Resonance phenomenon during wrist pulse-taking: A stochastic simulation, model-based study of the ‘pressing with one finger’ technique

This study analyzed the ‘pressing with one finger’ technique for wrist pulse-taking and explored the identification of internal organs according to the resonance theory in the circulatory system. A five-section discretized-transmission-line model of the distal upper limb was proposed considering the radial artery, the distal positions chi–guan–cun, and the hand vasculature. The transfer function of the model was parameterized in terms of its resonance frequency and respective amplification factor. Rheological and geometrical parameters of the modeled arterial system were used to simulate a sample of 1000 healthy volunteers subjected to wrist pulse-taking examination. The ‘pressing with one finger’ technique was simulated individually at each position by varying the vertical (minor) diameter of the elliptical cross-sectional radial artery from 0% to 99%. The pulse waveform harmonics were calculated in the frequency domain and had their internal organs assigned according to the resonance theory. Compressions in range 0–70% resulted in resonance frequencies around 3–6 Hz (related to the spleen) and amplification factors > 1. Compression in range 70–85% shifted up the resonance frequency of the majority of cases up to 6–8 Hz (related to the heart) and a minority of cases was shifted down to 0–2 Hz. A large decrease in the amplification factor occurred with module values <1. Compressions in range 85–99% increased the resonance frequency to 7–10 Hz (related to the gallbladder) with an even decent amplification factor. These effects were more pronounced in the proximal to distal sequence of positions. Therefore, pressing with one finger amplified specific pulse wave harmonics as a function of depth in all three positions, but it did not explore all harmonics described by the resonance theory.

► Resonance phenomenon is observed during the ‘pressing with one finger’ technique.
► Pulse wave harmonics were amplified as a function of depth during pulse palpation.
► Not all pulse harmonics are explored during pulse palpation at the radial artery.