Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Cesarean delivery: a randomized trial of epidural versus patient-controlled meperidine analgesia during labor.
Reports indicate that the administration of epidural analgesia for pain relief during labor interferes with labor and increases cesarean deliveries. However, only a few controlled trials have assessed the effect of epidural analgesia on the incidence of cesarean delivery. The authors' primary purpose in this randomized study was to evaluate the effects of epidural analgesia on the rate of cesarean deliveries by providing a suitable alternative: patient-controlled intravenous analgesia. ⋯ Epidural analgesia was not associated with increased numbers of cesarean delivery when compared with a suitable alternative method of analgesia.
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Randomized Controlled Trial Clinical Trial
Blood flow velocity of middle cerebral artery during prolonged anesthesia with halothane, isoflurane, and sevoflurane in humans.
It is not clear whether the increase of cerebral blood flow (CBF) produced by volatile anesthetics is maintained during prolonged anesthesia. In a previous study, the authors found that CBF equivalent, an index of flow-metabolism relationship, was stable over 3 h, suggesting no decay over time in CBF for 3 h during volatile anesthesia in humans. However, it may be possible that CBF changes in a parallel fashion to functional metabolic changes. In this study, to estimate the response of CBF to three volatile anesthetics, the authors used transcranial Doppler (TCD) ultrasonography to measure time-averaged mean velocity in the middle cerebral artery (Vmca). ⋯ The results indicate that there was no decay in Vmca over time during prolonged (3 h) inhalation of volatile anesthetics at 1.5 MAC in humans. The fluctuation of Vmca during burst suppression on EEG at 1.5 MAC indicates that the flow-metabolism coupling occurred.
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Comparative Study
Prevention of methacholine-induced changes in respiratory mechanics in piglets: a comparison of sevoflurane and halothane.
Sevoflurane is a new volatile anesthetic agent that may be a useful alternative to halothane for anesthesia in children. However, there is insufficient information about its effects on respiratory mechanics, particularly in the presence of constrictor stimuli. ⋯ Sevoflurane and halothane can prevent methacholine-induced changes in lung function.
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The morphologic effect of positive end-expiratory pressure (PEEP) and of two tidal volumes were studied by computed tomography to determine whether setting the tidal volume (Vt) at the upper inflection point (UIP) of the pressure-volume (P-V) curve of the respiratory system or 10 ml/kg have different effects on hyperinflation and alveolar recruitment. ⋯ Positive end-expiratory pressure promotes alveolar recruitment; increasing Vt above the UIP seems to predominantly increase hyperinflation.