Anaesthesia
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Randomized Controlled Trial Clinical Trial
Clinical usefulness of the bispectral index for titrating propofol target effect-site concentration.
The bispectral index, a new processed electroencephalographic parameter which may give information on depth of anaesthesia, was used in 58 patients undergoing outpatient gynaecological surgery in order to study if the addition of bispectral index monitoring to standard clinical monitoring could improve the titration of target propofol concentration when using effect-site target-controlled propofol infusion for sedation. In Group 1 (n = 30), the bispectral index was recorded but the anaesthetist was unaware of the readings and therefore only classical signs of depth of anaesthesia were used to guide the anaesthetist in controlling the effect-site concentration. In Group 2 (n = 28), bispectral index readings were available to the anaesthetist and effect-site concentration was adjusted to ensure that bispectral index was maintained between 40 and 60. ⋯ There was a trend towards more implicit awareness in patients in Group 1. Bispectral index was found to be useful for measuring depth of sedation when using propofol target-controlled infusion. Propofol dosage could not be decreased but a more consistent level of sedation could be maintained due to a more satisfactory titration of target effect-site concentration.
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Randomized Controlled Trial Comparative Study Clinical Trial
Pain on injection of propofol. A comparison of cold propofol with propofol premixed with lignocaine.
Propofol is frequently associated with pain on injection. Previous studies have suggested that chilling of the propofol decreases pain significantly. This prospective, randomised, double-blind trial was designed to assess the effectiveness of cold propofol compared with propofol premixed with lignocaine in minimising pain on injection. ⋯ The results of this study show that cold propofol is associated with a very high incidence of injection pain while lignocaine 0.1 mg.kg-1 premixed with propofol significantly decreases the incidence of pain (p < 0.001). Increasing the dosage of lignocaine above 0.1 mg.kg-1, however, does not significantly decrease the incidence of pain further. The addition of lignocaine also significantly decreases the incidence of excitatory side-effects.
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Randomized Controlled Trial Clinical Trial
Dose-response and time-course of the effect of rocuronium bromide during sevoflurane anaesthesia.
To evaluate the influence of sevoflurane on the dose-response relationship and on the time-course of the effect of rocuronium, 60 adult patients undergoing elective plastic surgery were randomly allocated to either the control or the sevoflurane group. Anaesthesia was maintained with 60% nitrous oxide in oxygen and thiopentone in the control group and with 60% nitrous oxide in oxygen and an end-tidal concentration of 1.75% sevoflurane in the sevoflurane group. Neuromuscular function was assessed mechanomyographically with train-of-four stimulation at the wrist every 12s and the percentage depression of the first twitch of the train-of-four was used as the study parameter. ⋯ The effective doses of rocuronium required to produce 50%, 90% and 95% twitch depression in the sevoflurane group were decreased by 30.5%, 26.7% and 25.2%, respectively, compared to the control group. Following the administration of a total dose of rocuronium of 400 micrograms.kg-1, the duration of action of, and the recovery from, rocuronium were both significantly prolonged by sevoflurane. There were significant differences in the duration of peak effect, clinical duration, recovery index and the total duration of action between the control and the sevoflurane groups.
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We studied the influence of the timing of injection of bupivacaine into the vas deferens on the intensity and duration of scrotal pain following vasectomy. Forty-two patients undergoing vasectomy under general anaesthesia were randomly allocated to have the operation performed on either the left or the right side first. On the first side to be operated upon, 5 ml bupivacaine 0.5% was infiltrated along the line of the scrotal incision. ⋯ Median [interquartile range] visual analogue pain scores on the first side to be operated upon were significantly lower than on the second side on day 1 (7 [1.5-19] vs. 11 [2.5-47]) (p < 0.01) and day 7 (0 [0-8.5] vs. 0 [0-18.8]) (p < 0.05) postoperatively. The median [interquartile range] duration of postoperative discomfort was less on the first side operated upon than on the second (3 [1-7] vs. 6 [2-7]) (p < 0.01). Although statistically significant differences occurred between the treatment groups, the actual differences were small and may not be clinically significant.
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Comparative Study Clinical Trial Controlled Clinical Trial
A comparison of near-infrared spectroscopy and jugular bulb oximetry in comatose patients resuscitated from a cardiac arrest.
One cause of cerebral damage in comatose patients resuscitated from a cardiac arrest is cerebral ischaemia occurring during the postresuscitation period. Near-infrared spectroscopy has been advocated as a useful monitor of brain oxygenation, but data on clinical use in comatose postarrest patients are not available. Therefore, we compared regional oxygen saturation measured with the INVOS 3100 with global oxygen saturation measured using jugular bulb oximetry in 10 comatose patients successfully resuscitated from an out-of-hospital cardiac arrest. ⋯ This increase was significantly correlated with the rise in cerebral blood flow and cardiac index, indicating that regional oxygen saturation is influenced by both cerebral and extracerebral components. We conclude that regional cerebral oxygen saturation measured with the INVOS 3100 cannot be compared with global cerebral oxygen saturation measured with jugular bulb oximetry in comatose patients resuscitated from a cardiac arrest. This may be due to characteristics of the INVOS 3100 or to the distribution of cerebral blood flow after cardiac arrest.