Der Anaesthesist
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Randomized Controlled Trial Comparative Study Clinical Trial
[Psychometric changes as well as analgesic action and cardiovascular adverse effects of ketamine racemate versus s-(+)-ketamine in subanesthetic doses].
The intravenous anaesthetic ketamine is widely used in subanaesthetic doses as a potent analgesic in emergency and disaster medicine. At present, ketamine is commercially available only in its racemic form, although the S(+)-isomer has proved to be approximately three times as potent than the R(-)-isomer. In first clinical trials in Germany, S(+)-ketamine was reported to be markedly advantageous with regard to analgesia in anaesthetized patients. ⋯ S(+)-Ketamine at half-dose of ketamine-racemate is as potent as ketamine-racemate in subanaesthetic doses with powerful analgesic properties. The (+)-isomer exerts less adverse effects on measurable cerebral functions and induces a significantly smaller increase in heart rate. Since states of impaired consciousness and disorientation are especially disturbing under emergency conditions, further investigations should be carried out to define S(+)-ketamine's position as a potent analgesic for therapeutic use in emergency and disaster medicine.
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Slices of the rabbit caudate nucleus were incubated with [3H]choline for 30 min and then superfused continuously with Mg(2+)-free medium at 37 degrees C. Stimulation with N-methyl-D-aspartate (NMDA) caused a concentration-dependent release of [3H]acetylcholine (ACh), which was abolished in the presence of MG2+. This release of ACh was exocytotic and mediated by action potentials. ⋯ At the neuropathologic level, Parkinson's disease is characterized by an overshoot of striatal cholinergic transmission due to the decreased inhibitory dopaminergic input from the substantia nigra. The well-known antiparkinsonian effect of memantine and amantadine is most probably due to a blockade of NMDA-receptor-linked ion channels on striatal cholinergic interneurons, leading in turn to a diminished release of ACh. Since ketamine diminished cholinergic neurotransmission to a similar degree to that achieved with memantine and amantadine and even more potently than the adamantanes, and that at concentrations far below those needed for its anaesthetic and analgesic properties, it seems worthwhile to test this drug as an antiparkinsonian agent clinically.
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Randomized Controlled Trial Clinical Trial Controlled Clinical Trial
[Esmolol as a bolus for prevention of sympathetic adrenergic reactions following induction of anesthesia].
In addition to laryngoscopy, endotracheal intubation, and other stressful intraoperative phases, hypertension occurs during recovery from anaesthesia, provoking post-operative complications like bleeding and increased intracranial or intraocular pressure. Furthermore, these hypertensive reactions result in life-threatening complications, especially in patients with pre-existing cardiovascular diseases. In this study, the effect of the new, short-acting beta-blocker esmolol given as a single bolus for preventing the increases in blood pressure and heart rate during recovery from anaesthesia and extubation in patients with hypertension was investigated. ⋯ Thus, the potential risks of beta-blockers due to half-life are minimised. The results of this study show that a dangerous increase in BP and HR with increased myocardial oxygen consumption can be prevented by a single bolus, and better by a double bolus of 100 mg esmolol. Although bradycardia with HR below 50.min-1 in 8 patients might indicate a risk of cardiac instability, the systolic BP did not fall below 100 mm Hg, and the episode of bradycardia was so short that there was no risk to the patients.
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Randomized Controlled Trial Comparative Study Clinical Trial
[Different opioids in patients at cardiovascular risk. Comparison of central and peripheral hemodynamic adverse effects].
Efficient analgesia may be the major objective in the cardiovascular risk patient following myocardial infarction, acute occlusion of peripheral vessels, or dissection/perforation of major abdominal vessels. It was the purpose of the study to investigate the haemodynamic and respiratory side effects of eight different opioids in 57 circulatory risk patients prior to major vascular surgery. METHODS. ⋯ CONCLUSIONS. For interpretation of the results, factors such as respiratory depression, histamine release, secretion of endogenous catecholamines, and hypoxia-induced pulmonary vasoconstriction have to be discussed. Tramadol, an opioid with moderate potency, seems to offer some advantages due to its minor cardiovascular and respiratory side effects.
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Randomized Controlled Trial Clinical Trial
[Endocrine stress reaction, hemodynamics and recovery in total intravenous and inhalation anesthesia. Propofol versus isoflurane].
This prospective, randomised study compared total intravenous anaesthesia (TIVA) and inhalation anaesthesia with respect to endocrine stress response, haemodynamic reactions, and recovery. METHODS. The investigation included two groups of 20 ASA I-II patients 18-60 years of age scheduled for orthopaedic surgery. ⋯ Slightly shorter recovery times did not lead to an increased stress response. With respect to intra- and postoperative stress reduction, significant attenuation of sympatho-adrenergic reaction comparable SAP and reduced HR, sympatholytic and hypodynamic anaesthesia with propofol and fentanyl seems to be advantageous for patients with cardiovascular and metabolic disorders. For this aim, careful induction and application of individual doses is essential.