WO2024035354A1

WO2024035354A1 - Blood pressure meter

Info

Publication number: WO2024035354A1
Application number: PCT/TR2022/050840
Authority: WO
Inventors: Ahmet TEMİZHAN
Original assignee: Aygo Sağlik Hi̇zmetleri̇ Bi̇li̇şi̇m Ve Danişmanlik Li̇mi̇ted Şi̇rketi̇
Priority date: 2022-08-11
Filing date: 2022-08-11
Publication date: 2024-02-15

Abstract

The present invention relates to a blood pressure meter that is used in the field of health and that is used to measure blood pressure for 24 hours with a cuffless transdermal technique from the superficial temporal artery. The present invention particularly relates to a blood pressure meter that comprises an inner membrane (24) that moves with the expansion and contraction of the vessel (A) and transmits this movement to the air gap (23); a piezoelectric element (22) that moves with the movement of the air gap (23) and converts this movement into an electrical signal; an arterial line locator sensor (30) that provides the correct placement of the Piezoresistive pressure sensor (20) on the axial plane by giving a green signal when it detects the artery that causes a strong heartbeat.

Description

BLOOD PRESSURE METER

TECHNICAL FIELD

The present invention relates to a blood pressure meter that is used in the field of health and that is used to measure blood pressure for 24 hours with a cuffless transdermal technique from the superficial temporal artery.

The present invention particularly relates to a blood pressure meter that comprises an inner membrane that moves with the expansion and contraction of the vessel and transmits this movement to the air gap; a piezoelectric element that moves with the movement of the airgap and converts this movement into an electrical signal; an arterial line locator sensor that provides the correct placement of the Piezoresistive pressure sensor on the axial plane by giving a green signal when it detects the artery that causes a strong heartbeat.

STATE OF THE ART

The heart works continuously, pumping the blood in the circulatory system to the body. A certain amount of pressure occurs in all the vessels when the heart pumps blood to the whole body through the aorta. Intra-arterial pressure, defined as blood pressure, is of great importance for vital tissues and organs to be adequately nourished and to maintain their normal functions. The oxygenated blood in the lungs first comes to the heart and is pumped from there to the body through the aorta. The aorta, which can be defined as the main vessel leaving the heart, divides into many branches. These large vessels are known as arteries. The great vessels are also divided into branches and become thinner arterioles, or in other words, they are connected to medium-sized vessels and finally to capillaries known as capillaries medically. Different types of cells in the body are oxygenated and obtain the energy they need by means of this entire vascular network. After the oxygen carried in the veins is delivered to the body, the venous blood returns to the heart via a vein, and the heart delivers it to the lungs by pumping it to re-oxygenate the blood. The blood is delivered to the arteries by the pressure created during the pumping process of the heart. Meanwhile, the pressure created is at its highest level. The heart muscle then relaxes, and less pressure remains within the blood vessels during this time. The pressure created during the beating of the heart is defined as systolic blood pressure, while the pressure remaining in the vessels with the relaxation of the heart is defined as diastolic blood pressure. When blood pressure is measured, data for both pressure types are obtained. Ideal blood pressure measurement should be comfortable and easy to apply, as well as giving the closest value to the real blood pressure in the arteries especially central aortic pressure. Today, internationally approved blood pressure measuring instruments that are generally used are as follows; 1- mercury blood pressure monitors (gold standard), 2- aneroid (sphygmomanometer-oscillometric) blood pressure measuring instruments, 3- automatic (sphygmomanometric-oscillometric) blood pressure measuring instruments, 4- hybrid (mercury-free) blood pressure monitors.

In the state of the art, blood pressure measurement is traditionally performed by applying pressure to the brachial artery (the part of the arm vessel that is superficial on the inside of the elbow) through a cuff (inflatable cuff) and hearing Korotkoff sounds (pulse sounds) while the cuff is slowly lowered (oscillometric technique). This method has been used unchanged since Scipione Riva-Rocci described it 125 years ago. Today, this method is done using an inflatable cuff, but with automatic electronic monitors. These automatic monitors measure blood pressure by sensing the pulse rate as the cuff air slowly descends. Namely, it doesn't need a stethoscope or microphone. Therefore, the person making the measurement is not affected by the outside noise.

Even if it is done in accordance with the rules and repeated several times in the state of the art, blood pressure measurements made in the hospital environment show an instant value, and it does not allow us to obtain the patient's blood pressure course throughout the day (24 hours). In addition, this approach does not allow to diagnose white coat hypertension (high blood pressure in the hospital) and masked hypertension (low blood pressure in the hospital). In order to overcome this difficulty, automatic blood pressure measurements of the patient at home (sphygmomanometric- oscillometric) and ambulatory (measurements involving 24 hours, with intervals of 15- 30 minutes) are used in appropriate (necessary) situations.

