The adoption of wireless network technology in medical applications has become one of the major progresses which have been realized in healthcare field, a step that has been considered as cost saving (Jain, 2011). It has also played a crucial role of enhancing access to patient information and medical services.
Studies reveal that wireless technology network and its application in health provision is increasingly gaining popularity, a consideration which medical analysts cite could reduce medical errors which have led to ineffective provision of treatment and eventual death of patients (Newbold, 2004).
In concurrence, Khan, Hussain and Kwak (2009) point out that wireless network technology provide tools which aid doctors and nurses in obtaining patients’ data on insurance, lab results, tests, medications, treatments and clinical histories.
As this paper analyses, governments, insurance agencies and hospitals as well as other health care providers are increasingly turning to wireless technology to limit medical errors and save costs of managing patients. This paper takes a critical look at the role of wireless network technology in heath monitoring and concludes by examining the challenges and issues facing its application.
The healthcare industry has been regarded as one of the industries that have been faced by a myriad of challenges related to efficient and effective provision of services (Athens Informational Technology, 2009). Analysts argue that some of the hard hitting problems which healthcare providers grapple with today include the inability to effectively and fully reach less developed urban and rural areas with medical services, acute staff shortages, never ending medical errors and high costs of delivering healthcare services (Newbold, 2004).
Wireless technologies as Malan et al (2005) posit have become important tools in healthcare provision due to their unique and resourceful features such as smart structures, web access and event driven messages and notifications. These features play a crucial role of aiding caregivers to check for vital signs and obtaining patients’ information necessary for effective treatment, offering personal healthcare and assisted living.
In healthcare monitoring, the application of wireless technologies requires measuring a patient’s signals or important symptoms (Athens Informational Technology, 2009). The latter are used by physicians to make diagnosis and are commonly termed as vital signs. Malan et al (2005) add in their article that vital signs in a patient vary and may include acceleration of body core temperature, saturation of blood pressure and oxygen (SpO2), electrocardiogram (ECG) and heartbeat rate depending on a health problem.
Khan, Hussain and Kwak (2009) point out that in monitoring healthcare provision, context becomes an important aspect which encompasses an entity and characterizes its position and situation. Wireless technology employs the use of context to link an application with its user thereby building an interaction (Athens Informational Technology, 2009).
Maurer et al (2006) point out that context can be high level with user activities which are complex, low level like bandwidth, temperature and time, and can consist of information that is either explicit or implicit. In a healthcare setting, context is an important component which doctors and nurses to characterize fully a patient’s health status. This may be in terms of age, stress levels, location and low or high body temperatures among others (Jain, 2011).
Wireless health monitoring therefore plays a crucial role in deriving informational items from patients such as a patient’s specific condition, medical knowledge, and current vital signs as well as medical history. This information as Maurer et al (2006) continues to posit aid in reducing medical errors and false positive incidences.
In measuring patients’ vital signs, a context-aware system has been efficient in providing active and passive as well as relevant information regarding a patient’s situation (Athens Informational Technology, 2009). Through wireless technology, physicians have been able to measure and monitor different contexts and vital signs with success seen in their ability to determine their characteristics. Malan et al (2005) argue that the monitoring may be passive or active with the former entailing the process of recording vital signs.
Wireless sensor node
In their publication Ko et al (2010) describe a wireless sensor node (WSN) as a micro-electromechanical tool which is made up of many units which include a radio transceiver, a microcontroller unit (MCU) and a sensor actuator unit. A wireless sensor node has a transducer in its sensing unit, a component that enables it to measure temperature and other physical quantities (Athens Informational Technology, 2009).
It then applies signal processing to amplify and filter signals after converting them. The wireless sensor node has been made in such away that it can measure a variety of entities including real world phenomena (Jain, 2011).
It is important to note that it can use ADC to convert the measured materials into electrical forms which it then sends to analog sensors, SPI and 12C for actuators and digital sensors. Khan, Hussain and Kwak (2009) argue that like a CPU in a PC, the MCU performs a critical function of coordinating the architecture of the wireless sensor node (Khan, Hussain & Kwak, 2009).
Figure 1: A diagram showing a sensor node
There are various types of network platforms and wireless sensor nodes which have evolved over the years due to the growth and development of technology. Some of the most common aforementioned elements include the free scale ZigBee nodes and the Berkeley mote which has been designed in such a manner that they the use of an accelerometer (Jain, 2011).
