Der Anaesthesist
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Randomized Controlled Trial Clinical Trial Controlled Clinical Trial
[Low-flow anesthesia with desflurane].
Due to its low solubility and negligible metabolism, desflurane is assumed to be especially suitable for application by low-flow anaesthetic techniques. The aim of this clinical investigation was the development of a standardised dosing scheme for low-flow and minimal-flow desflurane anaesthesia. ⋯ The pharmacokinetic properties of desflurane, resulting in especially low individual uptake, and the wide output range of the vaporizer facilitate the use of low-flow anesthetic techniques in routine clinical practice. Even in minimal-flow anesthesia, the duration of the initial high-flow phase can be shortened to min. If the flow is reduced to 1 l/min, the inspired desflurane concentration achieved in the initial high-flow phase can be maintained without any alteration of the vaporizer setting. In minimal-flow anesthesia, however, with flow reduction to 0.5 l/min, the fresh gas concentration has to be increased to a value 1%-2% higher than the inspired nominal value. Due to the wide dialing range of the desflurane vaporizer, the amount of vapour delivered into the breathing system can be increased to about 110 ml/min even at a flow of 0.5 l/min. The large amount of agent that can be delivered into the system even under low-flow conditions, together with the very low individual uptake, results in a time-constant that is sufficient short for the clinically required rapid increase in inspired desflurane concentrations. The short time-constant of low-flow desflurane anaesthesia improves the control of the anaesthetic concentration. If all measures are taken to safely avoid inadvertent drying out of the soda lime, there is no evidence that low-flow anaesthesia with desflurane is liable to increase the risk of accidental carbon monoxide poisoning. (ABSTRACT TRUNCATED)
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Randomized Controlled Trial Clinical Trial
[The preemptive action of ketoprofen. Randomized, double-blind study with gynecologic operations].
Ketoprofen exerts its clinical effect by inhibition of prostaglandin synthesis, but also acts as an NMDA-receptor antagonist by means of the kynurenic acid. Based on ketoprofen's supposed central mechanism of analgesia, we expected a preemptive effect, which was assessed by the present study. ⋯ Ketoprofen is an effective post-operative analgesic in combination with an opioid, but has no preemptive effect according to the results of this study.
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Randomized Controlled Trial Comparative Study Clinical Trial
[Combined 3-in-1 sciatic block. Prilocaine 500 mg vs. 650 mg].
The objective of the study was to investigate the clinical effectiveness of increasing the dosage of prilocaine for a combined 3-in-1/sciatic nerve block from 500 to 650 mg (open study with 29 patients compared with 30 patients from a former study) and to validate these findings in a second stage (randomised study comparing two groups of 30 patients each). Not only was clinical effectiveness improved by increasing the dose to 650 mg, but methaemoglobinaemia and toxicity were not relevant problems. With the higher dosage, development of the block was slightly faster (onset and completion); there were fewer unsatisfactory blocks; and clinically relevant plasma levels of methaemoglobin did not occur.
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Review Randomized Controlled Trial Clinical Trial
[S-(+)-Ketamine and circulation].
The S-(+) isomer of ketamine has about twice the analgesic potency of the clinically used racemic mixture. Therefore, the known side effects may be reduced when one-half of the usual dose is administered. Several prospective, randomised, and double-blinded studies have been performed to assess whether the S-(+) isomer of ketamine is superior to the racemic mixture with respect to circulatory side effects. ⋯ One patient in the S-(+)-ketamine group showed severe arterial hypertension and tachycardia after induction of anaesthesia and was withdrawn from the study. With respect to haemodynamic changes, the pharmacodynamic effects of ketamine racemate and S-(+)-ketamine are comparable. Therefore, it can be concluded that neither ketamine nor S-(+)-ketamine should be used in patients who suffer, e.g., from arterial hypertension and coronary artery disease.
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Randomized Controlled Trial Comparative Study Clinical Trial
[Single-dose spinal anesthesia with a mixture of isobaric bupivacaine 0.5% and hyperbaric mepivacaine 4%].
Single-dose spinal anaesthesia with hyperbaric local anaesthetic provides profound analgesia and motor blockade and allows exact assessment of the analgesic level. The present prospective, randomised study compares a mixture of plain 0.5% bupivacaine and hyperbaric 4% mepivacaine with hyperbaric 0.5% bupivacaine with regard to onset time of analgesia and duration of the sensory and motor blockade. ⋯ The local anaesthetic mixture may be preferred to hyperbaric 0.5% bupivacaine in patients requiring a fast onset of analgesia associated with a 2-3 h duration of sensory and motor block.