British journal of anaesthesia
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We have studied, in the monkey, the critical volume for the production of severe pneumonitis following pulmonary aspiration of gastric contents. Aspiration of 0.4 ml kg-1 and 0.6 ml kg-1 at pH1 produced mild to moderate clinical and radiological changes, but no deaths. ⋯ At 1.0 ml kg-1, 50% of the animals died--a mortality rate considerably less than that reported previously in animal studies. If these results were to be extrapolated to humans, the critical volume for severe aspiration could be increased from 25 ml to 50 ml (0.8 ml kg-1), considerably reducing the percentage of patients perceived to be "at risk".
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of two ventilators used with the T-piece in paediatric anaesthesia.
The Nuffield 200 ventilator was compared with a new valveless ventilator (CW 200) in 20 children undergoing general anaesthesia for paediatric surgery. The new ventilator incorporates design features which overcome the main disadvantages of the Nuffield 200 and make it an inherently safer machine. At identical ventilator settings it produced a significantly greater tidal volume with a reduction in end-tidal carbon dioxide partial pressure. This may have advantages in avoiding pulmonary barotrauma in children.
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Clinical Trial Controlled Clinical Trial
Total i.v. anaesthesia with propofol and alfentanil: dose requirements for propofol and the effect of premedication with clonidine.
We determined in 51 healthy patients undergoing body surface surgery the dose requirements for propofol, as part of a total i.v. anaesthesia technique with an alfentanil infusion. After premedication with temazepam, patients received alfentanil 50 micrograms kg-1 followed by an infusion of 50 micrograms kg-1 h-1. Patients were anaesthetized with a loading dose of propofol followed by a three-stage infusion designed to reach one of five preselected blood concentrations of propofol. ⋯ Whole blood concentration!of propofol at the time of the incision was related linearly to the inf!sion rate and the EC50 and EC95 (probit analysis) were derived as !.44 (95% confidence limits 0.62-1.87) and 4.05 (95% confidence lim!ts 2.78-30.5) micrograms ml-1, respectively. Post-operative recovery was!rapid, uncomplicated and uneventful. In a subgroup of eight patients,!the addition of clonidine 0.6 mg to the premedication significantly decreased the requirement for propofol (P less than 0.05) during surgery, but resulted in prolonged recovery times.