British journal of anaesthesia
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Comparative Study
Decontamination of halothane from anaesthetic machines achieved by continuous flushing with oxygen.
The contamination of four types of anaesthetic machine with halothane was sequentially sampled by mass spectrometry while the machines were continuously flushed with oxygen 8 litre min-1 for up to 24 h. Contamination decreased in an exponential manner. Machines fitted with Selectatec vaporizer mounting systems and with the vaporizer removed showed contamination less than 0.02 parts per million (p.p.m.) of halothane after 12 h flushing. ⋯ Background contamination concentrations of greater than 0.05 p.p.m. were measured in a patient-free recovery area of an operating theatre suite. Concentrations increased to 1 p.p.m. when patients were admitted following halothane anaesthesia. Decontamination of anaesthetic machines to concentrations of halothane below those detected as background contamination within recovery areas may allow such machines to be used safely to anaesthetize patients at risk from halothane.
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Randomized Controlled Trial Clinical Trial
Magnesium and coronary revascularization.
Twenty patients, who underwent coronary revascularization without cardioplegic arrest, were given (during cardiopulmonary bypass) either magnesium chloride 16 mmol in 10 ml of water (magnesium group) or 10 ml of water alone (control group). Plasma and urinary magnesium concentrations were measured for 24 h after operation. ECG was recorded continuously during this period. ⋯ Urinary magnesium excretion was higher in the magnesium group, with 58% of the administered magnesium excreted in the first 24 h. The observed incidence of frequent or ventricular arrhythmias was 22% in the magnesium group compared with 63% in the control group. No significant differences in QTcorr intervals were observed between the groups.
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Alfentanil was administered, together with midazolam, as part of a total i.v. anaesthetic technique. The pharmacokinetics of alfentanil were determined in 10 female patients undergoing lower abdominal surgery. The dose regimen of alfentanil, based on simulation studies, consisted of a two-stage infusion following an initial bolus dose. ⋯ Neither lower abdominal surgery nor the simultaneous administration of midazolam seemed to affect the kinetics of alfentanil as compared with results from studies in healthy volunteers. The short half-life of alfentanil, resulting from a small volume of distribution, makes it suitable as part of a total i.v. technique. Consideration must be paid, however, to interindividual differences in the pharmacodynamic response and in plasma clearance.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intrathecal morphine in the management of pain following cardiac surgery. A comparison with morphine i.v.
Forty-four patients undergoing coronary revascularization received either intrathecal morphine 1 mg (n = 15), intrathecal morphine 2 mg (n = 15), or i.v. morphine 30 mg (n = 14) after the induction of anaesthesia. Morphine 2.5 mg i.v. was given, as required, in the postoperative period and pain score, respiratory rate and PaCO2 measured every 2 h. FVC, FEV1 and PEFR were measured before, and 24 h after, the induction of anaesthesia. ⋯ Postoperative PEFR was significantly better in patients given intrathecal morphine (P less than 0.01). These results suggest that intrathecal morphine provided better analgesia after cardiac surgery than did a conventional regimen. The lower dose (1 mg) was associated with less respiratory depression as assessed by PaCO2 measurements.
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Randomized Controlled Trial Clinical Trial
Effect of the addition of adrenaline to extradural diamorphine analgesia after caesarean section.
In a randomized double-blind study the effect of the addition of adrenaline to extradural diamorphine was assessed in 54 patients after Caesarean section. Patients received extradural diamorphine 5 mg in saline 10 ml with or without adrenaline 1 in 200,000 for postoperative pain relief. Analgesia was profound and of rapid onset in both groups. ⋯ Analgesia was also more consistent in the adrenaline group, with 77% of patients having more than 8 h of good analgesia compared with 48% in the saline group (P less than 0.05). Plasma morphine concentrations, measured in 12 patients, were lower, although not significantly so, in the adrenaline group and mean time to peak concentration markedly delayed. No serious side effects were observed, but there was a higher incidence of vomiting in the adrenaline group.