JP2011526498A - Integrated cardiac monitoring device and method of using the same - Google Patents

Abstract

  In an apparatus for monitoring a patient's heart, a housing, a calculation device, and an optical sensor configured to provide the calculation device with a signal indicating a distance from the optical sensor to a blood vessel carrying blood and a diameter of the blood vessel. An optical sensor, a Doppler sensor configured to provide the calculation device with a signal indicating the velocity of blood passing through the blood vessel, and a signal indicating a plurality of electrical stimuli that move the heart in a pumping manner. An ECG sensor configured in the apparatus. The calculation device calculates parameters including blood oxygen saturation, blood flow, blood pressure, heart rate, and cardiac output using signals from the optical sensor, Doppler sensor, and ECG sensor.

Description

Disclosure details

[Priority claim]
This application is a US patent application No. 12 / 119,315 with the name “OPTICAL SENSOR APPARATUS AND METHOD OF USING SAME”, and US Patent Application No. 12/119 with the name “DOPPLER MOTION SENSOR APPARATUS AND METHOD OF USING SAME”. No. 119,339, US Patent Application No. 12 / 119,325 with the name “INTEGRATED HEART MONITORING DEVICE AND METHOD OF USING SAME”, US Patent Application No. 12 with the name “METHOD AND SYSTEM FOR MONITORING A HEALTH CONDITION” No. 119,462 (all filed on May 12, 2008) and US Patent Application No. 12 / 206,885 (filed September 9, 2008) with the name “DOPPLER MOTION SENSOR APPARATUS AND METHOD OF USING SAME” ) Claim priority. These are all due to the same inventor as the present application, and all applications are incorporated herein by reference in their entirety.

(Field of the Invention)
The present invention relates to sensing devices, and more particularly to devices for monitoring cardiac behavior.

[Background of disclosure]
Cardiovascular disease is a major health problem that is growing around the world. Several studies show that about 15% of Western countries suffer from one or more cardiovascular diseases. In the United States, nearly 25% of the population is affected, resulting in over 6 million hospitalizations each year.

  There are a variety of devices that monitor certain parameters related to the behavior of the heart. In some cases, the patient's in vivo parameters may need to be monitored over a period of time; for example, such monitoring may be necessary for patients with occasional irregular heartbeats . Cardiac arrhythmias are changes in the normal sequence of electrical impulses that cause the heart to pump blood systemically. Since such abnormal heart rhythms may only occur sporadically, detection may require continuous monitoring. By conducting continuous monitoring, medical personnel determine whether they tend to produce sustained irregular beats that endanger their lives. Medical personnel also use monitoring results to establish an appropriate course of treatment.

  One prior art device for measuring heart rate is the “Reveal” monitor by Medtronic (Minneapolis, MN, USA). This device includes, for example, an implantable heart monitor that is used in determining whether a patient's fainting (falling) is associated with a heartbeat problem. The Reveal monitor continuously monitors heart rate and heartbeat for up to 14 months. After waking up from the onset of symptoms, the patient places the first recording device outside the skin on the implanted Reveal monitor and presses a button to transfer data from the monitor to the recording device. The patient gives the first recording device to the doctor, who in turn provides the patient with the second recording device for acquiring data. The physician then analyzes the information stored in the first recording device to determine whether an abnormal heart beat is recorded. The use of a recording device is neither automatic nor autonomic and therefore requires patient awareness or another human intervention.

  Another known type of implantable monitoring device is a transponder-type device in which the transponder is implanted in a patient and subsequently accessed non-invasively with a handheld electromagnetic reader. An example of the latter type of device is described in US Pat. No. 5,833,603.

  In many cases, medical personnel are interested in collecting a variety of different types of data regarding heart behavior and patient status. Furthermore, as mentioned above, it is desirable to obtain as much relevant data as possible without requiring the patient to visit a health care provider. Related information includes oxygen saturation of blood flowing through the aorta, blood pressure, heart rate, blood flow, stroke volume, cardiac output, cardiac electrical activity (to generate electrocardiogram (ECG) data) ), And body temperature.

〔Overview〕
An integrated cardiac monitoring device that obtains signals and transmits data is disclosed herein.

  In a first exemplary embodiment, an apparatus for monitoring a patient's heart is provided. This device is a housing, a calculation device attached to the inside of the housing, and a light sensor attached to the inside of the housing, which calculates a distance from the light sensor to a blood vessel carrying blood and a signal indicating the diameter of the blood vessel. An optical sensor configured to provide to the device and a Doppler sensor mounted within the housing and configured to provide a signal indicative of blood velocity through the blood vessel to the computing device. And an ECG sensor configured to provide a signal indicative of a plurality of electrical stimuli for pumping the heart to the computing device, wherein the computing device is a signal from the light sensor, the Doppler sensor, and the ECG sensor. To calculate parameters including blood oxygen saturation, blood flow, blood pressure, heart rate, and cardiac output

  In a variation of the first exemplary embodiment, the device further includes a temperature sensor mounted within the housing and configured to provide a signal indicative of the patient's temperature to the computing device.

  In another variation of the first exemplary embodiment, the apparatus further includes a communication device mounted within the housing, the communication device coupled to the computing device and configured to transmit information regarding the parameter. Has been.

  In a further variation of the first exemplary embodiment, the housing is configured to be implanted subcutaneously.

  In yet another variation of the first exemplary embodiment, the timing of operation of the Doppler sensor is based on a signal from the ECG sensor.

  In another variation of the first exemplary embodiment, the photosensor assembly includes an emitter array and a detector array.

  In a further variation of the first exemplary embodiment, the apparatus further includes a connector attached to the housing, the connector configured to be coupled to the ECG lead. In one example, the connector is configured to allow one of programming of the computing device and downloading of information about the parameters.

