Articles: anesthetics.
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Journal of anesthesia · Sep 1987
Epidural pressure and its relation to spread of epidural analgesia.
The relationships between the epidural pressures following the injection of local anesthetic solution and the spread of epidural analgesia were investigated. In 46 patients, 15 ml of 2% mepivacaine was injected into the lumbar epidural space at a constant rate (1 ml/sec) using an electropowered syringe pump. Injection pressures and residual pressures were recorded and the spread of analgesia to pinprick was assessed. ⋯ The spread of analgesia closely correlated with the epidural pressures during and following the injection of local anesthetic solution. The most close correlation was found between the epidural pressure immediately after the completion of injection and the spread of analgesia (r = -0.5659, P < 0.001). In conclusion, the lower the terminal injection pressure and the residual pressures associated with higher age, the wider the spread of epidural analgesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Ventilatory CO2 response, respiratory drive and timing in children anaesthetized with halothane, enflurane or isoflurane.
Ventilatory CO2 response, respiratory drive and timing were investigated during anaesthesia prior to surgery in 24 spontaneously breathing cardiopulmonary healthy children. Anaesthesia was maintained with halothane, enflurane or isoflurane combined with oxygen-nitrous oxide (FIO2 0.5). The MAC values were 0.97 for halothane, 0.92 for enflurane and 0.92 for isoflurane. ⋯ End-tidal CO2 tensions were significantly higher during enflurane than during both halothane and isoflurane anaesthesia, before as well as during CO2 stimulation. Respiratory rates were lower in children anaesthetized with enflurane and were unresponsive to CO2 when all three volatile agents were used. During CO2 challenge, mean inspiratory flow and maximal occlusion pressure were similarly increased in all groups.
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Patients with a history of adverse reactions to a local anesthetic may often be incorrectly labeled as "allergic." Determining if a patient is allergic to a local anesthetic is essential in the selection of appropriate pain control techniques. Local anesthetic allergy testing may be performed safely and with reasonable accuracy by a knowledgeable practitioner. This paper presents guidelines for an allergy testing method.
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Ten patients, with a range of illness severity, received a continuous 8-hour infusion of undiluted propofol for sedation while undergoing mechanical ventilation in a general intensive care unit. The level of sedation was assessed hourly and measurements were made of haemodynamic, respiratory, haematological and biochemical variables. Sedation remained satisfactory in most patients throughout the study period, with only occasional alterations in infusion rate, and eight patients required further sedative therapy within 45 minutes of discontinuation of the propofol infusion. ⋯ Adrenal steroidogenesis was not inhibited significantly. Propofol infusion proved to be a useful and readily controllable sedative agent, and discontinuation of the drug was followed by rapid recovery in most cases. The critically ill may be particularly sensitive to the cardiovascular depressant properties of the drug.