen saturation (ScO2) was spectroscopically measured. The patient experienced circulatory arrest for 34 min; for 15 of the 34 min ScO2 was < 34% (minimum 32%). The patient tolerated the procedure without new neurological deficit, thus demonstrating that the previously suggested "critical" level of 35% ScO2 is not absolute.
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J Neurosurg Anesthesiol · Apr 1997
Comparative StudyThe influence of acute and chronic alcohol treatment on brain edema, cerebral infarct volume and neurological outcome following experimental head trauma in rats.
The aim of this study was to determine the influence of acute and chronic ethanol treatment on neurological outcome following head trauma in rats. Eight-two Sprague-Dawley rats were divided into 10 groups. Four groups received sham head trauma (surgical incision of the scalp but no trauma) and were treated with (A) nothing, (B) chronic ethanol (6% ethanol in drinking water for 40 days), (C) acute ethanol 1.5 g/kg, intraperitoneally (IP) and (D) acute ethanol 3 g/kg IP. ⋯ Specific gravity was also lower in the acute ethanol-treated groups compared with no ethanol, chronic ethanol, and acute ethanol plus ketamine groups (p < 0.03). Based on these observations, we conclude that in this rat head trauma model acute ethanol treatment increases mortality, neurological deficit, hemorrhagic necrosis volume, and brain edema. On the other hand, chronic ethanol treatment has no apparent effect and ketamine treatment does not counteract the effect of acute ethanol treatment.
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J Neurosurg Anesthesiol · Apr 1997
Jugular bulb oxygen saturation and middle cerebral blood flow velocity during cardiopulmonary bypass.
This study investigates changes of jugular bulb oxygen saturation (SjO2) measured by fiberoptic jugular bulb oximetry and changes of intracranial hemodynamics using transcranial Doppler sonography (TCD) during cardiopulmonary bypass (CPB) for coronary artery bypass graft (CABG) in 17 ASA III patients. Anesthesia was maintained with fentanyl, midazolam, and continuous infusion of etomidate. Hypothermic CPB (27 degrees C) was managed according to alpha-stat conditions. ⋯ However, a major alteration in the balance of the cerebral oxygen supply and demand may occur in response to rewarming despite increases in Vmean. Findings suggest inadequate increases in CBF to meet cerebral metabolic demand. Further investigations need to validate these findings with biochemical techniques and neuropsychological tests.