  In a second exemplary embodiment, a monitoring device is provided that measures a parameter indicative of the behavior of a patient's heart. This device is a multi-sensor mounted inside an implantable housing that measures the oxygen saturation of blood flowing through the aorta, a Doppler sensor that measures blood velocity, and heart electrical activity A plurality of sensors, including an ECG sensor for measuring the temperature and a temperature sensor for measuring the temperature of the patient, and a communication device mounted within the housing, configured to wirelessly transmit information regarding the measurement parameters A communication device and a calculation device that executes a program for determining blood pressure and cardiac output based on signals from a plurality of sensors.

  In a variation of the second exemplary embodiment, the device further includes a rechargeable battery mounted within the housing to provide power to the plurality of sensors, the communication device, and the computing device.

  In another variation of the second exemplary embodiment, the computing device includes a first stage of a cardiac cycle that corresponds to a maximum blood flow condition through the aorta and a first cycle of the cardiac cycle that corresponds to a minimum blood flow condition through the aorta. In two steps, the Doppler sensor is activated. In one example, the calculation device operates the Doppler sensor in the first stage and the second stage based on the information received from the ECG sensor. In another example thereof, the calculation device activates the Doppler sensor a plurality of times at the first stage to obtain a plurality of first measurement values and a plurality of times at the second stage to obtain a plurality of second measurement values. In operation, the calculation device averages the plurality of first measurement values and the plurality of second measurement values.

  In a further variation of the second exemplary embodiment, the housing includes a plurality of loops to facilitate implantation.

  In yet another variation of the second exemplary embodiment, the optical sensor emits an infrared beam toward the aorta and detects an infrared beam reflected from red blood cells flowing through the aorta.

  In another variation of the second exemplary embodiment, the light sensor includes an emitter array having a plurality of emitter cells and a detector array having a plurality of detector cells. In one example, all of the emitter cells emit a beam simultaneously during the oxygen saturation measurement. In another example, the computing device individually activates each of the plurality of emitter cells and processes the signals received from the detector cells to determine the distance from the light sensor to the aorta and the diameter of the aorta. .

  In another variation of the second exemplary embodiment, the Doppler sensor includes three transducers arranged in a K-shape. In one example, each transducer emits a wave of a different frequency.

  In another variation of the second exemplary embodiment, the monitoring device is integrated with an implantable heart device.

  In a third exemplary embodiment, an apparatus for determining characteristics of blood and blood vessels carrying blood is provided. The apparatus includes an optical sensor configured to measure the size and location of a blood vessel using an IR beam, a Doppler sensor configured to measure the velocity of blood moving through the blood vessel, and the optical sensor and Doppler. And a housing surrounding the sensor.

  In a variation of the third exemplary embodiment, the blood vessel is an aorta.

  In another variation of the third exemplary embodiment, the blood vessel is a pulmonary artery.

  In a further variation of the third exemplary embodiment, the device further includes an ECG sensor enclosed within the housing and configured to measure an electrical impulse applied to the heart.

  In yet another variation of the third exemplary embodiment, the device further includes a computing device coupled to the light sensor and the Doppler sensor, the computing device determining a blood pressure as the blood moves through the blood vessel. Implement the program.

  In a variation of the third exemplary embodiment, the calculation device further determines cardiac output.

  In another variation of the third exemplary embodiment, the device further includes a temperature sensor encapsulated within the housing.

  In a further variation of the third exemplary embodiment, the light sensor is further configured to measure blood oxygen saturation.

  By integrating multiple sensors and the other components described above, embodiments of the present invention relate to the behavior of the heart, including cardiac output, in a single device attached to one location on the patient's body. It is possible to accurately measure a comprehensive parameter group. In addition, the integrated monitoring device described herein performs parameter analysis and supports “on-board” analysis as opposed to other sensing devices that export raw data for analysis by another device. Can perform functions. As mentioned above, the integrated monitoring device according to embodiments of the present invention also communicates with other devices wirelessly or otherwise to provide information and receive commands and data. Thus, the monitoring device collects, analyzes, and communicates data without human intervention.

  BRIEF DESCRIPTION OF THE DRAWINGS The features of the present invention and the manner of achieving them will become more apparent and the invention itself will be better understood with reference to the following description of embodiments of the invention understood in conjunction with the accompanying drawings. Let's go.

  Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be emphasized in order to better illustrate and explain the present invention. The illustrations set forth in this specification illustrate embodiments of the invention in several forms, and such illustration is not to be construed as limiting the scope of the invention in any way. .

Detailed Description of Embodiments of the Invention
The embodiments discussed below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments have been chosen and described so that others skilled in the art can utilize their teachings.

  FIG. 1A shows an integrated monitoring device according to an embodiment of the present invention. The monitoring device 1 generally includes an optical sensor assembly 2, an Doppler sensor 60, an ECG sensor including probes 50A and 50B (hereinafter collectively referred to as ECG sensor 50), a temperature sensor 70, a calculation device 20, a communication device 30, and A plurality of components including the energy storage device 40 are included, each of which is attached to the board 80 and in electronic communication with the computing device 20. The component is surrounded by a housing 90.

  Throughout this application, references made to the optical sensor assembly 2 refer to the optical sensor assembly 2 described above in the Optical Sensor Apparatus application incorporated herein by reference. Also, reference to the Doppler sensor 60 refers to the Doppler sensor 60 described in the Doppler Motion Sensor application incorporated by reference above. The complete description of the light sensor assembly 2 and the Doppler sensor 60 will not be repeated in this application.

