Anaesthesia
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Case Reports
Patient-controlled analgesia using remifentanil in the parturient with thrombocytopaenia.
Patient-controlled intravenous remifentanil was used to provide analgesia in labour for three thrombocytopaenic women. The most successful regimen comprised a patient-demand bolus of 0.5 microg x kg(-1) with a lockout period of 2-3 min, allowing for a successful demand with each contraction. ⋯ Apart from one episode of maternal sedation and fetal heart rate decelerations resulting from an excessive demand bolus, mothers and neonates tolerated the remifentanil without sequelae. Owing to rapid metabolism by tissue esterase, the use of remifentanil allows adequate doses of opioid to be administered to the mother to achieve good analgesia, without its accumulation in the fetus.
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Comparative Study
A comparison of anaesthetic tensions in arterial blood and oxygenator exhaust gas during cardiopulmonary bypass.
This study evaluates the usefulness of the analysis of gas sampled from the exhaust port of a membrane oxygenator in the estimation of anaesthetic tension in arterial blood. Sixty-seven arterial blood samples were drawn from patients undergoing hypothermic cardiopulmonary bypass with anaesthesia maintained by either isoflurane or desflurane. ⋯ There was no difference in anaesthetic tension measured in arterial blood and gas leaving the oxygenator exhaust (isoflurane: n = 29, range: 0.3-0.8%, 95% limits of agreement: -0.08% to 0.09%; desflurane: n = 38, range: 1.5-5.4%; 95% limits of agreement -0.65% to 0.58%). We conclude that anaesthetic tensions in arterial blood can be accurately monitored by analysis of the gas emerging from the exhaust port of a membrane oxygenator.
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An ambient pressure oxygen reservoir bag apparatus for connecting to the nonventilated lung as soon as single-lung ventilation is initiated is described. The theoretical benefits are the facilitation of collapse of the lung on the side of surgery and a reduced likelihood of arterial desaturation. Although these main benefits are yet to be proven, the authors believe that the weight of theoretical argument and practical observation serves to justify the use of the apparatus while the outcome of suitably designed clinical trials is awaited. It can be used for all one-lung anaesthetics and is especially recommended for thoracoscopic surgery, where temporary re-expansion of the nonventilated lung is either counter-productive or contraindicated, and where there is a possibility that lung collapse may be delayed.