Case Study Concept of an Environment lor Mobile Medicine

Patients with chronic diseases require continuous care, but making them stay in hospitals would be very costly and would drastically lower their quality of life. In the case of patients with e.g. memory loss, expensive hospital care would be unreasonable. Today's preventive medicine is able to deliver long-term care to patients.

There exist a number of more or less advanced solutions allowing patients to feel safe at least at their homes, by being continuously monitored. They rely on PAN and WWAN wireless communication technology application. The simplest systems provide the patient with a remote alarm button in a watch (or similar appliance) which, when pressed in an emergency, connects the patient to an operator. A more sophisticated approach involves equipping the patient with devices, either implants or ones mounted externally, which monitor vital signs and can measure different quantities, such as glucose level, blood pressure, blood temperature or heart rate. (Sometimes they are even able to perform some actions, e.g. deliver insulin.) The quantities are then processed by a local monitoring system usually running on a PDA device or a home PC; exceeding the preselected threshold values triggers an alarm sent to an appropriate medical center. Reader interested in details of such solutions can consult [15], [17], or [18].

On the medical professionals' side, existing technology enables them to be equipped with small wireless computers allowing them to access patients' data or be notified by their monitoring systems whenever needed.

Current systems are based mainly on wireless personal area networks (PAN), thus overcoming the need to wire the patient's body. The standard used most commonly for communication in personal networks is Bluetooth [19]. Communication with a medical center is realized either by using a predefined static Internet connection, which limits the monitored area to patients' homes, or by using a wide-area GPRS connection.

The available wearable equipment is a basis for creating a personal medical environment, which can improve the quality of life of a chronically ill patient. It is important to distinguish the key components of such an environment, considering three different states of the chronically ill patient's life:

• stable state (e.g. the usual day of a diabetic) — in such a case, the personal environment may assist the patient in gathering and processing measurements of health-related parameters,

• dangerous state (e.g. reduction in blood sugar levels) — in such a case, the personal medical environment should start performing measurements more frequently and alert a medical center to pay attention to the patient,

• unstable state (e.g. loss of consciousness) — in such a case the personal medical environment should determine the location of the patient and alert a medical center to send an ambulance.

In order to perform the mentioned tasks, a personal medical environment should contain not only wearable sensors or implants, but some kind of an electronic agent able to process the measurements.

The e-soul concept. As proposed in our paper [20], the most innovative feature of this environment is the concept of an agent that is flexible enough to cooperate with many different sensors. Despite the diversity of places, environments and circumstances in which a patient may be situated, the agent should be able to pervade the medical environment in order to rescue the patient. That demanding task is taken on by the e-soul. The e-soul pervades the environment, i.e. gathers every piece of information from the patient monitoring sensors and — by "incarnating" into a hosting device — communicates the gathered results outside. Since there are many different types of devices (mobile phone, PDA, etc.) which the e-soul can use as means of communication, it needs to be able to utilize available network connections irrespective of their underlying technology.

Of course, there is no need to embed all of the above functionality into an e-soul. Some elements, such as network communication support, may be implemented in hosting devices; others — such as localization support — may be added as a wearable device (e.g. through wireless GPS-enabled devices) but all of them should be recognizable by an e-soul and taken into consideration when performing the required action. The key features of e-soul are as follows:

• Incarnates into hosting devices,

• Identifies and organizes a personal medical environment,

• Operates autonomously.

Typically, a personal medical environment will consist only of a few sensors, but their number can increase dramatically when the patient changes his/her location (e.g. is transported to a hospital or is attached to many different sensors in an ambulance). The e-soul will contain the information needed by a hosting station to configure the patient's personal medical environment as well as to identify the patient. Moreover, it will perform some basic interpretation of the monitored parameters' values. It should be able to decide which data is important and should be stored and which can be discarded, and so forth. Moreover, the e-soul should be equipped with a set of rules needed for deciding whether to alert a medical center. Such a decision is taken by the e-soul without any support from outside. In that sense, the e-soul is an autonomous entity.

The e-soul can be understood as an immaterial entity which has only to interoperate with devices it incarnates into. However, the concept of an e-soul with functionality detailed above can be implemented by using a smart card. Using this "smart" piece of hardware, particular features may be implemented as follows:

• incarnation into a hosting device — the e-soul as software placed on a smart card is able to copy itself into and run on a hosting station; the functionality should be supported both by the e-soul and the host.

• identification of a personal medical environment — the software needed by wearable devices connected to the e-soul can be stored on a smart card and run immediately following incarnation or can be downloaded by using the hosting station's communication abilities.

• authentication of a patient — smart cards are equipped with specialized processors and memory for generating private/public key pairs and digital signing data. Along with certificates, this is the most straightforward solution for accomplishing the task of patient identification.

• alerting —specialized code performing this functionality may be stored on the smart card and run if needed.

• autonomous activity — smart cards offer memory space which may be used to store a critical subset of collected measurements. The code of the e-soul stored on a smart card can contain a set of pre-programmed decisions to be taken autonomously when it loses connection with the Internet (e.g. using hosting device's storage to save encrypted measurements).

