Challenge Scenarios
This section presents the detailed scenarios for exploring methodologies. Each scenario presented in this section should be confronted with the different methodologies to see how well they can handle that scenario. The questions were built having in mind different phases that concerns software engineering. Thus, the questions aim to address aspects like requirements elicitation, design decisions, software architecture evaluation, coding, test generation and software evolution, though new methodologies could bring new interpretations to these software engineering concepts.
The
scenarios (and later the questions, in Sec 5) are grouped into two different
sets. The first one, represented as EAx.y – where x and y are sequenced
numbers, would represent scenarios that pose questions pertinent to the software
development process, while the second one, represented as EBx.y, would represent
scenarios that pose questions pertinent to the evolution of the software, i.e.
after the software is deployed. Scenario EA0.n depicts the general idea of the domain used to
extract the scenarios. Most of the scenarios can be found there were directly
extracted from the project report GA proposal document [Szolovits94]
and are italicized. Others were added to tackle specific questions that we
wanted to raise.
The General Scenario
EA0.0- Guardian Angel proposes, among other things, to shift the focus to the consumers, i.e. the patients, rather than its providers, i.e. hospitals, clinics etc. One of the main reasons for changing the focus relies on the fact that nowadays when a patient moves or changes doctors or hospitals, it is most likely that many if not all of his or her medical records become effectively lost. The GA would store and integrate over a lifetime all health-related information about a patient. The software is not intended to be a simple repository of data; rather, it is intended to be proactive giving information and alternative solutions to patient’s problems. Among other features, GA is supposed to engage in data collection interacting with the patient as well as with other devices as blood pressure meters or glucometers, to monitor progress of medical conditions, to help explain new facts to the patient, to allow patient to customize therapy plans, to understand patient’s preferences and negotiate them with other systems e.g. scheduling appointments. It is supposed to be run in a small device such as a PDA that will in turn communicate with a home computer and other facilities like hospitals, clinics and laboratories to send appropriate data when necessary. The GA allows the patient to customize therapy plans with bounds established by care providers, giving the patient “ownership” of his or her therapy.
EA0.1- Although envisioning in the long run that GA will be a routine health assistant to cover a wide range of diseases and all classes of patients, the GA will initially focus on patients with chronic conditions such as diabetes and high blood pressure problems. Therefore, the software architecture has to be flexible enough to allow new diseases and services to be added over the years.
Detailed Scenarios, During Development
EA1.0- When hypertension is first suspected or noted during a routine examination the physician will load and activate the hypertension GA in the patient’s computer.
EA1.1- The GA should assist the screening and the diagnosis process for the physician collecting any additional needed demographic information together with latest risk factors for myocardial infarction and stroke. Still, all information gathered in the clinics must be transferred to the patient’s computer at home.
EA2.0- Once the patient and physician have established a management plan, the GA will help the patient follow the plan and monitor the progress.
EA2.1- For most patients, who are able to check their blood pressure with the home pressure cuffs now available, the GA will track the pressure against the expectations for therapy effect and use the data to provide correction and reinforcement for the patient.
EA2.2- The GA will also monitor other aspects of the plan including drug compliance, weight, and lifestyle changes.
EA2.3- The degree of monitoring of side effects and lifestyle changes such as diet and exercise will depend on the needs and desires of the patient. It could vary from simply making information available to having the patient fill out a progress report each session. Importantly, the GA will be able to ask about most of the potential side effects of the drugs.
EA2.4- The GA allows the patient to customize therapy plans with bounds established by care providers, giving the patient “ownership” of his or her therapy. For example, the GA can use its knowledge of the patient’s tastes and budget to suggest variations on the diet or changes to the amounts and types of exercises. On the one hand, the GA software wants to stay close to the original therapy plan to achieve best results and for safety. On the other hand, overly strict enforcement could result in the patient dropping out of the diet or exercise regime.
EA3.0- Abby Kaye is a 14 year old girl who has had insulin-dependent diabetes mellitus for the last five years. Two years ago she began to measure her blood glucose and administer insulin without direct parental supervision. She has recently been enrolled as a participant in the Guardian Angel program. Today, Abby just come back from school upset because one of her friends teased her about becoming chubby. She steps on the bathroom scale and notes her weight; she has gained 10 pounds since her last doctor visit 4 months ago. She has already tried skipping her snacks but that leaves her feeling awful from hypoglycemia (and even hungrier) subsequently.
EA3.1 The GA_PDA is aware of several unexplained instances of hypoglycemia in the past month. The pattern of insulin dosing and recorded periods of exercise makes it most likely that these hypoglycemic episodes are due to skipped snacks. The GA_PDA makes a note to itself to use the opportunity of a query about diet to ask her at the end of the interaction whether she has been missing snacks and to warn her about the dangers. The GA_PDA is also aware of the heights and weights obtained at the doctor's office in the last two visits (and downloaded from the IHIS by the GA_hospital_process to the GA_home_computer and then to the GA_PDA) and recognizes that Abby has indeed an increased weight for height over the past visits. GA_PDA asks Abby if she would like to review her meals and snacks for the past days as well as go over her favorite foods.
EA4.0-
Abby is uncertain what insulin dose to give this morning as she has a
double session dance class at 10:00 and she remembers all too well that she has
had mild hypoglycemic symptoms towards the end of even single session dance
classes. She draws an exercise symbol spanning 10 to 11:30 on her daily schedule
on the GA_PDA interface and then selects the Advise Dose icon. The GA_PDA
informs her that she can either keep the dose unchanged if she thinks she can
manage a double carbohydrate snack before the dance class or she can reduce her
morning dose of insulin by two units of short acting (regular) insulin.
