Sensor technology is playing an important role in the use of medical field.

Using sensor technology, implantable medical devices will gain more powerful functions. Through observing the patient’s action and orientation, the new observation method can bring a more free life to the patient’s friends, such as heart rate management (CRM), surgical instrument positioning, invasive and non-invasive pressure measurement, etc. If the signal of the sensor is combined with the results of other detection methods, it can effectively prevent the deterioration of the disease.

Another important application of sensors in the medical and health industry is non-contact vital sign monitoring. At present, non-contact vital signs monitoring has been applied in sleep analysis, nursing monitoring of elderly patients and other scenes. It is an economical and easy-to-use health observation method.

1 demand

Human vital signs can transmit a lot of personal health information. However, long-term monitoring of heartbeat rhythm, body temperature, respiration, body movement in sleep, etc. is usually not easy to achieve, because wearable measurement will make people feel uncomfortable, inconvenient, and even bring additional psychological pressure.

In an aging society, fall prevention is the main concern when nursing the elderly. Although there are many solutions, if you can monitor vital signs such as heart rate, respiratory rate and various activities at the same time, it will help to deeply understand personal health status and provide nurses with fall prevention alarm.

In recent years, various activity trackers and similar instruments have introduced sleep analysis into the consumer market. Polysomnography (PSG) used in sleep analysis is the “gold standard” of sleep analysis. However, sleep analysis instruments on the market can not provide enough accurate vital sign data for sleep analysis.

2 Challenges

From a technical point of view, non-contact vital signs monitoring also faces many challenges, including:

Instruments and equipment need to be miniaturized

It must have good signal-to-noise ratio

High precision and stability

low power consumption

It is a hot topic in the application field of vital sign monitoring to use wireless bed sensor bcgmcu and pressure sensing element to detect non-invasive and maintenance free cardiogram (BCG) on the user’s bed.

3 application of BCG in bed monitoring

There are many methods to monitor the function of the heart. What people often hear is electrocardiogram (ECG), which reveals the ECG function of the heart; In addition, cardiologists can simultaneously monitor the operation and flow of valves with ultrasound, and observe the blood pressure or pressure wave generated by heartbeat with blood pressure measurement. The advantage of ECG is that it can detect faults in cardiac electrical operation, such as arrhythmia, signal delay or block, abnormal polarization or depolarization, etc; Its limitations include the requirement for additional electrodes and the lack of information about the true pumping of the heart.

The monitoring of cardiac function by cardiac impulse signal gram (BCG) has no above limitations of ECG. Cardiac impulse signal is the recoil signal caused by blood flowing into the aorta, aortic rotation and continuous blood pressure pulse entering the artery. The motion is mainly along the longitudinal axis of the body, and the acceleration amplitude is usually on the order of 1mg (1cm / S2). Typical BCG signals are shown in the figure below.

Application analysis of sensor technology in non-contact vital signs monitoring in medical industry

Typical BCG signal

The advantage of cardiogram (BCG) is that it measures the mechanical pumping process of the heart, and the signal can give the time and relative pumping volume of each heartbeat. On the other hand, the BCG sensor can be installed on the user’s bed, which is non-invasive and maintenance free. This method is suitable for long-term and night measurement. Therefore, it is also an excellent tool to measure rehabilitation status and sleep quality. It can also reveal potential sleep apnea or nocturnal arrhythmia.

By combining the BCG measurement in bed with the bracelet daytime pulse (BPW) measurement, the state of the user’s heart and autonomic nervous system can be monitored 24 / 7. BPW is also a non-invasive measurement tool for monitoring the function of heart and blood vessels.

With such a combined scheme, non-invasive vital sign monitoring can be applied to various scenarios with different needs.

Good sleep is very important for everyone to prevent all kinds of diseases and prolong life. The positive effects are not limited to those related to heart or vascular function. Good sleep can also contribute to people’s mental health and even prevent cancer.

For the elderly, it is necessary to continuously monitor vital signs, both in family and elderly care, in order to improve health, facilitate their independent living ability and improve the safety monitoring of patients. At the same time, it is also necessary to save the labor cost of the hospital, if the patients can leave the hospital earlier and remain safe outside.

For athletes, recovery and good sleep are the decisive factors to achieve good training and competition results. The best training and recovery make athletes become top athletes.

Heartbeat and respiratory parameters are excellent indicators of a person’s general condition and life expectancy. They measure not only the condition of the heart, but also the condition of the whole body through the autonomic nervous system, and indicate many pathological conditions, such as stroke measurement.

It should be noted that the spring constant and damping factor in the user’s bed change greatly, resulting in different signal amplitude and attenuation time constant. Therefore, the BCG measurement in bed has very high requirements for the sensor capability and corresponding signal analysis capability used in the application.

Murata BCG solution

Murata’s improved second-generation BCG solution opens up new possibilities for condition monitoring of people sleeping in hospitals and families. It can detect people leaving bed and analyze sleep state from biological signals such as pulse, respiratory rate and respiratory time of sleeping people.

Application analysis of sensor technology in non-contact vital signs monitoring in medical industry

Murata BCG solution

Murata BCG solution consists of two parts:

It consists of pre programmed microcontrollers bcgmcu-d01 and scl3300-d01.

Component level solutions composed of inclination sensors, as well as products for software solutions and service providers and OEM system integrators.

Application analysis of sensor technology in non-contact vital signs monitoring in medical industry

BCGMCU-D01

The working principle of Murata’s cardiogram (BCG) sensor SCA10 / 11h based on acceleration sensor is as follows:

The sensor is connected to the bed.

When blood flows out of the human heart, there will be small activities in the whole body, which is called cardiogram signal.

When someone is in bed, the BCG signal is transmitted to the bed.

Murata acceleration sensor captures these vibrations, and then converts the data on the acceleration sensor into vital sign data through our patented algorithm.

Sca10h is a PCB module with built-in acceleration sensor and MCU for BCG algorithm processing.

Sca11h provides WiFi connection for easy integration.

Murata core impact graph (BCG) sensor SCA10 / 11h product features:

Report once per second:

Heart rate (BMP)

Heart rate variability (MS)

Respiratory rate (times / minute)

Stroke output (A.U)

Signal strength (measurement activity, a.u.)

The precise breathing time previously detected

WiFi connection, cloud support

Support software and simple connection for easy integration

Sleep analysis algorithm is used with SCA10 / 11h data

At present, Murata cardiogram (BCG) sensor SCA10 / 11h products are widely used in fall prevention and bed occupation monitoring, long-term screening of physiological conditions, sleep analysis, physical rehabilitation and other applications.

Responsible editor; zl

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