Getting started: pulse techniques, procedures and the development of a methodical approach to pulse assessment

Before the pulse is assessed, the patient needs to be positioned appropriately. Appropriate patient positioning allows the practitioner maximal access to the radial artery for assessment purposes while preventing any postural changes that may affect blood flow. For example, if the patient slouches, their respiration will be poor and this will cause a corresponding decrease in pulse strength. Postural slouching and arterial compression from poor arrangement of the upper limbs impede blood flow from the central arteries into the peripheral arteries, limiting the propulsion effect that the pressure wave has on moving blood. In this situation any assessment of the pulse will be inaccurate and unreliable.

The pulse is most commonly taken when the patient is seated, but assessment can also occur when the patient is lying supine (Box 5.1). Irrespective of the positioning approach used, the arm is always placed at the level of the patient’s heart. Holding the arm lower or higher than the heart level affects the pulse pressure, causing changes in the pulse wave. Ensuring that the arm is level will minimise these postural related pressure differences. Pulse examination is undertaken on both the left and right arms (Fig. 5.4).

If sitting, the patient’s legs should be uncrossed with feet placed flat on the floor. Their posture should be relaxed but upright so that the thorax region is not constricted during respiration, allowing the lungs to expand and contract freely. The wrist should be extended straight with the palm facing upwards (Fig. 5.1). Similarly, when lying supine, the patient should have their legs uncrossed, wrist extended with the palm facing upwards (Fig. 5.2).

A folded towel or small cushion can be used to support the wrist if necessary in either the supine or sitting positions. This ensures that the radial artery is easily accessible and that the blood flow is unimpeded. Additionally, such support limits any movement in the wrist that maybe introduced by the practitioner when applying finger pressure to assess the pulse at different levels of depth.

Once the patient and wrist region are appropriately positioned, the next step is to locate the artery, andin particular, the radial pulse sites used for pulse examination. As described in Chapter 2, the radial artery is located on the lateral portion of the anterior forearm. It extends from the elbow, where the brachial artery bifurcates, to the wrist crease, at which point the radial divides further into other arterial segments. (When seen from the perspective of channel physiology, the radial artery follows the course of the Lung channel.) The CM pulse sites used for pulse assessment are located in the wrist portion of the artery only. At this region, the radial artery is usually quite easily palpated because of its close proximity to the skin surface and its position over a hard surface — in this case the radial bone. The radial bone provides a firm support to the radial artery when external pressure is applied. If there were no support then it would be difficult to clearly distinguish the pulse parameters or apply different levels of pressure without the artery moving.

The portion of the radial pulse used for assessment is located proximal to the wrist crease directly above the pulsation of the radial artery adjacent to the styloid process of the radius. This is known as the Cun Kou pulse, and from the time of the Nan Jing it was considered to be the convergence point of movement through all the conduit vessels. The Second Difficult Issue in the Nan Jing discusses the length of the Cun Kou position, describing it as 1.9 Cun in length. Proportionally, this is about one sixth of the area between the transverse elbow crease and the wrist crease, assuming the length of the forearm is 12 Cun (or anatomical units) (see Fig. 5.3). In metric measurement this is approximately 3–5 cm. However, exact measurements are not necessarily applied because locating the pulse positions primarily depends on the location of the styloid process and the relative size of the patient.

Once the Cun Kou region of the artery proximal to the wrist is located, the pulse positions used for pulse assessment must be identified. There are three of these positions, and they are found by dividing the Cun Kou region into three portions using the styloid process of the radius as a guide. The three positions are:

Because the three pulse positions are determined proportionally according to an individual’s size, this means that the same procedure needs to be followed every time to ensure exact location of these positions within the same physique and between different physiques (Box 5.2). Of the three positions Cun, Guan and Chi, it is the central position Guan which is associated with a specific surface anatomical landmark; the styloid process. For this reason, the Guan position should always be located first as the locations of the Cun and Chi positions depend on the initial location of Guan.

