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Overview of e-Health Architectures

Omessaad HAMDI

IEEE, Rennes, France

1.1. Introduction

Digitization occupies a central place in all our daily activities, and the healthcare field is particularly affected by this digital evolution, which has considerably improved patient care (Hermes et al. 2020; Gupta et al. 2021). This improvement is based on two key factors: the increased involvement of patients in the management of their health, and easy access for healthcare professionals to digital tools and services.

Digitization is also improving people's quality of life, in terms of well-being and autonomy, and is helping respond to the growing number of elderly people worldwide. The phenomenon of aging is becoming a growing concern. To enable this population to age in a secure environment with a good quality of life, while reducing costs, several approaches have been developed.

In this chapter, we focus on e-health architectures. We begin by introducing the terms used in e-health. Next, we present the services offered by e-health systems and their requirements. The final sections will focus on security and the techniques used to guarantee the required security services. Finally, we look ahead to the future of e-health.

1.2. Definitions

1.2.1. e-Health

The term e-health refers to information and communication technologies (ICT) combined with the Internet in the service of health.

1.2.2. Telehealth

Telehealth is part of e-health. It refers to the use of tools for producing, transmitting, and managing digitized medical information. Telehealth encompasses telemedicine and mobile health (m-health).

1.2.3. m-Health

m-Health is part of telehealth. It refers to healthcare practices supported by mobile devices, such as cell phones, patient monitoring systems and other wireless devices. The term includes, among others, applications such as wellness apps. Bashshur et al. (2011) point out that m-health is the only ICT-based healthcare field that can be justified solely based on mobility.

1.2.4. Telemedicine

Telemedicine is part of telehealth. It refers to the digital transmission of medical information (images, recordings, etc.) for remote diagnosis, specialist advice and continuous monitoring of a patient.

There are four forms of telemedicine (2010 decree):

• Remote consultation is between a healthcare professional and a patient: It refers to the use of communication technologies to provide health consultations to patients in geographically different locations.
• Remote education is between healthcare professionals, in the absence of the patient: It consists of a remote request for advice from colleagues based on information provided by the patient.
• Remote monitoring involves remote monitoring of a patient's health parameters, providing assessments of the patient's state of health.
• Remote assistance occurs when a doctor remotely guides a medical act. This can take place between two healthcare professionals or between a healthcare professional and a third-party present with the patient, for example, in an emergency.

Figure 1.1 summarizes the components of telehealth.

Figure 1.1. Components of e-health

1.3. e-Health services

e-Health offers a wide range of services designed to improve the quality of care and accessibility to medical services thanks to digital technologies:

• Cost reduction: e-health considerably reduces hospitalization and the need to keep elderly people in nursing homes. It also enables early detection of illness. Both services can significantly reduce healthcare costs (Atienza et al. 2007; Kostkova 2015).
• Social inclusion: the use of e-health technologies enables patients to remain active and independent as long as possible, enabling them to overcome their illness and/or disability without being excluded from society.
• Prevention: body and environmental data collected from sensors can be interpreted. By effectively managing these data, doctors can uncover facts and detect illness at an early stage.
• Support: e-health systems are designed to help people who are ill, elderly or disabled, and to promote their autonomy, safety and well-being. They make it possible to maintain and monitor patients at home, instead of hospitalizing them.
• Supervision: the acquisition and processing of patient data and the use of several devices enable the patient's condition to be monitored. This system is particularly interesting when it comes to high-risk patients, such as the elderly suffering from a wide range of chronic illnesses, for whom effective supervision is essential.

1.4. Requirements for e-health systems

e-Health systems must meet certain requirements if they are to be adapted by users.

In this section, we present some of these requirements:

• Acceptability: patients often wear sensors, and these are deployed in their environment to provide continuous monitoring. The sensors deployed must meet conditions of comfort and acceptability.
• Reliability: an e-health system must generate a very low false alarm rate.
• Energy autonomy: the energy autonomy of sensors plays an important role. Replacing sensor batteries is often complicated and/or costly.
• Ergonomics: it is essential that the devices and applications used are ergonomic and user-friendly to guarantee ease of use.
• Safety: devices and applications must comply with standards and regulatory requirements.
• Privacy protection: this is of paramount importance when dealing with media information, as this is sensitive data. To guarantee this protection, appropriate mechanisms must be put in place, especially in an environment where several users are involved.

Figure 1.2 summarizes the services and requirements of e-health systems.

Figure 1.2. Services and requirements for e-health systems

1.5. e-Health system architecture

Different e-health system architectures have been developed to meet the specific needs of each project.

An architecture that summarizes most of the architectures proposed in the literature is shown in Figure 1.3.

In all e-health architectures, information flows from the patient to a medical server. Data are transferred from the sensors to a gateway that manages the sensors. Data transfer in the network can be continuous or ad hoc. Collected data are stored in a gateway, and then uploaded to a medical server.

1.5.1. Components of an e-health architecture

The main components of an e-health system are as follows (Hamdi et al. 2014):

• Sensors: these are devices that capture, store, process and transmit data.
• Wireless body area network (WBAN): it provides short-range wired or radio communication capability for sensors to exchange data with a gateway around an individual's body.
• Gateway: it collects vital and environmental data from sensors. It analyzes the data received from body and/or environmental measurements, compiles them and uploads them to a medical server via the network.
• Local area network (LAN): it provides wired or wireless communications for sensors to exchange data with a gateway.
• Wide area network (WAN): it provides wired or wireless (e.g. cellular) communications capability for gateways to download data to a medical server.
• e-Health systems platform: it includes servers for storing, processing and securing medical data.

Figure 1.3 gives an overview of the main components of e-health systems.

1.5.2. Features of e-health systems

• Data capture: this layer refers to the collection of patient data from vital signs and/or environmental sensors.
• Computation: this layer includes data analysis, management and personalization of care.
• Communication and storage: this layer covers vital signs communication, calculation and storage modules.
• Access: this layer refers to the way in which data are accessed. It often takes the form of a web portal or mobile application connected to a secure system hosted in the cloud, enabling continuous monitoring of patients' health status.

Figure 1.3. Architecture of e-health systems (Hajar et al. 2021)

1.6. e-Health system technologies

Connection technologies such as Bluetooth, WiFi, Internet and ZigBee play a key role in the growth of e-health applications and systems. When used in conjunction with other technologies, such as the Internet of Things (IoT), robotics, artificial intelligence (AI), cloud and Big Data, high-performance e-health systems can be created (Devedzic et al. 2021).

Figure 1.4. e-Health technologies

Figure 1.4 illustrates the main technologies used in e-health systems. These are grouped into medical devices, connection technologies and other technologies, and are detailed below.

1.6.1. Devices

Devices are mainly made up of sensors and connected objects, which play a key role in monitoring and...