British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Randomized controlled study of colloid preload before spinal anaesthesia for caesarean section.
We randomized women having elective Caesarean section to receive either no preload (control group, n=33) or 4% gelatin solution (Gelofusine) 15 ml kg(-1) (colloid group, n=35) i.v. before spinal anaesthesia. Intravenous metaraminol was titrated at 0.25-0.75 mg min(-1) to maintain systolic arterial pressure (SAP) in the target range 90-100% of baseline after the spinal injection. ⋯ Nausea was less frequent in the colloid group (6 vs 24%) but neonatal outcome was similar in the two groups. Colloid preload improved haemodynamic stability but did not affect neonatal outcome when arterial pressure was maintained with an infusion of metaraminol during spinal anaesthesia for Caesarean section.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of minor surgery and endotracheal intubation on postoperative breathing patterns in patients anaesthetized with isoflurane or sevoflurane.
We studied the effects of minor surgery and endotracheal intubation on postoperative breathing patterns. We measured breathing patterns and laryngeal resistance during the periods immediately before intubation (preoperative) and immediately after extubation following minor surgery (postoperative) in eight patients anaesthetized with sevoflurane and eight patients anaesthetized with isoflurane, breathing spontaneously through a laryngeal mask airway at a constant end-tidal anaesthetic concentration (1.0 MAC). In both sevoflurane-anaesthetized and isoflurane-anaesthetized patients, expiratory time was reduced and inspiratory and expiratory laryngeal resistance increased after surgery. ⋯ Occlusion pressure did not change and T(I) was greater in isoflurane-anaesthetized patients after surgery. Minor surgery may have a small but significant influence on breathing and increased laryngeal resistance following endotracheal intubation may modulate these changes. The difference in breathing pattern between sevoflurane and isoflurane may be a result of different responses of the central nervous system to different anaesthetics in the presence of increased laryngeal resistance.
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Review Case Reports
Grand mal convulsion and plasma concentrations after intravascular injection of ropivacaine for axillary brachial plexus blockade.
We report a patient to whom ropivacaine 1.1 mg kg(-1) was administered for brachial plexus blockade and who developed grand mal convulsions because of inadvertent i.v. injection. No symptoms of cardiovascular toxicity occurred. ⋯ The measured total plasma concentrations of ropivacaine were 3.3, 1.6, 1.2 and 1.0 mg litre(-1) respectively. Initial plasma concentration after the end of the injection period was estimated at 5.75 mg litre(-1) using a two-compartment pharmacokinetic model.
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Randomized Controlled Trial Comparative Study Clinical Trial
Influence of equianaesthetic concentrations of nitrous oxide and isoflurane on regional cerebral blood flow, regional cerebral blood volume, and regional mean transit time in human volunteers.
Nitrous oxide and isoflurane have cerebral vasodilatory effects. The use of isoflurane in neuroanaesthesia is widely accepted, whereas the use of nitrous oxide in neuroanaesthesia is still the subject of debate. In the present study, contrast-enhanced magnetic resonance (MR) perfusion measurement was used to compare the effects of 0.4 MAC nitrous oxide (n=9) and 0.4 MAC isoflurane (n=9) on regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and regional mean transit time (rMTT) in spontaneously breathing human volunteers. ⋯ Isoflurane, by contrast, increased rCBF and rCBV in basal ganglia more than did nitrous oxide. An increased rMTT was caused by a relatively greater increase in rCBV than in rCBF supratentorially by isoflurane and infratentorially by nitrous oxide. In conclusion, nitrous oxide increases rCBF and rCBV predominantly in supratentorial grey matter, whereas isoflurane increases rCBF and rCBV predominantly in infratentorial grey matter.
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Randomized Controlled Trial Clinical Trial
Spinal anaesthesia with 0.5% hyperbaric bupivacaine in elderly patients: effects of duration spent in the sitting position.
Sixty patients, aged 65-84 yr, undergoing minor urological surgery under spinal anaesthesia remained sitting for 2 (group 1, n = 15), 5 (group 2, n = 15), 10 (group 3, n = 15), or 20 (group 4, n = 15) min after completion of the subarachnoid administration of 3 ml of a 0.5% hyperbaric bupivacaine solution. They were then placed in the supine position. Analgesia levels were assessed bilaterally using pinprick. ⋯ Twenty minutes after the injection the upper analgesia levels were lower (P<0.05) in group 4 (median T9.0) than in the groups 1-3 (medians T6.6-T8.5). The highest obtained levels (medians T5.7-T8.0) did not differ between the groups, but occurred later (P<0.05) in group 4 (median 35 min) than in groups 1-3 (medians 19-24 min). There were no significant differences in the maximum degree of motor block or haemodynamic changes between the four study groups.