Features of medical sensors
Medical sensors have been specifically designed to perform critical roles such as those of obtaining context information and capturing vital signs which are crucial for healthcare monitoring purposes (Athens Informational Technology, 2009).
Studies reveal that normal wireless sensor nodes have been with the same architecture medical sensors have. However, medical sensors are distinguished from other sensor nodes as they operate in low power (Athens Informational Technology, 2009). In addition medical sensors are heterogeneous to mean they require a placement that is effective and specific.
Other characteristics of medical sensors include biocompatibility, user friendliness, usability, interoperability and higher reliability (Athens Informational Technology, 2009). In terms of usability, the device is convenient to ware and obtrusive, reasonably small non invasive, inexpensive and is of low specific absorption rate (SAR) and low electromagnetic radiation. Its user-friendliness is exhibited in its comfortability in the sense that it can be implanted safely in a patient’s body (Athens Informational Technology, 2009).
Types of medical sensors
There are different types of medical sensors which have been classified based on sensor location on a body, power supply and vital signs (Jain, 2011). The later has medical sensors that include environmental sensors bio-kinetic sensors and physiological sensor. Blood oxygen saturation, body temperature and blood pressure are measured using psychological sensors (Khan, Hussain & Kwak, 2009). Human movements in terms of angular rotational rate and acceleration are measured using biogenetic sensors.
Environmental phenomenon like light and temperature as well as other environmental contexts like floor vibrations and images are measured by environmental sensors. In the provision of healthcare services Noorzaie (2006) indicate that medical sensors can be used outside the body by patients. Such sensors include In-vitro sensors worn outside the body such as on the earlobes and arms
Applications scenarios of health monitoring
In health monitoring, wireless technology offers a variety of platforms where wireless networks and sensors can be effectively applied. Studies indicate that these applications can be categorized in several distinct ways (Jain, 2011).
Monitoring of vital signs can be done in the area of disaster response, emergency, recuperation, sleep disorder, remote outpatient, fitness and wellness. Depending on the place of monitoring employed application scenarios can be classified under home monitoring for chronically ill patients, care centers, ambulatory and hospital monitoring (Khan, Hussain & Kwak, 2009).
Chronic disease monitoring
Chronic disease monitoring is conducted for diseases such as sleep disorders; hear t diseases, asthma and diabetes (Athens Informational Technology, 2009). Other chronic diseases monitored using wireless devices include chronic respiratory diseases, cancer and stroke. Studies reveal that for effective monitoring of chronic diseases, it is important to conduct them a t certain stages of a disease (Noorzaie, 2006).
Studies reveal that for effective monitoring of chronic diseases, it is important to conduct them a t certain stages of a disease (Noorzaie, 2006). Chronic disease monitoring is of three types and they include patient alarm monitoring, continuous and episodic monitoring.
The latter is monitored periodically and specific indicators are used to determine a disease of its vital signs. These determinations are vital in studying the trends of a disease and spot anomalies (Jain, 2011). The information gathered on the trends of vital signs is fed into the medical device and transmitted to the data base server.
Personal wellness monitoring and personal fitness monitoring
In conducting personal wellness monitoring, contexts and vital signs information are monitored by physicians and assisted living safety and care is provided to patients (Athens Informational Technology, 2009). Personal wellness monitoring is done in three stages which include post operative, safety and senior activity monitoring. Personal fitness monitoring is used to track the fitness level of a patient using wireless sensor technology (Khan, Hussain & Kwak, 2009).
Senior activity monitoring scenario
This monitoring scenario plays a critical role of monitoring the daily activities of elderly people (Athens Informational Technology, 2009). Physician in a healthcare situation employ the use of non-medical sensors as well as wearable medical sensors to effectively measure heath changes and vital signs on elderly patients. In senior activity monitoring scenario, the devices used are always very effective. Every detection made on predetermined events easily triggers automatic responses (Athens Informational Technology, 2009).
Postoperative monitoring scenario
This scenario involves monitoring of patients who have undergone operation surgeries using wireless devices. In hospitals, postoperative monitoring scenario is done through measuring vital signs via wireless technology devices (Athens Informational Technology, 2009). The information obtained is then transmitted for checking in a healthcare facility.
