British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Haemodynamic effects of midazolam and thiopentone during induction of anaesthesia for coronary artery surgery.
The cardiovascular effects of thiopentone 3 mg kg-1 and midazolam 0.3 mg kg-1 were observed during induction of anaesthesia in 16 premedicated patients about to undergo myocardial revascularization. There were no significant changes in either group in cardiac output or central venous pressure. The heart rate in both groups showed an increase at 3 min and thereafter returned to control values. After 3 min, there was a significant decrease in both arterial pressure and peripheral resistance by 12% and 15% (mean values) respectively from control values in the group receiving midazolam, whereas after thiopentone the peripheral resistance increased by approximately 13% and was not affected by a further dose of thiopentone 1 mg kg-1.
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Clinical Trial Controlled Clinical Trial
Plasma pharmacokinetics of morphine after i.m., extradural and intrathecal administration.
Eighteen patients received morphine 0.2 mg kg-1 in 0.9% saline i.m. (n = 6), extradurally (n = 6), or in a 10% dextrose solution intrathecally (n = 6) for pain relief operation. Plasma unmetabolized morphine was isolated by extraction using liquid-solid chromatography and measured by radioimmunoassay. Conjugated morphine was calculated from the difference between total immunoreactive morphine and unmetabolized morphine. ⋯ Prolonged analgesia observed following extradural and intrathecal administration was caused by a small quantity of unmetabolized morphine. Extradural and i.m. groups showed the same pharmacokinetic patterns although extradural analgesia is much more prolonged. Morphine glucuronide appeared later in blood in the intrathecal group than in the two other groups.
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Randomized Controlled Trial Comparative Study Clinical Trial
Onset time and duration of action for atracurium, Org NC45 and pancuronium.
Speed of onset, maximum block, duration of action and 10-25% recovery time for atracurium, Org NC 45 and pancuronium were determined using equipotent doses: 330 micrograms kg-1, 66 micrograms kg-1 and 75 micrograms kg-1 respectively. Vein-to-muscle and artery-to-muscle onset times were measured by use of simultaneous recordings. Mean speeds of onset to 95% twitch depression were: atracurium 2.7 min, Org NC 45 2.8 min and pancuronium 3.6 min. ⋯ The differences were statistically significant. The recovery period from 10% to 25% twitch response was considerably longer for pancuronium than for the other drugs, which did not differ significantly from each other. We were unable to validate the artery-to-muscle technique in the determination of onset time.
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Sequential plasma samples from 30 patients showing clinical signs of hypersensitivity to Althesin were investigated to determine if a specific immune response to the drug was present (as measured by classical complement pathway activation) or if a non-antibody-dependent alternative complement pathway activation was taking place. The patients were classified as those reacting on first exposure to Althesin and those who reacted adversely only on a second exposure. ⋯ In contrast, classical complement pathway activation was demonstrated in the blood samples of all 17 patients reacting on repeat exposure. Severe reactions occurred in nine of the 17 previously exposed patients compared with only one of the 13 reacting on first exposure to Althesin.
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Clinical Trial Controlled Clinical Trial
Effect of extradural analgesia using bupivacaine and 2-chloroprocaine on intervillous blood flow during normal labour.
The effect of lumbar extradural analgesia on intervillous blood flow (IBF) during labour was studied in 26 healthy parturients using an i.v. bolus injection of xenon-133. There was a 19% decrease (n.s.) in mean IBF in six parturients (non-extradural control group). ⋯ This increase is statistically significant (P less than 0.05). The improvement in IBF after extradural block was considered to be a result of the decreased uterine vascular resistance, as no significant changes were observed in arterial pressure, uterine activity or uterine tone.