Anesthesiology
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Randomized Controlled Trial Clinical Trial
The effects of epidural ropivacaine and bupivacaine for cesarean section on uteroplacental and fetal circulation.
Ropivacaine is a new long-acting amide local anesthetic that has been shown in animal studies to have less dysrhythmogenic and cardiotoxic potential than bupivacaine. The intravenous administration of ropivacaine has not been associated with any detrimental effects on uterine blood flow in pregnant ewes. The purpose of this randomized, double-blind study was to examine the effects of epidural ropivacaine for cesarean section on blood flow velocity waveforms in uteroplacental and fetal arteries with color Doppler ultrasound and to assess whether the block modified fetal myocardial function. ⋯ Within this small study, epidural 0.5% ropivacaine for cesarean section did not compromise the utero-placental circulation in healthy parturient women with uncomplicated pregnancies. It provided surgical anesthesia that was equally effective as that provided by 0.5% bupivacaine.
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Randomized Controlled Trial Comparative Study Clinical Trial
Neurocirculatory responses to sevoflurane in humans. A comparison to desflurane.
Sevoflurane and desflurane are new volatile anesthetics with low blood solubilities that confer properties of rapid anesthetic induction and emergence. Desflurane has been associated with neurocirculatory excitation after the rapid increase in inspired concentrations. The current study evaluated and compared the sympathetic and hemodynamic responses associated with the administration of sevoflurane to those associated with administration of desflurane in humans. ⋯ The neurocirculatory excitation seen with rapid increases in desflurane did not occur with sevoflurane. At steady-state, increasing the concentration of sevoflurane was associated with lower sympathetic nerve activity and central venous pressure and similar mean arterial pressure and heart rate with that of desflurane.
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Randomized Controlled Trial Clinical Trial
Dynamic and static cerebral autoregulation during isoflurane, desflurane, and propofol anesthesia.
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Pharmacokinetically designed infusions have been demonstrated to achieve rapidly and maintain desired concentrations of drug in plasma after intravenous administration. In this study we tested whether a similar approach, targeting concentrations in cerebrospinal fluid (CSF), could be used with epidural administration of the alpha 2-adrenergic analgesic clonidine. ⋯ This study suggests that pharmacokinetically designed infusions of drugs in the epidural space in humans can maintain steady concentrations of drug in CSF. In addition to providing a useful tool for investigation of mechanisms of action and drug interactions, this technique may improve analgesia and diminish side effects from epidurally administered analgesics.
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When local anesthetic is used to produce epidural anesthesia intraoperatively, epidural catheter placement is confirmed. However, when epidural catheters are placed intraoperatively only to provide postoperative opioid analgesia, correct catheter placement may not be confirmed by administration of a local anesthetic. The current study tests the hypothesis that the extent of sensory blockade produced by a 10-ml dose of 1.5% lidocaine can be used to predict the adequacy of epidural opioid analgesia. ⋯ Extensive sensory block from 10 ml 1.5% lidocaine was associated with excellent epidural opioid analgesia. Extent of analgesia after a 10-ml test dose of 1.5% lidocaine can be used to predict the adequacy of analgesia resulting from an epidural opioid infusion. The failure of a local anesthetic dose to produce sensory blockade does not necessarily predict a failure to produce analgesia from an epidural opioid infusion, as indicated by the presence of analgesia in several patients without detectable sensory block.