The Reliable Measurement of Radial Pulse: Gender Differences in Pulse Profiles

The Reliable Measurement of Radial Pulse: Gender Differences in Pulse Profiles Emma King, Deirdre Cobbin, Damien Ryan Emma J King Clinical Tutor Deirdre M Cobbin Senior Lecturer College of Traditional Chinese Medicine Department of Health Sciences Faculty of Science University of Technology, Sydney, Sydney, Australia Damien Ryan Senior Lecturer Department of Complementary Therapies Victoria University, Melbourne, Australia Correspondence: Deirdre Cobbin d.cobbin@uts.edu.au Summary This study was undertaken to determine whether healthy adults exhibited characteristic pulse profiles. Pulse characteristics measured for 83 women and 65 men included presence at the Traditional Chinese Medicine (TCM) locations (Cun, Guan, Chi); and depth (superficial, middle, deep), overall pulse force, relative pulse force, pulse width and pulse rhythm. Most subjects had similar values for many of the characteristics investigated including relative pulse force at the three traditional palpation locations (Cun, Guan and Chi), pulse width and pulse rhythm. There were some significant gender differences. The pulse was present beyond Chi in 90% of males compared with 56% of females. Female pulses tended to be less forceful compared with males. However, with the exception of overall force, there was little support for TCM assumptions of gender differences in pulse such as in left/right balance. There was some support for the use of the TCM palpation locations Cun, Guan and Chi to discriminate between pulses since there was significant differences in manifestations of some pulse characteristics among these locations. Keywords Radial pulse, TCM, pulse diagnosis, inter-rater reliability, gender differences, diagnostic techniques. Introduction Radial pulse palpation is a key element in the Traditional Chinese Medicine (TCM) diagnostic process. However, descriptions of the normal pulse are typically vague, usually referring to the presence of the pulse at the middle level, with an average speed of between 70-75 beats per minute (bpm) and a quality that is spirited and neither hard and unyielding nor flaccid and indistinct. 1 These descriptions originated in classical TCM texts, written variously from 100 BC to 1500 AD. Given the dramatic differences in modern day lifestyle and health status from these previous eras, such characteristics may no longer be relevant. Careful documentation of the pulse characteristics for healthy people is essential in order to determine whether perceived differences between or within individuals reflect pathology or merely demographic differences, due to factors such as age or gender. For example, if a person s pulse is relatively more forceful in one of the pulse palpation locations than in the others, does this relative difference in force represent a healthy pulse value or is it a diagnostic indicator of illness? The absence of demographic pulse profiles reflects the lack of standardisation of both pulse taking procedures and definitions in TCM and the assumption that pulse is dynamic and highly susceptible to change. However, King using standardised recording procedures and fully operationally defined pulse characteristics, demonstrated that simple pulse categories can be reliably measured, achieving an average level of inter-rater agreement of 80% between two independent assessors. 2 Simple physical pulse characteristics, including pulse presence at the three TCM locations (Cun, Guan, Chi); and depth (superficial, middle, deep), overall pulse force, relative pulse force, pulse width and pulse rhythm were measured, rather than reporting TCM pulse terms such as Full or Wiry. Initially the research focused on demonstrating that acceptable levels of inter-rater agreement that could be achieved in detecting these pulse characteristics. 3 However, since all data were collected from healthy subjects, they were appropriate for a demographic analysis in order to develop normal pulse profiles. Clearly, gender specific profiles would be 160

required, in view of the gender difference in blood pressure (BP) that have been well documented in western medical literature. For example, the normal BP values for a young adult male are about 120 mm Hg for systolic and 80 mm Hg for diastolic pressure, those for young female adults are 8-10 mm Hg lower. 4 The aim of the present study was to develop normal radial pulse profiles for healthy subjects and to test the validity of the TCM gender assumptions concerning pulse, that relate to overall pulse force, relative force by side and by traditional pulse location (Cun, Guan and Chi). 5-8 Methods Subjects Data were collected from 148 subjects. These included the 96 subjects reported in the inter-rater reliability study of King et al 2002, together with an additional 52 subjects. Procedure Pulse data were collected for 148 subjects (83 females (F) and 65 males (M) (Mean age in years: F = 28.8, sd = 8.3; M = 30.8, sd = 8.3; mean height in cm: F = 164.4, sd = 6.7; M = 177.2, sd = 6.7 and mean weight in Kg: F = 59.4, sd = 10.0 ; M = 73.1, sd = 14.0). All pulses were measured by the one assessor (King), using the standardised procedure for pulse data palpation and recording previously detailed in relation to the inter-rater agreement study. 