System and method for synchronously monitoring and analyzing blood oxygen and body temperature of patient monitor

Abstract

The blood oxygen and body temperature synchronous monitoring and analyzing system comprises a blood oxygen monitoring module and an electrocardio, respiration and body temperature monitoring module, the blood oxygen monitoring module is used for monitoring the degree of blood oxygen saturation in human blood, and the blood oxygen monitoring module is composed of a power supply part, an analog part and a digital part so as to ensure the measurement precision and the data accuracy; the electrocardio, respiration and body temperature monitoring module integrates electrocardio monitoring, respiration monitoring and body temperature monitoring functions. Blood oxygen, electrocardio, respiration and body temperature signals are processed concurrently, data are analyzed in real time according to a computer protocol, analyzed results are displayed, the accuracy and the real-time performance are high, the blood oxygen, the electrocardio, the respiration and the body temperature of the human body can be accurately measured, and the measuring mode is simple and easy to operate.

Description

Technical Field

[0001] The present application relates to the technical field of medical equipment, and in particular to a patient monitor blood oxygen and body temperature synchronous monitoring and analysis system and method. Background Art

[0002] With the improvement of social medical level, more and more multi-parameter monitors have been widely used in hospitals. Doctors use monitors to monitor patients' vital signs such as ECG, respiration, blood oxygen saturation, pulse rate, body temperature, blood pressure, carbon dioxide, etc. The existing monitors have certain problems in measurement accuracy due to various design deficiencies, and cannot accurately and quickly measure the various physiological parameters of the tester. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention aims to provide a patient monitor blood oxygen and body temperature synchronous monitoring and analysis system and method to solve the problems raised in the above background technology.

[0004] According to one aspect of the present application, a patient monitor blood oxygen and body temperature synchronous monitoring and analysis system includes a blood oxygen monitoring module and an electrocardiogram, respiration and body temperature monitoring module;

[0005] The blood oxygen monitoring module includes a power supply part, an analog part and a digital part;

[0006] The power supply part adopts a DC power supply with stable voltage, small ripple and no burrs, and isolates the digital power supply from the analog power supply and the digital ground plane from the analog ground plane through magnetic beads;

[0007] The analog part includes a blood oxygen sensor driving circuit, a signal amplification circuit, a signal separation circuit and an AC small signal adaptive amplification circuit; the blood oxygen sensor driving circuit controls the light emitting diode to emit light alternately through a dual-channel analog switch chip; the signal amplification circuit converts the current signal output by the photosensitive diode into a voltage signal using a precision low-noise operational amplifier; the signal separation circuit separates the pulse wave signal from the mixed signal and transmits it to the AC small signal adaptive amplification circuit; the adaptive amplification circuit adjusts the signal amplitude through a digital potentiometer and outputs it stably;

[0008] The digital part includes a clock circuit, a reset circuit, a communication interface circuit and a JTAG interface circuit, which are used to digitally process the signal and output the blood oxygen saturation data;

[0009] The ECG, respiration and body temperature monitoring module includes an ECG monitoring part, a respiration monitoring part and a body temperature monitoring part;

[0010] The ECG monitoring part includes an ECG signal input part, an amplification part, a processing part and an output part; the ECG signal input part transmits ECG signals through electrodes, lead wires, overvoltage protection circuits and high-frequency filters; the amplification part amplifies ECG signals through three stages of pre-amplification, intermediate amplification and post-amplification, and uses a thin film capacitor external circuit to eliminate polarization voltage interference; the processing part uses an STM32 microprocessor to process ECG signals and output analysis results;

[0011] The respiratory monitoring part is based on the chest impedance method, which monitors the chest impedance change through a two-electrode method, and reduces the low-frequency signal interference through rectification, filtering and amplification;

[0012] The body temperature monitoring part adopts the bridge balance principle combined with the correction and compensation method to improve the body temperature measurement accuracy through precise linear interpolation correction.

[0013] Preferably, the blood oxygen probe driving circuit of the blood oxygen monitoring module adopts the SGM3005XMS dual-channel analog switch chip to realize alternating emission of red light and infrared light; the signal amplification circuit of the blood oxygen monitoring module adopts the SGM8634 operational amplifier to provide low-noise signal amplification; the digital part improves the ADC and DAC performance of STM32F103VCT6 through a decoupling circuit.

