Acta anaesthesiologica Scandinavica
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Acta Anaesthesiol Scand · Aug 1995
Comparative StudyComparison of vascular effects of ropivacaine and lidocaine on isolated rings of human arteries.
Ropivacaine is a new local anaesthetic agent. Previous animal studies have indicated that vasoconstrictor effects are elicited by ropivacaine in vitro and subcutaneously and that it produces blanching of the skin if injected subcutaneously in humans. Lidocaine is a widely used local anaesthetic reported to exert a biphasic effect on the microvasculature with contraction at low concentrations and relaxation at high concentrations. ⋯ No statistically significant differences in contractile or relaxing effects were seen between the two drugs. Removal of the endothelium did not significantly affect contractile activity. In this study of human mammary artery preparations, ropivacaine is not a stronger vasoconstrictor than lidocaine.
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Acta Anaesthesiol Scand · Aug 1995
Randomized Controlled Trial Comparative Study Clinical TrialQT interval of the ECG, heart rate and arterial pressure during anaesthetic induction: comparative effects of alfentanil and esmolol.
In a double-blind study the effect of esmolol and alfentanil on the QT interval of the ECG corrected by the heart rate (QTc), heart rate and arterial pressure during anaesthetic induction was studied in 59 oxycodone- and atropine-premedicated ASA class I-(II) patients with a mean age of 26 yr (range 15-50 yr). The patients were randomly allocated to one of the four groups: saline, esmolol 2 mg.kg-1, esmolol 3 mg.kg-1 or alfentanil 0.03 mg.kg-1. Both doses of esmolol prevented the prolongation of the QTc interval after thiopental and suxamethonium, but not after laryngoscopy and intubation. ⋯ Esmolol did not prevent the increase in the heart rate and arterial pressure in response to laryngoscopy and intubation. No cardiovascular responses to laryngoscopy and intubation occurred in the patients treated with alfentanil. No cardiac arrhythmias occurred in the esmolol 3 mg.kg-1 group, whereas the frequency of ventricular ectopic beats was 40% in the saline group and 13-20% in the other groups.
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Acta Anaesthesiol Scand · Aug 1995
Randomized Controlled Trial Clinical TrialAnaphylactoid skin reactions after intravenous regional anaesthesia using 0.5% prilocaine with or without preservative--a double-blind study.
Methylparaben, the preservative of various local anaesthetic solutions, is a potential allergen. In a double-blind study, 0.5% prilocaine with (Citanest, n = 100) or without (n = 100) methylparaben were compared for the occurrence of skin reactions after intravenous regional anaesthesia of the arm in surgical patients. Skin reactions were registered after the deflation of the tourniquet cuff, and intradermal tests were performed with 0.5% prilocaine, 0.1% methylparaben and saline in all patients. ⋯ The skin symptoms disappeared within an hour and were always restricted to the region which had been anaesthetised. None of the affected patients had positive intradermal tests. The observed skin reactions are probably non-IgE-mediated anaphylactoid reactions in which the presence of methylparaben in the local anaesthetic solution plays a major role.
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Acta Anaesthesiol Scand · Aug 1995
Randomized Controlled Trial Clinical TrialDesflurane: a new volatile anesthetic for cesarean section. Maternal and neonatal effects.
Desflurane, a new volatile anesthetic agent with low blood/gas solubility, has recently been studied in clinical and animal trials but its use in obstetrics has not been adequately evaluated. This prospective study was undertaken to evaluate the maternal and neonatal effects of desflurane in obstetrical patients. Seventy-five healthy parturients undergoing primary or repeat cesarean section were randomly assigned to one of three groups of 25 each, end-tidal 3% desflurane, 6% desflurane or 0.6% enflurane, combined with 50% N2O and O2. ⋯ Patients in all three groups developed transient hypertension and tachycardia during induction of anesthesia which returned to baseline values in approximately 5 min. Neonatal outcome was equally good in the three groups. More neonates in the 6% desflurane group had TSR > 90 s compared to the 3% desflurane group (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Acta Anaesthesiol Scand · Aug 1995
Propofol and isoflurane induced EEG burst suppression patterns in rabbits.
The aim of this study was to compare propofol produced EEG burst suppression with isoflurane produced burst suppression in rabbits and to see whether rabbits can serve as models in studying the effects of different anaesthetics on human EEG. We recorded EEG of eight rabbits anaesthetised with isoflurane and propofol. The isoflurane bursts had higher amplitude than propofol bursts (P < 0.005). ⋯ Rabbits did not have the rhythms seen in humans. We conclude that rabbits can be used to study the EEG effects of anaesthetics, such as the timing properties and reactivity of burst suppression pattern. However, this model seems less promising in the study of rhythmic activity seen in human EEG during burst suppression.