2-3 Additional information collected included BP, pulse rate and pressure and subject demographics such as age, weight, and height. Two consecutive BP readings and pulse rates from the left and right arm were obtained from each subject using an automatic Omron M4 Automatic Digital Blood Pressure Monitor. The order in which readings were taken was randomised. The assessor is a graduate of the BHealth Science (Acupuncture) at UTS, and a clinical tutor in the college of TCM at UTS, with five years of clinical experience. Statistical Analysis Statview SE Graphics for Macintosh was used for statistical analysis. All pulse data were expressed as overall percentage frequencies by gender and body side, in the development of typical pulse characteristic profiles. Statistical analyses included Chi square test for independence for pulse comparisons and t-tests for BP comparisons (alpha was set at 0.05). Results Individual radial pulse characteristics. Pulse presence in relation to the three TCM locations At the three traditional locations. For all subjects pulse was palpable at Cun, Guan and Chi (Table 1). In general, there was a typical pattern of pulse values for location by palpation depth. Pulse was virtually never present solely at the superficial level and was present at both superficial and Table 1 Pulse presence by TCM location and measurement depth, shown for males and females and body side. The percentage frequencies for the average of left and right radial pulses are also shown. Pulse characteristic Percentage frequency Females Males Females (N = 83) Males (N = 65) Left and right averaged Left Right Left Right Presence of pulse beyond Cun 46 52 51 41 53 51 Presence of pulse beyond Chi 56 91 52 60 86 95 Presence of pulse at Cun present at both superficial and deep levels 90 92 89 92 92 92 present only at deep level 10 8 11 8 8 8 present only at superficial level 0 0 0 0 0 0 Presence of pulse at Guan present at both superficial and deep levels 90 93 90 92 91 95 present only at deep level 9 7 10 7 9 5 present only at superficial level 1 0 0 1 0 0 Presence of pulse at Chi present at both superficial and deep levels 52 88 51 53 83 92 present only at deep level 47 12 49 46 17 8 present only at superficial level 0 0 0 0 0 0 161

deep levels in at least 90% of subjects. The one exception to this pattern concerned the Chi location where about half the female pulses were absent at the superficial level. Beyond Cun and beyond Chi. Pulse presence was recorded independent of depth at these two locations. Pulse was present beyond Cun, in approximately half of all subjects, regardless of gender. For beyond Chi, there was a significant gender difference, with the pulse palpable in 91% of males compared with 56% of females (χ 2 1 = 22.1, p = 0.0001). Relative force Relative force of pulse was examined in relation to depth, and body side (Table 2). Depth was examined first at two levels of depth (superficial and deep) and then at three levels of depth (superficial, middle and deep). Relative pulse force at two levels of depth (superficial and deep). In general, pulse was significantly more forceful at the deep than at the superficial level. This was the case irrespective of gender, body side or traditional pulse location (Cun: F = 75%, M = 77%; Guan: F = 85%, M = 81%; Chi: F = 97%, M = 90%). Relative pulse force at three levels of depth (superficial, middle and deep). Similarly, pulses were more frequently rated as most forceful at the deep level and least forceful at the superficial. There was a minor difference by body side concerning the relative frequency of the most forceful pulse at the middle level in females (χ 2 1 = 8.1, p = 0.02) with only 22% of pulses most forceful at the middle level on the left body side compared with 39% on the right. Ranking of Cun, Guan and Chi according to relative pulse force, regardless of depth. When relative force was compared at the three TCM locations, pulse was most often least forceful at the Chi location (F = 89%, M = 62%) and most Table 2 Pulse force by depth, TCM location, gender and body side. The percentage frequencies for the average of left and right radial pulses are also shown. Pulse characteristic Percentage frequency Females Males Females (N = 83) Males (N = 65) Left and right averaged Left Right Left Right Relative pulse force at Cun more forceful at the superficial level 12 9 10 14 6 11 more forceful at the deep level 75 77 80 70 82 72 equally forceful at both levels 13 15 10 16 12 17 pulse not felt 0 0 0 0 0 0 Relative pulse force at Guan more forceful at the superficial level 8 10 7 8 8 12 more forceful at the deep level 85 81 84 86 82 80 equally forceful at both levels 7 10 8 6 11 8 pulse not felt 0 0 0 0 0 0 Relative pulse force at Chi more forceful at the superficial level 0 3 0 0 3 3 more forceful at the deep level 97 90 100 94 88 91 equally forceful at both levels 3 8 0 5 9 6 pulse not felt 1 0 0 1 0 0 Ranking of relative pulse force at Cun, Guan, Chi most forceful least forceful Cun, Guan, Chi 54 36 51 58 37 37 Cun, Chi, Guan 6 18 6 6 21 16 Guan, Cun, Chi 35 26 36 34 22 30 Guan, Chi, Cun 1 4 0 1 5 2 Chi, Guan, Cun, 1 9 2 0 8 11 Chi, Cun, Guan 3 7 5 1 7 4å Relative pulse force by depth most forceful at the superficial level 0 1 0 0 0 2 most forceful at superficial and middle levels 1 3 1 1 3 2 most forceful at middle level 30 25 22 39 23 27 most forceful at middle and deep levels 10 13 7 12 12 15 most forceful at deep level 59 56 70 48 60 52 equally forceful at all three levels 0 2 0 0 2 2 162