  In one embodiment according to the invention, the monitoring device 1 is configured to measure the physiological behavior of the patient's heart. “Patient” means a human or animal. Although the invention disclosed herein is described in a medical context, the teachings disclosed herein are applicable in other situations where a small data acquisition assembly is desirable for taking measurements over time It may be.

  In one embodiment according to the invention, the monitoring device 1 is implanted subcutaneously in the patient's body. However, it should be understood that the monitoring device 1 may be implanted at different locations using various implantation techniques. For example, the monitoring device 1 may be implanted in the thoracic cavity under the rib cage. The housing 90 may be formed in the shape of a circular or elliptical disc, and the dimensions are approximately the same as two 25 cent coins stacked. More specifically, the housing 90 may have a diameter of about 3 cm and a thickness of about 1 cm. Of course, the housing 90 may be configured in a variety of other shapes and sizes, depending on the application. The housing 90 can include four outwardly projecting loops 92, shown in FIGS. 1B and 1C, for receiving sutures to secure the assembly subcutaneously within the patient's body. More or fewer loops 92 may be provided depending on the shape of the housing 90. When so secured, the optical sensor assembly 2, Doppler sensor 60, ECG sensor 50, and temperature sensor 70 are positioned facing inward, while the energy coupler 42, described in detail below, faces outward.

  In another embodiment of the monitoring device 1 according to the present invention, the monitoring device 1 is integrated with an implantable heart device, such as a pacemaker, a cardiac resynchronization therapy (CRT) device, an implantable defibrillator (ICD) or the like. In such embodiments, the monitoring device 1 communicates with, from, and from the implantable heart device, as described in the System for Monitoring application previously incorporated herein by reference. Information can be given to the external device from the sensor of the monitoring device itself. Since many implantable heart devices are now well understood and routinely prescribed, integrating the monitoring device 1 with such other devices provides an effective means to be accepted on the market. Can be done.

  Said integration can be achieved by combining the components of the monitoring device 1 and the heart device. If the cardiac device includes a computing device, for example, an algorithm that performs a function according to the present invention may be combined with the computing device of the cardiac device instead of adding a second computing device. Similarly, energy storage devices and communication devices may be combined to prevent duplication and reduce costs. In one embodiment, some components of the monitoring device 1 are included within the housing 90 and some components are included with the heart device. The heart device and components within the housing 90 are operably connected.

  In another embodiment, the monitoring device 1 is located outside the patient's body. A support member is provided to support the monitoring device 1 outside the body. The support member can be permanently or temporarily connected to the monitoring device 1. In one embodiment, the support member includes an adhesive layer that adhesively connects the support member to the patient's body. In another embodiment, the support member includes a belt that may be elastic to hold the monitoring device 1 against the patient's body.

  The monitoring device 1 can be implanted or positioned on a patient with the help of an external mapping system such as an ultrasound device. Proper placement ensures that the aorta is located within the sensing range of the various sensors of the monitoring device 1. For example, the monitoring device 1 may be positioned on a patient's chest or back where the measurements taken with the methods described herein reduce interference by the ribs.

1. Light sensor
As described in sufficient detail in the Optical Sensor Apparatus application, the optical sensor assembly 2 senses, among other things, the oxygen saturation of a patient's blood carried through the aorta. The sensing assembly 2 emits a beam of electromagnetic energy in the infrared (IR) region of the electromagnetic spectrum and detects an IR signal reflected from hemoglobin in the aorta. Hemoglobin is a metalloprotein that contains iron and carries oxygen in red blood cells.

  FIG. 2 shows an aorta 3 that carries blood 4 having hemoglobin in red blood cells 5, and a pair of photocells, ie, an emitter 101 and a detector 201 included in the emitter array 100 and the detector array 200 of the sensor assembly 2, respectively. The relationship between is shown. The emitter array 100 may include 16 emitters 101-116 (only the emitter 101 is shown), and the detector array 200 is 16 detectors 201-216 (only the detector 201 is shown). And each detector is paired with an emitter. The sensor assembly 2 and the arrays 100, 200 may be selected from 8572 based optical sensors manufactured by Motorola. The emitter 101 emits a beam of photons including photons 101 ′, some of the photons pass through the aorta 3 and the other part of the photons are reflected from the red blood cell 5, which includes the photons 101 ′. It is. As described in the Optical Sensor Apparatus application, the calculation device 20 controls the operation of the emitter 101, measures the time required for the detector 201 to sense the reflected beam, and is provided by the detector 201. The signal is interpreted to determine the force or intensity of the reflected beam. This information, together with the known characteristics of the radiation beam, allows the calculation device 20 to determine various characteristics of the aorta 3 and blood 4.

  According to one embodiment of the present invention, the computing device 20 processes the signal received from the detector array 200 and calculates the time required for the radiation beam to travel from the emitter to the aorta 3 and as a reflected beam to the detector. calculate. Since the speed of the beam is known and the distance between the emitter and detector is known, a simple calculation results in the distance from the monitoring device 1 to the aorta 3. The computing device 20 also uses the signal from the detector array 200 to determine the force of the reflected beam received by each detector of the detector array 200. These power values are then used to determine the diameter of the aorta 3 using the methods and principles described in the Optical Sensor Apparatus application.

  In determining the diameter of the aorta as described above, it should be understood that each emitter 101-116 is actuated individually in series. In one embodiment of the invention, the beams were emitted individually starting from emitter 101 and scanning row by row, which was followed continuously until emitter 116 was activated. In other embodiments, other sequences were followed.

