By Ming-Feng Chen, MD, PhD(Show Chwan Memorial Hospital)
In traditional Chinese medicine, the physician makes a pulse diagnosis by three fingers (the 2nd, 3rd and 4th fingers) of one hand. First, the physician should put three fingers over the radial artery near one wrist of patient. Recognition of the pulse condition is made usually by applying three grades of finger force on the pulse region. The commonly used method are touching, searching and pressing. Pressing refers to a heavy pressure, that is, applying with a force that almost stops the pulse beat; touching refers to a gentle pressure applied to obtain a superficial sensation; and searching refers to a moderate pressure between touching and pressing. The most difficulty in pulse diagnosis is that the applying pressure by the physician can not be quantitatively measured. Moreover, the sensation of fingers can not be recorded objectively.
In fact, the definition of pulse diagnosis in Chinese medicine is similar to that of definition on blood pressure in western medicine. In western medicine, the physician measures blood pressure by putting a cuff over one arm of patient, increases the pressure in the cuff through gas sac until obstruction of blood flow, and then gradually decreases the pressure in the cuff by releasing of sac gas. When the pressure in the cuff decreases to below the blood flow pressure during heart constriction, the blood flow reopens and produces a sound. The blood pressure at this time is named systolic pressure. And when the pressure in the cuff decreases to below the blood flow pressure during heart relaxation, the sound changes to be weak suddenly. The blood pressure at this time is named diastolic pressure. According to the above description, the meanings of systolic pressure and diastolic pressure in western medicine are almost near the meanings of pressing and touching for pulse diagnosis in Chinese medicine. Both of them apply pressure on the blood vessel from outside, gradually decrease the external pressure and observe the reaction of blood vessel. The difference is that, the physicians in western medicine apply the pressure with external cuff and express the reaction of blood vessel by pressure (mmHg). However, the physicians in Chinese medicine apply the pressure by their fingers and recognize the reaction of blood vessel by the feeling of fingers.
Dynapulse is an instrument developed by Cardio Vascular Metrics Inc. It is used to measure the blood pressure with a cuff, amplifying the signal of pulse through a machine, then connecting to a personal computer. The advantage of Dynapulse is that, it not only can measure the blood pressure (including systolic pressure, diastolic pressure and mean pressure) but also can record the waveforms under various blood pressures. Furthermore, through the analysis of these waveforms by computer, it can reveal the heart function (including left ventricle contractility, cardiac output) as well as the compliance and resistance of systemic and peripheral arteries. Using Dynapluse, we cooperated with Cardiac Vascular Metrics Inc to develop an automatic instrument for pulse diagnosis in Chinese medicine since Nov. 1, 2001.