When taking the pulse the practitioner should sit opposite or next to the patient. Using the tips of the fingers (Box 5.3), the practitioner’s left hand is used to feel the pulses of the patient’s right hand and the practitioner’s right hand is used to feel the pulses on the patient’s left (Box 5.4). Similarly, if the practitioner were to palpate their own pulses on the right wrist, the practitioner’s left hand wraps under the wrist with the index, middle and ring fingers sequentially falling on the three pulse positions Cun, Guan and Chi. This is reversed if feeling the left hand pulses. This ensures that the same fingers are always used to palate the same pulse positions (Fig. 5.4). For example, the right index finger is always placed on the left Cun position, irrespective of whether the practitioner is palpating someone else’s pulse or their own. This will assist in ensuring that a level of sensitivity and a reference range of pulses are built up for that particular finger and this in turn assists with reliable identification and assessment of any changes in the pulse parameters at the related pulse site.

Once the pulse positions are located, the fingers are moved in different directions and depths to assess the pulse wave and the anatomy of the arterial wall at each of the positions. In particular, discrete increments of pressure are applied by the fingers to feel the three levels of pulse depth. The fingers are also moved from side to side to assess the width and tension of the arterial wall, and longitudinally to assess pulse length. Of the three movements, depth assessment is particularly important in CM, as each pulse site can be further divided into different levels of depth with each level theoretically reflecting a different region of the body.

Assessment of pulse depth is discussed in greater detail below, and this requires a specific technique to locate the levels of depth. Lateral and longitude assessment of the pulse are respectively discussed in Chapter 6 in the section on assessing the pulse parameter length and in Chapter 7 in relation to assessment of the pulse parameter arterial wall tension.

A consistent technique for correct location of the levels of depth is just as important in pulse diagnosis as correct anatomical location of the Cun, Guan and Chi pulse positions. Each pulse/position site can be further divided into two levels (superficial and deep) of depth or three (superficial, middle and deep), depending on the theoretical CM model used. For example, in Five Phase pulse diagnosis, only the superficial and deep levels of depth are assessed (Fig. 5.6). In determining overall pulse qualities as presented in the Mai Jing and Bin Hue Mai Xue, three levels of depth are often required for pulse assessment. There are even systems of pulse assessment based on the writings of the Nan Jing that palpate up to five levels of depth, and other systems state up to eight levels of depth (Hammer 2001), but these systems are not widely used. There are three commonly used levels of depth: superficial, middle and deep.

The parameter of pulse depth may be interpreted in two ways. Firstly, it refers to the level of depth where the radial arterial pulsation is found to be the strongest, regardless of the overall intensity of the pulsation. That is, we need to determine the relative strength of each level of depth. An integral part of determining pulse depth involves examination of the effect on radial pulsation of differing amounts of pressure exerted on the radial artery.

Secondly, pulse depth can refer to the level of depth at which the radial artery is physically located. This may be the result of anatomical structural variations within the subcutaneous layer of tissue overlying the radial artery, or the anatomical variations in the musculature and tendinous insertions around the forearm and wrist area. Diagnostically, the level of depth may be affected by pathological processes occurring within the body, resulting in either a pulse that can be felt strongest at the superficial or deep level of depth, or perhaps equally strong at all three levels of depth. Other factors affecting where the pulse can be felt include the strength of cardiac contraction.

The normal pulse is a template used to identify variations in the pulse from an expected health range. Given that the pulse is a manifestation of the interaction of several different parameters, it is logical to also consider the normal pulse as a range of values within which the pulse can present and still be considered a reflection of health. For example, the normal pulse rate ranges from 60 to 90 bpm.

Yet the normal presentation for one pulse parameter does not necessarily exclude the potential that another pulse parameter is simultaneously presenting abnormally. For example, a pulse rate of 70 bpm is considered healthy, within the normal range, but when accompanied by increased arterial tension, where the arterial wall becomes hard, then the pulse is not normal. When determining whether the pulse is normal or not, all aspects of the pulse therefore need to be considered.

There are a range of additional variables specific to the individual that also need to be given consideration when determining if the pulse is normal or not. They include body size, physique, exercise levels, age, gender and seasonal variables. In this sense, the normal pulse refers to an individual’s usual pulse.