[0014] Preferably, the ECG signal input part eliminates the influence of the defibrillation pulse on the ECG board through an overvoltage protection circuit; the ECG signal processing part adopts an AD8226 operational amplifier to improve the signal amplification accuracy under high impedance conditions.

[0015] Preferably, the impedance measurement of the respiratory monitoring part adopts a two-electrode method, wherein one electrode is placed on the right chest of the patient and the other electrode is placed on the left abdomen, and the signal is processed by rectification, filtering and amplification.

[0016] Preferably, the body temperature monitoring part adopts a correction and compensation method based on an operational amplifier, and solves the nonlinear error of thermistor temperature measurement through linear interpolation correction to improve the measurement accuracy.

[0017] A synchronous monitoring method for a blood oxygen and body temperature synchronous monitoring and analysis system of a patient monitor comprises the following steps:

[0018] S1. Collect blood oxygen saturation data through the blood oxygen monitoring module;

[0019] S2, synchronously collect ECG signal, respiratory signal and body temperature signal through ECG respiration and body temperature monitoring module;

[0020] S3, filtering, amplifying and digitally processing the collected signals respectively;

[0021] S4. Output the monitoring results of blood oxygen, ECG, respiration and body temperature.

[0022] The patient monitor blood oxygen and body temperature synchronous monitoring and analysis system disclosed in the present application has the following beneficial effects:

[0023] 1. It can measure the blood oxygen, electrocardiogram, respiration and body temperature of the tester more accurately;

[0024] 2. The measurement operation is simple. DETAILED DESCRIPTION

[0026] In order to make the contents of this application easier to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in combination with the embodiments of this application.

[0027] A patient monitor blood oxygen and body temperature synchronous monitoring and analysis system: a blood oxygen monitoring module and an electrocardiogram, respiration and body temperature monitoring module.

[0028] The blood oxygen monitoring module consists of a power supply part, an analog part, and a digital part to ensure measurement accuracy and data accuracy.

[0029] The power supply module uses an external 5V DC power supply. To ensure system performance, the power supply uses a DC power supply with stable voltage, small ripple and no burrs. The 3.3V digital power supply and analog power supply are isolated by magnetic beads, and the analog ground plane (GND) and digital ground plane (DGND) are also isolated by magnetic beads to reduce noise interference.

[0030] The analog part includes the blood oxygen sensor driving circuit, signal amplification circuit, signal separation circuit and AC small signal adaptive amplification circuit:

[0031] Blood oxygen sensor driving circuit: Adopts SGM3005XMS dual-channel analog switch, and realizes the alternating control of light-emitting diodes (red light and infrared light) through software to accurately detect blood oxygen data.

[0032] Signal amplification circuit: Use the SGM8634 rail-to-rail precision low-noise operational amplifier to convert the current signal output by the photodiode into a voltage signal and pass it to the signal separation circuit.

[0033] Signal separation circuit: Separate the mixed signal through analog switches and use DC-isolating capacitors to extract the pulse wave signal.

[0034] AC small signal adaptive amplifier circuit: Dynamic adjustment based on the digital potentiometer and VDAC0 bias voltage to ensure that the signal amplitude is stable within an appropriate range.

[0035] The digital part includes system function module circuits (clock circuit, reset circuit, JTAG download circuit, decoupling circuit) and communication interface circuits. The STM32F103VCT6 microprocessor performs digital filtering and calculation on the signal, and finally displays monitoring data such as blood oxygen saturation (SaO2).

[0036] Blood oxygen detection is based on the difference in the absorption characteristics of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb) at different wavelengths of light. Blood oxygen saturation is calculated by analyzing the penetration and reflection of red light (660nm) and infrared light (940nm) on tissues.

[0037] Specifically, the blood oxygen saturation of the monitor is detected by pulse oximetry, that is, the mature dual-wavelength pulsation method is used for measurement. According to the Lambert-Beer law, when a beam of light is irradiated on a solution of a certain substance, the substance has a certain absorption and attenuation of the light, and the relationship between the transmitted light intensity I and the incident light intensity I0 is as follows:

[0038] I=I0e -εcd

[0039] The logarithm of the I0 / I ratio becomes the absorbance D, so the above formula can be expressed as:

[0040] D=ln(I0 / I)=εcd

[0041] In the formula, ε is the absorption coefficient of the substance, c is the concentration of the solution (such as blood), and d is the path that the light passes through. If the path of the light remains unchanged, the absorbance is proportional to the absorption coefficient of the substance and the concentration of the solution.