Table 3 Pulse force, pulse occlusion, pulse width and rhythm by gender and body side. The percentage frequencies for the average of left and right radial pulses are also shown. Pulse characteristic Percentage frequency Females Males Females (N = 83) Males (N = 65) Left and right averaged Left Right Left Right Overall pulse force Forceless 33 6 40 27 5 6 Neither forceless nor forceful 52 34 50 54 41 27 Forceful 15 60 10 19 54 67 Ease of pulse occlusion Easily occluded 75 55 71 80 48 63 Occluded with difficulty 25 45 29 20 52 37 Pulse width at the superficial level Thin 21 7 27 16 11 3 Not thin 79 93 73 84 89 97 Pulse width at the deep level Thin 13 12 19 7 3 0 Not thin 87 99 81 93 97 100 Irregularity of pulse rhythm/rate Irregular 2 4 1 2 5 3 Regular 98 96 99 98 95 97 Table 4 Comparison of relative pulse force for left and right body sides by gender. Percentage frequency Females (N = 83) Males (N = 65) Left pulse relatively more forceful 15 6 Right pulse relatively more forceful 73 69 Both pulses equally forceful 12 25 forceful in either the Cun (F = 54%, M = 36%) or Guan (F = 35%, M = 26%) locations. Overall pulse force and pulse occlusion There were significant gender differences in both overall force (χ 2 2 = 35.2, p = 0.0001) and ease of occlusion (χ 2 1 = 5.3, p = 0.02). Pulses for males were more likely to be forceful than for females (M = 60%, F = 15%). For females, pulses were more likely to be forceless (M = 6%, F = 33%) and to be easily occluded (M = 55%, F = 75%). These differences are in keeping with the TCM assumptions that females have softer and weaker pulses than males. Pulse width Irrespective of gender, for most subjects, pulse width was reported to be not thin at both the deep (M = 99% and F = 87%) and superficial levels (M = 93% and F = 79%). This finding does not support the assumptions found in some contemporary TCM texts that female pulses tend 9, 10 to be thinner than male pulses. Pulse rhythm Virtually all subjects had a regular pulse rhythm (M= 96% and F= 99%). Regular cardiac rhythm would be expected in this group of healthy, young subjects. Relative pulse force by body side Assessment of overall force encompassed a number of factors, including the force with which the pulse hit the fingers, pulse width and ease of occlusion. Table 4 shows that the right radial pulse was significantly more likely to be rated as more forceful (F = 73%, M = 69%) than the left radial pulse (F = 15%, M = 6%) for both genders. There were no significant differences by gender (χ 2 2 = 5.1, p = 0.06). Therefore, the results do not support the TCM assumption that male pulses should be stronger (ie more forceful) on the left and female pulses on the right. Blood pressure parameters Table 5 summarises the mean heart rate (HR) and systolic and diastolic BP by gender and body side as well as mean pulse pressures (systolic BP minus diastolic BP). For males, mean systolic and diastolic BPs were significantly higher than for females, independent of body side. For both genders, right mean systolic BP was statistically 163

Table 5 Mean BP, pulse rate and pulse pressure for females and males in the study (SD = standard deviation). Females (N = 83) Males (N = 65) Statistical significance mean SD mean SD t value p level Pulse rate (beats per minute) 70.4 9.1 66.9 9.4-2.2 0.027 Left systolic BP (mm Hg) 100.1 10.0 114.8 10.8 8.5 0.0001 Left diastolic BP (mm Hg) 65.0 7.2 70.1 7.3 4.2 0.0001 Right systolic BP (mm Hg) 102.2 10.3 117.0 11.9 8.1 0.0001 Right diastolic BP (mm Hg) 64.2 7.3 69.6 7.5 4.4 0.0001 Left pulse pressure (mm Hg) 35.1 6.1 44.8 7.4 8.6 0.0001 Right pulse pressure (mm Hg) 38.0 6.8 47.3 9.4 7.0 0.0001 Table 6 Pulse profiles for females and males. Pulse characteristic Gender differences 1. Presence at the TCM locations For all subjects pulse present at Cun, Guan and Chi. Only present beyond Chi for 56% of females compared with 91% males. Therefore males more likely to have 'longer' pulses (in TCM terms). 2. Presence at TCM location by depth Pulse generally present at superficial and deep levels in all three TCM locations; exception: half of female pulses absent at superficial level at Chi 3. Relative force No gender differences. For two levels of depth, pulse generally more forceful at the deep level. For three levels of depth, pulse least forceful at the superficial level. 4. Overall pulse force Male pulses commonly forceful. Female pulses rarely forceful. 5. More forceful radial pulse No gender difference. Right radial pulse more forceful in most subjects. 6. Ease of pulse occlusion Most female pulses easily occluded. No pattern for male pulses. 