RU2613086C2 - Device for long-term remote invasive monitoring of state and critical changes of cardiovascular system for patients with comorbidity - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment. The device for long-term remote invasive monitoring of state and critical changes in the cardiovascular system for patients with comorbidities comprises an implantable pressure sensor equipped with a wireless charger. The pressure sensor is configured to be mounted outside the vessel by a cuff. A wireless data transmitter is located in the electronics unit arranged in a sealed housing with the possibility of location outside the container, and connected to the sensor via a conductor. The pressure sensor is a MEMS sensor configured to monitor blood pressure, as well as for monitoring for status and critical changes in the cardiovascular system for patients with comorbidities for a predetermined period of time.

EFFECT: invention provides wireless connection to power supply for the pressure sensor.

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Description

Device for long-term invasive remote monitoring of the condition and critical changes of the cardiovascular system in patients with comorbidity

The invention relates to the field of invasive determination of the pressure level in the patient’s arteries and transmits this information wirelessly to a centralized database (doctors access it through special sites).

Known device The AngelMed Guardian

(http://www.angel-med.com/images/wgno/WGNO%20LA%Htart.html,

http://www.angel-med.com/index.php/medical-professionals/our-solution/11-guardian-components.html). This system is designed for the early detection, analysis and recording of heart performance (ST segment). The device consists of two parts (one part is implanted, the other is a portable pager. The device is implanted as usual pacemakers and provides continuous monitoring of heart performance. Signals are transmitted wirelessly from the implanted device to an external device. In case of a serious violation or predictors of angina pectoris / heart attack it informs the patient about the need to seek medical help with vibrational, acoustic, and visual signals. s information from the paging unit to the PC via an integrated Bluetooth. This device passes phase II clinical trials.

The main disadvantages of the device are: the lack of the possibility of a comprehensive assessment of the state of the cardiovascular system (CVS) (only ECG - ST segment); lack of the ability to remotely monitor a doctor and emergency response.

A wireless passive blood pressure monitoring sensor is also known (http://www.research.a-star.edu.sg/research/6651, http://www.kurzweilai.net/wireless-device-powers-implanted-blood-pressure -sensor-eliminating-batteries) - the implant is inserted into the artificial vessel during surgical prosthetics and is powered by a portable external reader that uses an inductive communication method for wireless energy transfer (two miniature coils in combination with an enlarged sound amplifier).

The lack of experimental data does not allow one to judge the advantages and disadvantages of the method, while the developers claim that it is possible to measure only systolic and diastolic blood pressure (BP) without other parameters of the cardiovascular system. In addition, there is no data on the possibility of remote data transmission.

In addition, a known system for collecting and managing physiological data for use in conjunction with an implantable wireless sensor (Pat. US 2012105248, 05/03/2012, IPC: G08C 19/16, H04B 1/04). The invention describes a system for receiving, processing and managing data received from an implanted sensor. In some modifications, the patient or others may use a flexible antenna to receive data from the implanted sensor. A flexible antenna can communicate with a patient device that collects information from an implanted sensor, creates a data file, and transmits to a remote server over the network. A doctor or other authorized person can access the remote server using an access device.

The disadvantages of the system include the dependence on the position of the patient’s body and the inability to process the signal inside the implantable device. In addition, the MEMS (microelectromechanical systems) sensor is not placed outside the limits of the wireless data transceiver, signal processing and power supply unit, which does not allow its use in smaller vessels.

Closest to the claimed group of technical solutions is an implantable wireless sensor for measuring pressure and the method of its operation (CardioMEMS Champion, USA, Abraham WT, Adamson PB, Bourge RC, et al. Wireless pulmonary artery haemodynamic monitoring in chronic heart failure: A randomized controlled trial . Lancet. 2011; 377 (9766): 658-66, http://www.sjm.com/cardiomems), including the electromechanical sensor EndoSure, made by MEMS technology and having dimensions of 3.5 × 2 × 1.5 mm. The device does not require implantable power sources (powered by an external antenna attached to the patient’s body) and determines the critical pressure level in the patient’s pulmonary artery by transmitting information wirelessly to a centralized database (doctors get access through special sites).

The main disadvantages of this sensor device are the dependence on the patient’s position (it is necessary to take measurements in a horizontal position), thermal sensitivity, inaccuracy when changing body weight, shortness of breath, etc. There is no possibility of registering several parameters of the cardiovascular system. In addition, this device is intended for implantation inside a large vessel (pulmonary artery, which determines the risk of thrombosis). The disadvantage is the high cost ($ 15,000 including the cost of hospitalization and implantation).

