Cai Dawei, Lu Weijun, Xu Guohui, Yu Aili (Shanghai First People's Hospital)
The purpose of this study is to investigate the influence of different parameters and methods of electric needling stimulation on the compound action potential induced by electrical stimulation, and thus find out the better parameters and method of stimulation for clinical acupuncture anesthesia, in which the same nerve stimulation with electric needling is often used.
In this study observations were made on the saphenous nerves of 27 dogs. Using the compound action potential induced by square wave stimulus as an index, observations were made about the influence of different methods and parameters of electric needling on A fibres.
Experiments were carried out in two groups. In one group, the effect of different frequencies (10, 50, 100, 200, 500 and 1000 Hz) and different intensities (maximal, ½ maximal and minimal for Aë excitation) of electrical stimulation on the compound action potential during the 5 minutes period of stimulation and also after it was studied. In the other group, the effect of different durations (5, 10, 20 and 30 minutes) of electrical stimulation with the some frequency (1000 Hz) and intensity (maximum for Aë activation) was observed.
The reduction of the A wave of the compound action potential produced by electrical stimulation varied considerably with the different parameters employed. Higher frequency stimulation induced a much better depressive effect and required shorter period of stimulation to obtain the same depression than the low frequency one. In our experiments, 1000 Hz was considered the best. Under the same frequency, the strongest depressive effect was induced by the maximal stimulus for Aë fibres and the weakest effect by the minimal stimulus for Aë fibres. Furthermore, there was inter-influence between frequencies and intensities of electric stimulation. Electric stimulation of high frequency and weak intensity gave similar depressive effect as the one with lower frequency and stronger intensity. The optimum duration of stimulation varied with the frequencies and intensities used. In the present experiment, using the maximal stimulation for the A à fiber (which is endurable by human subjects) with the frequency of 1000 Hz, the best depressive effect was induced by stimulation lasting 20-30 minutes and the next good was by that of 15 minutes, the 5 and 10 minutes' stimulation producing little effect. These findings suggest that in clinical practice, when we used the same nerve stimulation with maximal intensity endurable by the patient, the induction period should not be less than 15 minutes. From the above experiment it was shown that there was some inter-influence between the frequency, intensity and duration of electrical stimulation. Under the same intensity of stimulation, less time was required to get the same degree of depression with high frequency stimulus and longer time with low frequency one. Under the same frequency, the induction period was shorter with stronger stimulus and longer with weaker one. When the duration was the same, the intensity of stimulus to attain the same degree of depression was weaker with the high frequency stimulus and stronger with the low frequency one.
The effect of the same nerve electric needling was influenced not only by the parameters of electric needling, but also by the method of stimulation. The depressive action of two pairs of electric needling was proved to be stronger than the one pair needling. The study suggests that multiple needling on the same nerve would probably give better analgesic effect.
The purpose of this study is to investigate the influence of different parameters and methods of electric needling stimulation on the compound action potential induced by electrical stimulation, and thus find out the better parameters and method of stimulation for clinical acupuncture anesthesia, in which the same nerve stimulation with electric needling is often used.
In this study observations were made on the saphenous nerves of 27 dogs. Using the compound action potential induced by square wave stimulus as an index, observations were made about the influence of different methods and parameters of electric needling on A fibres.
Experiments were carried out in two groups. In one group, the effect of different frequencies (10, 50, 100, 200, 500 and 1000 Hz) and different intensities (maximal, ½ maximal and minimal for Aë excitation) of electrical stimulation on the compound action potential during the 5 minutes period of stimulation and also after it was studied. In the other group, the effect of different durations (5, 10, 20 and 30 minutes) of electrical stimulation with the some frequency (1000 Hz) and intensity (maximum for Aë activation) was observed.
The reduction of the A wave of the compound action potential produced by electrical stimulation varied considerably with the different parameters employed. Higher frequency stimulation induced a much better depressive effect and required shorter period of stimulation to obtain the same depression than the low frequency one. In our experiments, 1000 Hz was considered the best. Under the same frequency, the strongest depressive effect was induced by the maximal stimulus for Aë fibres and the weakest effect by the minimal stimulus for Aë fibres. Furthermore, there was inter-influence between frequencies and intensities of electric stimulation. Electric stimulation of high frequency and weak intensity gave similar depressive effect as the one with lower frequency and stronger intensity. The optimum duration of stimulation varied with the frequencies and intensities used. In the present experiment, using the maximal stimulation for the A à fiber (which is endurable by human subjects) with the frequency of 1000 Hz, the best depressive effect was induced by stimulation lasting 20-30 minutes and the next good was by that of 15 minutes, the 5 and 10 minutes' stimulation producing little effect. These findings suggest that in clinical practice, when we used the same nerve stimulation with maximal intensity endurable by the patient, the induction period should not be less than 15 minutes. From the above experiment it was shown that there was some inter-influence between the frequency, intensity and duration of electrical stimulation. Under the same intensity of stimulation, less time was required to get the same degree of depression with high frequency stimulus and longer time with low frequency one. Under the same frequency, the induction period was shorter with stronger stimulus and longer with weaker one. When the duration was the same, the intensity of stimulus to attain the same degree of depression was weaker with the high frequency stimulus and stronger with the low frequency one.
The effect of the same nerve electric needling was influenced not only by the parameters of electric needling, but also by the method of stimulation. The depressive action of two pairs of electric needling was proved to be stronger than the one pair needling. The study suggests that multiple needling on the same nerve would probably give better analgesic effect.
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