  As mentioned above, the optical sensor assembly 2 also provides the monitoring device 1 with the ability to determine the oxygen saturation of blood carried by the aorta. When measuring the oxygen saturation, the sensing device 1 operates all the emitters 101 to 116 of the emitter array 100 simultaneously. Since the size and location of the aorta has already been determined as described above, the predicted size or area of the reflected beam received by the detector array 200 can be calculated by the calculation device 20. However, the intensity or force of the reflected beam is not known prior to this measurement. Detector array 200 receives the reflected beam and provides a signal indicative of the intensity of the reflected beam. Since the intensity of the radiation beam is known, the oxygen saturation ratio of blood in the aorta can be calculated by measuring the intensity of the reflected beam. Under normal operating conditions, the monitoring device 1 can perform oxygen saturation measurements once or twice a day.

  In one embodiment, the monitoring device 1 also calculates the heartbeat. As discussed above, detectors 201-216 generate power signals that are representative of iron content in the blood. As the heart pumps oxygenated blood through the aorta, the power signal fluctuates. Multiple power signals can be obtained in succession to capture power measurement variations. More specifically, the saturation measurement exhibits a pattern or periodicity representing the heartbeat by performing a number of oxygen saturation measurements (eg, 10 times per second) over a period of time (eg, 15 seconds). . The calculation device 20 can define a curve, for example a sinusoid, to fit the saturation measurement, which directly corresponds to the cardiac cycle. The calculation device 20 can determine the frequency of the peak value of the curve and determine the period. Each period represents a cardiac cycle. By multiplying the number of cardiac cycles in a sample period (eg, 15 seconds) by an appropriate factor, the computing device 20 can determine the pulse rate in terms of cardiac cycles per minute. In one embodiment, the calculation device 20 stores a heart beat value as a normal reference value and detects an abnormal or irregular heart rhythm by comparing the heart beat value with a reference value.

2. Doppler Sensor In an embodiment where the monitoring device 1 includes a Doppler sensor 60, the diameter and location of the aorta provided by the optical sensor assembly 2 is determined by the velocity of blood flowing through the aorta, the volume of blood flowing through the aorta, It can be used to calculate blood pressure, and cardiac output. These parameters may be used to calculate and diagnose abnormal conditions related to cardiac output. As fully described in the above-referenced Doppler Motion Sensor application, one embodiment of Doppler sensor 60 includes three transducers that irradiate the aorta and receive the reflected ultrasound. The velocity of blood in the aorta is determined by directing the ultrasound towards the blood at a known angle, measuring the frequency shift of the reflected ultrasound energy, and then calculating the velocity of the blood. More specifically, the Doppler frequency shift is proportional to the velocity vector component parallel to the high frequency insonifying wave. The blood velocity v is determined by the following equation:
v = f _d · c / (2 · f · cos θ)
Where c is the speed of sound in the blood, f is the frequency of the high frequency irradiation wave, θ is the angle between the wave and the velocity vector, and f _d is the Doppler frequency shift.

  The Doppler sensor 60, which may be a continuous wave sensor or a pulse wave sensor, measures the frequency shift by comparing the phase shift between subsequently received waves according to principles well known in the art. Since the distance between the Doppler sensor 60 and the aorta has already been determined by the optical sensor assembly 2 and the speed of sound through the tissue is known, the frequency shift causes the calculation device 20 to calculate the actual velocity of the blood in the aorta. Can be determined.

  FIG. 3 illustrates a Doppler sensor 60 that includes linear array transducers A, B, and C, according to one embodiment of the present invention. Transducers A, B, and C are each operably connected to a driver device (not shown) that powers each transducer. Transducers A, B and C are arranged at an angle relative to each other. Transducers B and C are arranged at an angle of 45 ° to transducer A and 90 ° to each other. Other relative angles between the transducers may be used. Transducers A, B and C can each be driven at a different frequency to identify the source of the reflected wave received by Doppler sensor 60. For convenience, each transducer of the linear array is referred to herein as a transducer segment. In the illustrated embodiment, each linear array transducer includes five transducer segments. The transducer segments can be operably connected to be operated separately or simultaneously. It is desirable to operate one or more transducer segments separately to limit power consumption.

  As shown, transducer A includes segments A1-A5, transducer B includes segments B1-B5, and transducer C includes segments C1-C5. Each segment can transmit and receive ultrasonic energy in the form of waves. Arrows that occur at each segment and project perpendicular to the segment represent the direction of the waves transmitted by each segment. In addition, arrows 72, 74 and 76 generally represent the direction of the waves produced by transducers A, B and C, respectively. In one embodiment, one or more segments of transducer A are energized at a frequency of 5 Mhz, and one or more segments of transducer B are energized at a frequency of 4.5 Mhz, One or more segments of Ducer C are energized at a frequency of 5.5 Mhz. The frequency selection is a function of the distance between the transducer and the target fluid and is selected accordingly. The reflected wave can be measured at each segment of the linear array transducer. Each segment may be energized sequentially and may be energized multiple times.

  The Doppler shift or frequency shift is proportional to the velocity vector component parallel to the collision wave. Since the Doppler shift depends on the cosine of the angle θ between the wave and the velocity vector, and the cosine function ranges from 0 to 1, the signal generated by the wave directed parallel to the velocity vector is As the angle θ increases, it becomes increasingly difficult to determine the Doppler shift from these signals as the selected signals are generated. As fully described in the Doppler Motion Sensor application, the K-shaped arrangement of transducers A, B, and C ensures that at least one of the transducers is oriented at an acceptable angle θ. With three transducers, the Doppler sensor 60 provides a sufficient number of signals even if the relative position of the Doppler sensor 60 and the aorta 3 changes slightly with time or other factors such as patient activity level and posture. Obtainable. When a wide wave is transmitted, the reflected wave can be received by each transducer. However, since the wave has a frequency corresponding to each transmission transducer, the Doppler sensor 60 can select which signal to filter based on the relative position of the corresponding transmission transducer and its transmission frequency. .

