Pulse wave measurement method

Abstract

To provide a pulse wave measurement method which can easily non-invasively diagnose arterial sclerosis of an animal such as a pet not cooperative to examination, which is difficult to be measured.SOLUTION: A pulse wave measurement method provides means configured to: lay an animal such as a pet or a premature baby or child, on a hammock on which a sensor for ballistocardiogram detection is mounted, and measure easily and non-invasively a pulse wave propagation speed including an aorta in combination with a sensor for pulse wave detection. The present invention enables finding of cardiovascular disease which has an increasing tendency while aging of pets progresses in an early stage, and coping with needs of customers of animal hospitals such that arterial sclerosis of beloved pets can be found in the early stage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pulse wave measuring method and a biological information measuring method. [Background technology]

[0002] The number of pets kept as pets and their average lifespan are both increasing year by year, and in particular, the average lifespan of both dogs and cats has increased by about one year over the past decade. Moreover, the increase in the number of pets and their average lifespan has accelerated during this COVID-19 pandemic.

[0003] The aging of pets, coupled with lack of exercise, is causing an increase in the incidence of various diseases. In particular, the number of arteriosclerosis lesions, which cause cardiovascular disease, has been increasing, although it was rare in dogs and cats until now, and there is an increasing need for veterinary clinics to detect arteriosclerosis early in beloved pets.

[0004] In humans, Brachial-Ankle Pulse Wave Velocity (baPWV) is widely used as an indicator of arteriosclerosis, but because pets have diverse body shapes, it is not easy to estimate vascular length from body length, and baPWV is not suitable for pets.

[0005] In addition, when measuring PWV without anesthesia, it is often difficult to stop the animal from moving, which can lead to artifacts in the measurement results. Also, it is not easy to attach a test sensor to a moving pet.

[0006] Furthermore, photoplethysmography sensors, which are often used to detect pulse waves, are not well suited for use with pets because they require removal of body hair.

[0007] In addition, currently, there are almost no methods for easily and non-invasively diagnosing arteriosclerosis in animals that are not cooperative with testing, such as pets and animals kept in zoos, or in premature infants and children. [Prior art documents] [Patent documents]

[0008] As mentioned above, there are few prior art documents on non-invasive and easy means of diagnosing arteriosclerosis in animals such as pets that are not cooperative with the examination, or in premature babies and children. Here, we list the patent on which baPWV, which is widely used in humans, is based, and an invention on a feline pulse wave examination device.

[0009] Patent Publication No. 2002-301034 This is the invention that is the basis of PWV (baPWV). Cuffs are wrapped around the upper arm and ankle to measure the time difference between the arrival of the pulse wave. Although software-based noise countermeasures are incorporated, the test method is basically based on the premise that the subject cooperates with the measurement.

[0010] Special table 2022-552988 This invention relates to an examination device for measuring the blood pressure of animals with legs, such as cats. The device measures biological information such as blood pressure by having the cat sit on a measurement stand equipped with a photoelectric pulse wave sensor so that the soles of its front and back paws touch the sensor. However, it is not easy to get a cat to sit quietly for a certain period of time without anesthesia. Summary of the Invention [Problem to be solved by the invention]

[0011] There is currently no easy, non-invasive method for diagnosing arteriosclerosis in animals, such as pets, or premature babies and children, who are uncooperative with testing. [Means for solving the problem]

[0012] The present invention provides a means for easily and non-invasively measuring the pulse wave velocity including the aorta by suspending an animal such as a pet, or a premature baby or a child in a hammock equipped with a ballistocardiogram sensor and combining it with a pulse wave sensor. By suspending the subject in the hammock, the effect of body movement that interferes with the measurement can be minimized.

[0013] Ballistocardiogram detection can be easily performed by pressing the chest against the sensor on a hammock. The ballistocardiogram generated in the aortic valve of the heart propagates to the body surface via the ribs, which have a very high propagation speed. The time it takes to propagate through the ribs is short, and can be ignored in the measurement.

[0014] A pulse wave detection sensor is generally attached to the hip joint, but in the case of animals with tails, it is also possible to detect the pulse wave by wrapping tape with a pulse wave detection sensor attached around the base of the tail instead of using a hammock.