The idea that the superficial level of depth reflects Yang and the deep level of depth reflects Yin is used to associate a particular channel and organ to each of the pulses found at these two levels across the three positions. In particular, the three positions of each wrist at the superficial level of depth are said to reflect the functional strength of the Yang channels and organs. In the deep level of depth, at the corresponding positions, the pulses are considered to reflect the functional strength of the Yin channels and organs. This gives a total of 12 pulse positions: 6 located superficially and 6 deep.

There are various arrangements of the organs or channels at the wrist pulse positions that have been described in the CM literature in the past. Variations in arrangement of the organs and channels are discussed extensively in many texts and are not repeated here. However, listed below are two most commonly used arrangements which are relevant to contemporary clinical practice. Each of these arrangements is described in the Nan Jing and Bin Hue Mai Xue . The first relates to the arrangement of channels, the other to the organs. The channel arrangement at the wrist pulse positions is often used in acupuncture, while the organ arrangement at the wrist positions is often described for use in herbal medicine. There is also a third arrangement that blends aspects of the acupuncture channel and herbal organ arrangements together. These distinctions can be further described as follows:

Secondary English sources of the classics further distinguish the Kidney pulses in the Bin Hue Mai Xue model, with the Kidney pulse on the Left side reflecting Kidney Yin and the Kidney pulse on the right side reflecting Kidney Yang. The division of the Kidney pulse in this way appears to be a contemporary adaptation. For example, Birch (1992) in his literature review on radial pulse positions notes the division of the pulse into Kidney Yin and Kidney Yang as not occurring in the classical pulse literature he reviewed, whereas secondary English translations often denote this division.

In addition to the techniques for locating the pulse positions and different pulse depths, pulse assessment and some associated theoretical pulse assumption systems require examination of the relative differences in pulse strength, irrespective of the actual degree of strength or overall force in the pulse. Whether a pulse is forceful or forceless is irrelevant when assessing relative strength differences, as assessing relative differences in strength is achieved by:

A pulse method is a systematised approach that puts together the pulse procedures into an organised examination process. This includes:

In addition to the difficulties of applying different pulse assumption systems and pulse descriptions from the literature, the complexity of the CM radial pulse diagnostic process is heightened by other factors that must be taken into account when evaluating the pulse according to the patient’s individual characteristics and environment (Maciocia 1989). These include influences such as seasonal effects, gender, age, level of fitness, occupation and body type (Deng 1999, Maciocia 1989, O’Connor & Bensky 1981).

It has been assumed that these variables impact on the physiological presentation of the pulse, and therefore obviously have important implications for the interpretation of an individual’s pulse qualities. As a result, it is necessary to consider these factors when examining the pulse, to determine whether the pulse quality is appropriate for the individual rather than being caused by a pathological disturbance. For example, the Slow pulse in CM theory is usually associated with a Cold condition. However, if the patient is accustomed to regular exercise (such as an athlete) then a Slow pulse may be quite normal. What might appear to be a pathological pulse, when taken in the proper context and in the absence of any other abnormal signs and symptoms, could be considered to be normal for the individual in question.

The following discussion on factors affecting the radial pulse is reproduced and modified with permission from King (2001).

Although assumptions concerning the pulse and the effect of factors such as seasonal changes, gender, age and body type are usually included in modern CM pulse literature, this often appears cursory, with little elaboration on why or how these variables influences pulse characteristics. While physiologically based differences may help to possibly explain, to some degree, the influence of body type, age and gender on the pulse, the effect of the seasons appears to be slightly more esoteric.

The seasonal effects on the pulse are described in great detail in the classical literature such as the Nei Jing and Mai Jing, but have largely tended to fall out of favour in modern texts. This may reflect the theoretical rather than clinical relevance of the information. It should also be remembered that CM theory developed in a country with a wide geographical diversity, where the seasonal differences are sharply pronounced and temperature ranges extreme. This may indeed explain why certain disease patterns are more prevalent in certain regions of the country and at certain times of the year. Such effects on the body would therefore be expected to impact on the pulse. However, this may not translate into countries experiencing milder climatic changes.

One aspect of the seasonal relationship with pulse that may have some relevance to clinical practice is the body’s response to changes in temperature. It is well documented in biomedicine that in response to increased body temperature, there is vasodilatation of the blood vessels close to the surface of the skin to help release heat into the surrounding environment. Conversely, with decreased body temperature there is vasoconstriction, so that the blood vessel walls contract inward to conserve body heat. This may partially explain the CM assumption that the pulse is more superficial in summer and deeper in winter. Clinically, a deep pulse presenting in a patient in very hot weather may therefore be an indication of dysfunction, reflecting an inability of the body to regulate itself.

