Blood Pressure Monitor

Pulse wave examination apparatus, blood pressure monitor, pulse waveform monitor, and pharmacological action monitor

Blood Pressure Monitor Abstract
An FFT treating section (40) carries out the frequency analysis of a pulse waveform MHj excluding a body movement component to yield pulse wave analysis data MKD and then a tidal wave-character extracting section (50) and a dicrotic wave-character extracting section (60) yield a tidal wave-character data (TWD) and a dicrotic wave-character data (DWD) showing the characteristics of a tidal wave and dicrotic wave respectively. Then, a pulse condition judging section (70) yields pulse condition data (ZD) on the basis of this data (TWD, DWD) and in succession a notifying section (80) advises of the pulse condition of a subject.

Blood Pressure Monitor Claims
What is claimed is:

1. A pulse wave examination apparatus comprising:

a pulse wave detecting means for detecting a pulse waveform from a living body;

a tidal wave-character extracting means for extracting the characteristics of a tidal wave from the pulse waveform to yield tidal wave-character information;

a dicrotic wave-character extracting means for extracting the characteristics of a dicrotic wave from the pulse waveform to yield dicrotic wave-character information; and

a pulse condition judging means for judging the pulse condition of the living body on the basis of the tidal wave-character information and the dicrotic wave-character information.

2. The pulse wave examination apparatus as defined in claim 1,

wherein the tidal wave-character extracting means yields the tidal wave-character information on the basis of a variation in the amplitude in the time-domain of the tidal wave; and

wherein the dicrotic wave-character extracting means yields the dicrotic wave-character information on the basis of a variation in the amplitude in the time-domain of the dicrotic wave.

3. The pulse wave examination apparatus as defined in claim 2,

wherein the variations in the amplitude in the time-domain of the tidal wave and the dicrotic wave are calculated from the primary or secondary time derivative of the pulse waveform.

4. The pulse wave examination apparatus as defined in claim 1, further comprising a notification means for communicating the pulse condition judged by the pulse condition judging means.

5. A pulse wave examination apparatus comprising:

a pulse wave detecting means for detecting a pulse waveform from a living body;

a frequency analyzing means for performing a frequency analysis of the pulse waveform;

a tidal wave-character extracting means for extracting the characteristics of a tidal wave from the result of the analysis of the frequency analyzing means to yield tidal wave-character information;

a dicrotic wave-character extracting means for extracting the characteristics of a dicrotic wave from the result of the analysis of the frequency analyzing means to yield dicrotic wave-character information; and

a pulse condition judging means for judging the pulse condition of the living body on the basis of the tidal wave-character information and the dicrotic wave-character information.

6. The pulse wave examination apparatus as defined in claim 5,

wherein the tidal wave-character information extracting means specifies a period of the tidal wave in the pulse waveform and extracts the characteristics of the tidal wave from the tidal waveform on the basis of the result of the analysis of the frequency analyzing means in the period of the tidal wave to yield tidal wave-character information; and

wherein the dicrotic wave-character information extracting means specifies a period of the dicrotic wave in the pulse waveform and extracts the characteristics of the dicrotic wave from the dicrotic waveform on the basis of the result of the analysis of the frequency analyzing means in the period of the dicrotic wave to yield dicrotic wave-character information.

7. The pulse wave examination apparatus as defined in claim 5, wherein the frequency analyzing means performs FFT treatment of the pulse waveform.

8. The pulse wave examination apparatus as defined in claim 5, wherein the frequency analyzing means performs wavelet transformation treatment of the pulse waveform.

9. A pulse wave examination apparatus comprising:

a pulse wave detecting means for detecting a pulse waveform from the detecting position of a living body;

an auto-correlation calculating means for calculating auto-correlation data giving the auto-correlation of the pulse waveform detected by the pulse wave detecting means; and

a pulse condition-data yielding means for yielding pulse condition data giving the type of pulse waveform based on the auto-correlation data.

10. The pulse wave examination apparatus as defined in claim 9,

wherein the pulse condition-data yielding means produces the pulse condition data by comparing the auto-correlation data with a prescribed threshold value.

11. The pulse wave examination apparatus as defined in claim 10,

wherein the pulse condition-data yielding means comprises a minimum value detecting section for detecting the minimum value of the auto-correlation data during a period of one heart beat, and a comparing section for comparing the minimum value, detected by the minimum value detecting section, with the threshold value to yield the pulse condition data.

12. The pulse wave examination apparatus as defined in claim 10,

wherein the pulse condition-data yielding means comprises a minimum value detecting section for detecting an average minimum value by averaging each minimum value of the auto-correlation data detected in each of plural heart beat periods, and a comparing section for comparing the average minimum value, detected by the minimum value detecting section, with the threshold value to yield the pulse condition data.

13. The pulse wave examination apparatus as defined in claim 9,

wherein the pulse condition-data yielding means comprises:

a time measuring section for comparing the auto-correlation data with a prescribed threshold value to measure a time interval in which the auto-correlation data exceeds or is less than the threshold value;

a calculating section for calculating the ratio of the time interval, measured by the time measuring section, to a period of one heart beat; and

a comparing section for comparing the result, calculated by the calculating section, with a prescribed threshold value to yield the pulse condition data.

14. The pulse wave examination apparatus as defined in claim 13,

wherein the calculating section calculates the ratio of the time interval, measured by the time measuring section, to a period of one heart beat and calculates the average of the calculated results.

15. The pulse wave examination apparatus as defined in claim 9,

wherein the pulse condition-data yielding means comprises a change rate calculating section for detecting the change rate of the auto-correlation data on the basis of the auto-correlation data, and a change rate comparing section for comparing the change rate, detected by the change rate calculating section, with a prescribed threshold value to yield the pulse condition data.

16. The pulse wave examination apparatus as defined in claim 15,

wherein the change rate comparing section detects a maximum value of the change rate and compares the maximum value of the change rate with the threshold value to yield the pulse condition data.

17. The pulse wave examination apparatus as defined in claim 9, wherein the pulse condition data yielding means comprises:

a minimum value detecting section for detecting the minimum value of the auto-correlation data in a period of one heart beat;

a first comparing section for comparing the minimum value, detected by the minimum value detecting section, with a prescribed first threshold value to yield pulse condition data indicating a Xuan mai when the minimum value is less than the first threshold value;

a time measuring section for comparing the auto-correlation data with a prescribed second threshold value to measure a time interval in which the auto-correlation data exceeds or is less than the second threshold value;

a calculating section for calculating the ratio of the time interval, measured by the time measuring section, to a period of one heart beat; and

a second comparing section for comparing the result, calculated by the calculating section, with a prescribed third threshold value to yield the pulse condition data indicating a Ping mai or a Hua mai.

18. The pulse wave examination apparatus as defined in claim 17, wherein the auto-correlation data is a coefficient of auto-correlation, and the first threshold value used in the comparing operation performed in the first comparing section is 0.25 approximately.

19. The pulse wave examination apparatus as defined in claim 17,

wherein the auto-correlation data is a coefficient of auto-correlation, and the second threshold value used in the comparing operation performed in the time measuring section is designed to be in a range between 0.4 and 0.8.

20. The pulse wave examination apparatus as defined in claim 9, wherein the pulse condition data yielding means comprises:

a minimum value detecting section for detecting the minimum value of the auto-correlation data in a period of one heart beat;

a first comparing section for comparing the minimum value, detected by the minimum value detecting section, with the first threshold value to yield pulse condition data indicating a Xuan mai when the minimum value is less than the first threshold value;

a variation calculating section for detecting a change rate of the auto-correlation data on the basis of the auto-correlation data; and

a second comparing section for comparing the change rate, calculated by the change rate calculating section, with a prescribed threshold value to yield the pulse condition data indicating a Ping mai or a Hua mai.

21. The pulse wave examination apparatus as defined in claim 9, further comprising;

a body movement detecting means for detecting the waveform of the body movement indicating the body movement of the living body; and

a body movement-component eliminating means for eliminating a body movement component from the pulse waveform to yield a body movement-eliminated pulse waveform, said body movement component in the pulse waveform generated on the basis of the body movement waveform;

wherein the auto-correlation calculating means calculates auto-correlation data giving auto-correlation on the basis of the body movement-eliminated pulse waveform in place of the pulse waveform.

22. The pulse wave examination apparatus as defined in claim 21, further comprising judging means for judging the presence of body movement of the living body on the basis of the body movement waveform detected by the body movement detecting means,

wherein the body movement-component eliminating means stops the body movement eliminating operation when the judging means shows the absence of body movement to output the pulse waveform in place of the body movement-eliminated pulse waveform.

23. The pulse wave examination apparatus as defined in claim 9, further comprising:

a first wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse wave detecting means to yield pulse wave analysis data for every frequency zone;

a body movement detecting means for detecting the movement of the living body to output the waveform of the body movement;

a second wavelet transformation means for performing wavelet transformation of the waveform of the body movement detected by the body movement detecting means to yield body movement analysis data for every frequency zone;

a body movement component eliminating means for subtracting the body movement analysis data from the pulse wave analysis data to yield body movement-eliminated pulse wave analysis data; and

an inverse wavelet transformation means for performing inverse wavelet transformation of the body movement-eliminated pulse wave analysis data to yield a body movement-eliminated pulse waveform;

wherein the auto-correlation calculating means calculates auto-correlation data giving auto-correlation on the basis of the body movement-eliminated pulse waveform in place of the pulse waveform.

