British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Intra-articular analgesia for arthroscopic meniscectomy.
Intra-articular morphine has been shown to provide prolonged analgesia after arthroscopic knee surgery; the addition of local anaesthetic agents has been reported to improve this analgesic effect. Pethidine possesses local anaesthetic properties, and therefore this study was designed to evaluate its analgesic efficacy after arthroscopic meniscectomy. Sixty patients were allocated randomly to receive intra-articular injections of pethidine 50 mg, morphine 5 mg or saline after elective arthroscopic meniscectomy. ⋯ Both treatment groups had significantly lower pain scores compared with the control group. Patients in the pethidine group had lower pain scores than those in the morphine group at 0.5, 1 and 2 h, but significantly higher scores at 12 and 24 h. These observations suggest that the local anaesthetic effect of pethidine may be responsible for the improved early analgesia, but its duration of action appears to be less than that of morphine.
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Comparative Study Clinical Trial Controlled Clinical Trial
Temporal summation during extradural anaesthesia.
We have investigated in 10 patients the effect of extradural anaesthesia on temporal summation by comparing pain thresholds to single and repeated (five impulses at 2 Hz) electrical stimuli and compared these tests with pinprick and cold stimulation. Bupivacaine 0.5% (20 ml) was injected at L2-3. After extradural anaesthesia the threshold to repeated stimuli was significantly lower than the threshold to single stimuli (P = 0.0007). ⋯ Pain to single electrical stimulation disappeared in six patients and pain to repeated electrical stimulation in one. Pain may be evoked by temporal summation of repeated electrical stimuli even when pinprick sensation, cold sensation and pain to single electrical stimuli are inhibited. Thus temporal summation should be taken into consideration when extradural analgesia is assessed.
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Randomized Controlled Trial Comparative Study Clinical Trial
Histamine-release haemodynamic changes produced by rocuronium, vecuronium, mivacurium, atracurium and tubocurarine.
We have examined the effects of different benzyl-isoquinolinium and steroidal neuromuscular blocking compounds on plasma concentrations of histamine, heart rate and arterial pressure in surgical patients. A single, rapid (5-s) bolus of mivacurium 0.2 mg kg-1, atracurium 0.6 mg kg-1, tubocurarine 0.5 mg kg-1, vecuronium 0.1 mg kg-1 or rocuronium 0.6 mg kg-1 was administered to 75 patients (n = 15 in each group). Anaesthesia was induced with thiopentone 6 mg kg-1 i.v. and maintained with isoflurane and 70% nitrous oxide in oxygen. ⋯ Corresponding values at 3 min were 223%, 148% and 157%, respectively. These changes were significant (P < 0.01) at 1 and 3 min. In contrast, the rocuronium and vecuronium groups had no significant changes in either plasma histamine concentrations or haemodynamic variables.
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Randomized Controlled Trial Clinical Trial
Effects of clonidine premedication on the pressor response to alpha-adrenergic agonists.
It has been suggested that postjunctional alpha 1-adrenoceptor mediated vasoconstriction is enhanced by clonidine. We have examined in humans if the pressor responses to noradrenaline and phenylephrine are enhanced by clonidine premedication. Seventy-seven patients were allocated randomly to either clonidine (n = 38) or control (n = 39) groups. ⋯ When a stable haemodynamic state was obtained, either noradrenaline 0.5 microgram kg-1 (n = 40) or phenylephrine 2 micrograms kg-1 (n = 37) was administered randomly i.v. as a bolus, while arterial pressure and heart rate were measured noninvasively at 1-min intervals for 10 min. Although noradrenaline caused significantly greater increases in mean arterial pressure (MAP) in the clonidine group (from 2 to 4 min after i.v. injection) compared with the control group, there were no significant differences in the mean maximal increment in MAP or area under the MAP curve between the two groups. However, i.v. phenylephrine produced a significantly greater increase in MAP from 2 to 7 min (P < 0.05), and greater mean maximal increase in MAP from the baseline value (21 (9) vs 14 (7) mm Hg; P < 0.05) in the clonidine than in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Effect of i.v. lignocaine on the breathing of patients anaesthetized with propofol.
Local anaesthetics are ventilatory depressants, but previous investigators have not commented on the effects on ventilatory timing. There is concern about the possible ventilatory depression caused by systemic absorption of local anaesthetics injected extradurally. We have studied ASA grade I patients anaesthetized with a propofol infusion and breathing spontaneously; they were given in random order lignocaine 1.5 mg kg-1 i.v. and an equivalent volume of 0.9% saline. ⋯ Lignocaine had no effect on or promoted bimodality of expiratory time. End-tidal carbon dioxide increased by a mean of 0.1%; the largest individual change was 0.3%. This suggests that lignocaine may have reduced the metabolic rate, affecting ventilation indirectly, but we conclude that lignocaine in a normal extradural dose should not be an important ventilatory depressant.