Anaesthesia
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Letter Randomized Controlled Trial Clinical Trial
Sub-Tenon's block without hyaluronidase.
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Two recent studies have examined the pharmacokinetics of sevoflurane in adults. Lu et al.(Pharmacokinetics of sevoflurane uptake into the brain and body, Anaesthesia 2003; 58: 951-6) observed that jugular bulb sevoflurane concentration initially rose unexpectedly rapidly and then approached arterial concentrations unexpectedly slowly, suggesting that a blood-brain diffusion barrier exists. They also observed a large alveolar-arterial sevoflurane gradient, suggesting that an alveolar-arterial diffusion barrier exists. ⋯ We used a computer model to analyse both data sets and show that the observations of Lu et al. can be explained by contamination of jugular samples with extracerebral blood. It is possible that the alveolar-arterial gradients observed by Lu et al. are due to discrepancies in conversions between blood concentrations and gas partial pressures. Our study suggests that there is no blood-brain diffusion barrier for sevoflurane and that the data of Lu et al. must be interpreted with caution.
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Failed tracheal intubation due to a difficult airway is an important cause of anaesthetic morbidity and mortality. This study was undertaken to evaluate the effectiveness of the Bonfils intubation fibrescope for tracheal intubation after failed direct laryngoscopy. ⋯ Median (IQR [range]) time to intubation using the Bonfils intubation fibrescope was 47.5 (30-80 [20-200]) s. Tracheal intubation using the Bonfils intubation fibrescope appears to be a simple and effective technique for the management of a difficult intubation.