24. The pulse wave examination apparatus as defined in claim 9, further comprising:

a wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse waveform detecting means to yield pulse wave analysis data for every frequency zone;

a body movement component eliminating means for eliminating a prescribed frequency component corresponding to a body movement among the pulse wave analysis data to yield body movement-eliminated pulse wave analysis data; and

an inverse wavelet transformation means for performing inverse wavelet transformation of the body movement-eliminated pulse wave analysis data to yield a body movement-eliminated pulse waveform;

wherein the auto-correlation calculating means calculates auto-correlation data giving auto-correlation on the basis of the body movement-eliminated pulse waveform in place of the pulse waveform.

25. The pulse wave examination apparatus as defined in claim 9, further comprising a notification means for communicating the pulse condition data yielded by the pulse condition data yielding means.

26. A pulse wave examination apparatus comprising:

a pulse wave detecting means for detecting a pulse waveform from the detecting position of a living body;

a wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse wave detecting means to yield pulse wave analysis data for every frequency zone;

an auto-correlation calculating means for calculating auto-correlation data giving auto-correlation of the pulse wave analysis data in a given frequency zone; and

a pulse condition data yielding means for yielding a pulse condition data giving the type of pulse waveform on the basis of the auto-correlation data.

27. A pulse wave examination apparatus comprising:

a pulse wave detecting means for detecting a pulse waveform from the detecting position of a living body;

a first wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse wave detecting means to yield pulse wave analysis data for every frequency zone;

a body movement detecting means for detecting the movement of the living body to output the waveform of the body movement;

a body movement component eliminating means for subtracting the body movement analysis data from the pulse wave analysis data to yield body movement-eliminated pulse wave analysis data;

an auto-correlation calculating means for calculating auto-correlation data giving auto-correlation of the body movement-eliminated pulse wave analysis data in a given frequency zone; and

a pulse condition data yielding means for yielding pulse condition data giving the type of pulse waveform on the basis of the auto-correlation data.

28. A pulse wave examination apparatus comprising:

a pulse wave detecting means for detecting a pulse waveform from a detection position of a living body;

a wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse wave detecting means to yield pulse wave analysis data for every frequency zone;

a body movement component eliminating means for eliminating a prescribed frequency component corresponding to a body movement to yield body movement-eliminated pulse wave analysis data;

an auto-correlation calculating means for calculating auto-correlation data giving auto-correlation of the body movement-eliminated pulse wave analysis data in a given frequency zone; and

a pulse condition data yielding means for yielding a pulse condition data giving the type of pulse waveform on the basis of the auto-correlation data.

29. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure; and

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure.

30. The blood pressure monitor as defined in claim 29, further comprising a pulse pressure calculating section for calculating pulse pressure which is the pressure difference between the maximum blood pressure and the minimum blood pressure on the basis of the waveform of arterial pressure.

31. The blood pressure monitor as defined in claim 30, further comprising a blood pressure conversion section for converting the waveform of arterial pressure detected by the arterial pressure waveform detecting section into the waveform of cardiac-position arterial pressure which is a waveform of arterial pressure at a position corresponding to the height of a heart;

wherein the mean blood pressure calculating section calculates the mean blood pressure on the basis of the waveform of cardiac-position arterial pressure; and

wherein the pulse pressure calculating section calculating the pulse pressure on the basis of the waveform of cardiac-position arterial pressure.

32. The blood pressure monitor as defined in claim 30, further comprising:

a blood pressure-judging information storing section for storing blood pressure-judging information in advance; and

a blood pressure judging section for judging blood pressure on the basis of at least one of the mean blood pressure and the pulse pressure and on the blood pressure-judging information.

33. The blood pressure monitor as defined in claim 30, further comprising an output section for outputting at least one piece of information corresponding to the mean blood pressure, to the pulse pressure and to the blood pressure judgment.

34. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure; and

a pulse pressure calculating section for calculating pulse pressure, which is the pressure difference between the maximum blood pressure and the minimum blood pressure, on the basis of the waveform of arterial pressure.

35. The blood pressure monitor as defined in claim 34, further comprising:

a maximum blood pressure calculating section for calculating the maximum blood pressure on the basis of the pulse pressure; and

a minimum blood pressure calculating section for calculating the minimum blood pressure on the basis of the pulse pressure and the maximum blood pressure.

36. A pulse waveform monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure; and

a dicrotic wave height calculating section for calculating a dicrotic wave height which is the difference in blood pressure between a dicrotic notch and the peak of a dicrotic wave which are obtained from the waveform of arterial pressure.

37. The pulse waveform monitor as defined in claim 36, further comprising a dicrotic pressure difference ratio calculating section for calculating, based on the waveform of arterial pressure, the ratio of a dicrotic pressure difference, which is the pressure difference between blood pressure at a dicrotic notch and the minimum blood pressure, to a pulse pressure which is the pressure difference between the maximum blood pressure and the minimum blood pressure.

38. The pulse waveform monitor as defined in claim 37, further comprising a mean blood pressure-pulse pressure ratio calculating section for calculating, based on the waveform of arterial pressure, the mean blood pressure-pulse pressure ratio which is the ratio of the mean blood pressure to pulse pressure which is the pressure difference between the maximum blood pressure and the minimum blood pressure.

39. The pulse waveform monitor as defined in claim 37, further comprising:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the pulse waveform on the basis of the dicrotic wave height, the dicrotic pressure difference ratio and the pulse waveform-judging information.

40. The pulse waveform monitor as defined in claim 37, further comprising an output section for outputting at least one piece of information corresponding to the dicrotic wave height, to the dicrotic pressure difference ratio, and to the pulse waveform.

41. The pulse waveform monitor as defined in claim 38, further comprising a blood pressure conversion section for converting the waveform of arterial pressure detected by the arterial pressure waveform detecting section into the waveform of cardiac-position arterial pressure which is a waveform of arterial pressure at a position corresponding to the height of a heart;

wherein the dicrotic wave height calculating section calculates, based on the waveform of cardiac-position arterial pressure, a dicrotic wave height which is the pressure difference in blood pressure between a dicrotic notch and the peak of a dicrotic wave;

wherein the dicrotic pressure difference ratio calculating section calculates, based on the wave form of cardiac-position arterial pressure, the ratio of a dicrotic pressure difference, which is the pressure difference between the blood pressure at a dicrotic notch and the minimum blood pressure, to a pulse pressure which is the pressure difference between the maximum blood pressure and the minimum blood pressure; and

wherein the mean blood pressure-pulse pressure ratio calculating section calculates, based on the waveform of cardiac-position arterial pressure, the mean blood pressure-pulse pressure ratio which is the ratio of the mean blood pressure to a pulse pressure which is the pressure difference between the maximum blood pressure and the minimum blood pressure.

42. The pulse waveform monitor as defined in claim 38, further comprising:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the pulse waveform on the basis of the dicrotic wave height, the dicrotic pressure difference ratio, the mean blood pressure-pulse pressure ratio, and the pulse waveform-judging information.

43. The pulse waveform monitor as defined in claim 38, further comprising an output section for outputting at least one piece of information corresponding to the dicrotic wave height, to the dicrotic pressure difference ratio, to the mean blood pressure-pulse pressure ratio, and to the pulse waveform.

44. The pulse waveform monitor as defined in claim 36, further comprising:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the waveform of a pulse wave on the basis of the dicrotic wave height and the pulse waveform-judging information.

45. The pulse waveform monitor as defined in claim 36, further comprising an output section for outputting at least one piece of information corresponding to the dicrotic wave height and to the pulse waveform.

46. A pulse waveform monitor comprising:

a pulse waveform detecting section for detecting the pulse waveform from a living body; and

a dicrotic pressure difference ratio calculating section for calculating, based on the pulse waveform, the dicrotic pressure difference ratio which is the ratio of the pressure difference between a dicrotic pressure and the minimum pressure, to a pulse pressure which is a pressure difference between the maximum pressure and the minimum pressure.

47. A pulse waveform monitor comprising:

a pulse waveform detecting section for detecting a pulse waveform from a living body; and

a mean pressure-pulse pressure ratio calculating section for calculating, based on the pulse waveform, the ratio of the mean pressure to pulse pressure which is a pressure difference between a maximum pressure and a minimum pressure.

48. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure; and

a dicrotic wave height calculating section for calculating, based on the waveform of arterial pressure, a dicrotic wave height which is the difference in blood pressure between a dicrotic notch and the peak of a dicrotic wave.

49. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure; and

a dicrotic pressure difference ratio calculating section for calculating, based on the waveform of arterial pressure, the dicrotic pressure difference ratio which is the ratio of a dicrotic pressure difference, which is the pressure difference between the blood pressure at a dicrotic notch and the minimum blood pressure, to a pulse pressure which is the pressure difference between the maximum blood pressure and the minimum blood pressure.

50. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure; and

a mean blood pressure-pulse pressure ratio calculating section for calculating, based on the waveform of arterial pressure, the mean blood pressure-pulse pressure ratio which is the ratio of the mean blood pressure to a pulse pressure which is the pressure difference between the maximum blood pressure and the minimum blood pressure.

51. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

a dicrotic wave height calculating section for calculating, based on the waveform of arterial pressure, the dicrotic wave height which is the difference in blood pressure between a dicrotic notch and the peak of a dicrotic wave.

52. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

53. A blood pressure monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

54. A pulse waveform monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure; and

an ejection diastolic pressure calculating section for calculating, based on the waveform of arterial pressure, ejection diastolic pressure which is the pressure difference between systolic blood pressure and the blood pressure at a dicrotic notch.

55. The pulse waveform monitor as defined in claim 54, further comprising:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the pulse waveform on the basis of the ejection diastolic pressure and the pulse waveform-judging information.

56. A pulse waveform monitor comprising:

a pulse wave detecting section for detecting a pulse waveform from a living body; and

an ejection diastolic pressure ratio calculating section for calculating, based on the pulse waveform, the ejection diastolic pressure ratio which is the ratio of ejection diastolic pressure, which is the pressure difference between systolic pressure and dicrotic pressure, to pulse pressure which is the pressure difference between systolic pressure and diastolic pressure.

57. The pulse waveform monitor as defined in claim 56, further comprising:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the pulse waveform on the basis of the ejection diastolic pressure ratio and the pulse waveform-judging information.

58. A pharmacological action monitor comprising:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure; and

59. The pharmacological action monitor as defined in claim 58, further comprising a dicrotic wave height calculating section for calculating, based on the waveform of arterial pressure, a dicrotic wave height which is the blood pressure difference between a dicrotic notch and the peak of a dicrotic wave.

60. A pharmacological action monitor comprising:

a pulse wave detecting section for detecting a pulse waveform from a living body; and

an ejection diastolic pressure ratio calculating section for calculating the ejection diastolic pressure ratio which is the ratio of the ejection diastolic pressure, which is the pressure difference between systolic pressure and dicrotic pressure, to a pulse pressure which is the pressure difference between the diastolic pressure and the systolic pressure.

61. The pharmacological action monitor as defined in claim 60, further comprising a dicrotic wave height calculating section for calculating, based on the pulse waveform, a dicrotic wave height ratio which is the ratio of a dicrotic wave height, which is the difference in pressure between a dicrotic notch and the peak of a dicrotic wave, to pulse pressure which is the pressure difference between systolic pressure and diastolic pressure.

Blood Pressure Monitor Description
TECHNICAL FIELD

The present invention relates to a pulse wave examination apparatus suitable for specifying the type of human pulse wave, a blood pressure monitor using the mean blood pressure and pulse pressure as its parameters and a pulse waveform monitor and a pharmacological action monitor which use a parameter related to a dicrotic notch part of an arterial pressure waveform.

BACKGROUND ART

The pulse wave is usually defined as a wave of blood which is output from the heart and propagates through a blood vessel. For this reason, it is known that various types of medical information can be obtained by the detection of pulse wave and analysis of the detected pulse wave. with the progress of studies on the pulse wave, it has become clear that various types of information, not obtainable only from the blood pressure and the pulse rate, can be obtained by analyzing the pulse wave, collected from the human body, by various techniques, making a diagnosis possible on the basis of these types of information.

The inventors of the present invention remarked the relation between the pulse waveform and its distortion rate in PCT/JP96/01254 (Title of the Invention: DIAGNOSTIC APPARATUS FOR DETECTING CONDITION OF LIVING BODY AND CONTROLLER) and made it possible to diagnose the living condition of a subject by detecting and treating the pulse waveform of the subject, calculating the distortion rate of the waveform and specifying the waveform from the distortion rate.

Here, the relationship between a pulse waveform and a distortion rate which are mentioned in the above application will be described briefly.

First, there are various types of pulse waveforms and the forms are diversified. Here, typical forms of pulse waveforms by the classification of Chinese medicine which is one of a traditional oriental medicine will be described. FIGS. 45A to 45C are the charts showing representative pulse waveforms by this classification.

The pulse waveform shown in FIG. 45A is called a "Ping mai" which is the pulse condition of a normal man in good health. This "Ping mai" is characterized in that, as shown in the figure, the pulse is relaxed, and exhibits a constant rhythm without disruption.

Secondly, the pulse waveform shown in FIG. 45B is called a "Hua mai" which is the pulse condition of a man who shows an abnormality in his blood stream condition. The waveform of a Hua mai exhibits a sharp, rapid rise, and then falls off immediately, the aortic dicrotic notch is deep and at the same time the subsequent peak is considerably higher than that of a Ping mai. It is considered that diseases such as a mammary tumor, liver or kidney ailment, respiratory ailment, stomach or intestinal ailment or inflammation, or some other illness cause the movement of the blood to be very fluent and smooth, which causes this "Hua mai".

Moreover, the pulse waveform shown in FIG. 45C is called a "Xuan mai" which is the pulse condition of a man whose blood vessel wall tension has increased. The Xuan mai is characterized in that its waveform rises steeply and remains at a high pressure state for a fixed period of time without an immediate drop. This "Xuan mai" is seen in diseases such as liver and gall ailments, dermatological ailments, high blood pressure, and pain ailments. It is believed that tension in the automatic nervous system causes the walls of the blood vessels to constrict, decreasing elasticity, so that the effect of the blood pulsation of the pumped blood is not readily expressed, causing this phenomenon.

The ordinate and the abscissa in the graphs of FIGS. 45A to 45C show blood pressure (mmHg) and time (second) respectively.

The relationship between the pulse condition of the pulse waveform and its distortion rated is shown in FIG. 46. Here, the distortion rate d of the pulse waveform is determined by the following equation (1): ##EQU1##

wherein A.sub.1 is the amplitude of a basic wave component in the pulse wave and A.sub.2, A.sub.3, . . . , A.sub.n are the amplitudes of the second, third, . . . and nth harmonic components respectively.

It is therefore possible to specify the pulse condition of the pulse waveform quantitatively from the correlation shown in FIG. 46 if the pulse waveform of a subject is detected and the detected waveform is subjected to FFT (Fourier transformation) treatment to find the amplitudes A.sub.1 to A.sub.n from which the distortion rate d is calculated.

As shown in FIG. 46, when the pulse condition of the subject is judged to be a Hua mai, the distortion rate d is in a range between 0.98 and 1.22. When the pulse condition is judged to be a Ping mai, the distortion rate d is in a range between 0.92 and 1.10. When the pulse condition is judged to be a Xuan mai, the distortion rate d is in a range between 0.73 and 0.94.

In this case, the pulse condition can be judged to be a Hua mai or a Ping mai when the distortion rate d of the pulse waveform is in a range between 0.98 and 1.10. Also, the pulse condition can be judged to be a Ping mai or a Xuan mai when the distortion rate d of the pulse waveform is in a range between 0.92 and 0.94. It is therefore difficult to judge the pulse condition precisely by a conventional pulse wave examination apparatus.

In the meantime, a blood pressure gauge measuring a maximum blood pressure and a minimum blood pressure and displaying these pressures is used in noninvasive detection of blood pressure.

Although the maximum blood pressures or minimum pressures of subjects are alike, there are various types of waveforms for blood pressure. Hence the characteristics of the blood pressure of an individual expressed only by a maximum blood pressure and a minimum blood pressure are insufficient.

The mean blood pressure is an important parameter for knowing the condition of the blood pressure of an individual. The mean blood pressure cannot be obtained only by measurements of a maximum blood pressure and minimum blood pressure.

In sphygmic detection adopted in Chinese medicine or in Indian traditional medicine, a medical examination is carried out by examining the pulse waveform detected by the fingers when a medical examiner presses with an optimum pressing force against a distal position of the forearm from the arteria radialis, that is, a medical examination is conducted by detection of a variation with the pressing force, which variation is felt by the fingers of the medical examiner corresponding to a variation in blood pressure.

In Chinese medicine, for instance, the pulse waveform felt when a proper pressing force is applied to the arteria radialis is roughly divided into three categories, which are designated as a "Ping mai", "Hua mai" and "Xuan mai" respectively as aforementioned. The Ping mai is deliberate and mild and its rhythm is stable and reduced in turbulence. This Ping mai is a pulse image for a man in good health. The Hua mai is the type in which the flow of the pulse is felt to be very fluent and smooth, showing abnormality in the blood stream condition. The Xuan mai is felt to be a straight, tense and long pulse and is regarded to be due to tension or aging of a blood vessel wall.

Such a medical examination method, however, is dependent upon the pulse waveform classified by the sense of the medical examiner posing problems with regard to its objectivity and reproducibility.

The present invention has been conducted in the above situation and has an object of providing a pulse wave examination apparatus which can judge the pulse condition objectively and accurately.

Another object of the present invention is to provide a blood pressure monitor which can indicate blood conditions in more detail than the information of a maximum and minimum blood pressure and can monitor the monitor parameters signifying blood pressure noninvasively.

A further object of the present invention is to provide a pulse waveform monitor which can carry out an examination by the pulse waveform objectively and reproducibly.

DISCLOSURE OF THE INVENTION

(1) A pulse wave examination apparatus according to the present invention comprises:

a pulse wave detecting means for detecting a pulse waveform from a living body;

a tidal wave-character extracting means for extracting the characteristics of a tidal wave from the pulse waveform to yield tidal wave-character information;

a dicrotic wave-character extracting means for extracting the characteristics of a dicrotic wave from the pulse waveform to yield dicrotic wave-character information; and

a pulse condition judging means for judging the pulse condition of the living body on the basis of the tidal wave-character information and the dicrotic wave-character information.

(2) In the pulse wave examination apparatus according to (1), preferably the tidal wave-character extracting means yields the tidal wave-character information on the basis of a variation in the amplitude in the time-domain of the tidal wave, and the dicrotic wave-character extracting means yields the dicrotic wave-character information on the basis of a variation in the amplitude in the time-domain of the dicrotic wave.