[0042] The absorption coefficients of HbO2 and Hb in the blood to light of different wavelengths are different. In the red light (RED) region with a wavelength of 600-700nm, the absorption coefficient of Hb is larger than that of HbO2, while in the near infrared light (IR) region with a wavelength of 800-1000nm, the absorption coefficient of HbO2 is larger than that of Hb; the absorption point is around 805nm.

[0043] The probe used by the pulse oximeter is put on the finger. Two light-emitting diodes (LEDs) are fixed on the upper wall, emitting red light and infrared light. There is a photodetector on the lower wall, which converts the red light and infrared light transmitted through the finger artery into electrical signals. The weaker the photoelectric signal it detects, the more the light signal is absorbed by the tissue, bones, blood, etc. when it penetrates the probe.

[0044] The absorption coefficients of skin, muscle, fat, venous blood, pigment and bone to these two kinds of light are constant, so they only affect the magnitude of the DC quantity in the photoelectric signal. However, the concentrations of HbO2 and Hb in blood pressure change periodically with the pulsation of blood, so their absorption of light also changes pulsatingly, causing the signal intensity output by the photodetector to change pulsatingly with the concentration ratio of HbO2 and Hb in the blood.

[0045] The two wavelengths of red light and infrared light are passed through the detection part in turn, and the pulsating components in the two signals are separated. After amplification and filtering, they are converted into digital quantities by analog / digital converters respectively, and the blood oxygen saturation can be calculated according to the following formula:

[0046] SaO2=K1R 2 +K2R+K3

[0047] In this formula, K1, K2, and K3 are empirical constants, and R is the ratio of the amplitude changes of the two photoelectric signals in a very small time interval, that is:

[0048] R=ΔRED / ΔIR

[0049] The pulsation pattern of the photoelectric signal is consistent with the heart beat, so the pulse wave can be obtained and the pulse rate can be determined. The blood oxygen saturation measured by the pulse oximeter is usually called SpO2 to distinguish it from the results measured by other types of oximeters.

[0050] The ECG, respiration and body temperature monitoring module integrates ECG monitoring, respiration monitoring and body temperature monitoring functions.

[0051] ECG monitoring includes signal input part, amplification part, processing part and output part:

[0052] The signal input obtains the ECG signal through the lead wires and electrodes, and reduces the high voltage and high frequency interference through the overvoltage protection circuit and high frequency filter.

[0053] The signal amplification part adopts three-stage amplification technology (preamplification, intermediate amplification and post-amplification), combined with AD8226 low-noise operational amplifier to achieve high-precision signal acquisition. The post-amplification circuit is designed with dedicated film capacitors to eliminate the influence of polarization voltage.

[0054] The processing part is based on the STM32 chip, which achieves accurate analysis by loading the ECG signal processing algorithm.

[0055] Respiratory monitoring uses the chest impedance method for signal acquisition and analysis. Two electrodes are placed on the chest and abdomen respectively, and the impedance changes reflect the respiratory status. The circuit design combines rectification, filtering and amplification technology to reduce low-frequency interference and improve signal quality.

[0056] Body temperature monitoring is based on the bridge balance principle and operational amplifier circuit. Through the high-precision linear interpolation correction compensation method, the nonlinear error of thermistor is overcome and the measurement accuracy is improved.

[0057] Specifically, the temperature measurement of this monitor adopts the thermistor method. The principle is: using a thermistor with a negative temperature coefficient as a temperature sensor, the resistance of the thermistor changes with temperature. The temperature measurement of this monitor is to convert the temperature of the human body into an electrical signal by the sensor, amplify it by the amplifier, and then process the data. The temperature generates a voltage signal through the thermistor probe, which is amplified and sent to the A / D converter of the single-chip computer for processing. The thermistor placed at the top of the measuring part (body temperature probe) is used as a temperature sensing device. When the temperature of the external heat source being measured changes, the resistance of the thermistor will change accordingly. The internal microprocessor converts, processes, and corrects the resistance change of the thermistor in the measuring circuit, and then displays the measured temperature in digital form on the display screen.

[0058] A synchronous monitoring method for a blood oxygen and body temperature synchronous monitoring and analysis system of a patient monitor comprises the following steps:

[0059] Step 1: Data collection: Collect blood oxygen saturation data through the blood oxygen monitoring module; synchronously collect ECG signals, respiratory signals and body temperature signals through the ECG, respiratory and body temperature monitoring modules.