7. Pulse width No gender difference. Most pulses not thin. 8. Pulse rhythm No gender difference. Pulse rhythm typically regular. significantly higher than left (F: R = 102.2 mm Hg, L = 100.1 mm Hg and M: R = 117.0 mm Hg and L = 114.8 mm Hg). However within the one gender, left and right diastolic mean BP did not differ. As a result, for both genders, the right mean pulse pressures were significantly higher than the left (M: (t = -2.805, p = 0.0067 and F: t = -3.789, p = 0.0003). This is in keeping with the findings in Table 4 that showed that most subjects pulses were rated as most forceful on the right side. This also conflicts with the TCM assumption of a gender based difference in radial pulse strength by body side. According to western medical thought, pulse strength is associated with greater divergence between systolic and diastolic pressures. 12 Strong pulses are reported to have pulse pressures in excess of 40 mm Hg, for normal blood pressures. In the present study, the mean pulse pressures for males (L = 44.8 mm Hg; R = 47.3.0 mm Hg) were both significantly higher than for than for females (L = 35.1 mm Hg and R = 38 mm Hg), and were greater than 40 mm Hg. Therefore the findings do support the TCM assumption that males have more forceful (ie stronger) pulses than females. Summary of pulse profiles A number of typical pulse patterns emerged for the parameters measured by manual palpation. These are summarised in Table 6 and show both gender based similarities and differences. Body side had little effect on pulse with the main exception being relative pulse force. From the Table, it is evident that in general, the TCM assumptions of gender or body side pulse differences were not supported. Discussion From examination of the relative frequencies of 164

occurrence of individual values, in many cases there was tight clustering to single values of a pulse characteristic irrespective of gender or body side. For example, regardless of body side, in relation to the three TCM locations, the pulse was always present at least in the Cun, Guan and Chi locations; for depth, pulse was always palpable at the deep level and never only at the superficial level. Most subjects pulses were regular in rhythm and most were most forceful overall at the middle or deep levels. Relative pulse force at Cun was most commonly rated as the greatest of the three locations, followed by Guan and then Chi. However, there were several significant gender differences in pulse profiles. These included pulses for males being more likely to be present at both superficial and deep levels at the Cun, Guan and Chi locations. For half the females, the pulse was absent at the Chi location in the superficial level. The pulse was present beyond Chi in 90% of males and only 56% of females. (Thus, in TCM terminology, male pulses would be interpreted as generally being longer than female pulses, since they were typically present both at and beyond the three TCM locations). Female pulses were more easily occluded than male pulses and this may possibly be related to the overall force of the pulse, with male pulses generally being rated as more forceful than female pulses. While for both genders pulses were overwhelmingly rated as not thin, there was one significant gender difference, with more female pulses rated as thin on the left side. While there were strong patterns of typical values for many of the pulse parameters this should not be interpreted as indicating that the subjects showed homogenous pulse patterns or profiles. For example, among subjects for whom pulses were relatively most forceful at the deep level, there was a range of responses values for overall force, with some subjects rated as forceless, and others as forceful or neither. However, the main focus of the present research was not to link individuals by specific sets of characteristics, but rather to look at the profile of the typical normal pulse. Since most subjects had similar values for many of the characteristics investigated (for example pulse width, rhythm, and the relative force of pulse at the three TCM locations) the extent of individual variation was obviously not extreme but rather, was contained within a narrow range. The similarity of pulse values exhibited in the normal subjects may simply reflect the nature of the sample studied. They were healthy, urban dwelling subjects who, given their background as university students or staff or acquaintances of the same, were generally employed and/or studying and as such, may be considered relatively well adjusted individuals. In addition, possibly they may have a higher than usual level of health awareness and, in turn, a relatively healthy lifestyle, given that many were involved in a healthcare background (TCM or other Health Sciences studies). The pulse profiles for other samples from the general population may differ. This is of particular interest since some TCM texts suggest that the occupation of the individual affects the presentation of the pulse. Maciocia stated that pulses of individuals doing heavy physical work should be stronger than those undertaking mental work. 7 A possible factor in the similarity of the pulses in this study is that in relatively healthy subjects, extremes of pulse characteristics should be less frequently encountered if the extremes do, in fact, reflect an imbalance in Qi or blood as is thought in TCM theory. 6;7;11 Therefore, pulses would be more likely to show a wide range of values if an unhealthy sample of the population was examined: effects which Kaptchuk described as bodily disharmony leaving a clear imprint on the pulse. 1 That is, in normal healthy individuals, there is a relative balance within the body that, in western medical terms, could be equated with a reasonable level of homeostasis, described as a bodily state in which the internal environment remains within certain prescribed physiological limits and maintained by the interaction of many physiological functions. 4 Dysfunction in part of the body may affect the overall bodily functioning, causing imbalance. Therefore, in ill individuals it would seem plausible that illness (and therefore an imbalance in levels of homeostasis) may be reflected physiologically in the pulse presentation, causing changes to the normal values for basic pulse parameters. Overall, the study provided limited support for 165

