British journal of anaesthesia
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Comparative Study Clinical Trial Controlled Clinical Trial
The effects of adding adrenaline to etidocaine and lignocaine in extradural anaesthesia I: block characteristics and cardiovascular effects.
The addition of adrenaline 5 mug/ml, 1 : 200 000 to 1% etidocaine hydrochloride administered extradurally (L2-3) shortened significantly the onset time for sensory blockade, particularly with respect to the spread of the analgesia from the injection site, and shortened the already rapid onset of motor block. Etidocaine hydrochloride 1% plain caused a slower onset of block, laster longer and produced more profound analgesia over the caudal dermatomes than did 2% lignocaine hydrochloride. ⋯ With regard to cardiovascular variables, there were no significant differences between subjects receiving the plain etidocaine and the plain lignocaine. However, subjects receiving etidocaine with adrenaline exhibited increased cardiac stimulation and a decrease in total peripheral resistance over the first 150 min.
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Measurements of complement conversion and white cell variations were made on sequential blood samples obtained from a single volunteer following repeated administration of Althesin. The results suggest a mechanism by which a clinically significant hypersensitivity reaction to the drug might be mediated. Studies of patients receiving routine anaesthesia revealed a very high incidence of subclinical "hypersensitivity" reaction, some of which appear to be immune-mediated. These reactions occurred irrespective of whether the patients were induced with Althesin, methohexitone or propanidid.
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Plasma concentrations of lignocaine were measured in three groups of anaesthetized patients following spraying of the trachea and larynx with a lignocaine 10% aerosol spray. Greater venous plasma concentrations occurred in patients who were paralysed with suxamethonium. ⋯ In individual patients a concentration 50% in excess of the mean value may occur. The use of lignocaine 100 mg as a 10% aerosol spray can be considered safe.
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The effects of the establishment of an adrenergic blockade on suxamethonium-induced porcine malignant hyperthermia (MH) were investigated in Pietrain pigs. Six animals were fed reserpine 10 mg daily for 7 days and then challenged with suxamethonium. ⋯ The five year beta-blocked pigs all became hyperthermic and died whereas the phentolamine-treated group survived. However, both alpha adrenergic blockade and successful reserpinization failed to prevent the abnormal muscle response to the first dose of suxamethonium.