In the state of the art, the use of automatic measuring devices with cuffs that apply pressure both in home measurements and in ambulatory blood pressure monitoring accompanies similar problems. These are:

The pressure exerted by the inflated cuff on the forearm artery disturbs the patient, disturbs his/her comfort,

When the ambulatory devices measure at night, the patient's sleep is divided and his/her blood pressure is higher than it is when his/her sleep is interrupted, The need for a good training process (resting for 5 minutes in a quiet room, passively holding the arm at heart level in a sitting position, putting the cuff in the right place, measurements that should be made at regular intervals, technical conditions that must be complied with when an ambulatory device is inserted),

Conditions affecting oscillometric (aneroid or automatic) devices: Exercise (body movements affect the arm, and vibrates), position of the arm, tensing of the muscles, talking and noise in the room, anxiety of the person during the visit, (it can raise blood pressure by 20 mmHg), the effect of clothing on the measurement area.

Conditions that make measurement difficult are obesity, hardening of the arterial wall (the elderly), and atrial fibrillation (atrial fibrillation is a chaotic rhythm disorder and is common in hypertensive patients). In case of atrial fibrillation, the ratio of heartbeats that create a pulse wave in the periphery is not 1:1, and there is a loss of approximately 20% of the heartbeats occurs. This is called pulse deficit. Therefore, measurements made from the arm with the cuff cause the blood pressure to be measured incorrectly due to the loss in the pulse rate. The loss of pulse becomes more pronounced the further away from the heart. In other words, while the pulse deficit is less in the arteries close to the heart, it is more in the arteries that are further away from the heart. For example; the brachial artery (the part of the arm vein that becomes superficial on the inside of the elbow) and the radial artery (wrist artery) respectively.

It is necessary to choose the appropriate cuff size according to the patient's arm width.

Most available devices that perform measurements at the peripheral vasculature are not well correlated to central aortic pressure which is the best indicator for cardiovascular risk.

As the gold standard, the mercury blood pressure measuring instruments that are mentioned above are not used in practical life due to the harm of mercury to human health but are used in laboratory environments for calibration purposes.

In the state of the art, the search for ideal methods, devices and a peripheric artery that can measure blood pressure noninvasively and cuffless, also in the most accurate way for 24 hours continuously. For this purpose;

1- Multisensory application will be used. One of the sensors is the piezoresistive pressure sensor. The other sensor is the optic arterial line locator sensor, which will enable the pressure sensor to be placed on the artery to be measured with optimal accuracy.

2- The superficial temporal artery, which is closer to the central aorta than the brachial artery, will be used for cuffless transdermal blood pressure measurement.

Consequently, the requirement for a new, economical, convenient, practical blood pressure meter along with the insufficiency of existing solutions necessitated making improvements in the related technical field for the purpose of solving problems that are present in the state of the art. OBJECTS OF THE INVENTION

The present invention relates to a blood pressure meter that is used to measure blood pressure 24 hours a day using a cuffless transdermal technique from the superficial temporal artery, which was developed with the aim of overcoming the disadvantages and to introduce new advantages to the related technical field.

The most important object of the present invention is to make the blood pressure measurement less affected by external factors (body movements, position - keeping the forearm passive at heart level - clothes that tighten the arm, pressure of the muscles around the artery, thickness of the subcutaneous layers - obesity) and internal factors (atrial fibrillation).

Another important object of the present invention is to measure blood pressure from the superficial temporal artery where such interactions will not occur by using a cuffless method that will not disturb the person, instead of the brachial or radial artery which is affected by both external and internal factors. Our approach is to instead use the superficial temporal artery, which has several advantages as an optimal location for cuffless blood pressure measurement; the superficial temporal artery is a terminal branch of the external carotid artery with a mean outside diameter of 2.1 (standard deviation is 0.14) mm and it is easy to identify and localize; it runs along the temples in close proximity to the surface of the skin and strongly supported by the underlying bone structure; the superficial temporal artery moves much less than brachial or radial artery, and hence is less susceptible to motion artifacts during ambulatory monitoring; because the head is relatively stationary above the heart when in an upright position, the pressure at the superficial temporal artery can be consistently related to aortic blood pressure. It will provide a better estimate of arterial blood pressure (also central aortic pressure) rather than its corresponding measurements in the finger, brachial or radial artery considering its anatomical characteristics (it is closer to the ascending aorta than brachial artery); it could also be argued that measurements from superficial temporal artery might be less sensitive to the influences of age, gender and pathological conditions than those derived from measurements in the brachial or radial artery.