Architecture of the system. In light of its importance, alerting a medical center is worthy of special note. The alerted center should have means of controlling the process of monitoring the patient (e.g. changing measurement sampling rate). Therefore, because of the diversity of monitoring centers and personal medical environments, the e-soul should expose some commonly understandable monitoring and management interface. That interface should be implemented by code transferred to a hosting station.

For remote medical support, the medical center carries all responsibility. Its importance has already been mentioned several times, earlier on. This section introduces its main functions. Figure 5-3 shows the key tasks of the center. The most essential one, called Patient Remote Support, means giving the patient a feeling of safety, and is performed in collaboration with the e-soul. The task consists of collecting measurements and alerts from the patient's personal medical environment. The alerts may result in Case On-line Monitoring in a dangerous state or even in Emergency Action Initialisation, whenever the patient is in an unstable state. After an emergency team is sent to the patient, an important issue is Emergency Action Guiding — providing the ambulance with information on the patient's location and EHR, as well as recent measurements from his/her e-soul. All of the above may take place far from the patient's home monitoring center, in which case the Patient EHR Localisation action occurs.

Patient Remote Support

Case Analysis and Reporting

Emergency Action Guiding

Medical Monitoring Center

Case On-line Monitoring


Action Initialization

Patient EHR Localization

Figure 5-3 Roles of the Medical Monitoring Center.

As described, from the patient's point of view there is one home monitoring center and many possible foreign monitoring centers. As patients are mobile and may travel far from their original locations, it would be impossible to support them by their own monitoring centers, especially when an emergency team is to be sent. This task may instead be taken on by the nearest monitoring center.

The patient's home monitoring center should be distinguished for at least three reasons:

• it holds the patient's electronic health record (EHR),

• it is responsible for selecting the remote monitoring center to take care of a patient who is away,

• it is responsible for charging the mobile patient's insurance company.

All these tasks would certainly require formal agreements between medical sites. Moreover, to effectively support sharing EHR, the centers should implement a broker service operating continuously.

Irrespectively of the kind of monitoring center (home or foreign), it should be able to respond to an emergency signal either by starting continuous monitoring of the patient's state or — if needed — by sending an emergency team to the location indicated in the alert.

Handover between monitoring centers proceeds in the following way. The process is always controlled by the home monitoring center. In case of an emergency, the patient hosting station contacts the home center providing patient identity and localization and the reason for the alert. The home monitoring center localizes a remote monitoring center that is most suitable and closest to the current patient localization. In the next step, the selected center takes control over the patient.

The medical staff taking care of a patient who is monitored continuously should definitely be able to change locations. In some cases, a short textual information on a doctor's personal digital assistant (PDA) screen would be enough, unless a real emergency occurs. In a more complicated scenario, the doctor would need to download a part of the patient's EHR and e.g. review some X-ray scans. In general, the doctor changing locations should be able to "carry" a session containing some open files with him and continue to work on it in another place. For example, a doctor preparing for a surgical operation on a patient would like to transfer his notes to a screen installed in the operating room. From the system designer's point of view, there is a need to implement a mechanism for secure session transfer as well as a mechanism for adapting open sessions (that could contain various kinds of data) to the capabilities of end-user devices (varying from PDAs to diagnostic stations).

Scenario. To illustrate the usage of our conceptual system, let's imagine that John Smith, a 55-year-old scientist from Birmingham, has arrived in Krakow for a conference. Since he has undergone several serious surgical operations, including cardiosurgical ones, he must be continuously monitored. A few years before, he would surely have not decided upon such a journey. Fortunately, a new patient monitoring environment has been implemented all over Europe. Equipped with his three sensors and a mobile phone, John Smith feels safe. His personal e-soul, together with the hosting phone (or sometimes his pocket PC), continually process values acquired from sensors and, if the preset threshold is exceeded, it hands over control to the nearest center which begins monitoring Mr. Smith's state more accurately and prepares to help him immediately. The sole disadvantage for Mr. Smith is that he should remember to keep his phone charged and not forget to take it.

On the second day of his stay, Mr. Smith feels worse but his e-soul's hosting station does not indicate anything disturbing. He is tired and decides to take a walk in a nearby park, which is quite deserted, because evening is fast approaching. Suddenly he feels cold sweat and growing pain spreading through the upper body to the arms, neck and shoulders. His medical environment also realizes these worrying symptoms and initiates an alarm. Mr. Smith is unable to pick up the phone because he quickly loses consciousness. The alarmed monitoring center locates Mr. Smith's hosting station by means of GPS and hands over the treatment to the Krakow monitoring center, at the same time transferring part of his EHR. On the basis of the medical documentation and symptoms, one of Krakow cardiosurgical specialists is delegated to this case. His PDA device notifies him about the emergency just as he is on his way home. He comes back to the center and since there is no time to lose, he decides to look through the patent's documentation in the ambulance, which is ready to set off. In the meantime, the documentation is transferred to the ambulance where the doctor is acquainted with it. Thanks to GPS, finding Mr. Smith in a dark and empty park proves simple. From the documentation the doctor learns that Mr. Smith is allergic to a group of medicines and hence administers other medication. Help comes quickly enough to rescue Mr. Smith.

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