  As discussed above, the calculation of blood velocity requires knowledge of the incident angle θ between the radiated wave and the aorta 3. Other data characterizing the angle of incidence and the relative position of the aorta 3 and the Doppler sensor 60 can be obtained in various ways. Once obtained, it can be stored in the memory 26 (see FIG. 6) as a reference value. In one embodiment, relative position data can be provided to the computing device 20 by the light sensor assembly 2. With this information, the calculation device 20 calculates the blood velocity value by comparing the frequency of the transmitted wave and the received wave according to a well-known frequency shift and angle algorithm or table.

  The speed of blood flowing through the aorta varies depending on which part of the blood is being measured. In accordance with the well-known principles of hydrodynamics, fluid that flows near the outer wall of a blood vessel flows more slowly than fluid that flows through the central axis of the blood vessel due to shear stress between the fluid and the outer wall. From the distance and diameter measurements provided by the optical sensor device 2, the calculation device 20 can determine the location of the aorta 3 within the reflected wave detected by the Doppler sensor 60 from the measured values of the Doppler sensor 60. Each of the five velocity measurements in each of the three sets of measurements obtained with the method described in the Doppler Motion Sensor application determines the approximate overall blood flow through the aorta 3, and Averaged to account for velocity profiles across diameters. These sets of velocity measurements are obtained at maximum (systolic) and minimum (diastolic) flow conditions of the cardiac cycle. Accordingly, the computing device 20 determines an average maximum flow measurement by averaging five velocity measurements for each of the three sets of maximum flow measurements and averaging the three results from those calculations. The average minimum flow rate measurement is calculated similarly. Finally, the average minimum and average maximum blood flow measurements are averaged to determine the patient's average blood flow.

Next, the calculation device 20 can calculate the stroke volume by simply multiplying the average blood flow measurement value by the area of the aorta 3 (that is, average blood flow * πr ² ), where r is the aorta 3 Is the radius. Of course, the radius of the aorta 3 is simply half the diameter of the aorta and is determined using the photosensor assembly 2 as described above.

3. ECG Sensor In one embodiment of the present invention, the ECG sensor 50 is a unipolar induction device including an anode probe 50A and a cathode probe 50B (hereinafter collectively referred to as “ECG sensor 50”). The ECG sensor 50 detects a voltage change of an electric impulse given to the myocardium using the probes 50A and 50B. As is well understood in the art, these electrical signals that trigger the heartbeat usually begin at the top of the heart and travel from the top to the bottom of the right atrium. This electrical signal causes the myocardium to contract as the electrical signal moves through the heart. As the heart contracts, the heart pumps blood to the rest of the body. By monitoring the electrical activity of the heart over time, the ECG sensor 50 allows the computing device 20 to determine how fast the heart is by determining the number of cardiac cycles per minute (or part of a minute). Makes it possible to determine if is beating (ie a pulse). Pulse measurements can be used in conjunction with the stroke volume to determine cardiac output. More specifically, the stroke volume measurement is multiplied by the number of pulses per minute (ie, pulses) to give the total volume of blood displaced per minute (ie, cardiac output). Can be determined.

  In one embodiment of the present invention, the pulse measured by the ECG sensor 50 is compared to the pulse measured by the optical sensor assembly 2 as described in the Optical Sensor Apparatus application. If these measurements differ by more than a predetermined amount, the ECG pulse measurements can be rejected assuming that electrical interference or some other obstruction has caused an error in the detection signal. As described above, the optical sensor assembly 2 functions as a backup pulse measuring device for the ECG sensor 50.

  The ECG sensor 50 provides a voltage measurement to the computing device 20, which in turn processes the data by removing frequencies outside the known range of frequencies generated by the heart's electrical activity. . The ECG sensor 50 also provides a method and location for electrically isolating the ECG sensor 50 from other electronic components of the monitoring device 1 and minimizing electrical interference caused by those other electronic devices. Attached to. In one embodiment of the present invention, the output of the ECG sensor 50 passes through a bandpass filter having a lower cutoff frequency and an upper cutoff frequency. Furthermore, the computing device 20 can further process the data to produce a smooth ECG trace by applying any of several suitable digital smoothing functions.

  The output of the ECG sensor 50 also allows the computing device 20 to identify the maximum and minimum blood flow through the aorta that is used in the calculation of the stroke volume and cardiac output. In addition, this indicates the rhythm of the heart (stable or irregular) and where in the body the heart beat is recorded. The intensity and timing of the electrical signal as it passes through each part of the heart is also recorded.

Referring now to FIG. 4, ECG sensor 50 and Doppler sensor 60 are used in combination to determine the patient's blood pressure directly from aorta 3. One skilled in the art can accurately determine the maximum blood flow position and the minimum blood flow position of the cardiac cycle using the ECG trace provided by the ECG sensor 50. The Doppler sensor 60 facilitates the determination of the speed or velocity of blood in the aorta 3 at the maximum and minimum blood flow conditions as described above. The calculation device 20 uses the area of the known inner surface of the aorta 3 (determined from the diameter measurement promoted by the optical sensor assembly 2) according to the principle shown by the Bernoulli equation to calculate the velocity measurement under each condition. Convert to pressure measurement. These pressure measurements reflect the dynamic pressure of blood flowing through the aorta 3 under maximum and minimum flow conditions. More specifically, at T ₁ in FIG. 4, the dynamic pressure PD ₁ corresponds to a pressure determined from velocity measurements obtained under maximum blood flow conditions. In T _2, PD ₂ corresponds to the pressure determined from the velocity measurements taken at the minimum blood flow conditions. It is well known that the total pressure of fluid flowing through a blood vessel is the sum of dynamic and static pressure. In the case of the aorta 3, the static pressure under the maximum flow condition (PS ₁ ) (indicated by a force arrow pointing outward with respect to the outer wall of the aorta 3) directly corresponds to the systolic blood pressure measurement and the minimum flow condition (PS ₂ ) The lower static pressure directly corresponds to the diastolic blood pressure measurement.