Another important object of the present invention is that the person does not realize that his/her blood pressure is being measured.

Yet another important object of the present invention is to be easy to implement and thereby minimizing the possible application error of the measurer. Therefore, it will ensure that the blood pressure outside the hospital and in the hospital is accurately recorded for 24 hours during daily activities (exercise, rest), during sleep, and in case of rhythm disturbances. For optimized positioning of the blood pressure sensor and fine tuning of the superficial temporal artery localization, optic arterial line locator sensor will be used (multisensory application). As a mHealth (it is defined as medical and public health practice supported by mobile devices, such as mobile phones, patient monitoring devices, personal digital assistants and other wireless devices by the Global Observatory for eHealth), our another important object of the present invention is to transfer blood pressure measurements to a smart phone via Bluetooth (or RF chip antenna), to enable daily and weekly analyzes on the results and to send them virtually to the attending physician (health institution). Thus, it provides both awareness to the patient and the physician by remotely monitoring the patients' blood pressure and warning them both on values that go beyond the predetermined threshold. In addition to bringing the patient and physician closer, it is also efficient which saves us money and time.

Structural and characteristic features of the present invention as well as all advantages thereof will become apparent through the figures described below and by means of the detailed description written by making references to these figures, and therefore, the necessary evaluation should be conducted by taking said figures and the detailed description into consideration. THE FIGURES THAT ASSIST IN UNDERSTANDING THE INVENTION

FIGURE -1 is the drawing that illustrates the vessel where the blood pressure meter of the present invention will be applied.

FIGURE -2 is the drawing that illustrates the application of the blood pressure meter of the present invention.

FIGURE -3 is the drawing that illustrates the blood pressure meter of the present invention from the front.

FIGURE -4 is the drawing that illustrates the blood pressure meter of the present invention from the rear.

FIGURE -5 is the drawing that illustrates the sensors of the blood pressure meter of the present invention.

FIGURE -6 is the drawing that illustrates the piezoresistive pressure sensor of the blood pressure meter of the present invention in cross-section (static condition).

FIGURE -7 is the drawing that illustrates the piezoresistive pressure sensor of the blood pressure meter of the present invention in cross-section (vascular pulsation condition).

FIGURE -8 is the drawing that illustrates the piezoresistive pressure sensor of the blood pressure meter of the present invention in cross-section (vessel damping condition).

FIGURE -9 is the drawing that illustrates the static state diagram of the optic arterial line locator sensor of the present invention.

FIGURE -10 is the drawing that illustrates the working principal diagram of the optic arterial line locator sensor of the present invention. REFERENCE NUMERALS

10. Battery

20. Piezoresistive pressure sensor

21. Body-1

22. Piezoelectric Element

23. Air Gap

24. Inner Membrane

30. Optical arterial line locator sensor

31. Body-2

32. LED light source

33. CMOS light sensor (Complementary Metal Oxide Semiconductor)

34. Beam

35. Reflected light

40. Communication Module

A. Superficial temporal artery

B. Skin

C. Bone DETAILED DESCRIPTION OF THE INVENTION

In the detailed description provided herein, preferred embodiments of the blood pressure meter are described only to ensure a better understanding of the subject and without producing any limiting effects.

Figures 1 to 10 show the inventive blood pressure meter and its details. In the present invention, it is aimed to measure blood pressure transdermally with a cuffless method that will not disturb the person. The Piezoresistive pressure sensor (20) and the Optical arterial line locator sensor (30) used in the invention is preferably 2 cm in size. In the present invention, there is a communication module (40) that provides wireless operation and communication with mobile devices and a battery (10) that provides energy, apart from the Piezoresistive pressure sensor (20) and the Optical arterial line locator sensor (30).