[0060] Step 2: Signal processing: filter, amplify and digitize the collected signals; perform signal analysis in combination with algorithms and dynamically adjust the signal amplitude.

[0061] Step 3: Result output: The processed blood oxygen, ECG, respiration and body temperature data are displayed through display screens and other devices for clinical use.

[0062] The above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the embodiments of the present application are described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents, without departing from the spirit and scope defined by the claims of the present application.

Claims

1. A patient monitor blood oxygen and body temperature synchronous monitoring and analysis system, including a blood oxygen monitoring module and an electrocardiogram, respiration and body temperature monitoring module, characterized in that: The blood oxygen monitoring module includes a power supply part, an analog part and a digital part; The power supply part adopts a DC power supply with stable voltage, small ripple and no burrs, and isolates the digital power supply from the analog power supply and the digital ground plane from the analog ground plane through magnetic beads; The analog part includes a blood oxygen sensor driving circuit, a signal amplification circuit, a signal separation circuit and an AC small signal adaptive amplification circuit; the blood oxygen sensor driving circuit controls the light emitting diode to emit light alternately through a dual-channel analog switch chip; the signal amplification circuit converts the current signal output by the photosensitive diode into a voltage signal using a precision low-noise operational amplifier; the signal separation circuit separates the pulse wave signal from the mixed signal and transmits it to the AC small signal adaptive amplification circuit; the adaptive amplification circuit adjusts the signal amplitude through a digital potentiometer and outputs it stably; The digital part includes a clock circuit, a reset circuit, a communication interface circuit and a JTAG interface circuit, which are used to digitally process the signal and output the blood oxygen saturation data; The ECG, respiration and body temperature monitoring module includes an ECG monitoring part, a respiration monitoring part and a body temperature monitoring part; The ECG monitoring part includes an ECG signal input part, an amplification part, a processing part and an output part; the ECG signal input part transmits ECG signals through electrodes, lead wires, overvoltage protection circuits and high-frequency filters; the amplification part amplifies ECG signals through three stages of pre-amplification, intermediate amplification and post-amplification, and uses a thin film capacitor external circuit to eliminate polarization voltage interference; the processing part uses an STM32 microprocessor to process ECG signals and output analysis results; The respiratory monitoring part is based on the chest impedance method, which monitors the chest impedance change through a two-electrode method, and reduces the low-frequency signal interference through rectification, filtering and amplification; The body temperature monitoring part adopts the bridge balance principle combined with the correction and compensation method to improve the body temperature measurement accuracy through precise linear interpolation correction.

2. A patient monitor blood oxygen and body temperature synchronous monitoring and analysis system and method according to claim 1, characterized in that: The blood oxygen sensor driving circuit of the blood oxygen monitoring module adopts the SGM3005XMS dual-channel analog switch chip to realize the alternating emission of red light and infrared light; the signal amplification circuit of the blood oxygen monitoring module adopts the SGM8634 operational amplifier to provide low-noise signal amplification; the digital part improves the ADC and DAC performance of STM32F103VCT6 through a decoupling circuit.

3. A patient monitor blood oxygen and body temperature synchronous monitoring and analysis system and method according to claim 1, characterized in that: The ECG signal input part eliminates the influence of the defibrillation pulse on the ECG board through an overvoltage protection circuit; the ECG signal processing part adopts an AD8226 operational amplifier to improve the signal amplification accuracy under high impedance conditions.

4. A patient monitor blood oxygen and body temperature synchronous monitoring and analysis system and method according to claim 1, characterized in that: The impedance measurement of the respiratory monitoring part adopts a two-electrode method, wherein one electrode is placed on the right chest of the patient and the other electrode is placed on the left abdomen, and the signal is processed by rectification, filtering and amplification.

5. A patient monitor blood oxygen and body temperature synchronous monitoring and analysis system and method according to claim 1, characterized in that: The body temperature monitoring part adopts a correction and compensation method based on an operational amplifier, solves the nonlinear error of thermistor temperature measurement through linear interpolation correction, and improves the measurement accuracy.

6. A synchronous monitoring method using the patient monitor blood oxygen and body temperature synchronous monitoring and analysis system according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Collect blood oxygen saturation data through the blood oxygen monitoring module; S2, synchronously collect ECG signal, respiratory signal and body temperature signal through ECG respiration and body temperature monitoring module; S3, filtering, amplifying and digitally processing the collected signals respectively; S4. Output the monitoring results of blood oxygen, ECG, respiration and body temperature.