The objective of the invention is to develop the design of an invasive sensor, the operation of which will not depend on the position of the patient, as well as providing wireless wireless power for the pressure sensor.

The technical result consists in providing wireless power transmission for a pressure sensor.

The problem is solved in that in a device for long-term invasive remote monitoring of the state and critical changes of the cardiovascular system in patients with comorbidity, containing an implantable pressure sensor equipped with a wireless charging device, according to the claimed technical solution, the pressure sensor is configured to be installed inside the vessel, except Moreover, in the implantable device, reference and variable capacitive-temporal electric circuits based on low-power oscillations are used. s. The device contains a wireless data transmitter located in the electronics unit, made in a sealed enclosure with the possibility of its location outside the vessel, and connected to the sensor via a conductor. In this case, the pressure sensor is a MEMS sensor configured to control blood pressure, as well as monitor the status and critical changes of the cardiovascular system in patients with comorbidity for a given period of time. In addition, design options are possible when the pressure sensor is arranged to be installed by means of a cuff outside the vessel, or when the pressure sensor is made to be installed inside the vessel by means of X-ray endosurgical techniques.

The invention is illustrated by drawings: FIG. (a-c) - design options of the claimed technical solution.

The positions in the drawings indicate: 1 - artery walls, 2 - microelectromechanical sensor (MEMS), 3 - silicone case, 4 - conductor, 5 - silicone cuff, 6 - fluid, 7 - stent.

The device for long-term invasive remote monitoring of the state and critical changes of the cardiovascular system in patients with comorbidity is equipped with a wireless data transmission system in the MICS band (402-405 MHz) and a wireless power transmission module at a frequency of 13.56 MHz. The system consists of a capacitance-digital converter, the principle of which is based on the sigma-delta modulation method and a capacitive pressure sensor with a reference capacitance of about 6 pF.

The inventive device consists of a microelectromechanical sensor (MEMS sensor) 2 implanted in or outside the artery (depending on the design), an electronics unit taken out of the artery 1, installed in a sealed silicone case 3 and connected to MEMS 2 via a conductor 4.

The sensor has the following technical characteristics: the range of the measured pressure is 0.5-1.3 Bar, the average sensitivity is 0.451 pF / Bar, and the overall dimensions are 0.5 × 0.2 mm. The energy loss between the implant and the base station is determined by the Friis formula

,

,

- эффективная длина волны в среде с потерями, k - комплексное волновое число средней потери, a R - расстояние между приемной и передающей антеннами.Where

is the effective wavelength in the medium with losses, k is the complex wave number of the average loss, and R is the distance between the receiving and transmitting antennas.

A prototype of the transmitter of the electronics unit located in the silicone case 3 was developed, which includes the debugging board of the CC3200-LAUNCHXL microcontroller (based on the Wi-Fi + MK CC3200 architecture of the ARMCortexM4 architecture), a display, a model of the wireless data and power transmission module, and debugging board module GSM (SIM800H-EVM, which allows for the transfer of data and coordinates of the location of a person, as well as the reception and transmission of messages to the control chip microcontroller).

Distinctive features of the proposed technical solution are the presence of a wireless power supply system (inductive method), the presence of a signal processing unit (located in a silicone case).

The technical solution can be implemented in three versions: 1. The MEMS 2 sensor is located inside the artery 1, the electronics are moved outside the artery 1, connected by means of a catheter, inside which there is a micrometer-sized conductor 4 (Fig. - a). The antenna is located inside the electronics in a silicone housing 3.

2. The MEMS 2 sensor is located outside the artery 1 and is pressed against the external walls by means of a silicone cuff 5, the density of which is equal to the density of the artery 1. The MEMS 2 is connected to the electronics by means of a thin conductor 4. The antenna is located inside the electronics in the silicone case 3 (Fig. - b) In this case, the MEMS 2 sensor is configured to measure the pressure of the fluid 6 in the cuff 5. Silicone fluid can be used as the fluid 6.

3. The MEMS 2 sensor is located inside the artery 1, the electronics is moved outside the artery 1 and placed in a silicone casing 3, connected by means of a catheter, inside of which a micrometer-sized conductor 4 (Fig. C). The MEMS 2 sensor is held by a stent 7. The antenna is located inside the electronics unit in the silicone housing 3.