TCM assumptions concerning gender based differences in pulse qualities. Findings did support assumed differences in overall pulse force, with male pulse rated as more forceful than female pulses. However, they did not support the TCM assumption concerning gender differences and relative pulse force by body side, with most subjects pulses rated as more forceful on the right side regardless of gender. An interesting gender difference not specifically reported in TCM theory, was the difference in presentation of pulse 'length', with more males having 'longer' pulses than females, in that the pulse was more likely to be present both at and beyond the three TCM palpation locations. The three traditional locations of Cun, Guan and Chi were used in the measurement of the defined pulse characteristics in this research. However, both the need for these three locations and the notion that measurements may be different at each, are assumptions of TCM. Both assumptions were examined as a result of extensive comparison of the study data. For some pulse parameters, it was found that similar values were recorded for the three sites. For example, the pulse tended to be relatively more forceful at the deep level than the superficial at Cun, Guan and Chi in most subjects. For other parameters however, significant differences in relation to TCM location were observed. For example, the rating of Cun, Guan and Chi in terms of relative force showed that Cun and Guan were most frequently rated as most forceful of the three locations and Chi was most commonly rated as least forceful. While the pulse was present more frequently at both the superficial and deep levels at Cun and Guan it was often felt at the deep level only, at the Chi location. Therefore, the findings suggest that use of the three TCM locations was justified since they did improve discrimination between pulses. On one hand, such differences could be interpreted as support for the TCM use of three locations, and possibly the underlying TCM theory. Given that the subjects studied were relatively normal, it may well be that the values obtained at the Cun, Guan and Chi locations for different parameters may vary more extensively in disease states. On the other hand, it could be argued that the pulse differences are what would be expected, given the differing bony structures and the different presentation of the radial artery at the three TCM locations. Thus, while the study findings support the feasibility of scientific observation of the radial pulse, caution is needed in viewing them as support for a TCM interpretation, since the findings might be explained entirely in terms of such factors as haemodynamic characteristics, arterial wall features or local anatomy. Further, measuring the pulse is by no means an exclusive feature of TCM. Typical pulse abnormalities are well-established clinical signs in western medicine, especially cardiac disorders, such as aortic stenosis and incompetence. Conclusion This study examined the radial pulse characteristics for a sample of healthy subjects. It was evident that there were typical values present for the pulse characteristics measured. These included presence at the three TCM locations, depth, force, ease of occlusion, relative force and width. There were few differences found between right and left radial pulse values with the exception of the relative force of the left and right radial pulses. This was in keeping with the differences in western BP measures (in particular, mean pulse pressures). There were differences in pulse profiles for males and females for some pulse characteristics, including pulse force and presence across the three TCM locations. The findings did not support TCM assumptions of gender bases differences in the relative pulse strength and body side but were in keeping with the TCM assumption that males generally have more forceful pulses than females. The aim of this study was to develop normal radial pulse profiles for healthy subjects and to examine the validity of several TCM assumptions about pulse differences relating to gender and or body side. As such, this study has provided clinically relevant information that may be useful in the radial pulse diagnostic process. Reference list 1. Kaptchuk TJ. Chinese Medicine: The Web that has no Weaver. London: Random House; 1983. 2. King, EJ (2001) Do the radial pulse qualities of Traditional Chinese Medicine provide a reliable diagnostic tool? An examination of pulse relationships 166

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