Anaesthesia
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The purpose of this study was to determine the optimal bolus dose of remifentanil required for the successful insertion of the laryngeal mask airway during propofol induction in children without a neuromuscular blocking agent. Twenty-six paediatric patients, aged 3-10 years, requiring anaesthesia for short ambulatory surgery were recruited. A predetermined bolus dose of remifentanil was injected over 30 s, followed by propofol 2.5 mg.kg(-1) over 10 s. ⋯ Laryngeal mask insertion was attempted 90 s after the end of remifentanil injection and the response of patients was classified as either 'movement' or 'no movement'. The bolus dose of remifentanil at which there was a 50% probability of successful laryngeal mask insertion (ED(50)) during induction with 2.5 mg.kg(-1) propofol was 0.56 (0.07) microg.kg(-1) in children without a neuromuscular blocking agent. From probit analysis, the ED(50) and ED(95) of remifentanil were 0.52 microg.kg(-1) (95% confidence limits, 0.42-0.62 microg.kg(-1)) and 0.71 microg.kg(-1) (95% confidence limits, 0.61-1.40 microg.kg(-1)), respectively.
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The ProSeal laryngeal mask airway (PLMA) has been used routinely for anaesthesia and for difficult airway management including airway rescue in non-fasted patients. Compared with the classic laryngeal mask airway the PLMA increases protection against gastric inflation and pulmonary aspiration, by separating the respiratory and gastro-intestinal tracts. The PLMA has potential advantages over use of the tracheal tube including smoother recovery, reduced pharyngolaryngeal morbidity and even reduced postoperative pain. ⋯ Anaesthesia was induced and maintained with remifentanil, target controlled propofol and rocuronium. A series of 102 cases were managed without complications and high rates of first time placement of the PLMA (inserted over a suction tube placed in the oesophagus). With careful patient selection the PLMA may offer an alternative airway for use by experienced anaesthetists in patients undergoing minor lower abdominal surgery.
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This study evaluated the stability and the compatibility of mixtures of morphine sulphate, bupivacaine, and clonidine hydrochloride and of hydromorphone, bupivacaine, and clonidine hydrochloride, when used in constant flow implantable pumps under simulated clinical use conditions. The pumps were filled with drug mixtures and incubated at 37 degrees C for a period of 90 days. Aliquots were sampled monthly from the reservoir and catheter outlet and the drug concentrations analysed using validated chromatography methods. ⋯ Both drug mixtures were found to be stable over 90 days in the pump at 37 degrees C. All device materials retained acceptable mechanical performance following exposure. These results demonstrate that both drug mixtures are stable when maintained at simulated body temperature in an implantable infusion system for 90 days.