In the present invention, Piezoresistive pressure sensor (20) and Optical arterial line locator sensor (30) adhere to the skin (B). As the measurement area, the superficial temporal artery (A) is preferred instead of the brachial artery, which is heavily affected by external factors (fat tissue, muscle thickness, clothing, arm movement). Measuring the value that best reflects the pressure of the aorta, which is the great artery leaving the heart, is very important in blood pressure monitoring. As the measurement artery is further away from the aorta and the muscle/fat tissues around it increase, the ability of an accurate measurement of the pulse and the blood pressure becomes harder. Also, the reliability of the measurements is reduced. The superficial temporal artery (A) is considered as a good target for measurement reliability due to its closeness to the aorta and there is no muscle/fat tissue around it, also it is strongly supported by the underlying bone structure (C), and it is less affected by pulse loss. The Piezoelectric Element (22) functional components are placed inside the body-1 (21). The Piezoresistive pressure sensor (20) is placed on the person's right or left superficial temporal artery (A). As can be seen in Figure 6-8, the inner membrane (24) moves as the artery (A) expands and contracts and transmits this movement to the air gap (23). The system works by the fact that the air gap (23) carries this movement to the piezoelectric element (22) and as a result of this movement, the piezoelectric element (22) generates an electrical signal. Said generated signal will be converted to measurement according to the pulse wave velocity principle. The inner membrane (24) contacting the skin (B) is preferably thought to be rigid (Si-based) rather than flexible, so it is aimed to better perceive the pressure in the artery (A). The measurements detected by the sensor 1 (21) using the pulse wave velocity method placed in the superficial temporal artery (A) will transmit the digitized data to the computer/mobile device application via the communication module (40), preferably using Bluetooth technology.

Algorithms will be developed to convert pulse wave velocity to systolic and diastolic blood pressure. The signal pipeline consists of four stages: signal amplification, digitization, Bluetooth transmission, and software processing.

The LED light source (32) and CMOS (Complementary Metal Oxide Semiconductor) light sensor (33) functional components are placed inside the body-2 (31). In order to accurately determine the localization of the superficial temporal artery where blood pressure will be measured, Optical arterial line locator sensor (30) will be brought closer to the right or left superficial temporal artery (A) region of the person. As can be seen in Figures 9-10, The LED light source (32) and the CMOS (Complementary Metal Oxide Semiconductor) light sensor (33) are positioned at approximately 45° to the artery (A). The beam (34) sent from the LED light source passes through the skin and subcutaneous tissues and reaches the artery (A). With the strong volume change caused by the heartbeats in the artery (A), the beam (35) reflected from the artery (A) is detected by the CMOS light sensor (33). The beam (35) detected by the CMOS light sensor (33) are qualified by filters, converters, and software, and undesirable impurities are removed. Therefore, when the arterial line locator sensor (30) detects the artery that gives a strong heartbeat, it gives a green signal and ensures the correct placement of the Piezoresistive pressure sensor (20) on the axial plane.

The protection scope of this application is defined in the pending patent claims, and under no circumstances may it be construed to be limited with the detailed description provided above for illustration purposes, moreover, it is obvious that a person skilled in the art may set forth the novelty of the present invention by taking advantage of similar embodiments and/or implement this embodiment in the fields with similar purposes used in the relevant art. Therefore, it is apparent that such embodiments will lack the novelty criteria, and particularly the criteria of surpassing the state of the art.

Claims

1- A blood pressure meter that is used in the healthcare field and that enables continuous measuring of blood pressure by a non-invasive (A) cuffless transdermal technique, characterized by comprising;

An inner membrane (24) that moves with the expansion and contraction of the vessel (A) and transmits this movement to the air gap (23), a piezoelectric element (22) that moves with the movement of the air gap (23) and converts this movement into an electrical signal, an arterial line locator sensor (30) that provides the correct placement of the Piezoresistive pressure sensor (20) on the axial plane by giving a green signal when it detects the artery that causes a strong heartbeat.

2- A blood pressure meter according to Claim 1, characterized by comprising; a rigid (Si-based) inner membrane (24), not flexible.

3- A blood pressure meter according to Claim 1, characterized by comprising; a communication module (40) that enables the measurements detected by the Piezoresistive pressure sensor (20) to be transmitted to the computer and/or mobile devices by the pulse wave velocity method.

4- A blood pressure meter according to Claim 1, characterized by comprising; an application that converts pulse wave velocity uploaded to computer and/or mobile devices into systolic and diastolic blood pressure.

5- An arterial line locator sensor (30) according to Claim 1, characterized by comprising; a LED light source (32) that is placed at an angle of approximately 45° to the artery (A) and that allows the emitted beam (34) to pass through the skin and subcutaneous tissues and reach the artery (A) 6- An arterial line locator sensor (30) according to Claim 1, characterized by comprising a CMOS light sensor (33) that is placed in the artery (A) at an angle of approximately 45° and that detects the beam (35) reflected from the artery (A) with the strong volume change caused by the heartbeats in the artery (A)

7- An arterial line locator sensor (30) according to Claim 1, characterized by comprising filters and/or converters and/or software that allow for removing undesirable impurities by qualifying the beams (35) detected by the CMOS light sensor (33) by filters, converters, and software.

8- A blood pressure meter according to Claim 1, characterized by comprising; a battery (10) that supplies energy to the Piezoresistive pressure sensor (20), arterial line locator sensor (30), and the communication module (40).