British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
IV clonidine for post-extradural shivering in parturients: a preliminary study.
We have studied the efficacy of i.v. clonidine to suppress post-extradural shivering in parturients. Forty healthy parturients who received extradural block for labour (n = 20) or for Caesarean section (n = 20) and who required treatment for shivering after delivery were allocated randomly to two groups. Group I received i.v. clonidine 30 micrograms diluted in saline to a total volume of 5 ml (therapeutic solution). ⋯ When patients in the placebo group received clonidine, improvement occurred. Arterial pressure, heart rate, core and peripheral temperature and oxygen saturation did not differ significantly between and within the groups before and after administration of clonidine. We conclude that a small dose of i.v. clonidine may be useful to suppress post-extradural shivering in parturients.
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We have studied the effects of bolus doses of midazolam 0.15 mg kg-1 i.v. on intracranial pressure (ICP), mean arterial pressure (MAP) and cerebral perfusion pressure (CPP) in 12 patients with severe head injury (Glasgow Coma Scale score < or = 6). The study was performed in patients aged 17-44 yr who were sedated (phenoperidine 20 micrograms kg-1 h-1) and paralysed (vecuronium 2 mg h-1). Midazolam reduced MAP from 89.0 mmHg to 75.0 mmHg (P < 0.0001), while CPP decreased from 71.0 mmHg to 55.8 mmHg (P < 0.0001). ⋯ However, when control ICP was less than 18 mmHg (n = 7 patients), an increase in ICP was observed. The remaining five patients (control ICP > or = 18 mmHg) exhibited a slight decrease in ICP. These findings suggest that bolus administration of midazolam should be performed with great caution in patients with severe head injury, especially when ICP is less than 18 mmHg.
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Randomized Controlled Trial Clinical Trial
Effects of different doses of thiopentone on the increase in serum myoglobin induced by suxamethonium in children.
We have studied the effects of different doses of thiopentone on the increase in serum myoglobin after administration of suxamethonium during inhalation induction of anaesthesia in children. Forty-three children were anaesthetized with halothane and nitrous oxide in oxygen and allocated to four groups: group S received suxamethonium 1 mg kg-1 to facilitate intubation; group ST2 received thiopentone 2 mg kg-1 and group ST4 received thiopentone 4 mg kg-1, before administration of suxamethonium 1 mg kg-1; group N did not receive thiopentone or suxamethonium. Serum myoglobin and creatine kinase (CK) concentrations were measured until 60 min after the injection of suxamethonium. ⋯ In group N, both values remained reasonably constant. Thiopentone 4 mg kg-1, but not 2 mg kg-1, attenuated the increase. The results indicate that to prevent a marked elevation in serum myoglobin after administration of suxamethonium, thiopentone 4 mg kg-1 should be administered.
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A fault in the assembly of a Matrix Large Animal Circle anaesthetic machine resulted in reversal of fresh gas flow through the vaporizer. The fault was discovered only after the sudden development of excessive depth of anaesthesia in two equine patients. Laboratory investigations were conducted to determine the effect of flow reversal on vaporizer output. Results indicated that output concentration was approximately doubled under these conditions.
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Ten healthy patients and 25 patients with cirrhosis of the liver (10 Child's A, 10 Child's B and 5 Child's C) received a bolus dose of mivacurium chloride 150 micrograms kg-1. The electromyographic response was monitored throughout anaesthesia until recovery of the first twitch of the train-of-four (TOF) (T1/T0) to at least 85% and the TOF ratio (T4:T1) to at least 80%. There was no significant difference between the two groups in the onset of neuromuscular block, but recovery was prolonged in the cirrhotic group compared with the healthy patients (respective mean times to recovery of T1/T0: to 5% = 20.2 vs 11.2 min (P < 0.05); to 10% = 23.8 vs 13.4 min (P < 0.005); to 25% = 28.4 vs 16.6 min (P < 0.005); to 50% = 41.1 vs 20.1 min (P < 0.005); to 75% = 43.8 vs 24.9 min (P < 0.005). ⋯ Recovery was most prolonged in the Child's C patients. Mean plasma cholinesterase activity was less in the cirrhotic compared with the healthy group (mean 582 (SD 254) iu litre-1 vs 1125 (303) iu litre-1) (P < 0.001) and there was a significant negative correlation between plasma cholinesterase activity and all the indices of recovery (P < 0.001 for all except recovery index (P < 0.01)). We conclude that patients with hepatic cirrhosis may be sensitive to mivacurium, which could be explained, at least in part, by the lesser plasma cholinesterase activity.