The implantable blood pressure sensor in all design options can be used in arteries of large and medium caliber.

The work of a group of devices for long-term invasive remote monitoring of the condition and critical changes in the cardiovascular system in patients with comorbidity is carried out on the basis of a capacitive pressure sensor as follows.

Regardless of the location of the sensor 2 in the vessel, the general principle of operation of the entire system remains unchanged: with increasing pressure, the distance between the plates of the capacitive sensor decreases. Since the capacitance is inversely proportional to the distance between the plates, then, having determined the capacitance by the sigma-delta modulation method, the pressure value is determined. These data are determined from the MEMS documentation of the pressure sensor 2.

The received signal from the implantable MEMS sensor 2 is recorded in the internal memory of the transmitter of the electronics unit in the form of a report and sent to the doctor’s workstation. The sensor interface is used to convert the capacitance value to a digital pulse signal. Thus, MEMS-sensor 2 carries out: 1) continuous measurement and conversion of the variable capacitor capacitance into a digital signal, 2) converting the variable capacitor capacitance readings into blood pressure indicators, 3) data transmission to an external device (transmitter) using wireless power supply and data transfer.

The operation algorithm of the debug board of the transmitter microcontroller is implemented on the basis of the real-time operating system for embedded FreeRTOS systems. The resonant circuit operates in series voltage resonance mode. The transmitter's debug board generates a 10 MHz signal, which is then amplified by the current driver. The current driver provides a current on the resonant circuit of up to 50 mA at a voltage of 5 V. The resonant circuit allows the amplitude of the signal on the coil to be up to 100 V (with a Q factor of 20), which allows transmitting power to MEMS up to 30 cm away. Data is transmitted over amplitude modulation account with a modulation coefficient of 100%. The maximum data transfer rate to the MEMS sensor is 20 kbit / s. Data is received in the following way: when transmitting data from the MEMS sensor, the signal level on the circuit is changed, the converted analog signal passes through a passive filter to filter out the "black" frequencies, then the filtered signal is fed to the amplifier and to the transmitter’s debug board. After which it is available for recording, processing and decryption by a doctor. Thus, not only simultaneous control of blood pressure is carried out, but also the state and critical changes of the cardiovascular system in patients with comorbidity for a certain period of time are monitored.

In the second embodiment (Fig. 6), the pressure changes due to a change in the pressure of the liquid in the cuff due to a decrease or increase in the diameter of the vessel. The MEMS 2 sensor measures the pressure of the liquid 6 in the cuff 5.

Example.

For the experiment, we used a mock blood pressure sensor connected to the power supply through an inductor. The output voltage was 5 V. A digital oscilloscope was used to obtain a time sweep of the signal. Capacitive values were measured in the range of 4–20 pF. The value of the reference capacitor was 5 pF and the resulting oscillator frequency was 1 kHz. To test and test the capacitive-temporal circuit, the pulse was transmitted to the receiver.

The use of a capacitive pressure sensor based on the technology of microelectromechanical systems with a reference and variable capacitive-temporal electric circuits based on low-power oscillators with a signal processing unit made it possible to place the MEMS sensor inside or outside the artery.

Thus, the creation of an implantable device for the comprehensive diagnosis of the heart, blood pressure, ischemic disorders, the work of which does not depend on the position of the body, is the newest promising direction for monitoring and preventing the development of cardiovascular diseases. The device under development is superior to foreign analogues, therefore it is patentable, competitive and has significant potential for commercialization.

Claims (3)

1. Device for long-term invasive remote monitoring of the state and critical changes of the cardiovascular system in patients with comorbidity, comprising an implantable pressure sensor equipped with a wireless charging device, characterized in that the pressure sensor is configured to be installed by means of a cuff outside the vessel, the device also includes a wireless a data transmitter located in the electronics unit, made in a sealed enclosure with the possibility of its location outside the vessel, and under for prison to the sensor via a conductor, wherein the pressure sensor is a MEMS sensor configured to control blood pressure, as well as the status and control of critical changes in the cardiovascular system in patients with comorbidity for a predetermined period of time. 2. A device for long-term invasive remote monitoring of the condition and critical changes in the cardiovascular system in patients with comorbidity according to claim 1, characterized in that the implantable blood pressure sensor can be used not only in arteries, but also in vessels of smaller caliber. 3. A device for long-term invasive remote monitoring of the condition and critical changes in the cardiovascular system in patients with comorbidity according to claim 1, characterized in that the conductor is placed inside the catheter.

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