[0015] In this manner, the time difference between the ballistocardiogram peak generated when the aortic valve opens and the femoral artery pulse wave peak detected at the hip joint or the tail artery pulse wave peak is measured, and the average value Ta of the time differences between multiple peak pairs is calculated.

[0016] The detection of peak pairs, the measurement of the time difference, and the calculation of the average time difference Ta are performed using a homemade PWV measurement software.

[0017] Peak pair detection is basically performed automatically, but in the case of animals with high body movement, etc., it is often difficult to detect peak pairs fully automatically due to the high probability of artifacts appearing. In such cases, it is effective to have a function that temporarily deletes the automatically detected results and manually points out the peak pairs to eliminate measurement errors due to false detection.

[0018] The blood vessel length Le is calculated from the distance Ls between the body surface and the neck (e.g., the seventh cervical vertebra) and the hip joint or the base of the tail, using the following formula. Le = Ls x a (1) Here, a is a correction coefficient calculated from the actual blood vessel length (L) measured from X-rays, CT scans, MRIs, etc., and the distance Ls between the body surface and the blood vessel length within the same species.

[0019] The Ls of the subject is measured, and the blood vessel length Le is calculated using formula (1).

[0020] From the average time difference between peak pairs, Ta, and the vascular length, Le, the pulse wave velocity, PWV, is PWV = Le / Ta (2) It can be found by:

[0021] As described above, by lowering a subject in a hammock, a ballistocardiogram is detected, and the pulse wave velocity PWV can be easily measured by combining it with the femoral artery pulse wave and the tail artery pulse wave. Furthermore, by lowering the subject in a hammock and manually pointing out peak pairs, it is possible to easily and non-invasively test arteriosclerosis in animals such as pets, or premature babies and children who are not cooperative in the test. Effect of the Invention

[0022] According to the present invention, it is now possible to non-invasively and easily diagnose arteriosclerosis in animals such as pets, premature babies and children, etc., which have previously been difficult to measure or which are uncooperative in tests. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 illustrates an embodiment of the present invention. [Diagram 2] 1 is an example of the structure of a hammock used in the present invention. [Diagram 3] 1 is an example of a tape for a tail artery detection sensor used in the present invention. [Figure 4] FIG. 13 is a diagram showing an example of a measurement result of the present invention. [Diagram 5] FIG. 2 is a diagram showing an example of a ballistocardiogram waveform obtained by the ballistocardiogram sensor of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, the mode for carrying out the present invention will be described in detail based on examples. EXAMPLES

[0025] First, a first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4. FIG.

[0026] In Example 1, two AYA-P piezoelectric vibration sensors 210 were connected to one AYA-P controller 240 via a dedicated cable 220, and this was further connected to a PWV analyzer 250 via a USB cable 230. The AYA-P piezoelectric vibration sensor 210 was an AYA-P06SS manufactured by Taiyo Yuden, the AYA-P controller was an AYA-P05C also manufactured by Taiyo Yuden, and the PWV analyzer 250 was a commercially available Windows PC equipped with self-made PWV analysis software AYA-PMulti.

[0027] One AYA-P piezoelectric vibration sensor 210 was attached to a hammock 120 used for trimming via a hard sponge sensor holder 130, as shown in Fig. 2. The other AYA-P piezoelectric vibration sensor 210 was attached and fixed to a hook-and-loop fastener tape 110 for attaching a sensor with double-sided tape, as shown in Fig. 3.

[0028] 1, a mongrel dog (male, 5 years old) 10 was hung from this hammock 120 and placed on a hanger stand (not shown). Furthermore, a hook-and-loop tape 110 with a sensor attached was wrapped around the base of the tail.

[0029] The two sensors 210, the controller 220, and the PWV analyzer 250 were connected as described above, and the ballistocardiogram and the tail artery pulse wave were input to the PWV analyzer 250 in synchronization with a sampling frequency of 800 Hz, and analyzed.

