Der Anaesthesist
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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in the S-(+)-ketamine group showed severe arterial hypertension and tachycardia after induction of anaesthesia and was withdrawn from the study.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 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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Generalized muscle weakness in critically ill patients can result in prolonged periods of artificial ventilation and longer stays in the intensive care unit. Both neuropathic (critical illness polyneuropathy) and myopathic (critical illness myopathy) abnormalities seem to play an important role for this prolonged weakness. ⋯ An efficient diagnostic plan is necessary for the exclusion of other curable causes of prolonged muscle weakness even in the presence of polyneuromyopathic changes. Psychological support of the patient and prophylaxis of secondary complications of prolonged immobilization are crucial when specific therapy is not possible.
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The phencyclidine derivative ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist with the thalamo-neocortical projection system as the primary site of action. Racemic ketamine consists of the enantiomers S(+)-ketamine and R(-)-ketamine. Racemic ketamine has never been considered an adequate anaesthetic agent in neurosurgical patients since it produces regionally specific stimulation of cerebral metabolism (CMRO2) and increases cerebral blood flow (CBF) and intracranial pressure (ICP). ⋯ In contrast, studies in unanaesthetised humans showed increases in CBF after racemic ketamine (2-3 mg/kg). This observation is consistent with animal studies and suggests that the cerebrovascular effects of racemic ketamine are related to the pre-existing cerebrovascular tone induced by background anaesthetics. Studies in humans with and without intracranial pathology confirm the data from animal experiments. (ABSTRACT TRUNCATED)