The systolic and diastolic blood pressure measurements further calculate the total pressure (PT) of blood flowing through the aorta 3, and the total pressure through the aorta at T ₁ (ie PT ₁ ) is the total pressure at T ₂ (ie Can be obtained by taking advantage of the fact that it must be the same as PT ₂ ). The total pressure is obtained by calculating the change in pressure from the minimum flow rate condition to the maximum flow rate condition. This change or acceleration, in conjunction with the stroke volume of the aorta 3 and the known elasticity, allows the calculation device 20 to determine the total pressure according to well-known principles in the art. Thus, at time T ₁ , the equation PT ₁ = PS ₁ + PD ₁ is given a solution for PS ₁ , and at time T ₂ , the equation PT ₂ = PS ₂ + PD ₂ is given a solution for PS ₂ . As noted above, PS ₁ and PS ₂ are systolic and diastolic blood pressure measurements, respectively.

  Although the above blood pressure calculation refers to the determination of blood pressure in the aorta 3, assuming that the pulmonary artery is within the sensing range of the monitoring device 1, the same process may be performed to determine the blood pressure in the pulmonary artery. It should be understood that it is good. As described in the Optical Sensor Apparatus application, the monitoring device 1 measures the oxygen saturation of the pulmonary artery and aorta 3 and determines which blood vessel carries blood with higher oxygen saturation, thereby determining the pulmonary artery. And aorta 3. The blood vessel should be the aorta 3. In another embodiment of the present invention, the monitoring device 1 instead identifies a lower oxygen saturation vessel as the vessel of interest (ie pulmonary artery). Next, the location and size of the pulmonary artery is determined as described for the aorta 3. With the pulmonary artery geometry defined, the pressure of blood flowing through the pulmonary artery is measured as described above for the aorta 3.

  In one embodiment of the invention shown in FIG. 1A, the housing 90 includes a connector 85 to allow connection of additional ECG leads. The connector 85 is electrically connected to the ECG sensor 50 and other components of the monitoring device 1 through the board 80. As additional ECG leads are connected to the connector 85, the connector 85 passes signals from the additional leads to the ECG sensor 50. As is known in the art, additional leads may be secured to various locations on the patient's chest, back, arms, or legs, each lead being a receiver for detecting electrical activity. including. As described above, the connector 85 can also function as an I / O port of the monitoring device 1 and enables downloading of data to the docking station 304 and uploading of data and instructions during program operation.

4). Temperature Sensor A variety of different devices can function as the temperature sensor 70. The temperature sensor 70 is a readily available resistance temperature detector (RTD) in one embodiment of the invention. In general, the temperature sensor 70 can include a metal component (wound wire or thin film) with physical properties of electrical resistance that change with temperature changes. Typically, the higher the temperature in the environment of the temperature sensor 70, the greater the electrical resistance of the entire metal component of the temperature sensor 70. A temperature sensor having a platinum metal component may be desirable because of the approximately linear relationship between resistance and temperature that platinum exhibits over a fairly wide temperature range. Of course, one skilled in the art can readily adapt a temperature sensor having a non-linear temperature / resistance curve as long as the sensor behavior over the desired temperature range is adequately reproducible.

As shown in FIG. 5, the temperature sensor 70 is connected to the constant current source 100, and the constant current source 100 is also located inside the housing 90. The current source 100 maintains a constant current through the temperature sensor 70 as the resistance of the temperature sensor 70 changes with temperature. Accordingly, the voltage (V _T ) across the temperature sensor 70 changes in direct proportion to the temperature change. More specifically, according to Ohm's law, voltage = current * resistance. Since there is a constant current source, a change in resistance with temperature change is detected as a change in V _T. In one embodiment of the invention, V _T passes through an analog-to-digital converter 22 that is read by the computing device 20. Next, the calculation device 20 determines the measured temperature and stores the measured temperature value in the memory 26.

  Although FIG. 5 depicts a constant current voltage measurement circuit for use with temperature sensor 70, a variety of different circuits may be used with temperature sensor 70, including circuitry for measuring the change in current through temperature sensor 70. It should be understood that it can be easily adapted to.

  The temperature sensor 70 is mounted within the housing 90, and the temperature sensitive components of the temperature sensor 70 are adjacent to the outer surface of the housing 90 and are caused by the operation of other electronic components mounted within the housing 90. Is substantially thermally separated from any thermal energy obtained. In this way, the temperature sensor 70 indicates the temperature change of the patient's body (when the monitoring device 1 is implanted or worn by the patient) as opposed to the temperature change of the electronic device of the monitoring device 1. Positioned to detect. However, it should be understood that the temperature sensor 70 can also be calibrated to compensate for changes in the detected temperature due to thermal energy from the monitoring device 1. The memory 26 of the computing device 20 includes a look-up table that associates the digital voltage across the temperature sensor 70 with the temperature according to certain operating characteristics of the temperature sensor 70. The calculation device 20 periodically reads the digital voltage signal and accesses the look-up table in the memory 26 to determine the current body temperature of the patient. The temperature is stored in the memory 26 and can be transmitted from the monitoring device 1 as described below for the communication device 30.

