Development of intelligent healthcare system based on ambulatory blood pressure measuring device

In the USA, the world’s largest medical device market, the blood pressure monitor market is continuously growing as the need for efficient and accurate blood pressure measurements increases due to the growth on the number of hypertension patients caused by the aging population. It is indicated that the market size amounted to U$ 973 million with an increase of 10.8% over the previous year [1‐3]. The occurrence of hypertension is expected to increase due to limited exercise activities and the aging of baby boomers [4]. In addition, the implementation of programs for the prevention and management of adult diseases at the government level will also increase the demand for blood pressure monitors. The primary consumers will be hypertension patients, baby boomers, and medical service institutions (i.e., hospitals, government facilities, nursing homes, etc.). The unveiling of such devices that are easy to use, minimizes discomfort, efficiently and accurately measures the blood pressure and stimulates consumer demand.

The reliability of a professional blood pressure monitor used in medical institutions is essentially important; thus, higher measurement accuracy has a significant influence on the purchase decisions. With the development of technology, the simple and small size design allows easy and portable handling at home, creating new demand, and in fact, many automatic blood pressure monitors are widely available resulting in a large-scale blood pressure monitor market. However, the availability of ambulatory blood pressure monitoring devices that is able to measure fragmentary blood pressure has more advantages in managing hypertension since it provides information on daily blood pressure fluctuation patterns which are limited in the market due to its inconvenience and less portability. This minimal market for blood pressure monitoring devices leads to meager investments in device development. The ambulatory blood pressure monitoring devices were not yet universalized and are merely used for research purposes. If such devices will be developed to provide higher efficiency and accuracy, minimize discomfort and increase convenience, the paradigm of blood pressure management can be changed from the existing concept of hypertension. It can also reduce costs in improving the efficiency of national health.

Ambulatory blood pressure monitoring has several advantages over fractional blood pressure measurement, which measures blood pressure several times during normal activities [5]. First, the white coat effect can distinguish an average person diagnosed with hypertension. Ambulatory blood pressure monitoring is useful in cost-effective ratios because it can reduce unnecessary medical expenses by identifying white coat hypertension. Second, the amount of time the patient was exposed to high blood pressure can be determined. Many clinical evidences were reported that there were more severe damages to the target organ whenever the mean blood pressure for 24 h will be higher than the blood pressure measured in the hospital and the longer the amount of time to have a higher blood pressure than the constant blood pressure (i.e., blood pressure load). Third, the fluctuation pattern of blood pressure can be determined which can be used to more efficiently treat hypertension. It is known that daytime blood pressure alone cannot predict the degree of nighttime blood pressure drop, and the non-dipper is observed in about 25% of hypertensive patients. Non-dipper hypertensions have been reported to have more complications such as left ventricular hypertrophy and asymptomatic stroke than the dipper hypertensions. Fourth, information about blood pressure fluctuations can be provided. The daily changes in blood pressure are more severe than with higher blood pressure, and the target organ damage is critical in people with sharp fluctuations in blood pressure regardless of the average blood pressure. Lastly, the evaluation of new blood pressure drugs can be advantageous. When evaluating new hypertension drugs, the effectiveness can be assessed in few patients through new indicators such as T/P ratios and effects on fluctuation patterns. Information on blood pressure variability is also provided to further characterize the new hypertension drugs.

Active measurement of ambulatory blood pressure monitoring should be undertaken, but the development of devices to perform such function is very slow. The current and widely used blood pressure meter measures the blood pressure through winding a cuff around the upper arm and inflated, which is too large and cumbersome to carry and gives a significant pain whenever the pressure is applied. In addition, pain can interfere with the patient’s sound sleep when blood pressure is measured whenever the patient is asleep, specifically if the measurement is required every hour. Thereby, the reliability of blood pressure measured during sleep is lowered as well as patient compliance of measured blood pressure. Moreover, if the patient inevitably loosens the blood pressure cuff to take a shower or change clothes and then wears it again, reliability of the measured blood pressure can be lowered since it may not be worn again in an accurate manner. Thus, the necessity of an ambulatory blood pressure monitoring device having high portability, capable of minimizing patient discomfort, and with high reliability is essentially important. This paper aims to develop an efficient healthcare management system and design a device that can efficiently measure and manage the ambulatory blood pressure.

