British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Alfentanil-mediated analgesia during propofol injection: no evidence for a peripheral action.
We have investigated if alfentanil acts via peripheral opioid receptors to relieve the pain which occurs on injection of propofol. Thirty seconds before induction of anaesthesia and immediately after a tourniquet at 50 mm Hg greater than systolic pressure was inflated on the upper arm, patients were given either placebo (n = 22), alfentanil 1 mg (n = 22) or lignocaine 40 mg (n = 22) via an i.v. cannula in the dorsum of the hand. ⋯ We found a significant reduction in pain after lignocaine compared with the two other groups (P < 0.001), but there was no difference between the placebo and alfentanil groups. We conclude that alfentanil does not relieve pain on injection with propofol via an action on peripheral opioid receptors when alfentanil is limited to the forearm for 30 s before induction of anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Spinal anaesthesia with 0.25% hyperbaric bupivacaine for Caesarean section: effects of volume.
To investigate the safety and efficacy of 0.25% hyperbaric bupivacaine for spinal anaesthesia in Caesarean section, we studied 60 parturients allocated randomly to one of three groups. According to the patient's height, groups 1, 2 and 3 received 3.2-3.6 ml (8-9 mg), 3.6-4.0 ml (9-10 mg) and 4.0-4.4 ml (10-11 mg) of 0.25% bupivacaine in 5% glucose, respectively. Subarachnoid injection was performed in the right lateral decubitus position, and parturients were then turned immediately supine with left uterine displacement. ⋯ The incidence of patients requiring analgesics during operation was significantly lower in groups 2 (25%) and 3 (10%) than in group 1 (70%). There was no difference in neonatal condition between the three groups. Spinal anaesthesia with 3.6-4.0 ml of 0.25% bupivacaine in 5% glucose was satisfactory for Caesarean section.
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Randomized Controlled Trial Comparative Study Clinical Trial
Single bolus compared with a fractionated dose injection technique of bupivacaine for extradural Caesarean section: effect on uteroplacental and fetal haemodynamic state.
We studied 26 healthy parturients undergoing elective Caesarean section, allocated randomly to receive extradural block with 0.5% plain bupivacaine in a double-blind manner in either a single bolus or fractionated doses. After a 3-ml test dose, an additional 20 ml of bupivacaine were given over a 5-min period in the single bolus group (n = 13) and over a 25-min period in the fractionated dose group (n = 13). We studied the effects of bupivacaine on blood flow velocities in the maternal placental and non-placental uterine and fetal umbilical arteries before and four times during establishment of extradural block using a pulsed colour Doppler technique. ⋯ Blood flow velocity waveform indices of the uterine and umbilical arteries did not differ significantly within or between groups during the study. There was no significant difference in neonatal outcome, as assessed by Apgar scores and umbilical artery pH values. In conclusion, we observed no deterioration in uteroplacental circulation after administration of a single bolus dose of bupivacaine.
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Randomized Controlled Trial Comparative Study Clinical Trial
Ketamine and norketamine plasma concentrations after i.v., nasal and rectal administration in children.
It has been suggested that nasal administration of ketamine may be used to induce anaesthesia in paediatric patients. We have examined the pharmacokinetics of ketamine and norketamine after nasal administration compared with rectal and i.v. administration in young children. During halothane anaesthesia, 32 children, aged 2-9 yr, weight 10-30 kg, were allocated randomly to receive ketamine 3 mg kg-1 nasally (group IN3) or ketamine 9 mg kg-1 nasally (group IN9); ketamine 9 mg kg-1 rectally (group IR9); or ketamine 3 mg kg-1 i.v. (group IV3). ⋯ Calculated bioavailability was 0.50 in groups IN3 and IN9 and 0.25 in group IR9. We conclude that nasal administration of low doses of ketamine produced plasma concentrations associated with analgesia, but using high doses via the nasal route produced high plasma concentrations of ketamine similar to those that induce anaesthesia. However, the large volume of ketamine required was partly swallowed and led to an unacceptable variability of effect that precludes this route for induction of anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Ventilatory effects of eltanolone during induction of anaesthesia: comparison with propofol and thiopentone.
We recorded the ventilatory effects of eltanolone 0.75 mg kg-1, propofol 2.5 mg kg-1 and thiopentone 4 mg kg-1 at induction of anaesthesia in 76 unpremedicated patients, aged 18-65 yr. Measurements were made using a pneumotachograph incorporated between a close-fitting face mask and a T-piece delivering 35% oxygen. Eltanolone caused significantly less apnoea than propofol (incidence 57% vs 100%) and less reduction in ventilation than propofol (median maximum decrease 4.8 vs 7.8 litre min-1), but the differences between eltanolone and thiopentone were smaller and generally not significant. Ventilatory frequency was maintained well in the eltanolone group.