Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Intrathecal bupivacaine in humans: influence of volume and baricity of solutions.
The effects of volume and baricity of spinal bupivacaine on block onset, height, duration, and hemodynamics were studied. ⋯ In this study, volume had no significant influence on either cephalad spread or duration of sensory blockade for either isobaric or hyperbaric bupivacaine. Time for offset of anesthesia was shorter with hyperbaric bupivacaine compared with isobaric solutions.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intrathecal ropivacaine for ambulatory surgery.
The rationale of this study was to evaluate intrathecal ropivacaine for ambulatory surgery. ⋯ Intrathecal ropivacaine 12 mg is approximately equivalent to bupivacaine 8 mg. At this dose, ropivacaine offers no significant advantage compared with bupivacaine.
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Clinical Trial
High thoracic epidural anesthesia does not inhibit sympathetic nerve activity in the lower extremities.
Sympathetic nerve activity was recorded in the leg during high thoracic epidural anesthesia with a segmental sensory blockade of the upper thoracic dermatomes to test the hypothesis that the sympathetic blockade accompanying thoracic epidural anesthesia includes caudal parts of the sympathetic nervous system. ⋯ A high thoracic epidural anesthesia with adequate sensory blockade of upper thoracic dermatomes may be achieved without blockade of caudal parts of the sympathetic nervous system. This finding differs from that of earlier studies that used indirect methods to evaluate changes in sympathetic nerve activity.
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Suppression of response to command commonly indicates unconsciousness and generally occurs at anesthetic concentrations that suppress or eliminate memory formation. The authors sought midlatency auditory evoked potential indices that successfully differentiated wakeful responsiveness and unconsciousness. ⋯ The approximately 40-Hz power index and the best combination of amplitude and latency variables perform as well as predictors of response to command during desflurane and propofol anesthesia as the steady-state concentrations of these anesthetic agents. Because clinical conditions may limit measurement of steady-state anesthetic concentrations, or comparable estimates of cerebral concentration, the approximately 40-Hz power could offer advantages for predicting wakeful responsiveness.
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This article describes a carbon dioxide absorbent for use in anesthesia. The absorbent consists of calcium hydroxide with a compatible humectant, namely, calcium chloride. The absorbent mixture does not contain sodium or potassium hydroxide but includes two setting agents (calcium sulphate and polyvinylpyrrolidine) to improve hardness and porosity. ⋯ The new material is an effective carbon dioxide absorbent and is chemically unreactive with sevoflurane, enflurane, isoflurane, and desflurane.