Articles: anesthetics.
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Acta Anaesthesiol Scand · Aug 1988
Randomized Controlled Trial Clinical TrialThe reduction of pain on injection of propofol: the effect of addition of lignocaine.
The effects of addition of 1 ml of lignocaine (10 mg) or isotonic saline to 19 ml of the emulsified preparation of propofol (Diprivan) were studied in a randomised, double-blind trial in 80 patients. The incidence and severity of pain on injection of propofol were significantly reduced by the addition of lignocaine (P less than 0.01).
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Comparative Study
Haemodynamic and heart rate reflex responses to propofol in the rabbit. Comparison with althesin.
Propofol was administered to eight rabbits by constant i.v. infusion at 0.2, 0.4 and 0.6 mg kg-1 min-1 to produce light sedation. The lowest dose was compared with an infusion of Althesin 0.1 mg kg-1 min-1. The rabbits had been previously implanted with aortic and vena caval perivascular balloon cuffs to examine the baroreceptor-heart rate reflex and an aortic thermistor catheter for cardiac output (CO) measurements. ⋯ A dose-related reduction in the range and gain of the baroreceptor-heart rate reflex was observed with propofol (P less than 0.05). The pattern of alteration of the reflex curve, however, differed between the two anaesthetics and the vagal efferent component was more resistant to blockade with propofol. The relative preservation of baroreceptor reflex responses, and the reduction in TPR by a reduction of resting constrictor tone, suggest propofol may have significant clinical advantages when used as a sedative infusion.
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When peripheral nerves of experimental rats are exposed to local anesthetics, distinctive and reproducible pathologic changes occur involving the perineurial sheath and endoneurial contents. Application of intermediate strength concentrations of the local anesthetics, 2-chloroprocaine, lidocaine, etidocaine, and intermediate or high concentrations of procaine to the surface of rat sciatic nerves resulted in the following changes. By 48 hours, the perineurial sheath exposed to the drug was disrupted and became permeable to granulocytes which infiltrated the subjacent endoneurium in conjunction with edema formation in the endoneurial interstitium. ⋯ Injury to Schwann cells by local anesthetics is temporary because these cells can replicate quickly. Autoradiographic studies of thymidine incorporation 1 week after procaine administration to the sciatic nerve showed intense proliferation of Schwann cells, but no such activity in controls. These findings support the view that their neurotoxic properties may account in some part for the function of local anesthetics, that Schwann cells of small unmyelinated fibers are more vulnerable to these agents than those of myelinated fibers, and that destruction of their supporting cells is followed by vigorous mitotic activity in the endoneurium.
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Twenty-three patients undergoing a wide variety of neurosurgical procedures were anaesthetised using fentanyl and propofol (Diprivan; Stuart Pharmaceuticals) for induction and a continuous infusion of propofol with 50% nitrous oxide for maintenance of anaesthesia. All patients were premedicated with midazolam, and hypotensive anaesthesia was employed using labetalol. ⋯ The quality of anaesthesia and surgical conditions were good. A rapid, smooth recovery was obtained in 22 patients.