(3) In the pulse wave examination apparatus according to (2), preferably the variations in the amplitude in the time-domain of the tidal wave and the dicrotic wave are calculated from the primary or secondary time derivative of the pulse waveform.

(4) A pulse wave examination apparatus according to the present invention comprises:

a pulse wave detecting means for detecting a pulse waveform from a living body;

a frequency analyzing means for performing a frequency analysis of the pulse waveform;

a tidal wave-character extracting means for extracting the characteristics of a tidal wave from the result of the analysis of the frequency analyzing means to yield tidal wave-character information;

a pulse condition judging means for judging the pulse condition of the living body on the basis of the tidal wave-character information and the dicrotic wave-character information.

(5) In the pulse wave examination apparatus according to (4), preferably the tidal wave-character information extracting means specifies a period of the tidal wave in the pulse waveform and extracts the characteristics of the tidal wave from the tidal waveform on the basis of the result of the analysis of the frequency analyzing means in the period of the tidal wave to yield tidal wave-character information, and the dicrotic wave-character information extracting means specifies a period of the dicrotic wave in the pulse waveform and extracts the characteristics of the dicrotic wave from the tidal waveform on the basis of the result of the analysis of the frequency analyzing means in the period of the dicrotic wave to yield dicrotic wave-character information.

(6) In the pulse wave examination apparatus according to (4) or (5), preferably the frequency analyzing means performs FFT treatment of the pulse waveform.

(7) In the pulse wave examination apparatus according to (4) or (5), preferably the frequency analyzing means performs wavelet transformation treatment of the pulse waveform.

(8) The pulse wave examination apparatus according to any one of (1) to (7), preferably further comprises a notification means for communicating the pulse condition judged by the pulse condition judging means.

(9) A pulse wave examination apparatus according to the present invention comprises:

a pulse wave detecting means for detecting a pulse waveform from the detecting position of a living body;

a auto-correlation calculating means for calculating auto-correlation data giving the auto-correlation of the pulse waveform detected by the pulse wave detecting means; and

a pulse condition-data yielding means for yielding pulse condition data giving the type of pulse waveform based on the auto-correlation data.

(10) In the pulse wave examination apparatus according to (9), preferably the pulse condition-data yielding means produces the pulse condition data by comparing the auto-correlation data with a prescribed threshold value.

(11) In the pulse wave examination apparatus according to (10), preferably the pulse condition-data yielding means comprises a minimum value detecting section for detecting the minimum value of the auto-correlation data during a period of one heart beat, and a comparing section for comparing the minimum value, detected by the minimum value detecting section, with the threshold value to yield the pulse condition data.

(12) In the pulse wave examination apparatus according to (10), preferably the pulse condition-data yielding means comprises a minimum value detecting section for detecting an average minimum value by averaging each minimum value of the auto-correlation data detected in each of plural heart beat periods, and a comparing section for comparing the average minimum value, detected by the minimum value detecting section, with the threshold value to yield the pulse condition data.

(13) In the pulse wave examination apparatus according to (9), preferably the pulse condition-data yielding means comprises: a time measuring section for comparing the auto-correlation data with a prescribed threshold value to measure a time interval in which the auto-correlation data exceeds or is less than the threshold value; a calculating section for calculating the ratio of the time interval, measured by the time measuring section, to a period of one heart beat; and a comparing section for comparing the result, calculated by the calculating section, with a prescribed threshold value to yield the pulse condition data.

(14) In the pulse wave examination apparatus according to (13), preferably the calculating section calculates the ratio of the time interval, measured by the time measuring section, to a period of one heart beat and calculates the average of the calculated results.

(15) In the pulse wave examination apparatus according to (9), preferably the pulse condition-data yielding means comprises a change rate calculating section for detecting the change rate of the auto-correlation data on the basis of the auto-correlation data, and a change rate comparing section for comparing the change rate, detected by the change rate calculating section, with a prescribed threshold value to yield the pulse condition data.

(16) In the pulse wave examination apparatus according to (15), preferably the change rate comparing section detects a maximum value of the change rate and compares the maximum value of the change rate with the threshold value to yield the pulse condition data.

(17) In the pulse wave examination apparatus according to (9), preferably the pulse condition data yielding means comprises:

a minimum value detecting section for detecting the minimum value of the auto-correlation data in a period of one heart beat;

a calculating section for calculating the ratio of the time interval, measured by the time measuring section, to a period of one heart beat; and

(18) In the pulse wave examination apparatus according to (9), preferably the pulse condition data yielding means comprises:

a minimum value detecting section for detecting the minimum value of the auto-correlation data in a period of one heart beat;

a variation calculating section for detecting a change rate of the auto-correlation data on the basis of the auto-correlation data; and

(19) In the pulse wave examination apparatus according to (17) or (18), preferably the auto-correlation data is a coefficient of auto-correlation and the first threshold value used in the comparing operation performed in the first comparing section is 0.25 approximately.

(20) In the pulse wave examination apparatus according to (17), preferably the auto-correlation data is a coefficient of auto-correlation and the second threshold value used in the comparing operation performed in the time measuring section is designed to be in a range between 0.4 and 0.8.

(21) The pulse wave examination apparatus according to any one of (9) to (20), preferably further comprises;

a body movement detecting means for detecting the waveform of the body movement indicating the body movement of the living body; and

a body movement-component eliminating means for eliminating a body movement component from the pulse waveform to yield a body movement-removed pulse waveform, said body movement component in the pulse waveform generated on the basis of the body movement waveform;

wherein the auto-correlation calculating means calculates auto-correlation data giving auto-correlation on the basis of the body movement-removed pulse waveform in place of the pulse waveform.

(22) The pulse wave examination apparatus according to (21), preferably further comprises judging means for judging the presence of body movement of the living body on the basis of the body movement waveform detected by the body movement detecting means,

(23) The pulse wave examination apparatus according to any one of (9) to (20), preferably further comprises:

a first wavelet transformation means for performing wavelet transformation of the pulse waveform to yield pulse wave analysis data for every frequency zone;

a body movement detecting means for detecting the movement of the living body to output the waveform of the body movement;

a body movement component eliminating means for subtracting the body movement analysis data from the pulse wave analysis data to yield body movement-eliminated pulse wave analysis data; and

an inverse wavelet transformation means for performing inverse wavelet transformation of the body movement-eliminated pulse wave analysis data to yield a body movement-eliminated pulse waveform;

wherein the auto-correlation calculating means calculates auto-correlation data giving auto-correlation on the basis of the body movement-eliminated pulse waveform in place of the pulse waveform.

(24) The pulse wave examination apparatus according to any one of (9) to (20), preferably further comprises:

a wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse waveform detecting means to yield pulse wave analysis data for every frequency zone;

an inverse wavelet transformation means for performing inverse wavelet transformation of the body movement-eliminated pulse wave analysis data to yield a body movement-eliminated pulse waveform;

wherein the auto-correlation calculating means calculates auto-correlation data giving auto-correlation on the basis of the body movement-eliminated pulse wave analysis data in place of the pulse waveform.

(25) A pulse wave examination apparatus according to the present invention comprises:

a pulse wave detecting means for detecting a pulse waveform from the detecting position of a living body;

a wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse wave detecting means to yield pulse wave analysis data for every frequency zone;

an auto-correlation calculating means for calculating auto-correlation data giving auto-correlation of the pulse wave analysis data in a given frequency zone; and

a pulse condition data yielding means for yielding a pulse condition data giving the type of pulse waveform on the basis of the auto-correlation data.

(26) A pulse wave examination apparatus according to the present invention comprises:

a pulse wave detecting means for detecting a pulse waveform from the detecting position of a living body;

a first wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse wave detecting means to yield pulse wave analysis data for every frequency zone;

a body movement detecting means for detecting the movement of the living body to output the waveform of the body movement;

a body movement component eliminating means for subtracting the body movement analysis data from the pulse wave analysis data to yield body movement-eliminated pulse wave analysis data; and

an auto-correlation calculating means for calculating auto-correlation data giving auto-correlation of the body movement-eliminated pulse wave analysis data in a given frequency zone; and

a pulse condition data yielding means for yielding pulse condition data giving the type of pulse waveform on the basis of the auto-correlation data.

(27) A pulse wave examination apparatus according to the present invention comprises:

a pulse wave detecting means for detecting a pulse waveform from the detecting position of a living body;

a wavelet transformation means for performing wavelet transformation of the pulse waveform detected by the pulse wave detecting means to yield pulse wave analysis data for every frequency zone;

a body movement component eliminating means for eliminating a prescribed frequency component corresponding to a body movement to yield body movement-eliminated pulse wave analysis data;

an auto-correlation calculating means for calculating auto-correlation data giving auto-correlation of the body movement-eliminated pulse wave analysis data in a given frequency zone; and

a pulse condition data yielding means for yielding a pulse condition data giving the type of pulse waveform on the basis of the auto-correlation data.

(28) The pulse wave examination apparatus according to any one of (9) to (27), preferably further comprise a notification means for communicating the pulse condition data yielded by the pulse condition data yielding means.

(29) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure; and

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure.

The blood pressure monitor of the present invention comprises the mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure detected by the arterial pressure waveform detecting section. Therefore the mean blood pressure can be monitored using the waveform of arterial pressure detected by the arterial pressure waveform detecting section.

