British journal of anaesthesia
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A closed-circle absorber system incorporating an in-circle Goldman vaporizer was used to administer halothane or enflurane in oxygen to adult patients. The attained inspired and end-tidal concentrations of volatile agent after a period of stabilization at each vaporizer setting were measured by mass spectrometry. ⋯ Minimal pre-oxygenation was used to assess the problem of nitrogen accumulation within the circuit. The maximum nitrogen concentration was 56%.
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Neuromuscular blocking agents are widely used in anaesthesia, and a simple quantitative method of monitoring their effects is desirable. This paper describes a new instrument which has been developed for electromyographic monitoring of neuromuscular block by a non-invasive technique which is both reliable and easy to use. The median nerve is stimulated at the wrist and the electromyogram (e.m.g.) from a thenar muscle is detected, rectified and integrated electronically to produce a meter display of the assessment of block. The method is recommended for routine use.