EA4.1-
Two weeks later, Abby's morning blood sugars have continued to climb
and they are in the mid 200's. Abby has not modified the GA_PDA default
authorization to communicate with her parents' desktop computer. Therefore, when
according to schedule, the weekly blood sugars are uploaded by the GA_PDA
component to the GA_home_computer component this worrisome trend is displayed to
the parents. However, to be compliant with personal feelings of some children
the GA must be able to understand that if the parents are getting too many
communications the GA must either start sending the communications directly to
the physician or start an education program to enforce the need for addressing
the problem. The GA_home_computer makes several suggestions as to how to modify
the nightly NPH. If the parents do not feel comfortable following these
suggestions, they are given several options for communications with the
health-care providers including electronic mail with attached measurements,
directions for paging or an emergency phone number. If they are comfortable with
the suggestions, then the recent data along with the alert are uploaded during
the routine daily modem connection of GA_home_computer with the
GA_hospital_process running on the hospital's information system.
EA4.2- Two months later: Abby's father realizes that next week Abby will be performing with her entire dance class for a school performance. However, this performance occurs the same day as a scheduled visit with Abby's endocrinologist. Abby's father goes to the weekly schedule view of the GA_home_computer and cancels the endocrinologist visit. The GA_home_computer asks him if he wants to reschedule (he does) and then negotiates with the hospital scheduling system (via the GA_hospital_process) two possible appointments for Abby in the coming month. After one is selected, the GA_hospital_process sends appropriate notifications to the hospital-based care providers.
EA5.0- Most common over-the-counter remedies for upper respiratory infections warn the patient to avoid them without consulting their physicians. GA should provide a selection of minimally problematic drugs and then monitor the patient's blood pressure response to those drugs and note the results for future reference.
EA6.0- After GA is in actual use, changes must not ever require a "reset".
EA6.1- Integrity of life-long records within a small portable computer that
would implement GA should be assured. One can imagine catastrophes
that would result in destruction of the device itself, loss or theft, temporary
unavailability, accidental or deliberate alteration, etc.
EA6.2
-One could
choose an infrequent (say monthly) backup tape for people with no serious
current conditions. At the other extreme, a direct cellular call to a system
providing guarantees of data integrity may be worthwhile when significant events
occur in a patient being monitored for possibly life-threatening events.
Fruitful synergies may also arise in such architecture. For example, a hospital
may choose to go into the commercial business of providing data integrity for
its patient's GA systems; in that case, communication costs can be reduced and
reliability increased if the same telephone call can be used both to report
time-critical data (part of the data repository and the alerting and
notification functions) and to assure that it is backed up in case the GA device
might malfunction (part of the backup function).
EA7.0-The
long-term development of GA will require a highly flexible, open architecture
that will support expansion of the concept and evolution of its implementation. Once
more, changes must not ever require a "reset". In addition, it is
absolutely critical to our ability to build the system that virtually all
technology components of GA be provided by generic, preferably standards-based
facilities. These include:
v
data repositories and retrieval, perhaps
based on the object-oriented data model
v
reliable checkpointing and backup
v
computer-based patient record
v
security and authentication
v
network-based communication
v
alerting and notification, including pagers,
electronic FAX, and email
v
interfaces to data-capture instruments
v
easy-to-use user interfaces
v
formal expressions of guidelines, practice
standards, etc.
v
hypertext-based bodies of medical
information
EA8.0-The GA should interface with many instruments to measure glucose, prothrombim, cholesterol etc. Interface software for these kinds of devices may be commercially available. The GA should incorporate these software rather than develop its own interfaces.
EA9.0–As a result of competitive pressure, halfway through the project, project management decides that a scaled-down version of the GA must be produced for delivery in 3 months. It will support only one type of instrument and offers only a narrower role of advising the patient to change habits
EB1.0- One year after GA has been put on the market some parents were concerned about the level of freedom that GA gives to a child like Abby (See scenario EA4.0). The GA has now to be changed so it can handle new levels of freedom without prejudicing the existing one.
EB1.1- The GA may now allow parents to know right away when some relevant data are read from instruments. These relevant data must be configurable by each parent based on their experience with their children and should include not only actual readings but also previous readings so parents can establish some sort of profile that could warn them in time to prevent any harm.
EB2.0-Due to the big success on the use of GA, it was asked to develop a new version of GA that includes new features to interoperate with many image instruments like ultrasound, CAT scans, magnetic resonance and others. The GA should handle images to facilitate physicians’ diagnosis.
EB2.1- Also, GA must now support the physician with possible alternative treatments for each disease accessing evidence-based medical knowledge bases over the Internet. Each treatment can affect differently each patient. For example, for some patients the use of drugs should be preferable to intense exercise and diet to treat diabetes since they would feel depressed soon and therefore give up the treatment. Hence, GA has to be able to trace a behavioral profile of the patient over the time and adapt its suggestions to this profile.
EB3.0-Despite the success of the GA, many people do not have access to it because it is too expensive to purchase and maintain. A new version of the GA will be produced that does not rely on a home computer. It will have the more limited function of supporting personal assessment. It will be able to read two different instruments (blood pressure meters and glucose meters) and will help patients to control safe levels for both tests.
EB3.1- GA will also keep a historical base of test results so the GA can alert for tendencies to high or low level of glucose and cholesterol.
EB3.2- Abby wants to spend a year abroad. The GA will now have to conform to international standards and national medical practices as well as government regulations.