British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Dose-response studies of the interaction between mivacurium and suxamethonium.
We have determined the effect of pretreatment with mivacurium on the potency of suxamethonium and the effect of prior administration of suxamethonium on the potency of mivacurium. We studied 100 ASA I or II patients during thiopentone-fentanyl-nitrous oxide-isoflurane anaesthesia. Neuromuscular block was recorded as the evoked thenar mechanomyographic response to train-of-four stimulation of the ulnar nerve (2 Hz at 12-s intervals). ⋯ The calculated doses producing 50% depression of T1 (ED50) were 86 (95% confidence intervals 83-88) and 217 (208-225) micrograms kg-1 for suxamethonium alone and after mivacurium, respectively. This study also demonstrated that prior administration of suxamethonium did not appear to influence either the slope of the regression lines or the potency of mivacurium. Combining the results of this study with a previous study (mivacurium ED50 = 20.8 (20.3-21.3) micrograms kg-1 during isoflurane-nitrous oxide anaesthesia), we suggest that the potency of mivacurium did not differ from that observed after suxamethonium (17.4 (16.9-17.9) micrograms kg-1).
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We performed an audiometric study in 20 patients who underwent surgery of the shoulder region under an interscalene brachial plexus block (IBPB). Bupivacaine 0.75% with adrenaline was given followed by a 24-hr continuous infusion of 0.25% bupivacaine. Three audiometric threshold measurements (0.25-18 kHz) were made: the first before IBPB, the second 2-6 h after surgery and the third on the first day after operation. ⋯ The maximum change in threshold was 35 dB at 6 kHz measured at the end of the continuous infusion of bupivacaine. This patient had hearing threshold changes (15-20 dB) at 6-10 kHz on the opposite side also. IBPB may cause transient auditory dysfunction in the ipsilateral ear, possibly via an effect on sympathetic innervation.
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Randomized Controlled Trial Comparative Study Clinical Trial
Recovery characteristics after early administration of anticholinesterases during intense mivacurium-induced neuromuscular block.
The time course of recovery after early administration of anticholinesterases during intense mivacurium-induced block was evaluated by recording the mechanomyographic response of the adductor pollicis to post-tetanic count (PTC) and train-of-four (TOF) ulnar nerve stimulation. Seventy-two adult patients receiving thiopentone, fentanyl, nitrous oxide, isoflurane anaesthesia and mivacurium 0.15 mg kg-1 were allocated randomly to one of six equal groups according to the type of anticholinesterase and intensity of block at which antagonism was attempted. Groups 1, 3 and 5 received neostigmine 0.07 mg kg-1, while groups 2, 4 and 6 received edrophonium 1 mg kg-1. ⋯ The longest clinical duration (CD) values (time from administration of mivacurium to T1 25%) were encountered in groups 1, 5 and 6 and were 17.4 (7.9), 19.7 (3.4) and 21.4 (4.8) min, respectively. CD was reduced significantly in groups 2, 3 and 4 and values were 13.9 (3.5), 13.7 (3.5) and 13.8 (3.3) min, respectively. Recovery indices (RI) (time interval between T1 25% and 75%) were 13.8 (7.3), 6.3 (1.4), 4.6 (1.8), 6.0 (2.1), 3.7 (2.2) and 4.8 (3.1) min in groups 1-6, respectively and was prolonged with neostigmine antagonism at PTC 0 (group 1).(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Low and high frequency stimulation tests to characterize the effects of edrophonium on vecuronium-induced neuromuscular block.
We recorded adductor pollicis mechanical activity in response to low (0.1 and 2 Hz) and high (50 and 100 Hz) frequency stimulation 15 min after edrophonium 250, 500 and 1000 micrograms kg-1, given to antagonize vecuronium-induced block at 10, 25 and 50% pre-reversal twitch height. We studied 54 ASA class I and II anaesthetized (methohexitone, fentanyl, nitrous oxide) young adult patients allocated randomly to nine groups of six patients each. The greater sensitivity of train-of four (TOF) ratio and residual force after 100-Hz, 5-s tetanic stimulation (RF100) to residual deficit allowed discrimination more readily between the effects of edrophonium dose and pre-reversal twitch height (P < 0.001, two-way analysis of variance). The highest reversal scores (approximately 0.9 TOF ratio and 0.6 RF100) were obtained when edrophonium 500-1000 mg kg-1 was given at 50% twitch height (P < 0.05, Duncan's test).
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Randomized Controlled Trial Comparative Study Clinical Trial
Effectiveness and sequelae of very low-dose suxamethonium for nasal intubation.
We have studied the effectiveness and sequelae of low-dose suxamethonium in 60 day-case oral surgery patients requiring nasal intubation. Anaesthesia was induced with propofol and alfentanil; 60 patients were allocated randomly to three groups of 20 patients and received no suxamethonium, suxamethonium 0.25 mg kg-1 or 0.5 mg kg-1. ⋯ Good intubating conditions were produced in all 20 patients receiving suxamethonium 0.25 mg kg-1, in 19 patients receiving suxamethonium 0.5 mg kg-1 and in 11 patients not receiving a neuromuscular blocker. The incidence of postoperative myalgia after suxamethonium 0.25 mg kg-1 (20%) did not differ significantly from the incidence after propofol and alfentanil alone (28%).