(30) The blood pressure monitor according to (29), preferably further comprises a pulse pressure calculating section for calculating pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure on the basis of the waveform of arterial pressure.

According to the invention, the pulse pressure can be monitored using the waveform of arterial pressure detected by the arterial pressure waveform detecting section.

(31) The blood pressure monitor according to (30), preferably further comprises a blood pressure conversion section for converting the waveform of arterial pressure detected by the arterial pressure waveform detecting section into the waveform of cardiac-position arterial pressure which is a waveform of arterial pressure at a position corresponding to the altitude of a heart;

wherein the mean blood pressure calculating section calculates the mean blood pressure on the basis of the waveform of cardiac-position arterial pressure; and

wherein the pulse pressure calculating section calculates the pulse pressure on the basis of the waveform of cardiac-position arterial pressure.

According to the invention, the waveform of arterial pressure detected by the arterial pressure waveform detecting section is converted into the waveform of cardiac-position arterial pressure, which is a waveform of arterial pressure at a position corresponding to the altitude of an artery, by the blood pressure conversion section. Then,based on the waveform of cardiac-position arterial pressure, the mean blood pressure calculating section calculates the mean blood pressure and the pulse pressure calculating section calculates the pulse pressure. At least either one of the mean blood pressure and the pulse pressure in an artery at a position corresponding to the altitude of an artery can be monitored using the waveform of arterial pressure detected by the arterial pressure waveform detecting section.

(32) The blood pressure monitor according to (30) or (31), preferably further comprises:

a blood pressure-judging information storing section for storing blood pressure-judging information in advance; and

a blood pressure judging section for judging blood pressure on the basis of at least either one of the mean blood pressure and the pulse pressure and on the blood pressure-judging information.

According to the invention, the blood pressure monitor can determine whether the blood pressure is high, low, or normal on the basis of at least either one of the resulting mean blood pressure and pulse pressure and on the blood pressure-judging information stored in advance.

(33) The blood pressure monitor according to any one of (30) and (32), preferably further comprises an output section for outputting at least one piece of information corresponding to the mean blood pressure, to the pulse pressure and to the blood pressure judgment.

According to the invention, at least one piece of information corresponding to the mean blood pressure, to the pulse pressure and to the blood pressure judgment can be output by the output section in the form of, for instance, numerals, graphs or voltages.

(34) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for continuously measuring blood pressure in an artery to detect a waveform of arterial pressure; and

a pulse pressure calculating section for calculating pulse pressure, which is a pressure difference between a maximum blood pressure and a minimum blood pressure, on the basis of the waveform of arterial pressure.

According to the invention, the pulse pressure can be monitored using the waveform of arterial pressure detected by the arterial pressure waveform detecting section.

(35) The blood pressure monitor according to (34), preferably further comprises:

a maximum blood pressure calculating section for calculating a maximum blood pressure on the basis of the pulse pressure; and

a minimum blood pressure calculating section for calculating a minimum blood pressure on the basis of the pulse pressure and the maximum blood pressure.

According to the invention, the maximum blood pressure calculating section determines a maximum blood pressure by making use of the fact that the maximum blood pressure can be given by a linear function of pulse pressure. Also, since the pulse pressure is a pressure difference between a maximum pressure and a minimum pressure, the minimum blood pressure calculating section can determine a minimum blood pressure if a maximum blood pressure and pulse pressure are clarified.

(36) A pulse waveform monitor according to the present invention comprises:

an arterial pressure waveform detecting section for continuously measuring blood pressure in an artery to detect a waveform of arterial pressure; and

a dicrotic wave height calculating section for calculating a dicrotic wave height which is a difference in blood pressure between a dicrotic notch and a peak of a dicrotic wave which are obtained from the waveform of arterial pressure.

According to the invention, the pulse waveform monitor can calculate a dicrotic wave height on the basis of the waveform of arterial pressure obtained by continuously measuring blood pressure in an artery by using the arterial pressure waveform detecting section.

(37) The pulse waveform monitor according to (36), preferably further comprises a dicrotic pressure difference ratio calculating section for calculating, based on the waveform of arterial pressure, the ratio of a dicrotic pressure difference, which is a pressure difference between blood pressure at a dicrotic notch and a minimum blood pressure, to a pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure.

According to the invention, the pulse waveform monitor can calculate a dicrotic wave height and the ratio of a dicrotic pressure difference on the basis of the waveform of arterial pressure obtained by continuously measuring blood pressure in an artery by using the arterial pressure waveform detecting section.

(38) The pulse waveform monitor according to (37), preferably further comprises a mean blood pressure-pulse pressure ratio calculating section for calculating, based on the waveform of arterial pressure, the ratio of the mean blood pressure to pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure.

According to the invention, the pulse waveform monitor can calculate a dicrotic wave height, the ratio of a dicrotic pressure difference, and the mean blood pressure-pulse pressure ratio on the basis of the waveform of arterial pressure obtained by continuously measuring blood pressure in an artery by using the arterial pressure waveform detecting section.

(39) The pulse waveform monitor according to (38), preferably further comprises a blood pressure conversion section for converting the waveform of arterial pressure detected by the arterial pressure waveform detecting section into the waveform of cardiac-position arterial pressure which is a waveform of arterial pressure at a position corresponding to the altitude of a heart;

wherein the dicrotic wave height calculating section calculates, based on the waveform of cardiac-position arterial pressure, a dicrotic wave height which is a pressure difference in blood pressure between a dicrotic notch and a peak of a dicrotic wave;

wherein the dicrotic pressure difference ratio calculating section calculates, based on the cardiac-position arterial pressure, the ratio of a dicrotic pressure difference, which is a pressure difference between blood pressure at a dicrotic notch and a minimum blood pressure, to a pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure; and

wherein the mean blood pressure-pulse pressure ratio calculating section calculates, based on the waveform of arterial pressure, the ratio of the mean blood pressure to a pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure.

According to the invention, the waveform of arterial pressure detected by the arterial pressure waveform detecting section is converted into the waveform of cardiac-position arterial pressure, which is a waveform of arterial pressure at a position corresponding to the altitude of an artery, by the blood pressure conversion section. Then, based on the cardiac-position arterial pressure, the dicrotic wave height calculating section calculates a dicrotic wave height, the dicrotic pressure difference ratio calculating section calculates the dicrotic pressure difference ratio, and the mean blood pressure-pulse pressure ratio calculating section calculates the mean blood pressure-pulse pressure ratio. Hence, using the waveform of arterial pressure detected by the arterial pressure waveform detecting section, at least one of the dicrotic wave height, dicrotic pressure difference ratio and mean blood pressure-pulse pressure ratio can be monitored.

(40) The pulse waveform monitor according to (36), preferably further comprises:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the waveform of a pulse wave on the basis of the dicrotic wave height and the pulse waveform-judging information.

According to the invention, the pulse wave judging section can judge the pulse waveform on the basis of the dicrotic wave height and the pulse waveform-judging information.

(41) The pulse waveform monitor according to (37), preferably further comprises:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the pulse waveform on the basis of the dicrotic wave height, the dicrotic pressure difference ratio and the pulse waveform-judging information.

According to the invention, the pulse wave judging section can judge the pulse waveform on the basis of the dicrotic wave height, the dicrotic pressure difference ratio and the pulse waveform-judging information.

(42) The pulse waveform monitor according to (38), preferably further comprises:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

According to the invention, the pulse wave judging section can judge the pulse waveform on the basis of the dicrotic wave height, the dicrotic pressure difference ratio, the mean blood pressure-pulse wave ratio, and the pulse waveform-judging information.

(43) The pulse waveform monitor according to (36), preferably further comprises an output section for outputting at least one piece of information corresponding to the dicrotic wave height and to the pulse waveform.

According to the invention, at least one piece of information corresponding to the information corresponding to the dicrotic wave height, and to the pulse waveform can be output by the output section in the form of, for instance, numerals, graphs or voltages.

(44) The pulse waveform monitor according to (37), preferably further comprises an output section for outputting at least one piece of information corresponding to the dicrotic wave height, to the dicrotic pressure difference ratio and to the pulse waveform.

According to the invention, the pulse waveform monitor can output at least one piece of information corresponding to the dicrotic wave height, to the dicrotic pressure difference ratio, and to the pulse waveform from the output section in the form of, for instance, numerals, graphs or voltages.

(45) The pulse waveform monitor according to (38), preferably further comprises an output section for outputting at least one piece of information corresponding to the dicrotic wave height, to the dicrotic pressure difference ratio, to the mean blood pressure-pulse pressure ratio and to the pulse waveform.

According to the invention, the pulse waveform monitor can output at least one piece of information corresponding to the dicrotic wave height, to the dicrotic pressure difference ratio, to the mean blood pressure-pulse wave ratio, and to the pulse waveform from the output section in the form of, for instance, numerals, graphs or voltages.

(46) A pulse waveform monitor according to the present invention comprises:

a pulse waveform detecting section for detecting the pulse waveform from a living body; and

a dicrotic pressure difference ratio calculating section for calculating, based on the pulse waveform, the dicrotic pressure difference ratio, which is a pressure difference between a dicrotic pressure and a minimum pressure, to a pulse pressure which is a pressure difference between a maximum pressure and a minimum pressure.

This aspect differs from the aspect according to (36) in that the dicrotic pressure difference ratio calculating section does not need an absolute value of blood pressure to calculate the ratio. In the aspect, therefore, the arterial pressure waveform detecting section used in (36) may be replaced by a pulse wave detecting section for detecting only a pulse wave which is a waveform corresponding to that in (36).