2. Calculation device The calculation device 20 includes a plurality of components. Although these components are described herein as if they were separate components, the components may be combined into a single device, such as an application specific integrated circuit. As shown in FIG. 6, the calculation device 20 includes an A / D converter 22 (which converts an optical signal into a digital signal), a processor 24, a memory 26, a program 28, an input 23, and an output 25. Memory 26 may include, but is not limited to, RAM, ROM, EEPROM, flash memory, or other memory technology. The A / D converter 22, the processor 24, and the memory 26 may be built in an integrated circuit. The integrated circuit can further include an emitter array 100, a detector array 200, and a communication device 30.

  Program 28 represents computer instructions that instruct processor 24 to perform tasks in response to data. The program 28 exists in the memory 26. Data including reference data and measurement data is also present in the memory 26. The reference data may be stored in ROM in response to external input or in response to characteristics of measurement data collected over time, or may be stored in RAM so that it can be changed over time. A protocol that responds to the measurement may also be provided. The protocol may be stored in persistent memory or may be stored in non-persistent memory, such as RAM, and is described in further detail in the System for Monitoring application referenced above.

  The computing device 20 can be configured to cause the communication device 30 to send an alarm when an abnormal condition is detected, particularly a condition that is determined to be a serious or dangerous condition according to a defined protocol. . The alarm can be used to trigger an alarm device or alert the patient to perform a therapeutic action. The therapeutic action may terminate or reduce physical activity. Alerts can also provide global positioning (GPS) information to emergency facilities. Referring to FIG. 7, if an abnormal condition is found to exist, it can be displayed on computer 36 and / or transmitted to the caregiver by communication device 30. The alert can include a text message or code corresponding to the condition. The computing device 20 can also initiate new measurement cycles and measurements continuously in response to detecting an abnormal condition.

  The calculation device 20 can also start treatment. The monitoring device 1 can receive an external command for executing treatment in response to the alarm through the communication device 30. Optionally, based on the protocol, an abnormal condition may be used to instruct a device configured to deliver a treatment to deliver such a treatment. Treatment can include, for example, electric shock or drug delivery.

  Parameter values and / or other information can be communicated to an external device. The parameter value is stored in the memory 26 and can be transmitted wirelessly by the communication device 30. The communication signal from the communication device 30 is in response to an abnormal state, in response to an externally received command, each time the use of the memory exceeds a predetermined amount, or whenever it is determined that the energy storage level is low. (The latter two states are established to prevent data loss or energy loss as a result of memory overflow) and are activated periodically (eg once a day, once a week, etc.) be able to. It should also be understood that the monitoring device 1 may include a communication device in addition to the communication device 30. For example, if the communication device 30 is a cellular modem, the monitoring device 1 can also include a backup Bluetooth or RF communication device. Such backup devices have been found that after one or more attempts, the cellular modem is unable to transmit information (eg due to low available power, poor network coverage, etc.). It may be desirable. In such a situation, the computing device 20 can activate the backup communication device to send information or alerts to an alternative external receiving device.

  Alternatively or in addition to the transmission, the computing device 20 causes the communication device 30 to transmit the requested data or information representing the requested data to the communication device 30 (eg, from a healthcare provider). Can be programmed to respond to a request for data received by.

  The communication signal is received by equipment near the patient, to alert the patient to the condition, or remotely (through the network by a health care provider, relative, or other predetermined recipient Etc.) can be received. Further descriptions of network systems, including at least some of the principles of the present invention, are described in the System for Monitoring application referenced above.

3. Communication Device In one embodiment of the present invention, the communication device 30 is a two-way communication device such as a mobile phone system and / or a GPS satellite system such as NOKIA model number KNL1147-V. In an alternative embodiment, the communication device 30 can send information but does not receive information or commands. As shown in FIG. 1A, the communication device 30 includes an antenna 32 that transmits and receives communication signals. The communication signal represented by symbol 34 travels wirelessly to and from one of a plurality of optional external communication devices.

  Referring back to FIG. 7, the external communication device may be any electronic device capable of receiving communication signals wirelessly, such as a computer 302 or a telephone 306 embodied as a mobile phone. By communication signal is meant a signal having one or more of the characteristics set or changed to encode signal information. As non-limiting examples, communication signals include acoustic media, RF media, infrared media, other wireless media, and combinations of any of the foregoing. The external communication device may also be a relay unit located outside the patient's body, for example clipped to the patient's belt. The relay unit can include a receiver that receives a transmission from the communication device 30 and a transmitter that retransmits the communication signal to another external communication device. The relay unit may also be fixed and wired so that it is connected to the Internet or directly connected to the healthcare provider's computer. Similarly, the relay unit can receive a communication signal from the healthcare provider and transmit the signal to the communication device 30.

4). Energy Storage Device Referring again to FIGS. 1A-1C, in one embodiment according to the present invention, a system for recharging the energy storage device 40 may be provided. The calculation device 20 receives energy from the energy storage device 40. The energy storage device 40 includes energy storage components such as a battery. Optionally, the monitoring device 1 may also include an energy coupler that receives energy from an external source to charge the energy storage device 40.

  An example of an energy coupler is an electromagnetic device, such as an induction coil 42, that receives an external electromagnetic signal 44 and converts such signal to electrical energy to recharge the energy storage component. An external electromagnetic device 46 generates an electromagnetic signal 44 that is received by the energy storage device 40 and converted to electrical energy. The energy storage device 40 can provide a charging signal to the calculation device 20. The computing device 20 can compare the charge signal with a reference charge signal, initiate a low charge communication signal, and alert the patient and / or health care provider. Alternatively, a detector such as a voltage sensor may be used to monitor the charging of the energy storage device 40 and provide a signal to the computing device 20 when the charging falls below a threshold. The electromagnetic device 46 can be placed near the monitoring device 1 to charge the energy storage device 40.

