British journal of anaesthesia
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The creation, possible complications and retrieval of an unusual, perhaps unique, arterial foreign body are described.
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Randomized Controlled Trial Clinical Trial
Spinal anaesthesia with 0.5% hyperbaric bupivacaine in elderly patients: effect of site of injection on spread of analgesia.
In this randomized, observer-blind study, we have examined, in elderly patients, the effect of site of injection on analgesia levels after spinal injection of 0.5% hyperbaric bupivacaine solution. Thirty male patients, aged 68-87 yr, undergoing minor urological surgery during spinal anaesthesia received 3 ml of a 0.5% hyperbaric bupivacaine solution at either the L3-4 (n = 15) or L4-5 (n = 15) interspace. The solution was injected with the patient in the sitting position. ⋯ The highest analgesia levels did not differ between groups (medians were approximately T7). There were no significant differences in the time to maximum cephalad spread of analgesia, maximum degree of motor block or haemodynamic changes. We conclude that injection at the L4-5 interspace has no advantage compared with injection at the L3-4 interspace.
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Comparative Study Clinical Trial Controlled Clinical Trial
Thoracic impedance used for measuring chest wall movement in postoperative patients.
Thoracic impedance (TTI) and rib cage inductance band (IB) signals were measured in 10 patients during the first night after abdominal surgery, and compared by successive correlation of the change in each signal. Poor matching of the signals occurred, on average, for 94 min either because of movement of differences in the waveform. There were frequent episodes of transient poor correlation, generally associated with transient respiratory disturbance, predominantly airway obstruction (58%). Thoracic impedance measurements are simpler than inductance band methods for detecting rib cage movement and may be useful for large studies of respiratory abnormalities in patients after operation.
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Unbound, rather than total, plasma concentrations may be related to the anaesthetic action of propofol. Therefore, we measured plasma concentrations of propofol and recorded Nb wave latencies of auditory evoked potentials (AEP) during continuous infusion of propofol in 15 patients undergoing coronary artery bypass grafting (CABG) surgery. After induction of anaesthesia with fentanyl, propofol was infused continuously at a rate of 10 mg kg-1 h-1 for 20 min, and then the rate was reduced to 3 mg kg-1 h-1. ⋯ The latency of the Nb wave did not correlate with total or unbound propofol concentration. We conclude that the changes in total and unbound concentrations of plasma propofol were not parallel in patients undergoing CABG. During CPB or at any other time during the CABG procedure, the unbound propofol concentration did not decrease and Nb wave latency was prolonged compared with baseline values measured after induction of anaesthesia before the start of CPB.
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Comparative Study
Inflammatory changes after extradural anaesthesia may affect the spread of local anaesthetic within the extradural space.
We have assessed cephalad spread of analgesia in 491 patients undergoing extradural anaesthesia at the L2-3 or L3-4 interspace. Patients were classified into one of three groups based on the number of previous lumbar extradural anaesthesia procedures: none (group I, n = 339), one (group II, n = 82), and two or more (group III, n = 70). ⋯ Extraduroscopy showed the extradural space to be patent in patients with no history of prior lumbar extradural anesthesia, but it was not clearly identified in patients who had received extradural anaesthesia one or more times because of aseptic inflammatory changes, including proliferation of connective tissue, adhesions between the dura mater and the ligamentum flavum, granulation and changes in the ligamentum flavum. Extradural anaesthesia may cause aseptic inflammatory changes in the extradural space which may reduce the spread of analgesia.