Personal fitness monitoring.
The practice of monitoring personal fitness using wireless technology applications has been considered as an effective way of dealing with health problems especially those affecting the youth (Noorzaie, 2006). This kind of monitoring involves tracking the progress which an individual has made in terms of fitness level.
In healthcare monitoring, wireless devices are used to measure parameters such as blood and oxygen level via wearable sensors. The information derived on vital signs from the measurements taken is then transmitted to a unit where data is collected for healthcare checking to analyze the level of fitness (Noorzaie, 2006).
Personalized fitness schedule scenario
Personal fitness schedule scenario employs the use of wireless sensor technology used in personal fitness monitoring to determine heart rate beat and pace during an individuals fitness training schedule. A trainer of an athlete uses a monitoring device to monitor respiration and heartbeat of an athlete. The data that is collected is then sent to a database server and kept as a record. Besides, the device used to monitor can send communication on a treadmill which acts as a control unit.
Healthcare monitoring Networks
Body Area Networks
Body area networks (BAN) is a widely used monitoring system through which the body of a patient is measured by a network of devices (Athens Informational Technology, 2009).
The concept that was advanced by Zimmerman has been very effective in its application of communication and processing facilities actuators and sensors in obtaining a patient’s information and determining vital signs like ECG. Actuators provide feedback obtained from sensors and these are important in determining the best treatment for any particular ailment (Noorzaie, 2006).
The article written by Ko et al (2010) highlights the important roles that BAN communication network system carry out in the effective monitoring of healthcare provision. The author proceeds that communication in BAN occurs in two ways namely extra-BAN communication and intra-BAN communication (Athens Informational Technology, 2009). In healthcare monitoring, physicians use BAN communication to pass information via wireless technology (Kwak, 2009).
This is implemented through intra-BAN communication, a communication that occurs between entities of a BAN. Some of the wireless technologies employed here include UWB, ZigBee and Bluetooth among others (Athens Informational Technology, 2009). Noorzaie (2006) indicated that intra-BAN communication can be carried out through either one or a mixture of the two.
In monitoring health practices in remote places, an extra-BAN communication is used as it can be able to foster external communication. ZigBee and Bluetooth technologies are short range wireless means which can only be effectively used intra (Jain, 2011). For long range communication, physicians prefer extra-BANs some of which include satellites, WiMAX, UMTS, GSM and GPRS.
General architecture of WPAN, Wireless Local Area Networks (WLAN), Home Area Networks (HAN), Metropolitan and Wide Area Networks as well as MWAN
In their publication, Maurer et al (2006) indicate that in healthcare monitoring, medical networks and sensors are two critical components which play a crucial in the provision diagnosis and treatment of chronic ailments. Medical experts employ the use medical sensors to obtain vital signs from patients and then relay this message through a server via monitoring networks remotely to a physician or a medical centre (Athens Informational Technology, 2009).
The communication to a remote medical centre is then passed to healthcare providers. It is imperative to note that the networks of monitoring healthcare provision are made up of an elaborate hierarchical arrangement comprising of WWAN and WMAN (long range), wireless local area networks (WLAN) and Home Area Networks, HAN (medium range) and WPAN and WBAN (short range) wireless technologies (Jain, 2011).
The Wireless Local Area Networks assist in assessing broad band of information within a short period of time especially when emergency care is needed (Khan, Hussain & Kwak, 2009). Two or more devices can be linked using WLAN without the use of wiring. It makes of infra red or radio signals to transmit vital information. The Metropolitan and Wide Area Networks is a well established set of computer systems that transmit data within a broad area such as a city (Athens Informational Technology, 2009).
It helps in health monitoring by ensuring speedy transmission of information regarding health matters (Malan, Jones, Welsh & Moulton, 2005). The Home Area Networks (HAN) makes use of digital devices to transfer data over residential areas. It can be used to relay important health information regarding health matters within a given perimeter of residential area (Jain, 2011).
Wireless Personal Area Networks (WPAN)
The design that has been used to create the WPAN is unique in the sense that it comprises of closely connected devices which are normally placed near a user and would follow that user anywhere he or she moves (Athens Informational Technology, 2009). One interesting feature about is technology is its ability to operate even without the existence of an infrastructure. Its close connection to an individual allows for a personal operating space (POS) of 10 meters all round.