(47) A pulse waveform monitor according to the present invention comprises:

a pulse waveform detecting section for detecting a pulse waveform from a living body; and

This aspect differs from the aspect according to (16) in that the mean blood pressure-pulse pressure ratio calculating section does not need an absolute value of blood pressure to calculate the ratio. In this aspect, therefore, the arterial pressure waveform detecting section used in (16) may be replaced by a pulse wave detecting section for detecting only a pulse wave which is a waveform corresponding to that in (16).

(48) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure; and

a dicrotic wave height calculating section for calculating, based on the waveform of arterial pressure, the dicrotic wave height which is a difference in blood pressure between a dicrotic notch and a peak of a dicrotic wave.

(49) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for continuously measuring blood pressure in an artery to detect a waveform of arterial pressure;

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure; and

a dicrotic pressure difference ratio calculating section for calculating, based on the waveform of arterial pressure, the dicrotic pressure difference ratio which is the ratio of a dicrotic pressure difference, which is a pressure difference between blood pressure at a dicrotic notch and a minimum blood pressure, to a pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure.

(50) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for continuously measuring blood pressure in an artery to detect a waveform of arterial pressure;

a mean blood pressure calculating section for calculating the mean blood pressure on the basis of the waveform of arterial pressure; and

a mean blood pressure-pulse pressure ratio calculating section for calculating, based on the waveform of arterial pressure, the ratio of the mean blood pressure to a pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure.

(51) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

(52) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

a dicrotic pressure difference ratio calculating section for calculating, based on the waveform of arterial pressure, the dicrotic pressure difference ratio which is the ratio of a dicrotic pressure difference, which is a pressure difference between a dicrotic blood pressure and a minimum blood pressure, to a pulse pressure which is a pressure difference between a maximum blood pressure and a minimum blood pressure.

(53) A blood pressure monitor according to the present invention comprises:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure;

(54) A pulse waveform monitor according to the present invention comprises:

an arterial pressure waveform detecting section for continuously measuring blood pressure in an artery to detect a waveform of arterial pressure; and

an ejection diastolic pressure calculating section for calculating, based on the waveform of arterial pressure, ejection diastolic pressure which is a pressure difference between a systolic blood pressure and a dicrotic blood pressure.

(55) The pulse waveform monitor according to (54), preferably further comprises:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the pulse waveform on the basis of the ejection diastolic pressure and the pulse waveform-judging information.

(56) A pulse waveform monitor according to the present invention comprises:

a pulse wave detecting section for detecting a pulse waveform from a living body; and

an ejection diastolic pressure ratio calculating section for calculating, based on the pulse waveform, the ratio of ejection diastolic pressure, which is a pressure difference between systolic pressure and dicrotic pressure, to pulse pressure which is a pressure difference between systolic pressure and diastolic pressure.

(57) The pulse waveform monitor according to (56), preferably further comprises:

a pulse waveform-judging information storing section for storing pulse waveform-judging information in advance; and

a pulse waveform judging section for judging the pulse waveform on the basis of the ejection diastolic pressure ratio and the pulse waveform judging information.

(58) A pharmacological action monitor according to the present invention comprises:

an arterial pressure waveform detecting section for measuring blood pressure in an artery continuously to detect a waveform of arterial pressure; and and the pulse waveform judging information.

an ejection diastolic pressure calculating section for calculating, based on the waveform of arterial pressure, ejection diastolic pressure which is a pressure difference between systolic blood pressure and dicrotic blood pressure.

(59) The pharmacological action monitor according to (58), preferably further comprises a dicrotic wave height calculating section for calculating, based on the waveform of arterial pressure, a dicrotic wave height which is the blood pressure difference between a dicrotic notch and a peak of a dicrotic wave.

(60) A pharmacological action monitor according to the present invention comprises:

a pulse wave detecting section for detecting a pulse waveform from a living body; and

an ejection diastolic pressure ratio calculating section for calculating the ejection diastolic pressure ratio which is the ratio of the ejection diastolic pressure, which is a pressure difference between systolic pressure and dicrotic pressure, to a pulse pressure which is a pressure difference between the diastolic pressure and the systolic pressure.

(61) The pharmacological action monitor according to (60), preferably further comprises a dicrotic wave height calculating section for calculating, based on the pulse waveform, a dicrotic wave height ratio which is the ratio of a dicrotic wave height, which is the difference in pressure between a dicrotic notch and a peak of a dicrotic wave, to pulse pressure which is a pressure difference between systolic pressure and diastolic pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the structure of a pulse wave examination apparatus of a first embodiment.

FIG. 2 is a flow chart for describing the action of the pulse wave examination apparatus of the first embodiment.

FIG. 3 is a block diagram showing the structure of a pulse wave examination apparatus of a second embodiment.

FIG. 4 is a block diagram showing an example of the structure of a wavelet transformation section of the second embodiment.

FIG. 5 is a block diagram showing the structure of a waveform shaping section of the second embodiment.

FIG. 6 is a timing chart showing the action of the waveform shaping section of the second embodiment.

FIG. 7 is a view for describing the action of a tidal wave/dicrotic wave detecting section of the second embodiment.

FIG. 8 is a view showing an electrocardiographic waveform, a waveform of arterial pressure and a waveform of blood pressure at a peripheral part in correspondence to each other.

FIG. 9 is a view for describing the relationship between pulse waveform and waveform parameters.

FIG. 10 is a view showing the relationship between a difference in blood pressures (y.sub.5 -y.sub.4) and a distortion rate d.

FIG. 11 is a view showing the result of frequency analysis of a Hua mai.

FIG. 12 is a view showing the result of frequency analysis of a Ping mai.

FIG. 13 is a view showing the result of frequency analysis of a Xuan mai.

FIG. 14 is a table showing the amplitudes of a tidal wave and dicrotic wave for each pulse condition.

FIG. 15 is a table showing a harmonic component of each pulse condition.

FIG. 16 is a view showing a coefficient of autocorrelation of a Xuan mai.

FIG. 17 is a view showing a coefficient of autocorrelation of a Ping mai.

FIG. 18 is a view showing a coefficient of autocorrelation of a Hua mai.

FIG. 19 is a block diagram showing the electrical structure of a pulse wave examination apparatus of a third embodiment.

FIG. 20 is a flow chart showing the action of the pulse wave apparatus of the third embodiment.

FIG. 21 is a block diagram of a pulse condition data yielding section according to a fourth embodiment.

FIG. 22 is a view showing the rate of variation in autocorrelation data of a typical pulse waveform.

FIG. 23 is a flow chart showing the action of a pulse wave examination apparatus of the fourth embodiment.

FIG. 24 is a block diagram showing the electrical structure of a pulse wave examination apparatus of a fifth embodiment.

FIG. 25 is a block diagram showing the electrical structure of a pulse wave examination apparatus of a sixth embodiment.

FIG. 26 is a view showing pulse wave analysis data during a partial period in a pulse waveform.

FIG. 27 is a timing chart for describing the action of a body movement eliminating section according to the sixth embodiment.

FIG. 28 is a view showing amended data MKDa of a pulse wave during the period Tc in the sixth embodiment.

FIG. 29 is a view showing body movement-amended data TKDa during the period Tc in the sixth embodiment.

FIG. 30 is a view showing body movement-eliminating pulse wave data MKDaj excluding a body movement component in the sixth embodiment.

FIG. 31 is a block diagram showing the electrical structure of a pulse wave examination apparatus of a seventh embodiment.

FIG. 32 is a block diagram of a body movement eliminating section of the seventh embodiment.

FIG. 33 is a view showing an example of body movement-eliminated pulse wave data of the seventh embodiment.

FIG. 34 is a block diagram showing the electrical structure of a pulse wave examination apparatus of an eighth embodiment.

FIG. 35 is a block diagram of a first wavelet conversion section of the eighth embodiment.

FIG. 36 is a block diagram showing the electrical structure of a pulse wave examination apparatus of a ninth embodiment.

FIG. 37A is a view showing the condition of a wrist watch-type pulse wave examination apparatus which is installed.

FIG. 37B is a view showing a pulse wave detecting section of a wrist watch-type pulse wave examination apparatus.

FIG. 37C is a view showing a connector section assembled in the body section of a wrist watch-type pulse wave examination apparatus.

FIG. 38 is a view showing an example of the structure of a pulse wave detecting section.

FIG. 39A is a view showing the outward appearance of a pulse wave examination apparatus when it is made into another wrist watch type.

FIG. 39B is a view showing the condition of the installed pulse wave examination apparatus shown in FIG. 39A.

FIG. 40 is a view showing the outward appearance of the structure of the pulse wave examination apparatus when it is made into a necklace type.

FIG. 41 is a view showing the condition in which a pulse wave detecting section of the pulse wave examination apparatus shown in FIG. 40 is attached around the carotid arteries.

FIG. 42 is a view showing the outward appearance of the structure of a pulse wave examination apparatus when it is made into a eyeglass type.

FIG. 43 is a view showing the outward appearance of the structure of a pulse wave examination apparatus when it is made into a card type.

FIG. 44A is a view showing the outward appearance of the structure of a pulse wave examination apparatus when it is made into a passometer type.

FIG. 44B is a view showing the condition of the installed pulse wave examination apparatus shown in FIG. 44A.

FIG. 45A is a view showing the pulse waveform of a typical Ping mai.

