Der Anaesthesist
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Since its commercial introduction in 1996, target-controlled infusion (TCI) has become an established technique for administration of intravenous anaesthetics. Modern TCI systems, however, are characterized by an increasing number of additional options and features, such as the choice between different pharmacokinetic models and modes of application, which may confuse the less experienced user. This review describes the differences between pharmacokinetic models, modes of application and the effect of covariates as well as the consequences for dosing. The aim is to explicate for the user of modern TCI systems the underlying scientific concepts and the relevance for clinical practice.
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The vast majority of anaesthetists considers application of cricoid pressure for reasons of patient safety an integral part of rapid sequence induction. Cricoid pressure is applied with the idea that it will prevent regurgitation of gastric content into the pharynx, thereby reducing the incidence of pulmonary aspiration. This review describes the background of the introduction of cricoid pressure into clinical practice, analyzes published data concerning clinical relevance of perioperative pulmonary aspiration and efficacy of cricoid pressure in reducing it, discusses problems associated with its use, assesses knowledge and technical performance of cricoid pressure and presents various recent recommendations regarding application of cricoid pressure. The combination of complete lack of evidence for the efficacy of cricoid pressure in preventing pulmonary aspiration and numerous reports of clinically relevant interference with airway management during its use, seriously question the rationale of recommending the general use of cricoid pressure during rapid sequence induction.
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The management of general anaesthesia in patients with neuromuscular disorders remains challenging. The underlying causes and clinical presentations of these rare heterogeneous diseases are highly variable and the only common feature is usually skeletal muscle weakness. ⋯ Neuromuscular monitoring can be complicated because of disease-induced alterations in neurophysiology; however, continuous monitoring of the neuromuscular blockade should be realized to accurately determine the recovery from the blockade. These patients very often have an increased risk for postoperative pulmonary complications, which increases further if a residual neuromuscular blockade is present.
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During cardiopulmonary resuscitation (CPR) with a chest compression rate of 60-100/min the time for secure undisturbed ventilation in the chest decompression phase is only 0.3-0.5 s and it is unclear which tidal volumes could be delivered in such a short time. ⋯ Ventilation windows of 0.25, 0.3, and 0.5 s were too short to provide adequate tidal volumes in a simulated non-intubated cardiac arrest patient. In a simulated intubated cardiac arrest patient, ventilation windows of at least 0.5 s were necessary to provide adequate tidal volumes.
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Friedreich's ataxia (FA) is a hereditary disease, which leads to degenerative changes in the spinal cord and cerebellum (incidence 1:50,000). These changes are caused by a defect in the gene that encodes a mitochondrial gene called frataxin and causes muscle weakness, scoliosis, cardiomyopathy and impaired glucose tolerance. ⋯ Due to increased sensitivity to muscle relaxants, peridural anaesthesia with 8 ml 0.75% ropivacaine and 10 microg sufentanil was used in this case. The perioperative neurological consultation revealed no undue exacerbation of symptoms.