European journal of anaesthesiology
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We studied whether long-term epidural catheter (nylon) placement for bupivacaine administration (morphine in 2 pigs) would cause any pathological changes in the epidural space and spinal cord of pigs. There were similar kinds of slight inflammatory changes in ligamentum flavum and dura mater in bupivacaine-treated (4 ml 0.5% bupivacaine, twice daily for 7 days, n = 8; 16 ml 0.25% bupivacaine infusion in 12 h, n = 3) and morphine-treated (2 mg preservative-free morphine, twice daily for 7 days, n = 2) pigs compared with corresponding control pigs (saline, n = 8) 24 h after treatment. There were minimal inflammatory changes in one of the two bupivacaine-treated pigs recovering for 3 weeks. ⋯ In this pig the overall level of bupivacaine plasma concentrations after an injection decreased stepwise during the 7-day period (sampling at 2-day intervals). In the other pigs treated for 7 days, the level of bupivacaine concentrations did not change markedly from first sampling to later samplings. It is probable that inflammatory changes in the epidural space, following prolonged administration of bupivacaine and morphine, are largely due to catheter irritation.
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To evaluate respiratory drive and timing in 11 spontaneously breathing infants anaesthetized with halothane, ventilation was followed before and during CO2 provocation, and occlusion tests were performed. All infants were younger than 6 months of age and their weights ranged from 3.8 to 7.5 kg. All measurements were performed prior to surgery. ⋯ The net effect of increased inspiratory drive during CO2 breathing resulted in a VT which on average was increased by 67% (P less than 0.001) so that the mean value of E'CO2 only rose by 0.98% (P less than 0.01) from 5.18% before to 6.16% during CO2 breathing. It was concluded that ventilatory compensation to CO2 was adequate, indicating preserved respiratory centre activity. Respiratory timing, however, was unaffected by CO2 indicating a discrepancy between the effects of halothane on respiratory motor centre activity and the bulbopontine pacemaker in these young infants.
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Randomized Controlled Trial Comparative Study Clinical Trial Controlled Clinical Trial
The effect of atracurium, vecuronium and pancuronium on heart rate and arterial pressure in normal individuals.
Heart rate and rhythm (from ECG) and systolic, diastolic and mean arterial pressures (using an oscillotonometer) were measured for 30 min following administration of atracurium 0.5 mg kg-1 (n = 20), vecuronium 0.1 mg kg-1 (n = 20) or pancuronium 0.1 mg kg-1 (n = 20) during steady-state anaesthesia, with nitrous oxide, oxygen and either 0.75% halothane or fentanyl 4-5 micrograms kg-1, in the absence of any surgical stimulation. Whereas atracurium and vecuronium were associated with only small and clinically unimportant changes in heart rate, pancuronium produced a marked and significant increase associated with a junctional rhythm in four patients. ⋯ No serious bradycardias were observed with either atracurium or vecuronium. Five patients showed cutaneous signs of histamine liberation after administration of atracurium.