FIG. 45B is a view showing the pulse waveform of a typical Hua mai.

FIG. 45C is a view showing the pulse waveform of a typical Xuan mai.

FIG. 46 is a view showing the relationship between distortion rate and the pulse waveform.

FIG. 47 is an explanatory view showing a structure used to record a waveform of arterial pressure in the arteria radialis to show a theoretical basis for a tenth embodiment.

FIG. 48 is a graph showing a typical waveform of arterial pressure.

FIG. 49 is a graph of experimental results obtained using the structure shown in FIG. 47, showing the relationship between the mean blood pressure and diastolic blood pressure.

FIG. 50 is a graph of experimental results obtained using the structure shown in FIG. 47, showing the relationship between the mean blood pressure and systolic blood pressure.

FIG. 51 is a graph of experimental results obtained using the structure shown in FIG. 47, showing the relationship between pulse pressure and systolic blood pressure.

FIG. 52 is a block diagram showing a blood pressure monitor of a tenth embodiment.

FIG. 53 is a graph showing the distribution of the dicrotic wave height .DELTA.BP.sub.D for each pulse waveform to show a theoretical basis for an eleventh embodiment.

FIG. 54 is a graph showing the relationship between a dicrotic pressure difference ratio BP.sub.Dd /.DELTA.BP and a dicrotic wave height .DELTA.BP.sub.D to show a theoretical basis for the eleventh embodiment.

FIG. 55 is a graph showing the relationship between an ejection diastolic pressure .DELTA.BP.sub.P and a dicrotic wave height .DELTA.BP.sub.D to show a theoretical basis for the eleventh embodiment.

FIG. 56 is a block diagram showing the structure of a pulse waveform monitor of the eleventh embodiment.

FIG. 57 is a block diagram showing the structure of a pharmacological action monitor of the twelfth embodiment.

FIG. 58 is a block diagram showing a modification in which a wavelet transformation section comprises a filter bank.

FIG. 59 is a block diagram showing a modification in which an inverse wavelet transformation section comprises a filter bank.

FIG. 60 is a face chart showing a modification of notification.

FIG. 61 is a view showing an example of a transmission-type photoelectric pulse wave sensor in a modification.

FIG. 62 is a view showing a modification in which a photoelectric pulse wave sensor is applied to a pair of eyeglasses.

FIG. 63 is a graph showing a variation in the pressure of each portion in arterial pressure waveform with administration of an antihypertensive agent.

FIG. 64 is a view showing arterial waveforms before and after administration of an antihypertensive agent.

BEST MODE FOR CARRYING OUT THE INVENTION

1. First Embodiment

A pulse wave examination apparatus according to a first embodiment of the present invention will be described below.

1.1 Theoretical Basis for the First Embodiment

Needless to say, the heart ejects blood by repeated contractions and dilatations. Here, the time of causing blood to flow from the heart by a contraction/dilatation in one cycle is called "ejection time". When the pulse rate, which is the number of contractions of the heart per unit time, is increased by, for instance, exercise, a catecholamine, e.g., adrenaline, is liberated, with the result that the ejection time tends to be short. This implies an increase in the contraction force of the heart muscle.

With increased ejection time, the output of blood by the contraction/dilatation in one cycle tends to increase.

Meanwhile, when a person exercises, it is necessary to supply much oxygen to the heart muscle, the skeletal muscle and the like, hence the product of the pulse rate and the output, that is, the flow rate of blood (per unit time) ejected from the heart increases. As a result of the increased pulse rate, the ejection time is short and the output is small. However, since the rate of increase in the pulse rate exceeds the rate of decrease in the output, the product of the pulse rate and the output increases on the whole.

Next, description of the relationship between the movement of the heart and the waveform of the blood pressure will be given. In the electrocardiogram shown in FIG. 8, generally the period from the R point to the terminal point U of the T wave is said to be "a ventricular systole", which corresponds to the foregoing ejection time. The period from the U point to the next R point is said to be "a ventricular diastole". In the ventricular systole, a ventricular contraction does not take place uniformly but proceeds at a slow pace as it spreads from the outside to the inside. Because of this, the waveform of the blood pressure at the proximal portion of an aorta has an upwardly convex form as shown in FIG. 8 in the ventricular systole ranging from the opening to the closing of the aortic valve.

The waveform of the blood pressure at the periphery (arteria radialis) corresponding to such a blood waveform at the proximal portion of an aorta, that is, the pulse waveform at the periphery is as shown in FIG. 8. The reason why such a waveform is formed is considered that a first wave called an "ejection wave" occurs by the ejection of blood from the heart, a second wave called a "tidal wave" successively occurs due to a reflex at furcations of the blood vessel close to the heart, and a third wave called a "dicrotic wave" then occurs due to the occurrence of a dicrotic notch concomitant with the closing of the aortic valve.

In the pulse waveform, therefore, the range from the point at which the blood pressure reach a minimum to the dicrotic notch corresponds to the ventricular systole, and the range from the dicrotic notch to the point at which the blood pressure reaches a minimum in the next cycle corresponds to the ventricular diastole.

Here, the point corresponding to the opening of the aortic valve in the pulse waveform is the minimum minimal point of blood pressure. Also, the point, specifically, the dicrotic notch, corresponding to the closing of the aortic valve is the third minimal point from the minimum minimal point viewing from time series and the second minimal point from the minimum minimal point viewing from the magnitude of the blood pressure.

Incidentally, the waveform of the peripheral blood pressure shown in FIG. 8, namely, the pulse waveform actually exhibits time delay with respect to the waveform of aortic blood pressure. However, in the figure, this time delay is neglected for the sake of simplicity and these phases are made to be uniform.

Next, the waveform of peripheral blood pressure, namely, the pulse waveform will be discussed. The pulse wave form detected at the peripheries of a subject is the so-called pattern of the pressure wave of blood which propagates through a closed system consisting of the heart as a pulsatile pump and the blood circulatory system as a conduit. Hence, first, the pulse wave form is regulated by the pumping function of the heart, namely, by the condition of a cardiac function. Second, the pulse wave form is affected, for example, by the diameter of a blood vessel, contraction/dilatation of a blood vessel, and viscous resistance of blood. It is considered that if the pulse waveform is detected to analyze it, the condition of the cardiac function of the subject as well as the aortic condition of the subject can be evaluated. It may be understood that specialists in Oriental medicine diagnose a living condition by the features of pulsation.

Now, a discussion will follow in which a portion is analyzed in the pulse waveform.

First the inventors of the present invention selected the parameters shown in FIG. 9 as those which determine the features of the pulse waveform. Specifically, the selected parameters are as follows:

(1) a time t.sub.6 between a peak point P0 (the minimum minimal point) of the ascending slope of one beat, at which point the value of the blood pressure in the pulse waveform reaches a minimum, and a peak point P6 of the ascending slope of the next pulse;

(2) the values of the blood pressure (difference) y.sub.1 to y.sub.5 at a peak points (maximal points and minimal points) which appear sequentially in the pulse wave form; and

(3) time passages t.sub.1 to t.sub.5 from the peak point P0 (the minimum minimal point) at the pulse wave starting point to the point at which each of peak points P1 to P5 appear respectively.

In this case, each of y.sub.1 to y.sub.5 denotes a relative value of blood pressure by setting the value of the blood pressure at a peak point P0 as a datum.

The inventors of the present invention actually detected the pulse waves of 74 healthy adults between the ages of 22 and 46. The waveform parameters of these pulse waves were calculated while each pulse waveform was subjected to FFT treatment as in the aforementioned PCT/JP96/01254 to calculate the distortion rate d of the pulse waveform by using the foregoing equation (1).

Then the inventors of the present invention investigated the correlation between the calculated distortion rate d and each waveform parameter or the differences between these parameters separately. As a result, it was clarified that the distortion rate d had a high correlation with the pressure differences (y.sub.5 -y.sub.4) in the values of blood pressure, which difference was the amplitude of a dicrotic wave from the dicrotic notch, with the coefficient of correlation (R.sup.2) being 0.77. This correlation is shown in FIG. 10.

From this fact, the inventors of the present invention made the following analysis on the hypothesis that specialists in Oriental medicine sensed the features of the dicrotic wave and tidal wave to diagnose the pulse condition.

In this analysis, each pulse waveform which was judged for the pulse condition by specialists in Oriental medicine was subjected to FFT treatment to calculate the ratio of each harmonic component to a fundamental wave component. FIGS. 11, 12 and 13 show the results of analysis of a Hua mai, Ping mai and Xuan mai respectively.

In FIGS. 11 to 13, f1, f2, f3, , f10 indicate the amplitudes and phases of a fundamental wave, second harmonic, third harmonic, . . . , tenth harmonic respectively. The waveform wfl is the sum of the fundamental wave f1 and the second harmonic f2, waveform wf2 is the sum of the fundamental wave f1 to the third harmonic, . . . , and the waveform wf9 is the sum of the fundamental wave f1 to the tenth harmonic f10.

Here, comparing the original waveform shown in FIG. 11, whose pulse condition was judged to be a Hua mai by the specialist, with the original waveform shown in FIG. 12, whose pulse condition was judged to be a Ping mai by the specialists, it is understood that both closely resemble one another but the height of the dicrotic notch is lower in a Hua mai than in a Ping mai and the amplitude of the dicrotic wave is larger in a Ping mai than in a Hua mai. When attention is given to the synthesized waveform, it is understood that each original waveform of the dicrotic waves of a Hua mai and Ping mai is almost reproduced by the waveform wf3 which is the sum of the fundamental wave f1 to the third harmonic f4.

