British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Influence of dose on suxamethonium-induced muscle damage.
We have examined postoperative muscle pain and early increases in serum concentrations of myoglobin after administration of suxamethonium to see if these changes were dependent on the dose of drug. Thirty ASA I and II adult patients undergoing day-case surgery received a standard anaesthetic technique, including one of three doses of suxamethonium: 0.5, 1.5 or 3.0 mg kg-1. The incidence of postoperative myalgia and the severity of fasciculations were greater after suxamethonium 1.5 mg kg-1 than after a dose of 0.5 or 3.0 mg kg-1. ⋯ Intubating conditions were significantly better with suxamethonium 1.5 or 3.0 mg kg-1 than with 0.5 mg kg-1. Changes in serum concentrations of calcium and potassium were small and similar in the three groups. We conclude that a dose of 3.0 mg kg-1 of suxamethonium provided a better combination of intubating conditions and minimal postoperative myalgia than the two lower doses.
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Three hundred and fifty consecutive patients (322 non-obstetric, 28 obstetric; 185 female) were assessed before operation using the modified Mallampati test and by measuring thyromental and sternomental distances, forward protrusion of the mandible and interincisor gap with the mouth fully open. Tracheal intubation was difficult in 17 (4.9%) patients, of whom four (1.14%) had a grade III or IV view on laryngoscopy. A sternomental distance of 12.5 cm or less with the head fully extended on the neck and the mouth closed predicted 14 of the 17 patients in whom tracheal intubation was difficult. ⋯ There was no correlation between the interincisor gap and the view on laryngoscopy (P > 0.05, one-way ANOVA). There was also no difference in mean interincisor gap between those patients who presented no difficulty with tracheal intubation and those who did (P = 0.7-0.8, two sample t test). Sternomental distance may be a useful bedside screening test for preoperative prediction of difficult tracheal intubation.
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Cholinesterase inhibitors antagonize neuromuscular block produced by mivacurium, but some may also decrease its metabolism by inhibiting pseudocholinesterase. These opposing interactions were examined in rats anaesthetized with pentobarbitone. After spontaneous recovery from an initial bolus dose of 0.03 mg kg-1, mivacurium was infused to produce 80-90% block of gastrocnemius muscle twitch. ⋯ Edrophonium, pyridostigmine and neostigmine reduced the subsequent maximum block, compared with the change in saline control, by 3%, 19% and 35%, respectively. Correspondingly, the time to recovery of T1 to 50% was decreased by 20%, 58% and 62%. In rats, acetylcholinesterase-mediated antagonism of neuromuscular block predominated over decreased pseudocholinesterase-mediated metabolism, such that prior administration of a cholinesterase inhibitor did not prolong the neuromuscular blocking effects of mivacurium.
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We describe the pregnancy and obstetric anaesthetic management of a patient with congenital tricuspid atresia who had undergone the Fontan procedure in childhood. The unique arrangement of the Fontan circulation combined with the haemodynamic alterations during pregnancy presents special anaesthetic considerations for both analgesia during labour and anaesthesia for Caesarean section.
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A postal survey of 160 members of the Neurosurgical Anaesthetists' Travelling Club was conducted in 1991 to investigate the current use of the sitting position in neurosurgery. There was a 78% response rate; at least one reply was received from every neurosurgical centre in the UK. ⋯ Thus in the period 1981-1991, the number of neurosurgical centres using the sitting position routinely, decreased by more than 50%. Current techniques of ventilation and monitoring for the sitting position are discussed briefly.