  Alternatively or additionally, energy may be provided in the form of ultrasonic vibrations. For example, a piezoelectric transducer may be included in the monitoring device 1. The ultrasonic vibration may be given from the outside. The transducer generates electricity when driven by ultrasonic vibration. As shown herein, energy or power may be provided to the monitoring device 1 through the connector 85.

  While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Furthermore, this application is intended to cover departures from the present disclosure that fall within known or customary practice in the art to which this invention belongs. For example, it should be understood that each or some designs of the optical sensor assembly 2, Doppler sensor 60, ECG sensor 50, and temperature sensor 70 may be modular. Thus, for example, a plurality of different Doppler sensors 60 may be produced with different performance characteristics (eg, different output frequencies). Depending on the application, any of the plurality of sensors can be attached to the monitoring device 1 to achieve the desired performance. Once the monitoring device 1 comprises a selected sensor, the computing device 20 may be programmed to adapt various algorithms to adapt to the selected sensor. In this way, the basic monitoring device 1 including the calculation device 20, the communication device 30, etc. can be manufactured “custom-made” with any of a variety of sensors and programmed to operate with the selected sensor. .

  As another example, the optical sensor assembly 2, the Doppler sensor 60, and the temperature sensor 70 are described herein as being actuated to obtain measurements relatively rarely (at least under normal conditions) to conserve power. It should be understood that the frequency of operation of these sensors can be increased as battery technology is improved, as described in the literature. Also, when the monitoring device 1 is worn externally, the connector 85 can be used to power the monitoring device 1, thereby eliminating power consumption problems, frequent operation of these sensors, or continuous Even driving is possible.

Embodiment
(1) In an apparatus for monitoring a patient's heart,
A housing;
A calculation device mounted in the housing;
An optical sensor mounted in the housing, the optical sensor configured to provide a signal indicating a distance from the optical sensor to a blood vessel carrying blood and a diameter of the blood vessel to the calculation device;
A Doppler sensor mounted within the housing and configured to provide the calculation device with a signal indicative of the velocity of the blood through the blood vessel;
An ECG sensor mounted within the housing and configured to provide the computing device with signals indicative of a plurality of electrical stimuli that pump the heart.
Including
The calculation device calculates parameters including oxygen saturation, blood flow, blood pressure, heart rate, and cardiac output of the blood using signals from the optical sensor, the Doppler sensor, and the ECG sensor. ,apparatus.
(2) In a monitoring device that measures parameters indicating the behavior of a patient's heart,
A plurality of sensors mounted in an implantable housing that measures the oxygen saturation of blood flowing through the aorta, the Doppler sensor that measures the blood velocity, and the electrical activity of the heart A plurality of sensors, including an ECG sensor that performs and a temperature sensor that measures the temperature of the patient;
A communication device mounted in the housing, the communication device configured to wirelessly transmit information about the measured parameter;
A calculation device that executes a program for determining blood pressure and cardiac output based on signals from the plurality of sensors;
Including a monitoring device.
(3) In an apparatus for determining the characteristics of blood and blood vessels carrying the blood,
An optical sensor configured to measure the size and location of the blood vessel using an IR beam;
A Doppler sensor configured to measure the velocity of the blood moving through the blood vessel;
A housing surrounding the light sensor and the Doppler sensor;
Including the device.

It is a schematic side view of the monitoring apparatus by one Embodiment of this invention. It is a figure which faces the outer side of the monitoring apparatus of FIG. It is a perspective view of the monitoring apparatus of FIG. FIG. 2 is a schematic side view of the monitoring device and the blood vessel of FIG. 1. 1 is a schematic side view of a Doppler sensor according to an embodiment of the present invention. FIG. It is a conceptual diagram of the fluid which flows through the blood vessel. It is the schematic of a temperature sensing circuit. It is a conceptual diagram of the calculation apparatus by one Embodiment of this invention. It is a conceptual diagram of the system comprised so that the communication signal from the monitoring apparatus of FIG. 1 might be transmitted / received.

Claims (3)

In a device that monitors a patient's heart,
A housing;
A calculation device mounted in the housing;
An optical sensor mounted in the housing, the optical sensor configured to provide a signal indicating a distance from the optical sensor to a blood vessel carrying blood and a diameter of the blood vessel to the calculation device;
A Doppler sensor mounted within the housing and configured to provide the calculation device with a signal indicative of the velocity of the blood through the blood vessel;
An ECG sensor mounted within the housing and configured to provide the computing device with signals indicative of a plurality of electrical stimuli that pump the heart.
Including
The calculation device calculates parameters including oxygen saturation, blood flow, blood pressure, heart rate, and cardiac output of the blood using signals from the optical sensor, the Doppler sensor, and the ECG sensor. ,apparatus. In a monitoring device that measures parameters indicative of the behavior of a patient's heart,
A plurality of sensors mounted in an implantable housing that measures the oxygen saturation of blood flowing through the aorta, the Doppler sensor that measures the blood velocity, and the electrical activity of the heart A plurality of sensors, including an ECG sensor that performs and a temperature sensor that measures the temperature of the patient;
A communication device mounted in the housing, the communication device configured to wirelessly transmit information about the measured parameter;
A calculation device that executes a program for determining blood pressure and cardiac output based on signals from the plurality of sensors;
Including a monitoring device. In a device for determining the characteristics of blood and blood vessels carrying said blood,
An optical sensor configured to measure the size and location of the blood vessel using an IR beam;
A Doppler sensor configured to measure the velocity of the blood moving through the blood vessel;
A housing surrounding the light sensor and the Doppler sensor;
Including the device.

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