British journal of anaesthesia
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Randomized Controlled Trial Comparative Study
Emergence and early cognitive function in the elderly after xenon or desflurane anaesthesia: a double-blinded randomized controlled trial.
Postoperative cognitive impairment after general anaesthesia, especially in the elderly, is a well-recognized problem. Xenon, known to be an N-methyl-d-aspartate antagonist, may be advantageous. In this study, the early cognitive function in the elderly after general anaesthesia with xenon was compared with that after desflurane. ⋯ There was no difference in the postoperative cognitive testing at 6-12 and 66-72 h. Xenon was associated in the elderly with a faster emergence from general anaesthesia than desflurane.
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Randomized Controlled Trial Comparative Study
Effects of ultrasound guidance on the minimum effective anaesthetic volume required to block the femoral nerve.
We tested the hypothesis that ultrasound guidance may reduce the minimum effective anaesthetic volume (MEAV50) of ropivacaine 0.5% required to block the femoral nerve compared with nerve stimulation guidance. ⋯ Ultrasound guidance provided a 42% reduction in the MEAV of ropivacaine 0.5% required to block the femoral nerve as compared with the nerve stimulation guidance.
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Randomized Controlled Trial
Effects of intrathecal and i.v. small-dose sufentanil on the median effective dose of intrathecal bupivacaine for Caesarean section.
Spinal anaesthesia with bupivacaine combined with sufentanil has been widely used for Caesarean section. However, the main site of action (spinal vs central) of intrathecal (IT) sufentanil is controversial. The aim of this study was to examine the predominant mechanism of action of IT, small-dose sufentanil when added to bupivacaine for Caesarean section, by comparing the effects of IT and i.v. sufentanil 2.5 microg on the median effective dose (ED50) of bupivacaine. ⋯ Compared with an equal dose of sufentanil i.v., intrathecally administered sufentanil 2.5 microg has a significant local anaesthetic-sparing effect via a predominantly spinal mechanism for Caesarean section.
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Randomized Controlled Trial
Autonomic cardiac control with xenon anaesthesia in patients at cardiovascular risk.
The cardiovascular stability found with xenon anaesthesia may be caused by absence of circulatory depression. Xenon may also act directly on autonomic cardiovascular control. ⋯ Propofol caused a decrease in arterial pressure as well as autonomic HR modulation, but xenon did not. The higher arterial pressure with xenon anaesthesia may be explained by less suppression of sympatho-vagal balance.
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Facial electromyography (FEMG) may have utility in the assessment of nociception during surgery. The difference between state entropy (SE) and response entropy (RE) is an indirect measure of FEMG. This study assesses an automated algorithm for remifentanil administration that is based on maintaining an entropy difference (ED) that is less than an upper boundary condition and greater than a lower boundary condition. ⋯ This feasibility study supports the concept that remifentanil may be delivered using an algorithm that maintains the difference between SE and RE between the upper and lower boundary condition.