British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
A double-blind comparison of 0.25% ropivacaine and 0.25% bupivacaine for extradural analgesia in labour.
Ropivacaine is a new aminoamide local anaesthetic. Compared with bupivacaine, ropivacaine possesses a higher threshold for systemic toxicity and a high selectivity for sensory fibres. We have compared prospectively these two agents in a concentration of 0.25% for extradural analgesia in labour. ⋯ The ropivacaine group had a higher incidence of spontaneous vaginal delivery (70.59% vs 52.00%). There was no significant difference in neonatal outcome as assessed by Apgar scores, umbilical acid-base status and neurological and adaptive capacity score at 2 and 24 h after delivery. We conclude that ropivacaine and bupivacaine in a concentration of 0.25% produced comparable analgesia for pain relief of labour with no detectable adverse effect on the neonate.
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Randomized Controlled Trial Clinical Trial
Absence of an early pre-emptive effect after thoracic extradural bupivacaine in thoracic surgery.
We have determined if thoracic extradural block before surgical incision for thoracotomy produces pre-emptive analgesia. Using a double-blind, placebo-controlled, crossover design, 45 patients (ASA II-III) undergoing posterolateral thoracotomy for lung resection were randomized to one of three groups: group 1 received 0.5% bupivacaine and adrenaline 1/200,000 (B+E) 8 ml through a thoracic extradural catheter (tip T3-T5) 30 min before skin incision and saline 8 ml 15 min after skin incision; group 2 received saline 8 ml extradurally before incision and B+E 8 ml after incision; group 3 received saline 8 ml extradurally before and after incision. General anaesthesia was induced and maintained with propofol, alfentanil and atracurium. ⋯ There was no significant difference between groups, either in PCEA requirements (P > 0.21) or in VAS scores (either at rest, during mobilization of the ipsilateral arm of surgery or after cough). No significant differences between groups were found in the VRS. Thoracic extradural block with bupivacaine did not produce an early preemptive effect after thoracotomy.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effects of sevoflurane and isoflurane on systemic vascular resistance: use of cardiopulmonary bypass as a study model.
We have examined the dose-related effects of sevoflurane and isoflurane on systemic vascular resistance (SVR) during cardiopulmonary bypass (CPB) in patients undergoing elective coronary artery surgery. Fifty-two patients were allocated randomly to one of six groups to receive 1.0, 2.0 or 3.0 vol% (inspiratory) sevoflurane or 0.6, 1.2 or 1.8 vol% isoflurane, or to a control group. During hypothermic (32-33 degrees C) non-pulsatile CPB, systemic vascular resistance index (SVRI) was recorded before administration of volatile anaesthetics and every 5 min for 20 min. ⋯ There was no significant change in SVRI in patients receiving 1.0 and 2.0 vol% sevoflurane, and 0.6 and 1.2 vol% isoflurane, compared with baseline values. However, 3 vol% sevoflurane decreased SVRI at 10, 15 and 20 min, and 1.8 vol% isoflurane decreased SVRI significantly at 15 and 20 min, whereas SVRI increased at 15 and 20 min in the control group. Thus during CPB, sevoflurane had similar vasodilator effects on SVRI as isoflurane.
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Randomized Controlled Trial Clinical Trial
Randomized trial of bolus phenylephrine or ephedrine for maintenance of arterial pressure during spinal anaesthesia for Caesarean section.
Thirty-eight healthy women undergoing elective Caesarean section under spinal anaesthesia at term were allocated randomly to receive boluses of either phenylephrine 100 micrograms or ephedrine 5 mg for maintenance of maternal arterial pressure. The indication for administration of vasopressor was a reduction in systolic pressure to < or = 90% of baseline values. Maternal arterial pressure (BP) and heart rate (HR) were measured every minute by automated oscillometry. ⋯ As a consequence atropine was required in 11/19 women in the phenylephrine group compared with 2/19 in the ephedrine group (P < 0.01). Mean umbilical artery pH [95% CI] was higher in the phenylephrine group (7.29 [7.28-7.30]) than in the ephedrine group (7.27 [7.25-7.28]). The results of the present study support the use of phenylephrine for maintenance of maternal arterial pressure during spinal anaesthesia for elective Caesarean section.
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We have studied the pharmacokinetics of a single bolus of rocuronium (Org 9426), followed by an infusion, in eight patients during anaesthesia with halothane and nitrous oxide in oxygen. Neuromuscular block was monitored using train-of-four (TOF) stimulation and recording the force of contraction of the adductor pollicis muscle. Rocuronium was administered as an initial bolus dose of 0.45 mg kg-1 followed by an infusion adjusted manually to maintain T1 (first response in the TOF) at 10% of control. ⋯ The rate of clearance, mean residence time and volume of distribution at steady state were 3.3 (0.77) ml kg-1 min-1, 67.2 (18.8) min and 212.5 (40.1) ml kg-1, respectively. The distribution (T1/2 alpha) and elimination (T1/2 beta) half-lives were 7.5 (3.33) min and 85.6 (18.4) min, respectively. These values were not significantly different from previously published data for a single bolus dose of rocuronium.