British journal of anaesthesia
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Flow-volume loops were monitored continuously in 39 patients undergoing thoracic surgery requiring one-lung ventilation. In 26 of the 39 patients (67%), auto-positive end-expiratory pressure (auto-PEEP) was seen on the flow-volume curves during both two-lung and one-lung ventilation. Eighty-seven percent of the patients whose trachea was intubated with a smaller size (35- and 37-French gauge) double-lumen tracheal tube exhibited auto-PEEP, compared with patients in whom the tube used was larger (39- or 41-French gauge: 54% and 50%, respectively). Before operation, mean airway resistance was significantly greater in patients who exhibited auto-PEEP during anaesthesia (2.4 cm H2O litre-1 s) than in patients without auto-PEEP (1.7 cm H2O litre-1 s).
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Randomized Controlled Trial Comparative Study Clinical Trial
Diamorphine-bupivacaine mixture compared with plain bupivacaine for analgesia.
We have studied the efficacy of two extradural infusions (10 ml h-1) in 50 patients in active labour. Patients in the diamorphine group (n = 25) received 0.0625% plain bupivacaine 6.25 mg h-1 mixed with 0.005% diamorphine 0.5 mg h-1 and those in the control group (n = 25) received 0.125% plain bupivacaine 12.5 mg h-1. ⋯ There were no differences in the incidence of hypotension, instrumental vaginal delivery, number of "top-ups", duration of the second stage or extent of motor block. However, patients in the diamorphine group had a high incidence of pruritus (44%, compared with 0% in the control group (P < 0.01)).
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Randomized Controlled Trial Clinical Trial
Optimum dose of neostigmine at two levels of atracurium-induced neuromuscular block.
There is controversy about the optimum dose of neostigmine for antagonizing neuromuscular block. We have studied 57 patients undergoing gynaecological surgery to establish a dose-response relationship when neostigmine was given to antagonize atracurium-induced block. Anaesthesia was induced with thiopentone and fentanyl and maintained with nitrous oxide and enflurane in oxygen and neuromuscular block was produced with a bolus of atracurium 0.5 mg kg-1. ⋯ There was little benefit in increasing the dose of neostigmine from 40 micrograms kg-1 to 80 micrograms kg-1 when antagonizing profound neuromuscular block. When light block was antagonized, neostigmine 20 micrograms kg-1 was the optimum dose. We suggest that smaller doses of neostigmine than are given commonly produce adequate antagonism of atracurium-induced neuromuscular block.
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We have defined the infusion dose requirements of propofol to suppress consciousness and response to a variety of graded non-noxious and noxious stimuli in 52 unpremedicated patients aged 16-40 yr and 32 patients aged 41-65 yr. They were allocated to receive one of five loading dose-infusion schemes designed to establish stable conditions covering the range from wakefulness, through sedation, to loss of consciousness and anaesthesia. ⋯ In both groups the dose-response curves for suppression of proprioception, finger counting and perception of light touch in conscious patients were shifted to the left of the curves for loss of consciousness and eyelash reflex. Dose-response curves for noxious stimuli were shifted to the right of those for loss of consciousness.
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Interaction of the steroidal neuromuscular blocking drugs pancuronium, pipecuronium, rocuronium and vecuronium with cardiac muscarinic receptors in rat hearts was investigated in vitro by a tritiated N-methyl hyoscine binding assay. We showed an interaction with cardiac muscarinic receptors with a rank order of potency pancuronium > vecuronium > pipecuronium > rocuronium and demonstrated complex binding characteristics for pancuronium, vecuronium and rocuronium, with "Hill coefficient" of less than unity. We conclude that the haemodynamic differences seen during the use of these neuromuscular blocking drugs may be a result of their interactions with cardiac M2 muscarinic receptors.