The Paraglide system consists of a set of computer-based "clinical assistants" that hold information about a clinician's current cases requiring assessment, along with associated data , and that communicate with a set of information services that supply relevant data or that accept the results of clinical assessments. Clinical assistants can be used on a variety of platforms, from full- sized workstations through laptops to hand-held devices. A clinician uses a clinical assistant to collect data (e.g. from a patient), to examine data (e.g. blood tests returned from a laboratory), to record their assessments, and to develop plans of drugs and techniques that will be used during an operation. Figure 22.1 illustrates the overall architecture.
The situation in which the clinician carries out his or her work is highly dynamic. There are several forms of context- and change-sensitivity, therefore, that the Paraglide system must be able to handle:
Changes to local data on the clinical assistan.
Mutual dependencies exist between a great deal of the data within the system. These frequently can only be expressed as probabilistic predictions rather than changes to case data. For instance, if a patient has a condition, like asthma, we can predict that they are going to be on a limited set of related drugs.
Changes to the relevance and accessibility of data from Paraglide services.
A clinician's case load changes from day to day; typically, only data for immediately upcoming cases will be relevant. Also, certain data, such as operating theatre schedules, staff rotas and lab test results, may become available at any time.
Changes in the context of use.
Paraglide clinical assistants operate in a wireless environment with intermittent connections. Additionally, they can operate outside the normal clinical environment (e.g., in the anaesthetist's home) where the nature of the connection may be very different, without access to sensitive data that must remain inside the hospital's LAN. Thus the system must also be sensitive to changes in the connection status and user location.
There are two dimensions of change that we consider in handling these types of change: predictions vs value updates and implicit vs explicit updates.
In cases like the relationship between a patient's condition and their current drugs, it is often inappropriate to change actual data in a case record; what is wanted is an update to the likelihood of its value. Our approach is to model both value and a predicted value in all case object attributes. The predicted value can be as simple as a default or a likely subset for menu selection through a complex probability distribution for the value set. Updates can be specified as affecting the value or the prediction (see section 3.2).
There are often updates that can be performed automatically. For instance, when the anaesthetist enters the height and weight of the patient, the system can generate the "body mass index", used to determine if a patient suffers from obesity. However, many such changes demand some user involvement, if only for clinical and legal reasons. For example, when a new set of blood results becomes available from a hospital lab, it would be inadvisable to perform the update of values in the case record without making the clinician aware of the update. We use our smart pasting mechanism, described in section 3.2 below, to support such explicit updates.
A Paraglide Clinical Assistant consists of the following components: a set of interactors, a set of resource managers, a set of dynamic links, a library of documents and a communications subsystem. The relationship between the components is shown in Figure 22.2.
Users interact via a set of configurable interactors , specially designed for deployment on differently sized displays . The interactors are used primarily to provide access to the service store , holding objects that represent clinical case data. However, a user can also interact with dynamic links when performing explicit updates (see section 3 below) and resource managers when viewing or interacting with general clinical domain data.
Resource managers are responsible for supplying domain-related information to the system as a whole and also for creating links associated with its domain. Currently there are four types:
the scene manager which maintains the collection of context-related interactors and links and handles and records navigation;
the case manager which produces new cases, held in the service store, and provides access to them;
the technical environment manager which maintains data about the system such as battery power and network connectivity; and
domain knowledge managers which maintain data about drugs, procedures, staff etc.
The librarian mediates queries to external information sources and incoming documents from these sources, providing a local cache and access to the broker that handles the transmission to, and reception of messages from, other Paraglide services.
Finally, dynamic links are components that provide appropriate responses to the various kinds of change described above .