This apace is necessary for establishing an effective system of communication which occurs ad hoc. There are various components of PAN key of which include implantable sensors, EKG-sensors, fall sensors, and mobile phones (Athens Informational Technology, 2009). These devises may be used differently depending on the nature of communication intended.
For instance, in BAN communication, WPAN devices can be attached around, on or in a body unlike the PAN. WPAN exists in three classes which include the low-data rate (ZigBee), Medium data rate (Bluetooth) and High-data rate (IEEE) (Athens Informational Technology, 2009).
Health monitoring using short range wireless technologies
Short range wireless technology (SRWT) as indicated earlier in this discussion has an inherent design which only allows it to operate at low power and a limited distance. In the healthcare infrastructure, a plethora of wireless technologies which operate in short distances have been increasingly used by many physicians, a consideration that is attributed to its user friendliness and low power mode of operation (Khan, Hussain & Kwak, 2009).
Maurer et al (2006) argue that SRWTs are effective and safe as they don’t interfere with vital signs. Some of the common short range wireless technologies include the ZigBee, Bluetooth, WilBree, Wireless USB (WUSB), Ultra Wideb (UWB), Radio Frequency Identification (RFID), near Field Communication (NFC), Intra data Association (IrDA), WMTS and the MICS (Khan, Hussain & Kwak, 2009).
ZigBee is one of the most common short range wireless technologies that are characterized by low data rate communication protocols (Athens Informational Technology, 2009). As a component that was made in 2002 by ZigBee Alliance, ZigBee has been lauded in healthcare practices for its unique and effective features such as long battery life, low cost, low data rate and battery-powered applications (Athens Informational Technology, 2009).
In its application, the devise is effective in in-home patient monitoring. Ko et al (2010) point out that ZigBee has been designed to support certain network typologies key of which include peer-to-peer and the Star. These typologies, also encompassing the IEEE which has the cluster tree and mesh typologies.
Figure 2: A diagram illustrating a ZigBee
The above ZigBee diagram illustrates the different IEEE typologies namely Mesh, Cluster tree and star. According to the IEEE standard, these components enable ISM radio band operations in ZigBee and define a mesh network which is self organizing, inexpensive and that serves a general purpose in medical data collection and embedded sensing.
The use of Bluetooth technology in the present healthcare monitoring has been considered unanimously by medical experts as a safe method as it operated outside and away from an individual’s body (Athens Informational Technology, 2009). This short range wireless technology is open, of low cost, low powered and robust in its functions.
It makes the task of monitoring easy ands fast by creating a personal area network with a system consisting of a protocol stack, a baseband and an RF transceiver (Khan, Hussain & Kwak, 2009). Ko et al (2010) point out that in healthcare monitoring and communication, Bluetooth acts as an effective communication tool due to its ad-hoc network typologies called scatternet and piconet.
On the other hand, a scatternet is made up of a group of multiple piconets which employ specific frequencies to communicate to the master piconet clock (Athens Informational Technology, 2009).
Radio Frequency Identification (RFID)
An RFID is a key component of wireless technology which identify signals via short range radio signals (Athens Informational Technology, 2009). In healthcare monitoring, an RFID frequency tags are generally used for offering prescriptions to visually impaired patients. The prescriptions in the tags are normally given out via a talking prescription reader which reads aloud to a patient dosage amount, patient’s instructions, drug name and specific warnings. They may also be used when physicians want to access patients’ information (Jain, 2011).
This short range wireless technology has interrogators and tags as its two basic components as well as a memory and identification number used to store data derived from detection and interrogations made. Its transmission, changing, accessing, storing and encoding of data depends on its manufacturers tag. RFID operates in different frequencies some of.which includes active frequencies like 2.5 GHz, 433 MHz and passive frequencies such as 915 MHz and 125 KHz (Athens Informational Technology, 2009).
The ubiquitous monitoring environment for wearable and implantable sensors (UbiMon) is a health application whose goal is to determine an efficient type of implantable and wearable sensor that can be used on and in a patient to determine vital signs without posing a threat to that patient (Athens Informational Technology, 2009). The UbiMon project has seen development of biosensors some of which include the SpO2, 2-lead ECG strip, 3-lead ECG strip among others.