On the other hand, in a Xuan mai as shown in FIG. 13, it is understood that the original waveform of the tidal wave is almost reproduced by the waveform wf6 which is the sum of the fundamental wave f1 to the seventh harmonic f7.

FIG. 14 shows the amplitudes of the dicrotic wave and the tidal wave in the pulse waveform representing the pulse condition which is described in FIGS. 11 to 13. The amplitudes of the dicrotic waves are relatively as high as 7.3 mmHg and 10.6 mmHg in a Hua mai and in a Ping mai respectively whereas the amplitude of the dicrotic wave in a Xuan mai is as small as 2.9 mmHg. The amplitudes of the tidal waves in a Hua mai and in a Ping mai are 0 whereas the amplitude of the tidal wave in a Xuan mai is 3.8 mmHg.

From these facts, in a Hua mai and Ping mai, each dicrotic wave has specific characteristics which are observed in the fundamental wave f1 to the fourth harmonic f4. In a Xuan mai, the tidal wave has specific characteristics which are observed in high frequency components, e.g., the fifth harmonic f5 to the seventh harmonic f7.

Next, FIG. 15 shows the percentage ratio of the amplitude of each harmonic to the amplitude of the fundamental wave for every pulse condition. Here, when attention is given to the ratio of the sum of the second harmonic f2, the third harmonic f3, and the fourth harmonic f4 to the fundamental wave f1 in terms of amplitude, namely, (f2+f3+f4)/f1, this is 1.74 in a Hua mai and 1.5 in a Ping mai. It is therefore possible to discriminate between a Hua mai and a Ping mai on the basis of these values. When attention is given to the ratio of the sum of the fifth harmonic f5, sixth harmonic f6, and seventh harmonic f7 to the fundamental wave f1 in terms of amplitude, namely, (f5+f6+f7)/f1, this is 0.36 in a Hua mai, 0.26 in a Ping mai and 0.42 in a Xuan mai. It is therefore possible to discriminate between a Xuan mai and other pulses on the basis of these values.

1.2 Structure of the Pulse Wave Examination Apparatus

The pulse wave examination apparatus according to this embodiment is structured based on the theoretical basis as described above. In the pulse wave examination apparatus, the pulse wave forms detected from subjects are treated by frequency analysis to extract a tidal wave component and a dicrotic wave component thereby judging the pulse condition on the basis of the results of the extraction. Incidentally, the external structure of the pulse wave examination apparatus will be described later in the section "10. External structures of aforementioned embodiments".

FIG. 1 is a block diagram showing the functional structure of the pulse wave examination apparatus according to this embodiment. In this figure, a pulse wave detecting section 10 detects the pulse waveform of, for instance, the periphery (e.g., arteria radialis) of a subject, to output the detected signal as MH to a body movement eliminating section 30.

A body movement detecting section 20 comprises, for instance, an acceleration sensor and detects the body movement of a subject to output the detected signal as a signal TH to a waveform treating section 21. The waveform treating section 21 comprises, for instance, a low-pass filter, and performs waveform-shaping treatment of the signal TH output from the body movement detecting section 20 to output a signal MHt showing a body movement component. The body movement eliminating section 30 subtracts the signal MHt showing a body movement component from the signal MH output from the pulse wave detecting section 10 to output a signal MHj showing a pulse wave component.

The pulse wave examination apparatus according to this embodiment is a type treating the pulse waveform detected from a subject. In general, when the subject itself carries some movement, in addition to the signal MHj showing a pulse wave component, the signal MHt showing a body movement component is superimposed on the signal MH detected by the pulse wave detecting section 10. For this, MH=MHt+MHj and hence the signal MH output from the pulse wave detecting section 10 does not show the exact pulse waveform of the subject.

Meanwhile, since the blood flow is affected by, for instance, blood vessels and organizations, the body movement component MHt included in the signal MH is not considered to be just the signal TH showing the body movement of the subject but is considered to be somewhat dulled.

Because of this, the body movement eliminating section 30 uses, as the signal MHt, a signal produced by shaping the waveform of the signal TH in the waveform treating section 21. The signal TH shows the body movement of the subject directly and is output from the body movement detecting section 20. The body movement eliminating section 30 subtracts the signal MHt from the signal MH output from the pulse wave detecting section 10 to eliminate the influence of the body movement, thereby outputting the signal MHj showing the pulse component. The type, number of stages, constant, and the like of the low-pass filter used in the waveform treating section 21 are determined based on the data measured in practice.

In the meantime, when the body movement component eliminating section 30 is made to operate for the elimination of the body movement component even if there is no body movement, the noise of the body movement detecting section 20 causes a deterioration of the S/N ratio of the signal output from the body movement component eliminating section 30, and power is consumed by the body movement eliminating operation. Hence, in this embodiment, a judging section 22 is provided. The judging section 22 determines whether body movement is present or not, based on the body movement waveform TH, to yield a control signal C. Specifically, the judging section 22 makes a judgment by comparing a threshold value with the body movement waveform TH. The threshold value is prescribed in advance, taking a noise level into consideration, so that whether the body movement is present or not can be determined. Then, when the control signal C indicates that no body movement is present, the operations of the waveform treating section 21 and body movement component eliminating section 30 are suspended. In this case, the pulse waveform MH is output directly from the body movement component eliminating section 30. This can improve the SN ratio of the output signal from the body movement component eliminating section 30 and reduce power consumption in the apparatus.

Next, an FFT treating section 40 provides the signal MHj, showing a pulse wave component, with FFT treatment to carry out frequency analysis of the pulse wave component. The result of the frequency analysis can be obtained in the form of a plurality of line spectrums. Then the frequency and the energy level of every line spectrum are calculated. The FFT treating section 40 compares this spectrum data and specifies one having the highest energy level as the fundamental wave f1 of the pulse wave component. The FFT treating section 40 also multiplies the frequency of the fundamental wave f1 integral-fold to specify each harmonic, and outputs pulse wave analysis data MKD showing each energy level of the fundamental wave f1 and of the second harmonic f2 to the tenth harmonic f10 .

In succession, a tidal wave-character extracting section 50 yield a tidal wave-character data TWD showing the characteristics of the tidal wave on the basis of the pulse wave analysis data MKD. As outlined above, the characteristics of the tidal wave can be expressed by the ratio of the sum of the fifth harmonic f5, the sixth harmonic f6, and the seventh harmonic f7 to the fundamental wave f1 in the pulse waveform. Hence the tidal wave-character extracting section 50 yields the tidal wave-character data TWD according to the following equation:

TWD=(f5+f6+f7)/f1

Then, a dicrotic wave-character extracting section 60 yields dicrotic wave-character data DWD showing the characteristics of the dicrotic wave. As outlined above, the characteristics of the dicrotic wave can be expressed by the ratio of the sum of the second harmonic f2, the third harmonic f3, and the fourth harmonic f4 to the fundamental wave f1 in the pulse waveform. Hence the tidal wave-character extracting section 60 yields the dicrotic wave-character data DWD according to the following equation:

DWD=(f2+f3+f4)/f1

Then, a pulse condition judging section 70 judges the pulse condition on the basis of the tidal wave-character data TWD and the dicrotic wave-character data DWD to yield pulse condition data ZD showing the type of pulse condition of the subject. In more detail, first, the pulse condition judging section 70 compares the tidal wave-character data TWD with a first threshold value to yield pulse condition data ZD1 showing that the pulse condition is a Xuan mai if the tidal wave-character data TWD exceeds the first threshold value. The first threshold value is prescribed in advance so as to determine whether the tidal wave-character data TWD shows a Xuan mai or not. In this instance, the first threshold value is designed to be 0.41.

When the tidal wave-character data TWD is less than the first threshold value, on the contrary, the dicrotic wave-character data DWD is compared with a second threshold value. If the dicrotic wave-character data DWD is less than the second threshold value, pulse condition data ZD2 showing that the pulse condition is a Ping mai is yielded, whereas, if the dicrotic wave-character data DWD exceeds the second threshold value, pulse condition data ZD3 showing that the pulse condition is a Hua mai is yielded. Here, the second threshold value is prescribed in advance so as to determine whether the dicrotic wave-character data DWD shows a Ping mai or a Xuan mai. In this instance, the second threshold value is designed to be 1.62.

A notifying section 80 is a type which outputs pulse condition data ZD by display or voice. For instance, the notifying section 80 displays the characters "Hua mai, Ping mai, Xuan mai" or symbols, e.g., icons. This allows the subject and a third party, e.g., a doctor to recognize the pulse condition.

1.3 Action of the Pulse Wave Examination Apparatus.

Next, the action of the pulse wave examination apparatus of the first embodiment will be described with reference to FIG. 2.

First, although a body movement component due to the movement of the subject is superimposed on the signal MH output from the pulse condition detecting section 10, the body movement component is eliminated by the body movement component eliminating section 30 and the signal MHj showing only a pulse wave component is supplied to the FFT treating section 40 (Step S1 and Step S2).

Next, in the FFT treating section 40, the signal MHj is subjected to FFT treatment to yield the fundamental wave f1 of the pulse wave component and each of harmonics f2 to f10 as the pulse wave analysis data MKD, which is then supplied to the tidal wave-character extracting section 50 and the dicrotic-character extracting section 60 (Step S3).

After this step, the tidal wave-character extracting section 50 calculates the ratio o