British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Spinal anaesthesia with 0.5% bupivacaine 3 ml: comparison of plain and hyperbaric solutions administered to seated patients.
In a double-blind study, 0.5% bupivacaine 3 ml in plain (n = 10) or hyperbaric (n = 10) solution was injected intrathecally to 20 patients who were in the sitting position, to produce spinal anaesthesia for transurethral resection of prostate. No statistically significant differences were found in time to maximum cephalad spread of analgesia nor in the level reached. ⋯ There was no difference in the incidence of complete motor block, but a longer duration of lesser degrees of motor block was found with the plain solution (P less than 0.05). The plain solution produced a more predictable level of blockade.
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Fetal aortic and umbilical blood flows were studied in 15 mothers before and during spinal (intrathecal) anaesthesia for elective Caesarean section, using a method combining real-time ultrasonography and a pulsed Doppler technique. Spinal anaesthesia with 0.5% bupivacaine hydrochloride 2.5 ml in 8% glucose monohydrate solution was administered after preloading with 2 litre of lactated Ringer's solution. Simultaneously with the subarachnoid injection, an infusion i.v. of ephedrine 50 mg in 500 ml normal saline was initiated. ⋯ Fetal heart rate increased (P less than 0.05) 30 min after the introduction of the spinal anaesthesia, but blood flows in the fetal descending aorta and umbilical vein were unaffected. The pulsatility index of the fetal blood velocity decreased (P less than 0.05) both in the fetal aorta and in the umbilical artery 30 min after induction of the spinal anaesthesia, indicating a possible decrease in the placental vascular resistance. We conclude that, when normotension is maintained in the mother with a preload infusion and an infusion of ephedrine, spinal anaesthesia for Caesarean section has no harmful effect on the fetal circulation.
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Anaesthesia was induced with propofol 2.5 mg kg-1 followed by suxamethonium 1.5 mg kg-1 in six young healthy females undergoing laparoscopy. ECG was monitored continuously. ⋯ The bradycardia may be prevented by premedication with atropine. In contrast to thiopentone, propofol apparently lacks central vagolytic activity and may exert a central vagotonic effect which can exaggerate the muscarinic effects of suxamethonium.
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Comparative Study
Potency of atracurium and vecuronium at the diaphragm and the adductor pollicis muscle.
Train-of-four stimulation was applied to the ulnar and phrenic nerves in 18 adult patients anaesthetized with nitrous oxide and halothane in oxygen. The response of the adductor pollicis and the diaphragm were measured. Incremental doses of atracurium and vecuronium were given, with an infusion to replace drug lost by elimination or distribution. ⋯ The mean (SEM) ED50 ratios were 1.56 (0.16) for atracurium and 1.47 (0.16) for vecuronium. ED90 ratios were 1.93 (0.29) and 1.55 (0.17) for atracurium and vecuronium, respectively. It is concluded that both atracurium and vecuronium exhibit a similar degree of sparing of the diaphragm.