Biomedical subjects
Publications and source records attributed to L R Redman.
Interference refractometry is a well-established method of determining the concentration of anaesthetic agents in gas mixtures. A photo-electric detector system has been fitted to a small portable, direct-reading interference refractometer to display automatically the concentration of the agent being measured. The design of the instrument is described and two possible methods of information display are suggested.
The technique of injection and the results of a series of 124 chemical lumbar sympathectomies, performed on 97 patients, are described. Sixty-eight patients, over 60 years of age, had their sympathectomy because of peripheral arteriosclerotic disease. Fifty-two of these patients benefited in terms of pain relief and only one required amputation. Sixteen patients, under 60 years of age, had their sympathectomy because of peripheral arteriosclerotic disease. Ten of these patients benefited but it is recommended that, where possible, other methods of treatment should be used in this younger age group. Thirteen patients, mostly elderly, had their sympathectomy because of diabetic ischaemic disease. Six only of these patients benefited, but it is felt that chemical sympathectomy can be recommended as a way of helping some of these patients who would otherwise have amputation.
Drugs which block the transmission of excitation from motor nerve to voluntary muscle fibre are used routinely in anaesthesia. The action of this group of drugs may be studied by stimulating a motor nerve and observing the evoked muscle response. Simple nerve stimulators are widely available and are designed to achieve supramaximal stimulation of a convenient peripheral motor nerve. Quantitative observation of the evoked muscle response is achieved by measuring either the action potential or the tension developed by the contracting muscle. While such techniques are commonly used for research and teaching purposes, they are not widely available to the practising anaesthetist. Electrocardiography, on the other hand, id frequently used in operating theatres and recovery rooms, so that medical personnel are accustomed to using ECG recorders and are trained to interpret the displayed information. We have developed an EMG pre-amplifier and signal processor to produce a signal which can be displayed by ECG equipment.