The information pertaining to the pulse and the effect of season, gender, age and body type has existed from early CM literature, yet there has been very little investigation into the validity of these relationships in a modern context. There is a paucity of demographic information available to document the effect of any of these factors on the pulse generally and it is therefore difficult to definitively say how these will impact on the pulse presentation in a clinical setting. Preliminary demographic investigations into the pulse and some of these variables, using a reliable pulse taking methodology and pulse terminology (shown to have high levels of inter-rater reliability), have revealed some interesting gender differences in a healthy group of subjects (King 2001). Male pulses were generally rated as more forceful than female, with the pulse also rated as more easily occluded in females than males. Differences in the length of the pulse were also apparent, with males classified with long pulses (90%) more often than females (56%). There was no support for the perceived CM gender-based difference in pulse strength between left and right sides, with a significant majority of subjects found to have a stronger pulse on the right side regardless of gender (73% of females and 69% of males) (King 2001: p. 85). It was surmised that this may have been due, in part, to the fact that most subjects were right handed and therefore blood flow to the dominant hand may be influenced by increased muscle mass; further research using a larger cohort of left-handed subjects is necessary to examine this theory. However, CM theory states that the relative increase in strength on one side compared to the other is influenced only by gender, not necessarily by handedness.

This study also provided some limited support for the existence of three individual pulse positions at the wrist area, with differences in strength perceived between Cun, Guan and Chi. It was found that the Chi position was found to be the weakest position overall in both males and females, while Cun or Guan were most frequently rated as the strongest (King 2001: p. 138). There was also support for the existence of three levels of depth, with the pulse rated as strongest at the middle or deep levels of depth in the majority of subjects. This would be expected in a healthy cohort and gives some credence to the CM theory of the healthy pulse having Root, that is, a presence at a deeper level of depth.

Body type and the relationship to pulse depth were also examined in the study. Generally, it was found that the pulse was less frequently found at the superficial level of depth in heavier people (body mass index (BMI) >25), while in slimmer people the pulse was found to be present more frequently at both the superficial and deep levels of depth.

Body type was also an important feature in the findings of an individual’s pulse being categorised as forceful or not forceful as reported by Walsh (2003). Generally, although it was not statistically significant, there was an overall trend towards the pulse being reported as less forceful as body weight increased (ANOVA, p = 0.06). However, when gender was considered in analysis using correlation coefficients, women with a greater body weight were more often reported to have ‘not forceful’ pulses in correlation assessments of tonometry and manual palpation. Further, when objective tonometry measurements of the time taken for the heart to contract were considered as well, there was a significant relationship between weight, gender and increase in systolic heart contraction variables, with an accumulative 81% explanation of the nature of the relationship for an assessor’s selection of the pulse as ‘forceful’ or ‘not forceful’. Women were reported to have less forceful pulses than men.

The concept of a seasonal effect on the pulse and level of depth was given limited support by the finding that generally the pulse was rated strongest at a relatively deeper level of depth in winter than summer, in the same group of subjects (King 2001: p. 143). However, the sample size was relatively small in this case, so replication of these findings in a larger sample size is necessary.

The scope for research into the most basic underpinnings of CM pulse theory is great. Many of the fundamental concepts for the various systems of pulse interpretation such as Five Phase and San Jiao are based on the assumption that three pulse positions exist at the wrist region, yet very little research has been undertaken to investigate the validity of this concept. This also holds true for the theoretical existence of different levels of pulse depth, which is particularly relevant for Five Phase pulse diagnosis and the traditional CM pulse qualities. Further demographic information needs to be collected about the features of the ‘normal’ pulse before the possible effects of factors such as body type, gender and seasonal effects can be investigated. Therefore, although they are interesting, the assumptions about these factors should be used with a degree of caution. It is more clinically valuable to examine a patient’s pulse in terms of the changes in individual pulse parameters and evaluate how these contribute to the pattern manifesting with the other presenting signs and symptoms.