The reliability of professional blood pressure monitors used in medical institutions is considered as the most important factor that greatly influences the acquisition decision. With the development of technology, small size, simple usage, and convenient devices in homes are regularly being released, which creates new demand. Various automatic blood pressure monitors have been distributed creating a large-scale market for blood pressure monitors [6‐10]. The ambulatory blood pressure monitoring devices can provide more advantages wherein it measures not only fragmentary blood pressures but can also manage high blood pressures through daily blood pressure fluctuation patterns. However, these devices provide usage inconvenience and were not portable such that its market is very limited, leading to a very low investment in its development. The previously developed ambulatory blood pressure monitoring devices are depicted in Table 1.

Many manufacturers are evaluating various measurement and analysis methods for the purpose of commercialization. However, most of the measuring devices were inconvenient to use, and even those good quality devices were insufficient in terms of the utilization of various information obtained by measuring ambulatory blood pressure. In addition, there are only few devices that were classified into the TOAST class which is the basis for the actual blood pressure analysis. Thus, this paper used more than 300 patient’s data to learn and make clinical evidence of the TOAST group, used the extracted TOAST group criteria as a guide, and reflected an evaluation process to distinguish normal or abnormal blood pressure measurements in order to develop an intelligent healthcare system based on ambulatory blood pressure monitoring device.

The proposed intelligent healthcare management system based on ambulatory blood pressure monitor can be developed as shown in Fig. 1.

The hardware represents the actual manufactured ambulatory blood pressure monitoring device, and it can be managed by the user through interlocking with the PC-based analysis program using the Bluetooth module. Many intelligent analytic monitoring systems were being developed and embedded into wearable devices linked into back-end systems [11, 12].

The proposed ambulatory blood pressure monitoring system requires the following conditions. First, the measuring device should be miniaturized so that it can be worn easily (e.g., on a wrist) and should be made of a material such as silicon for convenient wearing. Then, the system includes an algorithm that converts the gathered sensor signal into a measured blood pressure. In addition, blood pressure measurement is performed by both a control circuit module and an active pressure generator. The control circuit module controls the pressure so that it matches the intravascular pressure by contacting the pressure sensor to the blood pressure measuring area, while an active pressure generator changes the pressure continuously for blood pressure measurement. The portable ambulatory blood pressure monitoring device consists of a communication module that delivers measured information and a battery module that provides power to its components. The device is ultimately easy to use and provides a reliable and continuous blood pressure monitoring without pain. Moreover, in order to minimize the noise caused by external shocks, a fixed structure made of silicon that can closely adhere the pressure sensor to the wrist has been developed to compensate the noise caused by motion artifacts through a feedback algorithm by motor control.

Ultimately, a prototype was developed for a tonometer-type wrist-worn ambulatory blood pressure monitoring device that is highly portable, easy to wear, and improves the reliability on the measurement signal. Furthermore, this paper proposed the development of an intelligent healthcare system that can continuously and conveniently manage the ambulatory blood pressure of users by mounting a TOAST program that may analyze the measured blood pressures.

Ambulatory blood pressure monitoring measures and records blood pressure several times during normal activity and has several advantages over the fractional blood pressure measured in the hospital. With the development of technology, the small size and simple usage allow ease on handling devices at home, creating new demand, and in fact, various automatic blood pressure monitors have been sold and distributed such that the scale of blood pressure monitor market is very wide. The ambulatory blood pressure monitoring device which is capable of measuring fragmentary blood pressure has more advantages in managing hypertension since it can provide information on fluctuations of blood pressure patterns even though it is inconvenient to use and less portable.

This paper deals with the development of an ambulatory blood pressure device and intelligent healthcare management system that can continuously manage the ambulatory blood pressure of users. A prototype of tonometric wrist-worn ambulatory blood pressure monitoring device was developed which is highly portable, easy to wear, and capable of improving the reliability of measured bio-signals. The measured blood pressure values were compared with the existing popular equipment in order to verify the reliability of the developed prototype. And the proposed analysis method was found to be more effective through the comparison analysis with the existing classification methods. Finally, the health status of hypertension patients can be evaluated for a limited time. In addition, if there was a lot of impulse noise in the shrinkage, loosening data, the inaccuracy of the normalization curve generation could be identified. This caused a problem with the TOAST class judgment accuracy, but I think it will be improved if some additional filtering work for the preprocessing work is reflected. Filtering can take into account a variety of signal improvement filters, such as the median filter [28] or the low-pass filter [29], which eliminates impulse-based noise. In the future, as the concept of preventive healthcare is essentially needed, an additional study using deep learning-based prediction technology [30, 31] will be carried out.