[0030] In this example, the mongrel dog used in the test was docile and had little body movement, so peak pair detection was performed automatically. As a result, the blood vessel length was 319 mm, the average time difference was 74.6 ± 0.6 msec, and the PWV value was 428 cm / sec. EXAMPLES

[0031] Using the same setup as in Example 1, a rabbit (female, 7 years old) was lowered into a hammock and ballistocardial-tail artery PWV was measured, with a vessel length of 443 mm, an average time difference of 87.6 ± 12.4 msec, and a PWV value of 506 cm / sec. In the case of this subject, because of severe body movement due to tremors, the data related to the peaks obtained by the automatic measurement were deleted, and the peak pairs were newly manually pointed out to determine the average value of the time difference, and then the PWV was calculated. EXAMPLES

[0032] Using the setup used in Examples 1 and 2, a Pomeranian (male, 9 years old) was measured. As in Example 2, peak pairs were selected using the manual method, and the blood vessel length was 319 mm, the average time difference was 63.4 ± 5.3 msec, and the PWV value was 503 cm / sec. EXAMPLES

[0033] Other Embodiments The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention. (1) In the above embodiment, the tail artery is used as the pulse wave measurement point, but it is also possible to attach an AYA-P piezoelectric vibration sensor 210 to the hip joint of the hammock and have the subject sit on it to measure the pulse wave of the femoral artery. (2) In addition to the tail artery and femoral artery, it is also possible to attach tape to the ankle or dorsum of the foot and use the pulse waves at those sites. (3) In the present invention, an AYA-P piezoelectric vibration sensor manufactured by Taiyo Yuden is used for detection, but there is no problem in using a vibration sensor with similar performance. (4) In addition, as shown in Figure 5, the shape of the peak of the ballistocardiogram represents the vibration caused by the opening of the aortic valve and is known to differ depending on the subject. Therefore, detailed observation of this waveform can be used for screening whether or not an echocardiogram should be performed. [Industrial Applicability]

[0034] According to the present invention, it is now possible to non-invasively and easily diagnose arteriosclerosis in animals such as pets, which has previously been difficult to measure and which are uncooperative in testing. This makes it possible to detect cardiovascular diseases early, which are on the rise as the population ages, and meets the needs of veterinary clinic customers for early detection of arteriosclerosis in their beloved pets. [Explanation of symbols]

[0035] 10: Subject (example of dog) 110: AYA-P sensor attachment tape for tail artery 120:Hammock equipped with AYA-P sensor for ballistocardiogram detection 130: AYA-P sensor holder for ballistocardiogram detection 210:AYA-P Piezoelectric Vibration Sensor 220: AYA-P Piezoelectric Vibration Sensor Cable 230: USB cable 240:AYA-P controller 250:PWV analysis device 310: Channel 1 (ballistocardiogram) waveform 320: Channel 2 (tail artery pulse wave) waveform 330: Time difference between channel 1 and channel 2 340: Display of blood vessel length and average time difference 350:PWV measurement value display 400: Ballistocardiogram peak due to aortic valve opening 410: Ballistocardiogram of Subject 1 420: Ballistocardiogram of Subject 2 430: Ballistocardiogram of Subject 3

Claims

1. A ballistocardiogram measuring method in which a ballistocardiogram is detected by lowering a subject into a hammock incorporating a first sensor capable of detecting vibrations in the vicinity of contact with the chest.

2. A method for measuring pulse wave velocity, comprising the steps of: adding a second vibration detection sensor for detecting pulse waves to the ballistocardiogram measurement method of claim 1; measuring the time difference between the ballistocardiogram of the first sensor; and dividing the blood vessel length between the aortic valve and the pulse wave generation point by the time difference thus obtained to obtain the pulse wave velocity.

3. 3. The method for measuring pulse wave velocity according to claim 2, further comprising wrapping a second vibration detection sensor for detecting pulse waves around the base of the subject's tail.

4. 3. The method for measuring pulse wave velocity according to claim 2, further comprising the step of incorporating a second vibration detection sensor for detecting pulse waves in the vicinity of the hip joint of the hammock according to claim 1.

5. 3. The method for measuring pulse wave velocity according to claim 2, wherein when measuring the time difference between a pair of peaks of the ballistocardiogram of the first sensor and the pulse wave of the second sensor, the pair of peaks is manually selected.

Images