The UbiMon is an application that is network oriented and comprises of workstations, a patient’s database, a central server, local processing units (LPU) and a BSN node. Besides, it has a WBAN compact flash card that has been created to work in PDA’s. This component aids in gathering and displaying sensor signals which the PDAs have analyzed. In healthcare monitoring, the UbiMon integrates hospital patient information and vital sign data in its system (Jain, 2011).
A Ewatch is an application that has been designed to be worn as a wrist watch (Khan, Hussain & Kwak, 2009). The device has been designed in a manner that it senses temperature, audio, motion and light. Besides, it provides tactile, audio and visual notifications. The e-Watch has a Graphical User Interface (GUI) which allows it via Bluetooth to configure variables and execute functions.
As a computing platform for healthcare monitoring, a Ewatch is a devise that physicians use for research in context computing, and applications such a fall detection and context notification (Noorzaie, 2006).
Figure 3: A diagram showing eWatch
An e-AR sensor is a miniaturized low power device that healthcare providers give patients for well being, professional sports and personal training (Khan, Hussain & Kwak, 2009). The e-AR sensor is a component which has been made with unique design that makes it non intrusive, easy-to-wear and highly sensitive (Athens Informational Technology, 2009).
This ear-worn activity recognition device has a signal processing power that is highly sensitive and links its reception with the inner ear’s semicircular canals. Its detections include shockwave transmission, accelerations both steady and unsteady and gait cycles among other indices.
A codeblue is an important sensor device in health monitoring attributed to its high storage capacity, low bandwidth radios, low power and an integrated processor which works well with PC-class systems, PDAs and wireless vital sign sensors (Jain, 2011). In hospitals, codeblue applications are used to transfer patient data among various caregivers, assess patients and for effective allocation of resources.
Some of the features which distinguish codeblue from other applications are its decentralized security model, discovery scheme, flexible naming and ad hoc data delivery efficiency (Jain, 2011). In addition, Codeblue has the ability to easily scale across networks of a wide range of densities (Athens Informational Technology, 2009).
The effectiveness of Codeblue can be attributed to its architecture which has a subscriber model that publishes streams of identities, locations and vital signs via its sensing nodes and relays them to PCs and PDAs to be accessed by nurses and physicians. To enhance its operations and limit congestion, codeblue aggregates and supports filtration of information flowing through its network (Athens Informational Technology, 2009).
Challenges and Issues
Today, the demand for quality health care systems and the cost required to provide excellent services to communities has increased. Due to this, the need enhance safety in medical care provision, improve efficiency and quality of service as well as lower spending on healthcare monitoring has drawn a burgeoning attention towards wireless technology (Jain, 2011).
Usability and reliability
One of the major challenges of wireless technology is the real time issue related to usability and reliability which are important components for effectively meeting the requirements of a health service (Athens Informational Technology, 2009). This problem hinges on the common mechanical problems that are attached to electrical devices which can be attributed to unnatural or natural factors. This may lead to power failures which may prove challenging if physicians want to guarantee a patient effective and seamless service.
Power limitations and privacy
Another problem is the issue of reliability of the wireless technology being used (Newbold, 2004). Since most of them rely on battery, chances of power limitations may arise and cause an interference with measurement of vital signs and context information. Besides, the technology does not guarantee a patient privacy and security of information (Khan, Hussain & Kwak, 2009).
While keeping the privacy of a patient’s information has been a major problem that most hospitals embracing modern technology have been grappling with, employing complex encryption algorithms to guarantee a patient of privacy using wireless technology is still a problem (Newbold, 2004).
To sum up, the paper has critically looked into various wireless technology applications that are used in healthcare monitoring to measure vital signs like heartbeat rate and blood pressure and improve lives of patients.
Some of the wireless devices used as discussed in the literature include medical sensors which vary in type, mode of power supply and location of use. In addition, the analysis has focused on the various types of application scenarios and examined important ones which include chronic disease monitoring, personal wellness monitoring and personal fitness monitoring.
The paper has concluded by indicating that the application of wireless technologies has not escaped criticisms owing to the challenges associated with privacy, security, power limitations, usability and reliability posed by various devices. It is therefore necessary that proper application of wireless technology be implemented especially those that do not pose potential threats to patients.
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